Salvaged Lithium Ion Batteries for eBike Builds

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Used Battery description


My first eBike battery pack used brand new cells that I purchased for $2.75 each (EVE 25P). They were marked as 2500 mAh batteries and tested at 2200mAh. I thought it was a pretty good deal until I came across bulk modem batteries that are being sold for about 75 cents per cell (Samsung 26F) and the cells I have measured so far are showing capacity ratings between 2200 and 2500mAh.  They appear to be a far better deal than my brand new batteries.  I purchased 40 packs to get 80 cells and so far only 2 were not useable and 3 with capacity below 2000mAh.  I liked the value so much that I bought an additional 20 packs before they sold out.

Used Modem batteries delivered


I figure the additional cells will allow me to build longer range batteries or higher voltage batteries.

The 2 upcoming retrofits that I will be working on will be for my son who needs a higher voltage bike to get him up the steep hills where he lives but not necessarily longer riding distances and another for my wife who doesn't need a lot of power just some assistance to get up the hills.

2 extracted 18650 cells

The idea of building a rock bottom eBike Battery (13s4p) for about $60 is absolutely the best deal that can be had today.  My Son's $15 bike purchased from a neighbor, will be converted for well under $300 and even less out of pocket since I used credit card reward points to buy the motor and battery management board.


4 Month update:

I used the best batteries from the haul of used modem batteries to build my son's battery pack and whatever was left went into the battery pack for my bike.  I decided to keep the EVE batteries together and use them in my wife's bike as a 36v battery pack since she won't need more power to pull her 105lb frame up the hills.

There were a handful of batteries that were not suitable for anything but I still had enough cells to build 2 14S4P battery packs (112 cells in total).  After taking a few rides, I can extrapolate that my lower capacity pack will give me a range of 20-22 miles using the most conservative assist (PAS Level 1) and minimal throttle. While it's not too bad, it's not nearly enough to take me on the longer rides I wanted to be able to accomplish.  I may have a bad group of cells but I'm now researching adding a second battery with higher capacity reclaimed cells from the same vendor for about $1 per cell to hopefully double the range.

I found a pack of 38 cells for $38 (+$15 shipping) that will give me enough extra cells(Panasonic NCR18650B) to upgrade a few groups in my existing pack as well as create an auxiliary 14s2p pack for extra range.


I'm also getting a fair amount of voltage sag on throttle application which I intend to reduce by adding some copper wire to the series connections in the battery packs. This will hopefully allow the current a little more room to get out of the battery but it also means opening up the pack. I may take the opportunity to replace the lower capacity groups while I'm in there.


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