On 12/11/2015 12:59 PM, Jeff Liebermann wrote:

This battery pack does have connections from every between-cells
connection to the PC board, so I am assuming that this was supposed to
be part of the balancing circuitry.

I wasn't aware of that. Progress lurches forward, usually when I'm
not looking.

This might be of interest if you want to repair your battery pack:
"Cell Re-balance of Ryobi One+ 18V Li-ion Battery (130501002)"
https://www.ifixit.com/Guide/Cell+Re-balance+of+Ryobi+One%2B+18V+Li-ion+Battery+%28130501002%29/13286

I might try that.

"Rebuilding Ryobi 18v Batteries"
http://toolboyworld.com/eBay/Ryobi_Batt_Rebuild.htm
Looks like the balancing circuitry is in the battery pack, not the
charger.

He deals with minor voltage differences between cells, not the huge
differences I have (mV only, from the one paralleled pair).

I can buy two of the 4AH packs for $99, so replacing all ten cells (five
*pairs*) in the present one would probably cost about the same for less
capacity as one new one.

http://www.homedepot.com/p/Ryobi-18-Volt-ONE-High-Capacity-LITHIUM-Battery-2-Pack-P122/204321540
I would not trust the battery capacity (ma-hrs) as stated on the
label. However the goood price and less risk of buying these is
probably better than trying to rebuild a pack.

Any less trustworthy than the alleged 2.4Ah capacity of the present one?

Perce