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[john_rjs]

Has anyone successfully revived a dead Zero battery?

I purchased a 2011 Zero S that was left uncharged all winter long. The built in charger immediate detects an error and is incapable of charging.
I am in the process of attempting to manually force charge the parallel banks separately with a couple of lab power supplies. So far they seem to be taking a charge but I have not brought the entire battery backup.

I assume even if they all take a charge they may have diminished capacity. Has anyone else attempted this?
Does anyone have any information on the bikes cells, charger or balancer (BMS)?

[Knuckles_ds]

Forgive my English , but use a translator.
I relived my battery Ds2010 , I loaded the cells with much patience with a laboratory source to 3 volts.
Assembly and then you charge your OEM charger and so far I have had no problems .

[john_rjs]

Do you think have good capacity? How long were your cells dead?
Do you know if these are 3.7V nominal cells

[Knuckles_ds]

Nominal voltage is 3.7volts but I think from 2.5 v , the OEM charger can charge the battery and balance.
The battery works OK, the battery dead some months.

[john_rjs]

Thanks Knuckles,
Most of the cells have accepted a charge and appear to be holding. I do have one rung (a single parallel group / half a heat shrink pack) that is giving me trouble. The OEM charger has kicked in, but is unable to charge that. I just switched back to the lab supply to saturate this last group. I might have to just take it out if I don't feel confident with it.

[MrDude_1]

if they have a high internal discharge, you will have to remove them.
If you charge them up and use them anyway, theres a high chance they will eventually catch on fire.

If they are just slower to take the charge, but hold the charge... then they may be usable.

[john_rjs]

Fire never crossed my mind. I was more worried about the weakest link in the chain limiting the available current.
It charged up to 4.1V last night, but the others seem to make it to 4.2V. I put it back on the OEM this morning. Want to see if it ever makes it to green Full Charge.
I thought I read somewhere if it doesn't reach the balanced state the throttle will be disabled. I would hate to get it all buttoned back together and reinstalled to have no throttle.

[MrDude_1]

Fire never crossed my mind. I was more worried about the weakest link in the chain limiting the available current.
It charged up to 4.1V last night, but the others seem to make it to 4.2V. I put it back on the OEM this morning. Want to see if it ever makes it to green Full Charge.
I thought I read somewhere if it doesn't reach the balanced state the throttle will be disabled. I would hate to get it all buttoned back together and reinstalled to have no throttle.

im not a battery engineer, but how it was explained to me was that below a specific charge level, little dendrites start to form on one side of the battery. When recharged, they make "dead areas" of the cell, and now the cell has less area, so its weaker under load but it still works.
However if the dendrites grow large enough, they can short out the cell. if you then charge them, they will act as a weak short, slowly getting hotter and hotter until they create a thermal runaway.

this is backed up to me by watching RC cars with cheap lipos.. they eventually recharge ok, sit still, and a hour later they burst into flames. long after when they were off the charger.


Im not trying to scare you with this... by the time you read this you will have had enough time to know they're fine.  But its a scary thing ive personally seen with a few other lipos, and I keep a very close eye on charging any lipo that sat below 3v for any long time.