lithium polymer battery

Dear Friend,

How are you?

This is Lena from General Electronics Battery Co., Ltd(GEB),which is the best battery supplier in China. I am very glad to introduce our  hot-sale lithium polymer battery to you, I attached some pictures below for your reference, wish you will be interested in them: 

 If you have interesting, please feel free to contact us. We would like to assist your business at our best. We can offer the best price as our distributors in order to take more benefit for your business.

You can visit our website link to know more information. More surprises at www.gebattery.com.cn. For online-talking, please add my Skype: gebatterylena

Best Regards
Lena

 Sales manager

General Electronics Battery Co.,Ltd
Fl. 6, Bld. 2, Chaohuilou Hi-tech Industry Park,

Dalang, Longhua, Baoan District, Shenzhen 518109, P.R. China

Tel: +86 (0)755 81762726  ext 610

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Electric car battery daily maintenance methods

Battery life is, battery repair just keep it reaches normal design life. To promote the product to any factor battery repair battery repair the damage with the new batteries, ensure that the battery life can be extended many times, these are not scientific, it is not realistic. Without any damage to the battery of any factors, have an impact on the battery life, the question is how to reduce the damage to the battery, how to reduce the impact on battery life, following a brief introduction of several electric vehicle battery daily maintenance method for your reference.

Lead-acid batteries have no memory, so the capacity to rapidly decrease was primarily sulfide batteries and "dehydration", "loss of power" and for some reason, fear is the battery "power loss" Brown, batteries often "power loss" battery pole board easily injured, we found that up to 70 percent of the electric vehicle battery capacity to reduce high current (starting current) strain discharge electrode plate is caused (electrical 摩尤 its obvious), strain belonging to the battery electrode plates physical damage, this damage can not be repaired. Therefore, "every car, every charge" to ensure that there is always sufficient battery voltage has become inevitable.

Users generally thought, maintenance-free batteries do not add water, in fact, this statement is wrong. Maintenance-free battery charging and high-current discharge process generates heat, there will be a heat evaporation, although the process is very slow evaporation of water, but over time, the cumulative amount of water evaporation on can not be overlooked.

Electric car start clever force. Electric car start-up current is large, especially in high-power electric motor friction, higher starting current. It hurt a large current battery plates, the best way is like riding a bicycle after riding before you start, and then start the electric car power supply. Of course, many electric motor means no riding, which is no other way.

Quarterly on the battery deep discharge once. After the battery is bound to use for some time to sink some active substances, if not promptly activate the active substance is bound to cause some impact on the battery capacity, so often used in electric car, the battery should be done on a quarterly basis depth of discharge once.

Frequently observed charger is good or bad. New battery charging process is generally 6-8 hours, the charger will light green when fully charged, the charging time is too long if necessary to check whether the charger voltage protection device corrupted, corrupted if you need immediate replacement charger or vulnerable to charge a bad battery. Also, do not buy fast charger charger for fast charging battery plates have the same injury.

Long battery when not in use for at least a month to give the battery charging time. The aim is to prevent the battery from the battery caused by placing too long curing and "loss of electricity."

Prevent the battery from prolonged sun exposure. Prolonged sun exposure can cause the battery temperature rises, so pay attention.

The above part of a more comprehensive description of the battery damage, repair, and maintenance of the relevant skills and knowledge, which is based on our years of experience and market feedback information written in simple language articles, layman understand at a glance. At the same time, we also sincerely reader from one side of the electric car battery repair techniques uncover the mystery, which is battery repair can take many methods, but not all damage to the battery are effective, curing illnesses and small battery restored effective; plate mild softening, short circuit, may be effective after a short break after every repair, as supernatural, as will the use of time is not long fallen into place; also some very serious damage to the battery, repair largely ineffective, introduction this knowledge is mainly to facilitate the reader's understanding of the industry initially make the right choice on battery maintenance and repair.

After passing electric car batteries by battery manufacturers factory, battery life and performance depends in part on consumer use and maintenance.

(1) Matching charger and battery.

Electric car batteries are rechargeable bad, rather than bad, showing the importance of the charger and the battery match, there are two situations: First, the new parameters and battery charger provided by the manufacturer itself does not match, the charging voltage is too high and aggravated battery water loss, shortened life expectancy, more serious is the charge current drops to less than the current value of the conversion settings, battery temperature, charging current is further increased, the temperature rise much, resulting in thermal runaway cell expansion and deformation, and vice versa charging voltage is too low, the battery charge state owe a long period, not always part of PbSO4 conversion, resulting in sulfate, battery capacity drops, electric bikes continues the course shortened. Second, poor quality components charger itself, just started, fairly matched, as consumers charge and discharge cycles used. Charger itself due temperature, aging of components, resulting in the charging voltage and switching current drift, battery damage.

It is recommended that consumers and manufacturers of electric vehicles is best to buy a battery charger manufacturers supporting, not because it is cheap and filling joie de vivre of a bad battery, but not worth the candle.

(2) Often, replenish electricity.

Consumers using the nominal cycle life instructions usually have a misconception that one charge, the battery life is reduced once, so every time the battery power consumption, such as the protection voltage 31.5V to the controller began to supplement electricity , not knowing that not only can not protect the battery and shorten battery life. Because the positive active material is not strong PbO2 itself combined with each other, and the molar volume of PbO2 and PbSO4 are very different, more shallow depth of discharge, contraction, the lower the degree of expansion.

So remind consumers, where possible, the battery should charge it in time.

(3) Prohibited under undervoltage condition indicator shows continue riding. Some consumers after riding half way, the indicator displays the status of undervoltage take rest a re-ride some way, such great harm to the battery, the battery will discharge over serious salinization or lead generation branches crystal, short circuit the battery, affect life expectancy.

(4) electric bikes just starting, climbing, overloading should try to help.

(5) rain riding, switches and connectors should try to avoid getting wet, to prevent leakage.

Know more about some aspects of the knowledge about the battery lead-acid batteries for electric bikes maintenance and repair have positive side, through technical improvements compared with the great advantage especially to improve the colloidal technology, cost-effective lead-acid batteries and other batteries.

General Electronics Battery Co., Ltd. electric vehicle battery has been committed to the development, production, for consumers to create a safe, environmentally friendly batteries.

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Based on lithium-ion battery charging circuit design USB interface

Keywords: USB interface， lithium-ion battery， charging circuit

lithium-ion battery and USB Interface Overview

Lithium-ion (Li-ion) batteries, lithium battery for short <http://bbs.dianyuan.com/tech/battery>, is the increasing popularity in recent years, the use of a new type of battery, with small size, light weight, high capacity (high energy density), self-discharge rate and advantages such as no memory effect, but it also has some fatal flaw: the charging and discharging of the more stringent requirements, can not overcharge and over discharge, or likely to cause irreversible damage to, in short circuit, overcharge and other extreme cases there may be an explosion dangerous.

General lithium single nominal voltage 316 ~ 317V, charging, generally require the use of limited pressure limiting law, the first constant current charging, ie a current constant charging current by low magnification national standard charge is 0.2C (arbitration charge standard), the maximum does not exceed 1C; while charging the battery voltage is gradually increased as when the battery terminal voltage reaches the termination voltage 412 ± 0105V, should be changed to constant voltage constant current charging small current (about 011C) charge, the state general called trickle charge state. The charging current based on the saturation level of the batteries, with the charging process continues to gradually decrease, and when reduced to 0101C, that the charging is terminated.

USB interface is in English UniversalSerialBus abbreviation, Chinese meaning is "Universal Serial Bus." It is a new field in the PC interface technology applications. USB uses a 4-pin plug as a standard plug to connect with external devices. In this four-pin plug, there are two pins for data communication lines, while the outer two needles compared to an external device to provide power. According to the USB specification, each USB port should be able to provide 500mA output current; provided by the USB host or hub with a power supply of the USB interface, the connected peripheral end of the minimum available voltage is 4.5V, while the USB bus powered hub can provide should be a minimum of 4.35V. worth noting that, although the USB specification defines the current limit provided shall not exceed 015A, but in fact the current USB port output is often more than a few amps.

As can be seen from the above analysis, the use of USB interface for battery charge, the current terms should be enough, the key is how to control the size of the current. In addition, the use of a minimum of 4.35V voltage USB interface to the typical requirements for 4.2V lithium battery when charging, only a small margin on the voltage, which makes the charging circuit voltage drop becomes extremely important, is the difficulty of design.

PC-based USB interface charging circuit design

2.1 Option One

Figure 1 is a market of some of the "USB charging cable," the internal circuitry. The main principle is to use the maximum current limit resistor, a diode voltage drop (approximately 0.7V) about the USB interface 5V output voltage down to about 4.2V rechargeable lithium battery then. This circuit has a simple, low-cost advantage, but the disadvantage is obvious: the charging current and charging voltage and battery status vary in different USB interface vary, basically can not grasp, in many cases the battery is likely sufficient dissatisfaction (charging voltage of less than 4.2V), but sometimes it may overcharge and damage the battery. This circuit has some internal lithium battery protection circuit for sound acceptable, but for ordinary lithium batteries, there are certain dangers.

2.2 Option II

Figure 2 is a practical USB Li-ion battery charging circuit by MAX1551 / 1555 constituted. MAX1551 / 1555 is designed and manufactured by MAXIM USB single lithium battery charging chip, 5-pin thin SOT23 package, allowing the USB port or wall adapter 3.7V ~ 7V AC input voltage range. Internal chip also has a temperature limit circuit.

When For this circuit, when connected to a USB port, but no AC wall adapter DC power, the charging current is set to 100mA (Max). This is not required in the case of the communication port, allows the power from the USB port or power charging. When DC power is turned on, the charging current is set to 280mA (typ), while the USB input interface is automatically cut off. If both inputs are non-voltage input, the circuit is automatically turned off, then the reverse leakage current of the battery is less than 5uA, no external diode to prevent battery leakage losses occur.

When the battery voltage is lower than 3V, will enter 40mA charge current is limited to a pre-charge mode (trickle charge state), only when the battery is charged to 3V than when entering the normal charging mode (100mA or 280mA). This mode protects the deep discharge battery. Figures 3 and 4 are used as the DC power supply box curve USB interface input voltage and the charging current of the battery.

In addition, the MAX1551 ", / POK" is used to indicate the input power is turned on (when the input voltage is 3.95V output low); while for MAX1555 ", / CHG" is used to indicate the state of charge (when the charge current is greater than 50mA output low).

2.3 Option III

It should be said, Option II is a safe, relatively comprehensive consideration of all aspects of USB rechargeable lithium battery and perfect solution. The disadvantage of this solution is that: the charging current is fixed at about 100mA or 280mA, especially when the USB interface power supply, only the charging current of 100mA for larger capacity batteries, charging takes quite a long time. Another disadvantage is that there is no charge timer function, the charge can not be ended or not artificially controlled. Figure 5 is another practical USB interface charging circuit design using the LTC4053 as the core, while maintaining the advantages of the two programs again to solve the above problems.

LTC4053 is Linear (Linear) has introduced a USB interface can be powered directly from a lithium-ion battery termination constant current / constant voltage linear charger IC with Independent Timing for 10-pin MSOP package. May consist of a single lithium battery USB interface for charging directly, or you can allow the use of a wall AC adapter as the power supply of DC power. Required input voltage range is 4.25V ~ 6.5V. Includes an on-chip power MOSFET. The most important feature of this chip is that it allows designers to set their own charging current and charging time, charging termination voltage already preset to 4.2V.

In Figure 5, the charging current by PROG LTC4053 (7) pin resistor R to the set, which is calculated as: R = 1500V / ICHG, for example, to set the charging current is 500mA, then R = 1500V / 015A = 3kΩ. The maximum charging current can be set to 1125A. Figure 6 is a graph of the charging current and battery voltage.

LTC4053's TIMER (4) capacitance C pin is used to set the charging time is calculated as follows: T (h) = C (uF)? 3 / 011uF. When C = 011uF, the charging time of 3 hours.

This circuit has a similar program two pre-charge mode trickle charge mode and battery-specific fault detection function: When the battery voltage is lower than 2.48V, with 10% of full scale current trickle charge; If this state lasts more than a quarter of the total charge time is that the battery has been damaged and stop charging cycle.

LTC4053 itself has a perfect temperature measurement and compensation adjustment function that allows users to safely larger current charging thereby greatly reducing the charging time, charging current and Figure 7 is a graph of the ambient temperature. Similarly, when the LTC4053 no voltage input, the circuit can automatically cut-off, the reverse leakage current is less than 5uA, no external diode to prevent battery leakage, avoid battery depletion.

Conclusion

There is no doubt that in these three scenarios, features the third option is the most perfect, the flexibility of its design application is also the biggest, but more pins, the device cost of the chip may also be higher than other programs . In practice, we can according to the actual situation of use, cost, etc. to choose different options to meet different requirements. With the development of integrated circuit technology, the constant introduction of new devices, we believe there will be more and better USB charging scheme appears.

General Electronics Battery Co., Ltd. electric vehicle battery has been committed to the development, production, for consumers to create a safe, environmentally friendly batteries.

Contact :  Benny , SALE ,  Gebattery , Tel.  86-755-81762725,  81762726, 8 1762727, 23315028, 2331308  or e-mail : sell@gebattery.com.cn

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Lithium-ion battery cycle performance factors affecting Discussion

The importance of the cycle performance of a lithium ion battery without saying; additional terms of the macro, longer cycle life means less consumption of resources. Thus, the factors that affect the performance of lithium-ion battery cycle, every problem associated with lithium industry personnel have had to consider. The following are a few that may affect cell cycle performance factors, for your reference.

Material Type: 

The choice of materials is the first factor affecting the performance of lithium-ionbatteries. Select a poor cycle performance materials, processes and then reasonable to prepare for further improvement, batteries can not be guaranteed circulation is bound; choose a better material, even made ​​a slight problem follow the cycle of poor performance may not too outrageous (once played grams of lithium cobalt oxide is only about 135.5mAh / g and analysis of lithium batteries, 1C although hundreds of times diving but 0.5C, 500 times more than 90%; anode batteries have open after a black graphite particles batteries, the cycle performance of normal). From the material point of view, the performance of a full cycle of the battery, the positive electrode and the electrolyte solution cycle characteristics after the match, the cycle properties of the electrolyte and the negative electrode after the two match, the less one to decide. Poor cycling performance, one may change the crystal structure of the cycle can not proceed so fast lithium deintercalation one hand, since the active substance may be unable to generate the corresponding electrolyte membrane caused by dense, homogeneous active substance SEI side reactions with the electrolyte leaving prematurely excessive consumption thereby affecting electrolyte circulation. In the design of the batteries, if the material is poor cycle performance of a selection electrode is recognized, the other electrode is preferably no need to select the cycle performance material waste.

Positive and negative compaction: 

Positive and negative high compaction, although the energy density of batteries, but also to reduce the cycling performance to some extent. From the theoretical analysis, the greater the compaction, the greater the equivalent structural damage to the material, the structure of the material is the basis for a lithium-ion battery can be used; addition, the positive and negative high compaction is difficult to ensure than the batteries the high liquid retention amount, and the amount of fluid is guaranteed to complete the normal cycle batteries or more cyclic basis.

Moisture: 

Excessive moisture will be positive and negative electrode active material and side reaction occurs, and thus affect the structure of the destruction cycle, while too much water is not conducive to the formation of the SEI film. However, while difficult to remove traces of water, traces of water can be guaranteed to some extent, the performance of batteries.

Coated film density: 

Consider the impact of a single variable density film cycle is almost an impossible task. Film density inconsistencies or differences in the capacity to bring either batteries or winding difference laminated layers. With the same capacity of the same material type batteries, the lower the density of the film corresponds to an increase or a wound layer or layers laminated layers, corresponding to the increase of the electrolyte membrane can absorb more to ensure circulation. Considering the thinner the film density can be increased rate performance of batteries, and the bare core pole piece of baking will be easier to remove water, of course, the density of the coating film is too thin, the error may be difficult to control when the active substance large particles may also be coated, rolled a negative impact, more layers means more foil and diaphragm, in turn means higher costs and lower energy density. Therefore, when assessing the need to balance considerations.

Negative excess: 

Excess addition causes a negative initial irreversible capacity to consider the impact of the deviation and the coating film density than the impact on the cycle performance is also a consideration. For lithium cobalt oxide and graphite system, the negative cycle of graphite become "short board" one of the more common. If negative excess is not sufficient, batteries may not analyzed before cycling lithium, but hundreds of times the loop structure is minimal but the positive and negative changes in the structure was severely damaged but not completely positive reception thus providing lithium-ion analysis of lithium, resulting in over-capacity early fall.

Electrolyte volume: 

Produce insufficient amounts of electrolyte circulation affect three main reasons, one less than the amount of fluid injection, the second injection fluid volume is adequate, but despite the lack of time or aging infusion due to the positive and negative electrodes and other causes excessive compaction is not sufficient, the third is with cycle batteries inside the electrolyte is consumed. Note inadequate and insufficient fluid volume fluid volume Paul wrote, "electrolyte deficiencies on the performance of batteries" before and therefore not repeat them. On the third point, the negative electrode and the positive and negative electrolyte particular microscopic matching dense and stable performance of SEI formation and performance of the visible eye, both for circulation of the electrolyte during the consumption rate. Incomplete SEI film on the one hand and the electrolyte can not effectively prevent the occurrence of negative side effects and thus consume the electrolyte, while the SEI film with defective parts will be re-circulated in order to generate the SEI film and electrolyte depletion reversible lithium source . Whether circulating hundreds or even thousands of times the batteries or both diving for dozens of batteries, the electrolyte is sufficient and if the first cycle after cycle has been consumed electrolyte, the electrolyte increased ownership is likely to be some enhance the cycle performance degree.

Test objective conditions: 

Testing during charge-discharge rate, cut-off voltage, the charging cut-off current, tests overcharge and over discharge, the test room temperature, the sudden interruption during the test, the test point and the contact resistance of batteries and other external factors that will or less impact cycle performance test results. In addition, the sensitivity of different materials to the above objective factors varies, uniform testing standards and understand the characteristics of the common and important materials should be sufficient daily use.

To sum up: 

The same principle as the barrel, the factors affecting the performance of batteries circulation among many, the ultimate decisive factor is a number of factors in the shortest board. Meanwhile, among these factors, but also have a reciprocal influence. In the same materials and made ​​capacity, the higher the circulation, often means lower energy density, to find exactly the point of integration to meet customer needs, try to ensure the consistency of batteries made ​​of party is the most important task lies .

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12 E-bike KIT power levels, from 360W to 8,000W

If you are fairly new to the idea of an E-bike, and you think you might want one, this article hopes to give you some info to help you get some kind of an idea about what type of kit will fit your needs.

Factory E-bikes are very expensive compared to the kits that you can get and install on your own bike, but…some people don’t mind paying more to get good customer service from a local dealer, and getting a turn-key factory E-bike that they can begin riding immediately.

But…if you are mechanically handy, and can install a basic E-bike kit yourself…the kit ideas below may save you some money. Using a kit will also allow you to use a bicycle frame that you chose yourself…to allow you to save even more money, and to also get a bike frame that is the best possible fit for you.

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Before we get started, forget about the wattage ratings of the advertisements for these kits. One horsepower is 746-Watts, and the method of rating a kit is to multiply the voltage times the amps. So, a 36-Volt kit that has a controller that can use a max power of 20-Amps would be 36V X 20A = 720W.

The power that you need (or want) is further complicated because the true limit of the power you can put through a motor is how much heat it can survive. If you take a given motor and begin raising the volts, you will get some extra power, and also the motor will spin faster than it did at a lower voltage. If you begin raising the max amps, the acceleration will get faster, but…adding more amps will cause most of the heat that will kill a motor (and sometimes the controller).

Factory power ratings are rarely accurate. Legitimate sellers under-rate their kits, because so many buyers will overheat their E-bike and want to have the motor and controller replaced due to heat damage. Then, there are the other retailers…the ones that don’t answer their customer service lines…they claim their kit will put out thousands of watts and will climb anything!…and then when you melt something, they refuse to help you.

Here’s a tip about raising the power that you can use on all these kits. If you are running on fairlyflat land, you can run much higher amps for some very impressive acceleration. You will draw the max amps setting for only a few seconds while the bike is speeding up, and once your top-speed stabilizes…the amps draw slides back down to a low setting that only needs to maintain your speed, and that gives the motor and controller a chance to cool down before the next acceleration.

But here’s the worst-case-scenario…you loan your E-bike to a friend who doesn’t understand this and then they ride it up a very long and steep uphill at full-throttle. With no cooling-off phase, the motor and controller overheat, and your friend has to do the “walk of shame” back to your place. This is where you should have limited the max amps the kit can provide (a Cycle Analyst E-bike computer is an easy way to adjust the amps the controller can draw).

The popular MAC is generally regarded as capable of performing very well when using 25A, but…if you live in a very flat region you could actually use more. One of the reasons the MAC has grown in popularity is because it’s one of the few kits where you can order it with a temp sensor installed inside the motor from the factory (ebikes.ca is the other seller with temp sensors). If you have a Cycle Analyst (the best E-bike computer on the market), you can easily adjust how many amps the controller can use, so you can adjust it to get the max power possible…without melting anything.

Now that all that has been said…lets get on to these system recommendations!

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The stylish Faraday Porteur, with a small “mild assist” front geared hub motor.

360W

36V X 10A

Small front geared hub-motor…Tongxin

The Tongxin is so tiny, most people won’t realize you have an electric motor. There are several other 250W-rated motors of similar size, but I am recommending the Tongxin because of its one quirk…even though it is considered a geared hubmotor (the motor spins faster than the wheel to aid its torque and efficiency), it uses smooth rollers instead of toothed gears.

This is both it’s greatest benefit…and greatest weakness. The big deal about the steel rollers is that…because they are smooth, this motor runs almost silently. This ultra-quiet operation can further be emphasized by using a sine-wave controller, but…even with a common square-wave controller, the small-diameter sideplates are not very resonant. Another benefit is that the drive-roller can be very small, so these have a 12:1 reduction, instead of the common 5:1 when using toothed gears.

If you can be happy with 360W, this sweet little Tongxin motor runs very quietly. Oddly enough, it is also an inrunner, but…don’t even think about trying to hot rod it!

The reason the smooth rollers are also a weakness is because almost everyone who begins using an electric motor typically wants “just a little” more power. These roller will begin to slip a bit if you try it at higher power levels, but I’m not exactly sure where the limit is…because I’ve never been very interested in these extra-small motors (which are typically rated as 250W to appeal to countries with power limits). I suppose you could use these at 24V and higher amps, but…geared motors of all sizes shed heat poorly, so I recommend 36V and then use lower amps for a long life. About 10A is reported to be just right.

I’m recommending a front wheel motor, because at 36V X 10A = 360W, the extra hassle of mounting a rear motor isn’t needed, and just about any steel forks can easily handle 360W with a single torque-arm (yes, use a torque arm, even at only 360W). The Tongxin motors have also been re-branded as ethinkar / Nuergy / Tarn.

If you want to read about others brands of the small 250W-rated  geared hub motors,  check these out.

Here is the tiny Tongxin mounted in a custom bracket to make it a mid-drive, so the low-powered motor will have the use of the bikes gears. You can easily imagine one of these tiny motors discretely located in the front wheel.

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540W

36V X 15A

Front or Rear small geared hub-motor…Bafang SWXH

Our friend Kepler had decided at one point to put together a very stealthy carbon-fiber road bike, that he could ride on the bike paths near his home. In order to blend in with the pedal-only traffic, the motor would have to be small and quiet. After some research, he settled on a Bafang SWXH geared hub, mounted in the rear wheel.

This motor has teeth on its internal planet gears, and it also has more copper mass than the Tongxin, so it can take more power. These have been regularly used with 15A, so that’s a pretty safe heat level to run it at. I wouldn’t use it at less than 36V (36V X 15A = 540W), but be aware that several builders have used these at higher voltages (48V-72V) without a significant increase in the heat.

These run fairly quietly, but there is a slight buzz from the gears during acceleration. If you use asine-wave controller, the power control will be slightly quieter. However…with motors that have internal gears, you will always have some mechanical noise.

Its possible to use a Bafang SWXH on the front wheel, but it is just about large enough to occasionally draw attention (if you are trying to fly under the radar as a stealthy electric bike). Use a torque-arm, and if it is a high-quality torque arm, just one should be enough at 540W.

The Bafang SWXH is one proven option, but at this power level, there are dozens of 250W-rated hubs that will work well.

Once the SWXH is mounted between the sprocket-cluster and the disc brake, it’s practically invisible.

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720W

36V X 20A

Front Geared Hubmotor…Bafang-BPM

The Bafang BPM is one of the most prolific electric bike geared hub-motors on the planet. It is pretty much the default 500W-rated motor used by every generic E-bike manufacturer in China. This motor has a large enough diameter that you can’t really hide it. If you use a front motor while conveniently mounting the weight of the battery pack on a rear cargo rack, the balance of the bike will be fairly neutral.

By using it on the front wheel, the installation is very easy. Also, by adding some pedaling, you can have 2WD. The rear wheel can have any stock gearing system that appeals to you, with as many speeds as you like. Enthusiasts of this configuration have reported that a front motor is more stable in slippery conditions, but…it also slips more on a wet uphill compared to a rear motor. Of course, there is a rearBPM available, and also a cassette-geared version (as opposed to the common 7-speed freewheel).

You can use more volts (up to 72V has worked well because of the BPM’s low pole-count), but a 36V system uses an affordable battery to go with this affordable mid-sized motor. 20A controllers are common and cheap, and if you experiment with too many amps and fry the motor or controller…they are both cheap to replace.

I don’t recommend direct-drive hubs (or high-powered hubs of any type) on the front wheel. At high power they can damage the drop-outs and lead to a crash, and at low power the geared hubs are good enough because they are lighter and they freewheel easily without a DD hubs cogging. Performance-wise, a high powered front hub (whether DD or geared) can spin out easily…instead of accelerating.

Whether you use a DD hub or a geared hub on the front forks, use two torque-arms at this power level. Kits at this level of power work very well for the US federal speed limit of 20-MPH. Also, since this power level still allows you to safely use the hub-motor on the front…you can still use an Internally-Geared-Hub (IGH, like a Nexus-7) or the standard derailleur 21-speed external sprockets.

The mid-sized BPM looks fairly large here because the wheels are only 24-inch, and the brake disc is also a small diameter.

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960W

48V X 20A

Rear Geared hub-motor…Bafang-BPM

This is a very popular combination. Geared hub-motors freewheel easily when only pedaling because they have an internal freewheel. If you limit the amps to 20A, the BPM should last a long time, and…at 48V it will have about 30% more power than when it is driven with 36V. Of course a 48V battery will be more expensive, but if you have mild hills…a rear BPM at 48V will work better than a front BPM at 36V.

A hub-motor with a Kv (turn-count) that provides 20-MPH at 36V…will likely provide about 26-MPH at 48V.

Here’s the mid-sized Bafang BPM geared hub in the rear wheel. With the battery also in the rear, this bike will be tail-heavy and handle poorly. With this big cruiser frame triangle, there is plenty of room to put a triangle-shaped battery pack, which would dramatically improve the bikes weight-distribution and handling.

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1,200W

48V X 25A

Large diameter rear Direct-Drive hub…9-Continents (9C)/E-Bikekit.com/ebay:Yescomusa/Magic Pie/MXUS

These next two recommendations are the most popular, a large geared hub or a large direct drive (DD) hub at 1,200W. As long as you’re riding safely, kits with this power level will visually pass for the legal 750W in the USA, and 500W in Canada. A DD hub will probably remain the cheapest option at this power level because of their simple construction, but be aware the large diameter (which helps the leverage of the magnets to produce more torque-per-watt)…is also what means that these kits will never be stealthy, and people everywhere will stop you to ask what it is.

The big benefit of a DD hub is the low purchase price and quiet operation (which can be even quieter with a sine-wave controller upgrade). These often come with a 20A max controller, but there is a significant increase in acceleration when going to 25A, and also at 30A. Somewhere between 30A and 40A, they will be in danger of overheating, depending on how much time they spend at the max amps. DD hubs also have a small amount of magnetic drag when just pedaling without power (called “cogging”), so be aware the MAC geared hub listed below is lighter and freewheels easily when just pedaling. 25A is the most common max setting…high enough to have a lot of fun, low enough that it almost never overheats.

As to copper mass, these typically have a 28mm wide stator. If you live on flat land with few stops, you can use 40A every day for wicked acceleration (as long as your battery can survive that). But…if you ride up a hill that is long enough and steep enough…even just 30A will fry it…However, these are the cheap hub-motors that have been used at every voltage from 36V to 111V, so if you damage just the motor they are cheap to replace.

Any amperage above it’s saturation point will make a lot of waste heat, which is inefficient, but…drill some air-venting holes in the side-plates to let the heat out, and these motors can be abused until they scream.

Chris makes custom battery cell electrical wiring harnesses for his business at “LiPo Connection Solutions“. Here is his 66V rear DD hub E-bike. His battery is centrally located in a “Falcon EV” triangle bag, which is described here.

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1200W

48V X 25A

Rear geared Hubmotor…10T MAC

Here is an example of the MAC geared hub motor from em3ev.com (one of our top three favorite vendors). The MACs stator is 25% wider than the BPMs, so the extra magnet width provides about 25% more power per watt that’s applied. The extra 25% of copper mass also allows more amps to be used, so I am recommending a 25A limit when you only have mild hills (for flat land, you can increase the max amps because there is plenty of cooling off time when you’re just cruising along). But…for a long steep uphill, you really have to watch the motor heat.

Once you move the battery weight to the center of the frame, the bike will have a much better balance and feel when riding. A 10T MAC using 48V will provide about a 28-MPH top speed on flat land (45-kph) when using 26-inch wheels, and it climbs mild hills very well. This is the most popular recommendation at the forum endless-sphere.com for most new users, and it has many happy customers.

Like the DD hub listed above, you can get snappier acceleration when upgrading from 25A to 30A, but you have to watch the heat! Geared hubs have a poor heat-shedding path, so if you think you may want to hot rod the motor later with 40A or 72V…get the DD hub. If you are certain you can be happy with 1,200W, then…this is the most popular combination.

Here’s a rear geared MAC with a DIY triangle battery pack.

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1,200W

48V X 25A

Small mid drive…Bafang BBS02

This kit has created a lot of buzz recently, and here is our article on it to get more details. Bear in mind the MAC kit listed above (providing the same 1,200W) will cost less, but the place where the BBS02 really shines in on steep uphills. The BBS02 uses the bikes gears (usually 7 sprockets at the rear wheel), so that it can have high top-speed on flat land, and…then you can downshift to provide awesome hill-climbing…so the motor stays up in it’s best RPM range to keep it from getting too hot.

Plus the weight of the BBS02 motor is moved to the center of the frame, to make the bikes balance as good as it can possibly be. Another benefit of mid-drives is that the tires are easier to fix when they get flat, and they seem to get flat less when there isn’t as much weight on the tire (pushing the tire down onto sharp debris).

There are a couple of user profiles where this kit truly satisfies, and is worth the extra cost. If you live where there is a power limit (like 250W in Europe/Australia, or 500W in Canada/Switzerland), this small motor will usually pass for a low-watt system. The other place where this is really worth the extra money is if you have steep uphills. You can downshift the bike so the motor remains at the higher RPMs, unlike a one-speed hub motor.

Downshifting a mid-drive on an uphill is not only more efficient, it prevents the motor from overheating when compared to a different one-speed hub-motor system that might bog down. It is reported to have an internal over-heat protection circuit for those times when you accidentally try to climb a steep hill in too high of a gear.

The Bafang BBS02 750W mid drive at 48V.

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1,500W-2,800W

Mid-sized Off-Road Mid drive…LightningRods kit

About a year and a half ago, we wrote about a new kit from GNG, found here. The configuration was well laid out, and this motor is fantastic in this application, but the rest of the kit had many weaknesses, especially the 12T freewheel and the BB-cartridge. Endless-sphere member “LightningRods” began designing and making replacement upgrades for the kit until eventually, he was remaking the entire kit…except for the excellent motor.

It’s possible to use this kit on a hardtail street commuter, but where it really stands out is when it’s used on a full-suspension off-road frame. This motor has performed well at 30A, and it sheds heat well, since it is an inrunner. At 48V X 30A = 1,440W, it’s performance is outstanding! But...it gets better than that. The low pole-count means this motor can be run at very high RPMs without excessive waste-heat produced from eddy-current losses. This means that it was tried and successfully verified to run well at 72V (and also 100V!). 72V X 40A is an awesome 2,800w!

Of course, if you are running at 100V (and 100V X 30A = 3,000W), the  motor is spinning fast enough that you will not be able to pedal along with the bike to help. But…at 100V, I would recommend keeping your eyes on the trail instead of pedaling! If you add a temp sensor, you can use even more amps than 30A, up to 40A. Being a mid-drive, this kit puts the motors [fairly light] weight in the center of the frame. This makes the bike more nimble compared to using a heavy rear hub.

These kits can be ordered now, but since they are unusually popular and in limited supply (while this business ramps up production to keep up with demand), it will be a lucky few that can get their hands on this kit. There may be a waiting list, but it is well worth the wait if you want  a powerful and light off-roader that is robust, reliable, and will last.

If you want to run more than 3,000W, you will have to sacrifice letting the motor use the bikes gears, which is the biggest benefit of a mid-drive. 4,000W will break bicycle chains and sprockets (or at the very least, wear them out unusually fast).

The LightningRods mid drive kit.

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1,900W

48V X 20A…(times TWO for 2WD)

There have been several 2WD E-bikes featured recently. The Mental Manno from Croatia, Teklektiks Mundocommuter in the US, and Bens AWD “Duty Cycle” in Taiwan. If you scan this build index from a Russian E-bike forum, you will find a dozen 2WD E-bikes (because of the snow in Russia over half the year).

They all use one throttle and one battery, but…they also used two controllers, and two identical geared hub motors (which freewheel). So…why would someone want two smaller motors, when you could just use one very large motor (like the systems listed below this)?

There are several reasons. First of all…in slippery or extra steep conditions, 2WD will have bettertraction. There are some conditions where no matter how much power you have, a single motor would just spin out, instead of accelerate. Secondly, all of these builders mentioned they liked the redundancy. If you live where it is extra steep, being far from home when a motor or controller has an issue can be a nightmare. With 2WD, the second motor and controller allows you to have a “limp home” mode.

The 1,900W number above is from using Bafang-BPMs at 48V X 20A = 960W (times two motors for 1,900W), but Bens Duty Cycle uses a pair of the larger MACs, and he is running 57V X 53A = 3,000W (times two motors) for 6,000W of 2WD traction. And yes, he does have temp sensors on both motors to make sure he doesn’t fry anything. He uses a handy 3-way power switch from em3ev.com to limit amps when climbing, and to use max amps on flat land to embarrass drivers who think their cars are fast…

Bens AWD Duty Cycle. Notice the torque-arms!

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2520W

72V X 35A

Rear Direct-Drive hub…Crystalyte H35XX (available as an H3525 or H3540)

If you have sampled 35A in a rear hub…and you like it…you really need more copper mass than the common 28mm wide stators in the 9C sized DD hubs. The Crystalyte H35-series has a 35mm wide stator (25% more copper), and it still allows the use of a common 7-speed freewheel while also fitting in the common 135mm wide drop-outs of all the widely available bicycle frames.

We have featured two E-bikes so far with this well-regarded hub and all three builds have some similarities. They are Rodgah’s Big Hit FSR, and the Electra Townie by Nick. You could get more power from an even larger hub than the H35-series, but…even though these builders like the near silence of a DD hub, they didn’t want any more weight out at the rear wheel than necessary, so…they used higher volts in the smallest hub that would satisfy their needs.

After you have had a hub-motor for a while, and you decide you want a little more speed and acceleration, everyone tells you to up the volts to the most you can afford (and can fit into the frame), then…you raise the amps to the max possible while still keeping the motor under 93C/200F. For the performance of 72V and 35A minimum, the Crystalyte H35 is the most affordable and lightest hub that can reliably provide that.

But…if you read the build-logs listed above, some of these builders used 100V, along with temporary peaks of 50A (with air-venting holes in the sideplates and temp sensors), for a whopping 100V X 50A = 5,000W. If you want to spend a lot of time riding faster than 30-MPH, I recommend a DD hub instead of a geared hub. Even 2WD MACs work best when limited to 30-MPH, plus…at those speeds you really need a good front suspension, which doesn’t go well with a large and powerful hub in the front.

Here is Rodgahs Big Hit FSR, with a Crystalyte H35 and a large battery that you will NEED to provide high volts and high amps.

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2880W

72V X 40A, Crystalyte H40XX (available as an H4040, H4065, H4080)

This motor has an almost identical construction as the HT35XX listed above, but it has a wider 40mm stator, and the extra copper mass will let it use more amps than the HT35XX (under the same conditions), or…it will run cooler at the same amps.

The 4080 will fit into common 135mm wide bicycle frame drop-outs, but it’s extra width means it will easily fit only a 5-speed freewheel. The core of this motor is a common stamped steel plate, so it cannot absorb as much of a temporary heat spike as the Crown motor listed below (with the Crowns’ heavy aluminum core).

The Crystalyte 4080 with the thin stamped steel core is on the left, and the Crown with the thick aluminum spokes is on the right._________________________________________________________

3600W

72V X 50A

Rear Direct-Drive hub…The Crown

In this power category, you could use “The Crown” motor, also from Crystalyte. It uses a 40mm wide stator, which is bigger than the H35 listed above, and less than the 50mm stator on the Cromotor listed below.

The Crystalyte 4080 also uses a 40mm wide stator, but there are differences between these two motors though…the 4080 has a less expensive steel stamped core, and it also is narrow enough to allow you to squeeze in a 5-speed freewheel (not that you’ll be pedaling much with 2880W), and it uses common spokes.

The Crown is more expensive than the 4080. It uses a thick-spoked aluminum core that helps absorb temporary heat spikes, so the 4080 would be acceptable on a flatter commute, and the Crown would be preferable for frequent stops and some hills (which require more high-amp peaks). The Crown also hasdeeper stator slots, so it can hold more copper mass in the windings.

One limit on the Crown is that it will only fit a single-speed freewheel when using common frames, but both of these motors should still fit into any common steel-framed bicycle. If you want to use this on an aluminum frame, you will need custom steel clamping drop-outs, since this power level will likely break common torque-arms (even when using two of them).

Be aware the Crown uses a custom spoke arrangement so that it has better spoke angles when it is mounted on a smaller wheel. If you add a temperature sensor, and keep an eye on it, this motor should be able to use 72V X 65A for an impressive 4680W.

The Crown has four Kv’s available (ebikes.ca only retails two, the TC80, and the TC100). This may be a consideration, because the Cromotor below is only supplied with one Kv selection.

The Crown motor from Crystalyte.

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4300W-8000W

72V X 60A–100V X 80A

Rear Direct-Drive hub…Cromotor

I can’t imagine going to the trouble of buying an expensive and heavy hub motor, and running it on only 48V and lower amps, so…these recommendations will require a lot of Watt-Hours (WH) of battery volume. This is going to be the single biggest issue in this category…fitting enough battery mass on a bike frame to supply 72V-100V and also 60A-80A.

The popular choice by a longshot is the monster Cromotor, with its 50mm wide stator. The most popular frames for it are frame kits from Phasor, the Greyborg Warp, and also Qulbix Raptor. Our friend Martinbuilt a street commuter using a robust downhill (DH) bicycle frame, but he had to order some custom rear drop-outs to accept the Cromotors 145/155mm wide axle shoulder. He also used an unconventional twin suitcase saddle arrangement to house the high-WH battery that is needed to feed this hungry beast because there was no room in the frame.

The three frame kits listed above have each chosen to house their large battery packs inside a hollow boxed frame. Any of these full-suspension frames can be run on the street…or off-road. Most of the Greyborg builders seem to be running on the street, where the muscular mass of the Cromotor is not an issue.

However, the Phasor and Raptor builders are more likely to build an off-road E-bike, as a sort-of lightweight dirt motorcycle, that can still be pedaled home on the streets due to the quiet motor (instead of a dirt-bike gasser engine). This is likely because the Phasor and Raptor frames allow a much longer rear shock than the Greyborg.

The Phasor has the slimmest frame at 100mm wide (for easier pedaling) but…if you want the absolute highest battery volume, the 160mm wide Raptor is the one. The Greyborgs 110mm wide frame is in the middle…slim enough for easy pedaling, but more battery volume for higher volts and amps.

72V X 60A is 4300W, which is the minimum watts that make the cost of a Cromotor system worthwhile, but…all of these frames have also been successfully run with a Cromotor at up to 100V X 80A for a brutal 8,000W. On frames this light, you would be shocked at how easily it can out-accelerate some VERY expensive and exotic sports cars at that power level.

The Cro has the massively wide 50mm stator, but it also has the very thick aluminum stator core to absorb the temporary extra heat of large amp-spikes.

Here’s a fat Cromotor driving motorcycle tires on an off-road-spec Raptor. If you hooked this bike up with an inverter, a battery this big could run your TV during a power outage for days!

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Written by Ron/Spinningmagnets, 2014

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