Lithium iron phosphate (LiFePO4) is the safest lithium battery chemistry you can choose for an electric bike, and the BtrPower 36V 12Ah is one of the lower-priced options for finding some peace of mind. With 432 watt-hours and a 30A BMS and 3A charger included, it falls in a competitive spot on our comparison table for people seeking longevity and safety versus raw power. BtrPower has been in the ebike battery market for quite a while now, and this pack is specifically for 36V ebike systems with motors up to 540 watts.
Safety-wise, the biggest draw is the chemistry. LiFePO4 (lithium iron phosphate) is incombustible, meaning it cannot burn or suffer thermal runaway like other lithium-ion chemistries can in extreme cases. While this is particularly important for riders that store their battery indoors or charge at night, it's equally important to the safety-conscious rider simply seeking the safest option available. However, there is a tradeoff in terms of energy density, as LiFePO4 has less energy density than lithium-ion. For a 36V commuter ebike, however, 12 amp-hours is plenty of juice for almost every daily commute.
Specs and Value
Core specs include 36 volts nominal, 12 amp-hours, for a total of 432 watt-hours. Cell configuration is 12S1P, twelve cells in series and one parallel string. The 30A BMS protects everything, and BtrPower bundles a 3A fast charger, which is a bit faster than the 2A chargers bundled with a lot of the lower-priced packs.
Physical specs
The battery measures 10.6 x 3.5 x 2.8 inches, making it a relatively compact rectangle that should fit easily into a variety of mounting solutions, such as a frame bag, a custom bracket, or a case you already have for a previous battery. The form factor is described as generic and not specific to a certain downtube or shark/hailong shape, so you'll need to figure out how to mount it yourself.
The 3A charger charges the pack from zero to full in approximately 4 to 5 hours. Maximum full charge voltage is 43.8V, and the normal operational voltage range is between 40.2V and 43.8V when fully charged. Once the pack has been turned off, the voltage returns to around 3.35V per cell or greater, which is typical of LiFePO4.
BMS and motor range
The 30A BMS includes overcharge protection, over-discharge protection, and short circuit protection. Since 30 amps continuous on a 36V system translates to approximately 1080 watts of theoretical output, BtrPower is conservatively limiting the pack to motors up to 540 watts, providing a reasonable safety margin. As a result, the 540W limit will accommodate the vast majority of 36V hub motor systems currently installed on ebikes in the US and Europe, including those with motors rated at 250W and 350W.
One of the key points is the cycle life. The LiFePO4 chemistry has inherent advantages in terms of cycle life compared to typical lithium-ion batteries. BtrPower indicates that the battery can go through 1500+ cycles. In reality, this equates to approximately twice the number of cycles compared to similar NMC (nickel manganese cobalt) batteries. Based on a single charge per day, this would translate to greater than four years of daily riding, until the battery falls to 80 percent of the original capacity. With this level of longevity, this is difficult to find in commuter batteries.
Form Factor and Compatibility
The battery is designed for 36V ebike systems with controllers rated at 30 amps or lower and motors with a maximum of 540 watts. Before making your purchase, please ensure that the following conditions apply to your ebike: the voltage of your controller is 36V, the current rating of your controller is 30 amps or less, and the dimensions of the battery (10.6 x 3.5 x 2.8 inches) will accommodate the mounting setup on your bike.
The form factor of the battery is a generic rectangular-shaped pack. Therefore, there are no built-in railings for mounting to a specific downtube mount or shark-pack carrier. You will require your own mounting solution for the battery, such as a frame bag, custom bracket, or existing battery case. BtrPower recommends that you check to ensure that the battery size fits your case prior to making your purchase, which is good advice.
For ebike commuters using a 36V system with either a 250W or 350W hub motor, this battery provides the ideal power profile. This battery is not suitable for high-power applications. Riders with 750W or 1000W motors will need to consider a 48V or 52V battery option from our comparison table.
Real-World Range
With 432Wh available to your ebike from a 36V system, your range is dependent upon your motor, terrain, and riding style. Assuming a 250W motor with moderate pedal assist on relatively flat terrain, you could potentially achieve 30 to 45 miles per charge. If you use more throttle input on mixed terrain with a 350W motor, your estimated mileage per charge would be approximately 20 to 30 miles. These are approximate estimates as the actual mileage will vary depending on your weight, wind resistance, tire pressure, and ambient temperatures.
The 12Ah capacity is acceptable for a 36V ebike battery. Most ebikes come with a 36V battery that has an 11Ah to 15Ah capacity. The 12Ah capacity of this battery places it squarely in the middle. Commuters with short daily commutes of under 20 miles round trip will easily get through one charge with some reserves left over.
What Amazon Reviewers Are Saying
The BtrPower 36V 12Ah LiFePO4 has a 4.0 star rating on Amazon. As the review count is currently low due to the newness of the product listing, the full picture is still developing. However, BtrPower has a large number of reviews associated with the majority of their products. Specifically, their 48V and 52V LiFePO4 batteries have accumulated hundreds of reviews across varying configurations, so the brand itself has a track record.
As with many ebike battery vendors, BtrPower has a 30-day return policy and a 12-month warranty. Additionally, BtrPower has an active support channel via the Amazon order messaging system, which provides peace of mind when purchasing a battery that requires technical support for compatibility questions.
In addition to the 36V LiFePO4 battery discussed above, BtrPower offers a variety of other ebike battery solutions including 36V, 48V, 52V, 60V, and 72V batteries in both LiFePO4 and standard lithium-ion chemistries. If this particular configuration is not suitable for your application, BtrPower has a battery configuration that is likely to meet your needs.
Who Should Buy This
The BtrPower 36V 12Ah LiFePO4 is best suited for ebike commuters who operate their bikes within a 36V system, value battery longevity and safety over maximum power output, and do not plan to use their ebike in high-power applications. Due to the characteristics of the LiFePO4 chemistry, this battery will provide approximately double the cycle life of standard lithium-ion batteries, the cells are incombustible, and the 30A BMS will protect motors of up to 540 watts.
Commuters with daily commutes of 10 to 25 miles will be able to obtain the greatest benefit from this battery. The 432Wh capacity is sufficient to support those daily distances. Furthermore, the 1500+ cycle rating will allow you to ride your ebike daily for years without the need to replace the battery. The included 3A charger is capable of charging the battery in less time than the chargers provided by many of the competing products in this price range, so you will not need to leave the battery plugged in overnight for most daily commute scenarios.
If you require additional power or longer range, you should evaluate 48V ebike battery options. Also, if you require a specific form factor (downtube, shark, rear rack), the generic rectangular shape of the battery may require a custom mounting solution. But for the rider who wants safe, long-lasting LiFePO4 chemistry in a 36V package at a reasonable price, this pack delivers.
Frequently Asked Questions
What factors make LiFePO4 batteries safer than regular lithium-ion? LiFePO4 (lithium iron phosphate) cells are chemically more stable and non-flammable than traditional lithium-ion cells. Since they do not experience thermal runaway, the potential fire hazard associated with standard lithium-ion batteries is greatly reduced. They are generally considered to be a safer choice for indoor charging and storage.
How long will it take to fully charge the BtrPower 36V 12Ah LiFePO4 battery? The 3A charger included with the battery will fully recharge it in approximately 4 to 5 hours. The charger has automatic cutoff to prevent overcharging. Typically, ebike commuters will not charge their battery from a completely dead state, so the actual time required to recharge the battery will usually be less than 4 to 5 hours.
Will this battery work with my 36V ebike? Yes. Any ebike with a 36V controller rated at 30 amps or less, and a motor with a maximum of 540 watts will be compatible with this battery. Please verify that the physical dimensions of the battery (10.6 x 3.5 x 2.8 inches) will fit within your mounting arrangement and that the connector types will be compatible or can be converted.
How many charge cycles will my LiFePO4 battery last? According to BtrPower, this battery is rated to last 1500+ charge/discharge cycles until the battery capacity drops to 80 percent. Using the example of one charge per day, this will result in more than 4 years of daily usage. Standard lithium-ion batteries typically last 500 to 1000 cycles.
Can I use this battery on my 48V or 52V ebike? No. This is a 36V battery and it must be used with a 36V controller. Using a 48V or 52V battery with a 36V controller will result in damaged electronic components. Always match your battery voltage to your controller voltage.
What is the warranty on this battery? BtrPower offers a 12-month warranty and a 30-day return window through Amazon. If you have issues with the product, you can contact their support team directly through the Amazon order messaging system.