Small ebike batteries

Moogster10

1 µW
Joined
Mar 29, 2022
Messages
4
Hi all - I have a downhill bike with 36w 350w mid-drive motor.
There isn't a lot of space for big batteries with the suspension in the frame. I am wondering what the smallest size of battery you could get to support about 2hrs of riding. Essentially it is used to get you up the hill so you can ride down it!
I carry my normal battery in my backpack but it weighs quite a bit.

Any ideas welcome
John
 
Moogster10 said:
Hi all - I have a downhill bike with 36w 350w mid-drive motor.
There isn't a lot of space for big batteries with the suspension in the frame. I am wondering what the smallest size of battery you could get to support about 2hrs of riding. Essentially it is used to get you up the hill so you can ride down it!
I carry my normal battery in my backpack but it weighs quite a bit.

Any ideas welcome
John

It this is a physical size and location question, then yes, pics would help.

If this is a battery capacity question, then I'd buy an inline wattmeter and just test how much capacity you use climbing the hill with your backpack battery, then you'd know the actual capacity you'll need. Then provide a little buffer on top of that. Otherwise, you need to supply all of the specifics about the climb, how much effort you contribute, and all of the information about your setup, besides the battery.
 
Grin claims that you can get three LIGO batteries into this Rockbros saddle bag. LIGO batteries are 36V and 98 WH each. You are probably going to use 15-35 WH/mile depending on the terrain, how fast you ride, how much you pedal, etc. You might be able to stuff five into a handlebar bag.

seatbag_rockbros_3ligos.jpg


This seller claims to fit six in a Topeak saddle bag, but you are going to need a lot of seatpost showing to fit it.

https://www.bikepartners.net/topeak-seat-bag-for-ligo-batteries.html

topeak-seat-bag-for-ligo-batteries.jpg
 
A friend of mine rides a Bafang rear hub 36v. I recommended to him to consider Ryobi 40v 6aH batteries to supplement his ride.

I ride a 48v Bafang mid engine on a dual suspension frame. My batteries are 5-6aH, between 56v-60v depending on brand of lawnmower battery. These batteries weigh in at 5 lbs. I mount one on a seat post rack and it stays there, nothing comes loose. My ride is 99% sidewalks (sometimes bumpy) and/or off-road /away from road. I do not attempt to interact with traffic!

I use a backpack to carry charger and spare 5aH battery. Not much weight to carry on a ride.
 
GRIN EBIKES said:
Unfortunately several key IC's used on the LiGo BMS boards became impossible to source in 2021 due to the semiconductor shortages. We had enough stock to produce one final batch of 2000 BMS boards for LiGo and LiGo+ batteries over winter, and sold the last of these in July 2022.  

They go on to tell us a new version is in development. Should be good.
 
I'll second the "try a ryobi 40 v" idea.

You can get them in a range of output wattage and AH, the quick chargers are small and light, the system is rugged and reliable (so long as you don't leave the battery on the charger for weeks at a time) and the biggest battery they sell (6AH HC) is often available on ebay for $65, from pallet breakers (compared to $300 full retail)

The onboard BMS limits current to 20A or 22A, depending on the model of battery. Not enough for a high power Ebike, but for your use, should work fine.

You can buy the docking ports to fit the ryobi 40v batteries 3D printed and wired from a robotics competition supply for about $15 each.
 
2X For RYOBI P108 18V 9.0AH 6.0Ah Battery 18 Volt Lithium One+ Plus / Charger
thissenergysystem_6688 (1380)
99.1% positive feedback
$9.49Free shipping
Est. delivery Thu, Jan 12 - Tue, Jan 17
Found this on eBay I can't believe the price what kind of batteries do they sell out there that's two 40 volt 9 amp hour batteries and a charger 999 what kind of stuff is this on eBay.
 
"2X For RYOBI P108 18V 9.0AH 6.0Ah Battery 18 Volt Lithium One+ Plus / Charger"

That's for an 18v battery, and it's a knockoff replacement, not OEM Ryobi.

Buying used, I won't buy anything that isn't authentic Ryobi, and it has to show a pic of all four bars lit, and say "tested and working" So far, every one like that has worked fine, for over a year, under regular use and recharge.

If you're tearing packs down to salvage the cells,you don't need to be so picky, but I'm not interested in building packs when I can get working ones so cheap. ($10-15/AH )
 
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