ecovelo

Greetings E-bike riders!! I need some help... I finally had installed an E-bike front wheel drive "kit" on one of one of my older model rigid MTBs..... back in 2016!!

I rode it a few times to work... promptly packed it away for the winter... and haven't thought about it much less ridden it since ("life" and a couple of surgeries got in the way!). I also realize I either never bought a charger... (my neighbor who has since moved had one) and/or the charger I thought I had is no longer in my possession.

I have several questions:

* given that the battery (36V 12Ah Li) has sat for 3 years without a charge, can I expect it to recharge if I can find the correct charger?

* Judging from pictures, it seems my battery has an RCA type adaptor - and the chargers that I see listed online for sale (RCA) tend to be 42V chargers. Can I use this for a 36V battery?

I am trying to decide if I even want to invest further in this project in order to get it up and running... but wanted to educate myself a bit more before deciding. I understand the E-bike world has grown substantially since I first invested in the "kit" (2010-12' era) - and I'd appreciate any feedback regarding this "older" project.

Thanks so much for your time!!
Ecovelo

2old

Many 36V Li batteries (10s which means there are 10 groups of batteries in series) charge to 42V (4.2V X 10) so the charger probably is the correct one for your battery. However, it's very likely that the battery is toast. You could check the voltage to determine it's current SOC (state of charge). There are methods to try to "nurse" the battery back to accepting a charge, but if you attempt any, IMO do it where you wouldn't mind a fire.

ecovelo

Ok, great. Yeah... I don't think I want to try to "nurse" anything.... I will check it's SOC. Thanks so much for the education/info! - ecovelo

chas58

Well, chargers are relatively cheap. But with lithium batteries, once they get below a certain level of discharge, the don't really come back. So, maybe it will work, but I wouldnt' get my hopes up. I'm gonna guess best case - some cells are beyond recovery so you won't get very good power or range...

MNebiker

My 36V 12A battery uses a 42V charger. The original charger failed so I just picked up one from eBay. A 2 or 3 amp unit is adequate for your battery.

As for recovery of the old battery - a lot will depend on the SOC when stored and how it was stored. Deep discharge and temperature extremes will kill a li-ion pack. It's worth giving it a try with the precautions 2OLD mentioned. Good luck!

ecovelo

Thanks for all the replies... they've all been very helpful!

TonyVov

I am just going through similar issue though not 3 years.
As per previous suggestion if you can find, beg,borrow or steal a charger you can give it a go. I would do that before investing in anything.

As you describe an in wheel system it is quite likely that it has a 'smart' everything to protect the user.
This could include the required charger.
So unless you can find the one specified for your machine I would ask for help with more details of what you actually want to charge.

My suggestion would be to look closely for a sticker or specification plate on the wheel and post the details here. With luck someone else has one.

In my case I had a bike conversion with a Bafang kit. 43V nominal 12sx4p. The bike was dormant for 6 months and then refused to charge.

The hot tip I found too late for myself was to put the bike on a stand or take it for a ride. The motor will act as a generator and could bring the battery back to life.

Inside the battery pack is a safety device called BMS. You probably have 10 cells stacked in line to make 36V.
LiIon battery cells are fully charged at about 4.2V each (42V) and the BMS will stop the power of voltage drops below 2.75V (27-30V)

This thing will turn the battery off and a smart one will also turn off the charger if the voltage per cell drops too low so even a charger won't work.

This happened to me, my To smart charger turned off and would not turn on, to get the pack back alive is a major operation involving opening the battery which needs knowledge before proceeding.

Good luck.
Find a charger. (Post your system Spec)
Try it out,
Go for a ride.
Try it again.
If you don't succeed ask for advice.