Trying to revive my Delfast battery

devon

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Jul 2, 2022
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I have a Delfast Top 2.0. I’m actually hoping to sell it. I pulled it out of the shed. It had been a few months since ridden. And it wouldn’t turn in. The 72V battery seems to be 100% dead.

I verified the charger works at 84 volts.
I help from a neighbor who works on ebikes and he tried using The Satiator to get the battery going and I have attached a video of that. It starts showing the volts go up but no amps. Then after a few seconds it stops trying and you have to force start.

Any hope for reviving this battery? Very low cycles. The bike was bought in august 2020 with 200 miles on it.

It was last ridden maybe 3 months ago. I’m guessing it may have been left on so it may have been drained 2-4 months ago and sitting since then.

653be948094487f66fe4990c3bdd164b.jpg



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Link to video attempting to use satiator

https://share.icloud.com/photos/0de3taD6Zk5vkg0t6vDy4oGNQ


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You'll have to open up the battery and measure the actual cell voltages. I'd do this wiht a multimeter set to 20VDC, then black meter lead on the main thick black lead from battery to BMS, and red meter lead on the positive end of the most negative cell group (where the balance wire connects to the group). Note that voltage down and move the black lead to where the red lead is, then move the red lead to the next more positive balance wire point on the next cell group. Measure the rest of the groups until the red meter lead is on the main thick red wire from the cellls, and then put that list of voltages in a post here in this thread.

If they are less than around 2v they are probably damaged and possibly unsafe to recharge.

If they're above that, you *might* be able to recharge the cells by bypassing the BMS and using the Satiator with a custom profile that only allows a tiny trickle charge of a few mA until they reach say, 3v each, then trying a normal charge thru the BMS (since it should now allow charge). But the cells probably won't have the same performance or capacity that they did before, and there is still the chance they are damaged enough to be a potential fire hazard, depending on how low they went.

So in this eventuality, you need to let any buyer know the battery condition and potential risk, and tell them to assume the battery must be replaced. (if you don't tell them about the risk, and then there actually is a fire later on, you'll be responsible for that fire, and will have to live with that, even if no one else ever finds out).
 
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