Alternative Batteries for ebike self build projects

[Thecopterdoctor]

Hi, I'm new to this community but feel that seeing as I have been researching the whole Pedelec subject for a while now, and reading many post here, I feel its only right to share my experience for what its worth!

I posted a piece earlier today on my introduction to ebikes on the subject thread of kits and mentioned that I am using a fairly low capacity Bosch power tool 36volt 4ah li ion battery to power my Cyclotricity 250W front geared 700c hub kit. I know there has been some mention of using alternative batteries on this site but haven't really heard of any recorded results.

After CAD designing a Hot Shoe type mount that I have 3d printed and mounted on the down tube in place of the water bottle carrier I have had great results and intend buying more of these top quality cell packs .

Firstly my reason for doing this was that when purchasing the kit I couldn't buy a battery from Cyclotricty as they where totally out of stock, I then couldn't decided on what bottle battery to buy online and got totally confused with all the ones on offer, and fears of cheap li ion cell quality in low end battery packs got totally put off so I figured for the cost of a power tool pack of a know quality (and good manufactures Guarantee!) it was worth a try

My only possible modification is to add a Volt/Watt meter display to keep an eye on the pack as there are only three capacity indicator LEDs on the battery itself.

If anyone has a similar experience I would like to hear .

JJB

 

[Fat Rat]

Hi welcome to the site
Thanks for sharing your findings

 

[wheeliepete]

Power tool batteries have been widely used for quite a few years on ebikes, esp. in the US where their cost is a lot lower than here. You are right that buying a battery for your bike can be really confusing without hours of research, as you say, too much choice. You may find this a useful read and a bit of insight of lithium batteries.

https://www.electricbike.com/cordless-tool-batteries-for-ebike/

Also have a look on Endless Sphere for some real world use. The only drawback I can see to your setup is that your pack only contains 10 cells, albeit top quality ones, so you may suffer fairly rapid capacity loss, esp. if you use high PAS or full throttle a lot. They would fair better if you ran 2 together in parallel and thus share the load. Having said that, you have an excellent warranty on them. Let us know how you get on.

 

[Thecopterdoctor]

Hi there, thanks for your reply to my post, I did previously read the link you sent me after doing my conversion and was relieved to see they said to put the Bosch batteries on your short list!

I have been a keen RC modeler for many years and have been using Lipo batteries ever since they became available for use in Fixed wing and large scale Helicopters too. I did consider using my 6s 5000mah packs that I have several of, but maybe for my next project!
Thanks again for your response. JJB

 

[scott gaza]

Hi Cop Doc, I've got the same view as Wheeliepete, a 4ah battery is not a lot in the terms of assisted range. As you would need multiple packs for any ride over a given range. I now use a 7.8ah pack with lg cells that only gets me 6-10mls or less which are mainly as fast as possible, on a front hub drive not unlike yours. I used to do about the same with 4x 18v drill batteries using pairs of them at a time in parallel. Just less time charging batteries now.

 

[Kinninvie]

As you have and understand lipo thats you easiest upgrade .
I have various Multistars allowing me to use 10 , 12 and 14S at up to 64Ah.
Charging is taken care of using several Meanwell power supplies.
Some are set to 3.8V (storage level) and are used after a ride while others are set at 4.1V so as to give more battery cycles.
This way it takes 2 hours at most to reach full charge.
I always check for balance before and after EVERY ride.