Looking for small battery options

goingup4m

New Member
I just finished a build on my wife's mountain bike but I am not real happy with the battery set up. The battery in the rack over the read tire makes the bike feel real top heavy. The issue I have is it is a very small frame (XXS). So there is very little room for a battery in the triangle.
The motor is a Bafang 1000w mid drive (BBSHD) with a 48v battery. Any suggestions on where I would find a small 48v battery that may fit inside the triangle?
Ideally I would find a smaller battery for shorter rides and if we are going on a long ride I could but the rack back on.
 

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PedalUma

Active Member
Region
USA
The underside of the downtube looks good. Poke around amazon and eBay. Look for high quality cells. Use at least three Topeak Versamounts to support it. Keep in mind clearence with the front tire and the height of the mounts and battery mounting bracket system. I adore small batteries.
 

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harryS

Well-Known Member
Now I would agree that is a top heavy rack.

Maybe a 52V4AH Luna Wolf Pup will fit in the triangle. I would expect 10-15 miles out of it.
 

indianajo

Well-Known Member
I hung the battery the first time off the handlebar and the front fender holes on the fork. Was 18 lb, a bit cumbersome. But if you buy something smaller and LiIon, shouldn't be as much trouble steering it. Supports will need a axle joint at junction handlebar-upper struts since you have a suspension. Clamped to handlebar with bands cut from box fan shell, wrapped around and clamped with 10-32 screws. vertical struts were 3/4x1/8" angle. warning use safety glasses when using power tools.
You see in my avitar the battery up front now hung off the frame mounts for a "bread basket" in my bodaboda. I like the way the battery balances the groceries in the back. Same aluminum cage of angle captured both batteries, with plastic foam inserts to keep the battery warm and dry. With 18 screws that are tightened from opposite side with 8" phillips driver, thieves don't know how to access the battery. Screws have been removed twice when I was grocery shopping. Ineffective both times. Use elastic stop nuts for permanent connections. (mcmaster.com but also available from grainger). SS hardware from mcmaster usually comes from countries not known for counterfeiting or embrittlement failures.
I'm carrying a 17.5 ah 48 v battery. Should have bought 21 AH, battery got red lights uphill about 30 miles with ebikeling motor. 30 miles takes 53-45 v on Mac12 motor.
 
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goingup4m

New Member
Thanks for the help. I think the wolf pup would work, they are currently out of stock on those, but I am not in a big hurry so maybe they will get some more soon.
 

PedalUma

Active Member
Region
USA
I tried looking for you for small batteries that will work for this project and have quality cells. It looks like they are in very short supply because of the supply chain issues with the ingredients inside the cells inside the batteries. Sizes have gone up for less power.
 

indianajo

Well-Known Member
Luna sells quality parts that actually work. But they take 16 weeks to ship things they already show in stock. And that was after a kick in the ****. By contrast, Amazon delivers garbage the next day.
 

6zfshdb

Well-Known Member
It's pretty common for a 48V battery to actually be 52V. Such is the case with my Pedego batteries. I use this cordless tool battery with an adapter as a backup:

61aThHjfHgL._AC_SL1500_.jpg 714wWY5WK+L._AC_SL1500_.jpg
Adapter:

Battery:

Under average conditions, it's good for about 12 miles. It's rated at 60V but measures 58.8V at full charge, the same as a 52V bike battery. It weighs 3 pounds and fits in a variety of places on the bike.
 

harryS

Well-Known Member
The other approach is sturdy pannier bags. I've had non-sturdy bags tear apart, scattering my little batteries all over the West Orange Trail in FLorida.
 

goingup4m

New Member
Any thouggts about a battery pack like this that I could put in a bag?
 

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indianajo

Well-Known Member
Big lie. that is not 58 AH.
You can put any generic battery with XT90 or Andersn connector in a bag, if you tape over the end to keep it from shorting on your tire tools or pump. Mount to be arranged before you need to use it. I wrap battery in 3/4"x1/8" aluminum angle cage with hangers or clamps to frame or bike basket mounts. 10-32 SS screws with elastic stop nuts to hold it all together. Use safety glasses using power tools. Saw yesterday lowes was selling SS machine screws $2.28 for four. Mcmaster.com sells them $5.50 for 100, +$8 freight.
 

harryS

Well-Known Member
It's a crap shoot to buy cheap batteries. There's not much financial risk because they're cheap, but there's the safety risk if they catch fire. Luckily, that's still a rare event. You do have to be more careful with these soft sided packs, One bad drop.

I've bought hard case packs from U.P.P.

Drop them a note on ebay and ask for a quote on two 13S-2P packs with 21700 5AH cells, 30A BMS, maybe 7 cells wide and 4 cells deep, instead of the usual 13 cells wide and 2 cells deep, You only need two 21700 cells to get 10AH. This will make a rectangular 48V10AH packs that you can put in both sides of a pannier, and either will have enough power for a BBSHD.