Yes those 510 Ohm resistors are designated RF1 - RF10 on the board and connected to each 2-in-parallel Cell as shown in the schematic above where they are connected to the - end of each pair. If those were removed it would isolate that pair from the drain circuit. i don’t know how long it would take to drain a pack, best not to wait to salvage the cells. (EDIT note: The 18V ryobi packs have 5 cells and use 51 Ohms for the RF resistors)
i think RF11 and RF12 are in circuits that provide power for the digital section so those could be removed as well to just turn off the controller and stop the bleeding. i ended up taking them all off the boards.
i have 3 packs that indicated bad, one was actually overcharged at ~42.8 V, the others were around 3 to 4V, with cells at .2 to .4. i put them on a power supply and slowly stepped up in 1V increments while monitoring the current and temperature.
The 4V pack immediately took current at 50-90 mA and then it tapered back to about 25mA, then i incremented 1V and repeated this until the voltage got up to ~23 V for the pack. At that point the current draw was increasing with each 1V increment, , e.g. 200 to 300 mA. Again i let it hold at that voltage until the current dropped to ~25mA, then increment. Got the pack up to 32V and stopped, will see how it is in the morning.
The 3V pack didn’t seem to draw any current like the other one did—i stepped it up from 3 to 23 in 1 V increments with little to no current flow, then at 23V it started to draw/charge at 25mA, and after a few more increments it soon started behaving like the pack above until reaching 32 Volts, will check it tomorrow.
On the 42+V pack i had removed the fuse between the top and bottom modules (2P5S bricks that make up half-packs). Over just 2 days the bottom module had been drained off to 18 V, whereas the top half was still reading high at 22.8. The digital controls seem to be powered from the upper half, and likely sensed the “blown” fuse and initiated the drain-off for the bottom half. i connected a resistor and bled the top down to 20, and charged the bottom up to 19, will check it in the morning to see how it holds.
So long story short, nothing thermal was noted, but that doesn’t mean they are safe and good to go. Metal dentrites grow inside a cell during any charging that is done after an over-discharge event. These are sharp shards of metal that will puncture the plastic separator sheet in the cell and cause an internal short circuit, which leads to thermal runaway—much heat and eventually fire. So don’t try doing this unattended, recharging after a discharge below 2.5V is not a recommended practice and they can go off AT ANY TIME and burn down your garage, house or trailer. If it happens while you are sleeping, then you might just wake up dead…