the Blwny 48V 21Ah LiFePO4 battery is built into a spray-alloy shell and contains 1008Wh of energy. It also includes a 30a BMS (battery management system), and a 3A fast charger. Blwny’s 48V 21Ah LiFePO4 battery employs automobile grade lithium iron phosphate cells. Thus, making it very much different from the lithium ion (NMC or NCA) type battery used by almost all ebike manufacturers. Also, instead of using a plastic casing, the blwny battery utilizes an alloy housing which is able to withstand impacts, oxidation, and moisture way better than a traditional pvc-wrapped battery pack. As such, this battery is suitable for use with 250W to 1500W motors and intended for diy ebike projects as well as go-karts, balance bikes, mini trikes, and Custom electric conversions.
As of the date of writing, the Blwny 48V 21Ah LiFePO4 battery has an overall 5-star rating from three reviewers on Amazon and features an xt60 connector for a plug-and-play experience. At approximately eighteen point five pounds, the battery's weight is consistent with what you would expect from a twenty-one ah lfp battery pack encased in a protective alloy shell. Check the current price on Amazon.
Specs and Value
The primary specifications of the Blwny 48V 21Ah LiFePO4 battery include a 48-volt nominal output and twenty-one amp hour storage capability resulting in 1,008 watt-hours of stored energy. The thirty-amp BMS (battery management system) offers overcharge protection, over-discharge protection, short circuit protection, and over-current protection. In addition, blwny indicates that their thirty-amp BMS allows for greater than two thousand deep discharges prior to reduced capacity. They claim that with normal usage conditions, the blwny thirty-amp BMS will support up to four thousand deep discharges.
Physical design
The most distinguishing aspect of the Blwny 48V 21Ah LiFePO4 battery is its alloy housing. Almost all aftermarket ebike batteries utilize pvc-wrapped plastic housings that can crack or become saturated with water overtime. The alloy housing utilized on the blwny battery has been coated with a specialized coating that protects against rust, denting, and weather exposure. Due to these qualities, it makes a great option for both indoor and outdoor applications as well as for projects that require heavy-duty handling. Although the alloy shell adds some weight to the battery, it results in a battery weighing approximately eighteen point five pounds which is slightly heavier than a similar sized forty-eight volt twenty-amp hour lithium ion battery encased in a plastic housing. However, for many build types, the increased durability offered by the aluminum shell is acceptable for the slight increase in weight.
BMS and motor range
The thirty-amp BMS provided with the Blwny 48V 21Ah LiFePO4 battery can provide up to fourteen hundred forty watts of continuous power while maintaining a fifty-two volt nominal output. Therefore, it should be able to handle most motors within the stated two hundred fifty to fifteen hundred watt range. The three-amp charger included with the blwny battery is capable of charging the battery at a faster rate than many lower-cost lithium ion batteries have stock chargers that only offer two amps. Based upon average charging rates, it would take around seven to eight hours to completely fill a discharged battery.
The inclusion of an xt60 connector facilitates the connection of a variety of motor controllers and conversion kits to the battery. While some customers may find that they need to add additional adapters to complete their connections, the majority will not encounter issues with connecting a motor controller or conversion kit.
LiFePO4 Safety: The Real Advantage
One of the greatest reasons to select the Blwny 48V 21Ah LiFePO4 over a traditional ebike battery is based on its lithium iron phosphate chemistry. Unlike standard lithium-ion batteries that employ either nickel-manganese-cobalt or nickel-cobalt-aluminum chemistry, lithium iron phosphate batteries are fundamentally safer in terms of potential fire hazards. When subjected to thermal runaway caused by being punctured, over-charged, internally shorted or otherwise physically damaged, lithium-ion batteries often result in significant fires. This is a direct result of the decomposition of the oxide bonds present in lithium-ion batteries releasing oxygen and thereby creating a thermal runaway condition. Since lithium iron phosphate creates significantly stronger phosphate bonds than oxide bonds present in lithium-ion batteries, lithium iron phosphate batteries cannot produce oxygen through decomposition when subjected to excessive temperatures. Therefore, lithium iron phosphate batteries will never undergo thermal runaway. What this essentially translates to in real-world application is that lithium iron phosphate batteries are completely non-flammable and therefore safe for use in virtually any environment.
Lithium iron phosphate batteries generally have longer lifetimes than lithium-ion batteries as well. Traditional lithium-ion batteries can generally perform up to one-thousand total charge/discharge cycles prior to experiencing notable reductions in capacity. Conversely, lithium iron phosphate batteries can generally perform up to four-thousand total charge/discharge cycles prior to experiencing noticeable degradation. With proper maintenance and care, this equates to many years of continued service.
In exchange for extended lifespan and inherent safety benefits of lithium iron phosphate chemistry versus lithium-ion chemistry, lithium iron phosphate batteries inherently possess lower weight-energy-density characteristics than standard lithium-ion batteries. For example, since lithium iron phosphate batteries weigh more per watt-hour of energy stored relative to standard lithium-ion batteries of equivalent size and capacity, lithium iron phosphate batteries weigh nearly nineteen pounds while standard lithium-ion batteries of comparable capacity would likely weigh considerably less. Therefore, users requiring extremely lightweight batteries for high-performance mountain-style ebikes will need to evaluate alternative options. However, since go-karts and trikes usually do not rely heavily on light-weight aspects of ebikes or scooters, utilizing a lithium iron phosphate battery provides numerous advantages including extreme safety characteristics and longer lifespan.
Build Quality and DIY Compatibility
The alloy housing utilized by the blwny battery is far superior to standard plastic casings utilized in the vast majority of aftermarket ebike batteries. Plastic casings are prone to cracking under repeated physical abuse while allowing moisture entry due to their porous nature. The alloy housing utilized by blwny is sprayed with a proprietary coating providing improved corrosion-resistance. The alloy itself provides exceptional resistance to dents as well as shock/vibration-related failures common in ebike-type applications. These traits make it ideally-suited for use outdoors as well as in workshops/indoor applications where ebike projects are created.
Due to the utilization of an xt60 connector on the blwny battery, users can connect their motor controllers/conversion kits directly via this connector without having to utilize adapter cables (in most instances). As previously mentioned, an xt60 connector is an industry-standard connector commonly employed in various e-bike/motorbike conversion kits. Users may opt to design Custom mounting solutions for the blwny battery or alternatively utilize tie-down straps to securely hold the battery in place.
Who Should Buy This
The Blwny 48V 21Ah LiFePO4 battery was developed specifically for those diy enthusiasts who place priority on both safety and durability rather than weight-savings. The battery is an excellent option for:
- Custom go-kart/minitrike projects where ruggedized alloy shells prevent damage from accidents
- kids' power wheel/balance bike conversions requiring non-flammable lithium chemistry
- workshops/equipment conversions operating at forty-eight volts
- weather-exposed outdoor e-vehicle projects
- those seeking reassurance related to non-flammable chemistry
- project creators intending to maintain a battery for multiple years
While the blwny is an ideal candidate for users prioritizing safety and reliability over weight-savings, it is not as well-suited for individuals requiring ultra-lightweight battery packs (such as high-performance mountain-style ebikers).
Frequently Asked Questions
why does LiFePO4 matter?
LiFePO4 represents lithium iron phosphate chemistry. A type of rechargeable battery that does not burn when punctured, overcharged or short circuited. Standard lithium ion chemistries however can be subject to thermal runaway when exposed to aforementioned stressors. The safety differences between LiFePO4 and standard lithium ion chemistries represent the largest difference between them.
how long does the blwny take to charge?
With the supplied 3A charger, a fully drained blwny will be charged in roughly seven to eight hours. All partial charges will occur proportionally quicker than full charges.
what type of connector is utilized on this battery?
An xt60 connector is provided on this product. Which is an industry-standard connector among e-bike/motorcycle conversion kits and other devices.
does the blwny require special mounting hardware?
The blwny is a simple rectangular block with an alloy shell. Therefore it requires no Custom mounting hardware. Customers will need to secure it with straps or Custom enclosures/designs.
what motors are compatible with this product?
Blwny recommends compatibility with motors ranging from 250-1500W.
how many cycles will this battery last?
As previously mentioned. Lfp products can easily exceed 2000+ cycles until they begin losing capacity. Thus lasting much longer than standard lithium-ion products.
may i use this product indoors or in my garage?
Yes. Since lfp chemistry is completely non-combustible. Thus free from producing toxic fumes. Lfp products can safely operate indoors or even inside garages/gasoline storage areas. Unlike standard lithium-ion products.
Final Thoughts
The Blwny 48V 21Ah LiFePO4 represents an important new offering for diy enthusiasts seeking safety and durability in their ebike/motorcycle conversion project(s). The combination of safety (non-flammable) and durability (alloy shell) makes it an attractive option for indoor/outdoor projects requiring long-term usability.
Although it may be slightly overweight for certain build styles. The Value proposition offered by this product is unmatched by anything else currently available today.
Please continue reading articles on our blog. Browse additional offerings on our ebike battery comparison chart. Or visit Amazon.com to purchase this product today.
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