Should I wrap with my fiberglass tape underneath or ontop of the fish paper?
I wrap with kapton first. Then fish paper second. Then with fiberglass third. Then more fiberglass after bms wires are hot glued in place. Then you can shrink wrap if you want after you have charged and tested everything for funtionā¦
Or you can tape then shrink then solder through the shrink for series conections then shrink wrap again with clear so you can see the beautiful sexy porn wiring
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I donāt have kapton so is it okay to do fiberglass, fish, fiberglass, shrink? I do have clear packing tape.
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Packaging tape does like not what kapton does but it looks like it. Not good for heat
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This is excessive in my opinion. Kapton is an electrical insulator. It can also be used structurally, but itās not the best for that. Fish paper is also an electrical insulator, with the added benefit of being abrasion resistant. Fiber tape is purely structural.
From what you say, you are wrapping your p-groups with two electrical insulators and one structural layer. I think the first wrap of kapton is not needed, since the fish paper is already doing that job.
For my batteries, I wrap the p-groups with fish paper, and then kapton over that to hold the fish paper in place.
For your p-groups I would go fishpaper first, then wrap it with fiber tape to hold the fish paper on, and thatās it. Then if you need to tape the p-groups together, you can use more fiber tape.
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I think this is very likely. I would not personally trust a battery pack from china until I had taken it apart and checked the internals myself.
Also youāre much more likely to get fake or low-current cells from there.
Thereās a reason most of us build our own packs or get them from not-china.
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Just curious, I have this semi old 10s3p 30T pack that charged from 32v to 42v in about 2.5hrs, suggesting that it has a capacity of around 7ah. Would this age be of any concern?
What is the question here?
2.5h sounds good or bad, depending on your charging current.
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Yeah Iām with andy, this data doesnt mean squat without knowing your charging current.
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And also, the datasheet capacity of 3Ah/call is with a discharge to 2.5 volts. There is still some capacity between 2.5 and 3.2 volts.
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3a charger, whoops.
9Ah and 3A chargerā¦ 9/3 is 3h charge time plus balancing for a full charge cycle from 25V till 42V.
Disclaimer: thatās just a rough calculation, sure it will be longer due to less charge current to the end of the charge cycle.
Iāll range test the pack, but at 3p 30t it should be closer to 3.5hr charge time.
What was your charge time before?
sounds not too much off for me with 2.5h on a used pack.
I was basing that number on the charge time as it charged too fast for it to be 9ah. The pack is well over a year old.
Sure your pack will lose capacity over time.
If you had quite a lot charge cycles over the time you used it it might be the case that your cells holding less capacity.
I know itās inaccurate to test capacity by charging but that large of a difference signifies that there is some lost capacity.
32v to 42v is not the full voltage range for 9ahā¦so it should be fasterā¦ Iām not sure you can make the inference youāre trying to, maybe your charger runs at 3.3a as an example of just one variable that could be at play
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I guess I was wrong as it got similar range to my 10s3p 30q. I ran the battery down from 4.2v to 3.3v and my 30Q pack had about 1 extra mile of range taking the same route at the same speeds.
can i attach a second bms in parallel
i have a pack (from a friends scooter) where i suspect the bms is dead. can i attach an llt bms to it and see if it then charges through the llt