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I have a STEPS E8000 bike and wanted to make some improvements, like possibility to charge from any kind of CC/CV charger (even using solar panels when grid is not available) and to charge it to 41v to improve cycle life but things went wrong after first brief charge.

I charged(CC/CV) just a little from 40.3v to 40.6v when i observed that the battery level indicator is not working anymore.

The battery doesn't want to start at all and the Shimano charger is just blinking when connected, meaning some kind of error.

Now i have 2 options: buy a new battery or find some Shimano service but i have no ideea if Shimano fixes a battery without warranty.

The second problem is that im not sure if a new battery will work wihout pairing/programming.

Any thoughts why the battery(or BMS) got bricked when charging the cells directly and will a new battery work (plug'n'play)?

BT-E8010

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    I think this question would be better asked on Electrical Engineering: the only connection with cycling is that the battery you're having problems with happens to be from a bike. The test I'd apply is this: somebody who knows about batteries will be able to answer your question even if they know nothing about bikes, whereas a cyclist will only be able to answer your question if they also know about electronics. – David Richerby Aug 15 '18 at 14:06
  • It's quite possible its the battery itself that is reporting some sort of error/sabotage state and the management software is taking the appropriate action. It's an expensive mistake, but i'd just contact shimano (or a distributor for them) and find out what needs to be replaced – Andy P Aug 15 '18 at 14:11
  • Depending on how urgent the matter is, you could contact Clive: youtube.com/user/bigclivedotcom. He disassembles/reverse engineers/has fun with everything electronic or electrical and would probably be able to tell if what you want to do is possible while making quite entertaining video. People send him broken battery banks on a regular basis. – Gabriel C. Aug 15 '18 at 18:20
  • It really seems that bms bricked the battery when the voltage started to increase unexpectedly. I had another ideea that it sensed a spike in the current when I put the cc CV charger(the charger output caps had to charge themself) and something went wrong. – Joe Anderson Aug 16 '18 at 19:17
  • I still have a faint believe that the bms can be reset somehow by the manufacture's tools. I saw a lot of thin wires on the charge connector which means that there is more than plus and minus. I will look also into what Clive does. – Joe Anderson Aug 16 '18 at 19:20
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It looks like you might have bypassed the charge controller on the pack and charged the cells directly? The smarter pack controllers do a form of coulomb counting and will see anomalous or unexpected pack voltages as a risk and premptively brick.

But before you get to that conclusion, I’d measure the individual cell voltages and make sure they are all within 0.1 volts of each other and that none are anomalously low. Balances often have a limited capacity for rebalancing and will brick a pack that is unbalanced too far.

Finally if you want to repair the pack, you may find a new / used pack controller part on eBay or you might be able to scavenge off an older pack. But be aware some controllers do brick themselves at end of life so you might be SOL anyway.

The worst case scenario is that you bricked the controller on the pack and you can’t recover the controller. It’s not a huge loss. You can still break the pack apart and use the 18650 cells in other projects or sell them on eBay.

  • Well, the battery is brand new and I would exclude from the beginning that the cells are unbalanced. I was thinking too that the cells are closely monitored by the microcontrollers and just bricked itself when the voltage started to increase. I hate this kind of too smart Bms. It will be an expensive lesson. – Joe Anderson Aug 16 '18 at 19:12
  • If the controller has shut it down, it can probably be "rebooted" by carefully discharging the battery to about 70% of charge. – Daniel R Hicks Aug 17 '18 at 1:07
  • Do you think so? Have you worked before with shimano batteries? – Joe Anderson Aug 17 '18 at 18:36
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"The second problem is that im not sure if a new battery will work wihout pairing/programming.

... and will a new battery work (plug'n'play)?"

Yes, no problem, I've used three different batteries on my bike so far and no problem switiching between them, nor when the other batteries went back to their original bikes.

  • Yes, thank you. I've bought a new battery and it works without problems. Still not sure what to do with the old one. – Joe Anderson Sep 25 '18 at 7:46

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