Why some E-Bike batteries cheaper then others
Here at Fat Tire E-Bikes we get this questions a lot. Why is there such a price difference between e-bike batteries, especially between they are the same capacity? How can you have one battery that's $250 and one that's $550?
Here is a scenario we get all the time. It's like, "Well, I found this battery on Amazon. It's a 52 volt, 13 amp hour for $250. I'm going to go with that one because I saw this other seller, even you, have the same capacity for $550, so I'm going to save $200 and go with this one." The question is, why is it so cheap?
There's two different reasons why a battery pack has dramatically different pricing. One is the quality of the cells that are in there, and two is the quality of the pack being made. How was the pack made? The first point is the quality of the cells. You could get cheap, generic Chinese cells for probably a little under $2 a sell, and the very high quality cells can run up to $7 a sell. If you got something like a Samsung, 30Q or something with very high tolerances for discharging and extreme performance, it's going to cost you a lot more. That range between $2 and $7 spread over 70 cells in a big battery pack like that, that's $350 of difference.
So, if somebody's telling you that they have really high-quality cells, but they're only charging you $250 for it, do the math. Figure out how many battery cells are in it, which is rated on how many are in series and how many are in parallel. You just times those two and that'll give you your battery cell count. Divide the cost by that. If it's $2 or $3 and that's not even including the production of it, you want to pay a high-quality skilled worker to assemble these, and use good quality parts, like good quality BMS board, good quality soldering. All those things are what's going to keep your battery from exploding, shorting, blah, blah, blah. We call those house burners.
So, when you buy a $250 battery pack on Amazon, it's probably because it's made with poor-quality cells and it's made by a poor-quality worker who's not getting paid very well. That's a recipe for disaster of setting your house on fire or wherever you keep your batteries. I would allocate at least $200 to building the pack, just for paying an adult that's skilled at their job making that pack. Then a good battery sell should cost about $4 a sell at a minimum. So, if you got one that's 14 by 5, that's 70 cells, that's a 52-volt pack at like 17 and a half amp hour, somewhere around there, 14 to 17 amp hour. That's 70 cells.
At 4 times 70, that's $280 just in the cells, depending on the quality. That might be a little bit more. It might be $350 just for the cells. Now, I would add at least $200 onto that. Your battery should cost at least $450, and that's not including shipping, all overheads or anything. That's just $450 that that battery pack should cost for a good quality one. Now, if you want to buy one that you know is generic because you're like, "I just want to get a cheap one," that's fine. You just don't want to pay for something that says, "Hey, these are premium cells," if you know that it's costing $300, and they're saying that it's got premium cells in it for a high capacity better pack like that, they're lying to you.
That's a problem too, is if you buy things on, even Amazon, there's no regulation on there. I strongly recommend people not buy their e-bike components off of Amazon because there's no regulation. I know that Amazon supposedly is a, "Oh, I trust that," but it's just like eBay. You got to trust the seller that's selling on eBay. eBay may help protect you, but do you want to go through that long process of returns, fighting with the seller, trying to make it right, and then get a percentage of your money back after, I don't know.
That's why we always say buy it from a reputable e-bike seller that buys good quality packs, from quality bike manufacturers. You don't have to buy it from us, but we do buy from good quality suppliers.