…increase its internal resistance. 
Just a general note…it’s also one of the best ways to set a cell on fire. Never allow a cell to go below zero volts and still continue to be discharged (i.e., be reversed charged).
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Any additional information/links about that?
Thank you 
ohh ok, thx. If a group hits zero wouldn’t that break the circuit?
Increase it’s overall internal resistance, but decrease the discharging resistance.
Hi guys, I’m attempting to get rid of the downward arc my deck has, so I’m placing 2x 22kg weights on it to try and make it a little less arced. Is this a bad idea? Or will I be fine?
Well, I have never pressed boards, but I really doubt that this approach would work. The board can be formed into shapes during the manufacturing process, but not afterwards. It either breaks or returns back to original shape.
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No. The pack will still function but the cells in the zero-volt p-group will be reverse charged as the others continue to discharge. That’s what makes this scenario so dangerous, the current doesn’t stop when a group hits zero.
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I’m not familiar with the term discharging resistance. You’re saying one of the resistances in a cell decreases when the cell is damaged? Could you give me a brief explanation?
ahhh ok I understand now. Is that why some people do cell level fusing?
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Wow didn’t expect this detailed answer thanks a lot!
Once a cell begins to die, a common failure mode is increased internal self-discharge. As in, there is the equivalent of a parallel resistor that is constantly draining the cell. The worse the self-discharge gets, the lower that value is. For a very dead (0v) p-group that has been ridden that way, the equivalent parallel resistance can be pretty low, and therefore can pass a lot of current. E.G. the battery won’t take a charge at all unless you feed it a lot of current to overcome the self-discharge.
Discharging resistance is a poor choice of words, I admit.
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Yes, but it’s much more of an issue with very large packs (p-groups >10-15 or so), where a single dead cell would take down a very significant number of other cells. It’s not really worth it for our application.
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No. Cell level fusing won’t help here because the level of the current in/out of the cell is not the problem. The problem is that it’s going in the wrong direction once the cell reaches zero volts. A fuse won’t help prevent that. A fuse only helps if the current level is too high.
That might happen in these cases but is definitely not certain to happen.
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Okay, I understand what you were referring to.
I’m very familiar with accelerated self-discharge due to cell damage but hadn’t heard the term you used before. Thank you for taking the time to explain.
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Thx, I’m not sure if it’s a DEAD p group. My pack charges to 47.8V. 2 months ago it was 49.5V. I’ll cut the pack open to measure from the cells soon.
like a short?
Anyone have a suggestion for a 1/4" waterproof gasket to put between an enclosure and deck? I’ve seen butyl tape recommended, but I’ve only seen 1/8" thickness. I guess I could double up?
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Butyl tape is very waterproof, but also very messy. Double stacking it wont be a problem.
Soft neoprene foam is a lot cleaner and easier to work with, and you can get that in all kinds of thicknesses. It is less waterproof however, since it is not tacky and fluid like the butyl tape.
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Butyl neoprene butyl sandwich?
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Sounds messy as fuck 
A method that I have been considering but have not tested on my own board is using this stuff:
https://www.amazon.com/dp/B079YNC13G/ref=cm_sw_r_cp_apa_fabt1_5C-VFbC9501FV?_encoding=UTF8&psc=1
I run a bead along the enclosure flange, and a bead along the deck, and i stick a thin layer of neoprene (1/8th inch) to both sides. That way the neoprene is sealed to the deck and enclosure, and the two mating surfaces are neoprene-on-neoprene.
I did this on @DerelictRobot’s RoboBoogie build that I made for him, but the neoprene that I used on that was not the best quality. I tried out a different (cheaper) supplier and the stuff i got was stiff and nasty and barely squishy. So not ideal gasket material anyway. That board doesn’t have very many miles on it, so no word yet as to weather my “double sealed gasket” method is working well.
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