Buy this SHEWAIHE 36V 20Ah battery if you're doing a DIY ebike project and want lots of range without paying too much. It has huge capacity for its price. The big downside is that it doesn't have a protective case like a Shark or Hailong, which reduces the price. But if you're going to put it into a custom-built box, you'll have to do the assembly yourself.
Specs and value
The specs say this battery is a 36 volt unit with 20 amp hour (Ah) capacity, resulting in 720 watt-hours (Wh) of usable energy. While 20Ah is quite a bit of juice for a 36V system, many ebikes come with standard-range batteries that max out at 10Ah or 15Ah. So, if you choose 20Ah, you've got plenty of gas in the tank. And, the price is relatively low for a battery in this capacity class. That usually means someone has cut costs somewhere else. According to the specs, the manufacturer is using "A grade" cells that may retain over 80 percent capacity after 1500 cycles of deep discharging. That's a pretty strong claim for a cheap battery.
Inside the battery are the electronics for managing those cells. Specifically, inside this one is a 40 amp Battery Management System (BMS). The BMS takes care of keeping the cells charged within safe limits, preventing over-discharge and overcharge conditions, as well as short circuit protection. A 40 amp limit is telling us how much current this battery can deliver safely. As such, if you plan to run a motor that draws greater than 40 amps, the BMS will probably cut off the power supply to prevent damage to the cells. This means you will experience interruptions in service while climbing steep hills or trying to pull extremely high loads.
Essentially, you can only use mid-power motors that don't require large spikes of current.
Included with the purchase is a two amp (2A) charger. A charger rated for two amps is ridiculously slow for a 20Ah battery. With this charger, you can expect to spend approximately ten hours getting from completely discharged to fully charged. When you arrive home from a long ride, you'll have to plug it back in again and let it charge until morning.
Also included with the purchase are a T-to-XT60 adapter and XT60 connector extension cable. These components are nice additions for DIY builders because they provide options on how to connect the battery to your ebike controller. You won't have to solder connectors directly to the battery terminals immediately.
The bare pack reality
What you get from purchasing this battery is just a collection of cells and wiring. It is referred to as a "bare pack". This simply means there is no protective case surrounding the cells. Like other DIY-specific items, you will have to create your own enclosure to house the cells safely.
If you don't protect the cells from dust, water, etc., you risk damaging them. Damaged lithium cells are hazardous fires waiting to happen.
In the listing for this product, the seller cautions customers to check the dimensions of the pack prior to placing an order. Because there isn't already a pre-fabricated case around the cells, you will have to match the cells' internal layout to your available space on the bike. If the cells are longer than expected, they won't fit in your desired location.
So, this battery is definitely not designed as a "plug-and-play" solution. Instead, it is meant for the individual who likes building their own ebike from scratch.
Using a bare pack means you can save weight because you aren't including the extra heft of a heavy plastic case. Also, you can tailor your battery mounting system exactly to your needs. However, with great freedom comes great responsibility. Ultimately, you will have complete control over ensuring proper isolation and protecting against accidental penetration of the cells. Heat buildup due to poor air flow in an enclosed area can negatively affect the lifespan of your battery as well. Therefore, when purchasing this product, you are really purchasing nothing but the raw energy source.
Real-world range and power
The real advantage of this battery lies in its capacity for long-distance travel. At 720Wh of energy, this battery has sufficient energy reserves to propel you on a moderately paced journey for an extended period of time. If you compare this energy level to what you'll find in our ebike battery comparison table, the gap is obvious. Most standard-range batteries used for shorter journeys, doubling your range is a reasonable expectation. That said, if you commute and never have access to an outlet for several days at a time, this battery is ideal.
Regarding performance characteristics, however, the 40A BMS in this battery will limit your power delivery significantly. If you attempt to accelerate quickly on a steep slope, the battery will probably struggle to produce enough voltage to assist the motor in generating adequate thrust. Consequently, if you desire exceptional power and acceleration capabilities in your ebike, then this is not the battery for you. On the other hand, if you prefer maximizing efficiency over power and want to make cross-town commutes without having to stop frequently for recharging, this battery would serve your purposes admirably.
As previously mentioned, another consequence of the low-wattage charger included with this battery is the slow rate of recharge. Many newer high-capacity batteries now ship with chargers capable of delivering 4 to 5 amps, greatly reducing overall recharge times. Conversely, using a 2A charger means your ebike will be tied to a wall socket for lengthy periods of time after each ride. If you ride every day and consistently find yourself unable to obtain a full recharge within a suitable timeframe, consider investing in a higher-amperage charger that complements your battery's charge profile.
What Amazon reviewers are saying
There were only three customer reviews submitted for this product at this time. All three reviewers awarded this product 5 out of 5 stars. Unfortunately, since this review base is so small, we cannot determine whether there are any long term issues regarding durability or reliability associated with this particular model based upon independent customer feedback alone. Thus, we will have to rely on our general understanding of how 36-volt lithium ion packs function and interpret the specifications listed in the seller's description. From what little information we could gather from buyer comments thus far, buyers appear pleased with both the value and performance of this battery and are likely appreciative of its large capacity relative to price.
Until we receive more reviews from additional buyers we cannot confirm whether or not the seller's claim regarding A-grade cells holding over 80% capacity after about 1500 deep discharge cycles bears fruit in reality either. Additionally, we have no evidence regarding consistency of operation under heavy load by the BMS component. Any buyer considering a low-cost electronic device should proceed cautiously. The high rating count thus far is encouraging but represents only a fraction of the total number of potential users. Moreover, low inventory levels suggest that only individuals interested in unique products will be shopping for this product.
Who should buy this
This battery suits DIY builders familiar with working with electrical systems. They understand that they will have to assemble their own enclosures to fit the cells. If you currently have a 36-volt motor and seek a substantial increase in range capability, and you prioritize increased range over peak horsepower output, this battery is a strong option. Budget conscious DIY builders looking for affordable ways to achieve larger ranges will also find this product appealing. Our battery comparison table sorts every 36V pack by price per watt-hour if you want to see where this one lands.
On the other hand, if you are new to DIY projects, if you are seeking a battery that comes with an already fabricated enclosure ready to bolt on, or if you need an exceptionally powerful battery capable of handling intense currents and rapid acceleration on steep terrain, this product is not for you. Similarly, if you need to charge your battery rapidly, in under two hours, the provided 2A charger will prove woefully inadequate.
Frequently Asked Questions
Can I replace my existing ebike battery with this SHEWAIHE pack?
No, it is not a drop-in replacement for a Shark or Hailong packaged battery. It is intended strictly for DIY applications where you plan on providing your own housing and connections to support it.
How long will it take to recharge the pack?
The included charger puts out 2A. To fully recharge a 20Ah battery requires at least 10 hours. Plan on overnight charging.
How long will the pack last?
The seller estimates that the pack's cells will retain over 80% of original capacity after 1500 cycles of deep discharge. That estimate is based on the seller's own lab testing, and there is no independent confirmation yet, so regard it as a data point rather than a promise. Real-world lifespan also depends on maintenance. Storing the pack in direct sunlight or excessive heat for prolonged periods, storing it at 100% state of charge, and leaving it uncharged for long intervals all shorten overall life.
Will my motor get enough current from this pack?
Generally speaking, yes, for most commercially sold 36-volt motors. However, depending on your specific motor's characteristics, even modestly sized motors may exceed the 40 amp threshold when subjected to sudden increases in workload, like pulling heavy loads uphill. Verify compatibility between your specific motor and the stated amperage limitation before buying.