Revive 5s 5000 turningy pack?

[athletic91]

Hi took the pack out of storage for 5 months and the current readings is 4.1,3.9,4.1,4.1,4.1

I only bulk charge 2 such packs in series with a 10s charger at 42v
I have a couple of battery medics

How could i balance them without buying more equipment?
Was thinking of using the battery medics to discharge all other cells to 3.9v and bulk charge again, however i can only discharge at most 15mins before the battery medics overheat(screen turn black) and need a rest. Pretty confident this method will work although its very slow and troublesome

 

[Ykick]

Why bother balancing until you need them? I'd probably burn off a little charge closer to 3.9V/cell for all but worry about balance when you know you're gonna need 'em or imbalance gets much worse.

 

[ecobully]

@athletic91,

Do you know the cycle count of the battery pack? You should be able to bleed off the other cells connecting some small 3V flashlight bulbs to the balance connector. Start with the black wire (negative) and the first one next to it should be cell 1, then 2, 3, 4, and lastly cell 5 at the end--6 wires in total.

In your case try bleeding off some capacity on cell 1 (next to black wire) by taking 2 paperclips and connecting them to the light bulb and pushing the other side into the respective holes in your balance connector (black=negative). Based on the draw of the bulb, you can measure the time necessary to get cell 1 down to 3.9V. Then just use that same amount of time on cells 3, 4, and 5. Then all cells should be at around 3.9V each. Bulk charge and check again to see if they stay balanced.

** Try to keep your pack at around 3.7-3.8V if you don't plan on using it for a few weeks. Unfortunately you will want to use a balance charger in "storage" discharge mode so one of these days, you will want to spend a little bit more money--it will also extend the duty cycles of your battery packs if you do this.

 

[dogman dan]

I use 12v turn signal bulbs myself, so you could bleed off up to 3 cells at a time. But I'd charge fully first, then bleed down the high cells. it might surprise you which one ends up needing it. Might not be the 3.9v cell.

Solder some wire with a male jst pin on each one to the bulb to make the discharge rig.

 

[motomech]

Hi took the pack out of storage for 5 months and the current readings is 4.1,3.9,4.1,4.1,4.1

I only bulk charge 2 such packs in series with a 10s charger at 42v
I have a couple of battery medics

How could i balance them without buying more equipment?
Was thinking of using the battery medics to discharge all other cells to 3.9v and bulk charge again, however i can only discharge at most 15mins before the battery medics overheat(screen turn black) and need a rest. Pretty confident this method will work although its very slow and troublesome

You have the crappy Clone Battery Medics. I have one I got from Hobby King.
The other 5, I bought off Ebay work fine. You would think it would have been the other way around.