fuzzy guestimates:
31Ah 1C = 31A
so… you’re charging at 0.11C @ 4A 1C = 36A
take the min 31A.
so… run 0.5C =15.5A
so you’re fuzzy math probably maybe good on batteries taking more charge. can still cut it in half one more time and targbet 8A.
but… going above 4A your concern is probably charge wiring, and ports.
I’m about to get a FLIPSKY FS-SW1 Spot Welde to make my battery. is this Lipo:Turnigy Rapid 5500mAh 3S2P 140C Hardcase a good choice to welde 0.15mm pure nickel?
In summary he says:
use big brand name cells and fires are often caused by defective cells.
Don’t use lipo
Fairly new, full feature set, but TI and AD also have several chips that should be closely compared to this one before choosing IMO. It’s the tiny details that make one chip or another a better choice for a particular application.
I’ve had some decent wire from AliExpress and bad from a place in the Uk which was unexpected, the insulation was thick on one side and thin on the other.
ProgressiveRC is pretty cheap I would shop from them if I were in the US.
Thanks! That looks like a good site, will check it out
I have a battery conundrum.
I lent a buddy my Vesced Pint X and he let the battery drain below the level it would charge.
This is a stock Pint X battery with the BMS bypassed.
15S2P I forget what cells - 18650…
I got it back today and spun the tire with the electric bike and the Vesc turned on.
And it was at 25 volts.
So down to about 1.6 volts.
Maybe less… Eh
I spun it some more and it came up to 32, and then 35,
And then I plugged in the charger.
Quite fast it came up to 44 on the charger.
I decided to unplug it…
Am I ok to charge this up?
Or is it a Bomb and it’s time to take the battery out?
@rafaelinmissouri Check the balance on the cells. If they are balanced then technically speaking you’ll be okay.
But if they got below 2v, and especially being as it charged quick, you will lose all your capacity. So they will charge and balance but not do much more than that.
My bet is if you rode it you’ll get down the road and it’ll tell you no more
I would pull it out and put a new one in if it were me, you could do a load test but that’s kinda gettin to the picky side of things.
If you can’t check balance I would toss it. Definitely not something to mess with then imo
How long did it sit at that low voltage?
Possibly a couple weeks…
I also don’t know quite how low it got.
25volts was when I had already spun it andn charged it some.
I decided it’s going in the trash…
It went from 43v down to 40 over night…
I ordered stuff to make a 20S1P P45B pack to stick in here…
Got it open today…not much to it but a bunch of shrink…don’t know what I was expecting.
At least I now know it’s a 16s12p. The pack has the decency of telling you they’re using 2600mah cells.
On another note, the ESC has a hunka chunk of a thermal pad on it leading the heat towards … A plastic floorboard
If it’s 2600mah and It says 31.2ah so that means 12p. Someone correct me if im off here but this is my current thought process.
2600mah cells do 2.6a at 1c but they are generic unknown so i wouldn’t feel (personally) comfortable doing that and .5c is where i would go first. There is no airflow or cooling at all and it’s a pretty dense configuration of cells. Thats 1.3a a cell x 12 so 15 and some change. This is assuming the bms in there is ok with that.
That’s 900w of charging and some of that will turn to heat as it charges so do your due diligence and monitor and have an exit strategy bla bla bla be safe and all that cuz we like you 
. It’s harder to find a circuit that will support that so be aware of where you are plugging that in. If it is on the same circuit as a high load device like kitchen equipment or a heater/ ac it will pop the breaker.
That pack is about 1800wh so 15a is about a 2-3 hour charger ( some extra time on the top and bottom of the cycle to do its ca/cv thing). That’s still a little fast for most of my home charging and I would personally only charge at around 10a (600w) because I don’t have a dedicated outlet where i charge my pevs. I charge at 250w to 80% when im not in a hurry because my bms settings just hit the balancing start threshold at that point and i like to make sure everything gets the time it needs to keep everything at a .025v delta
Save that stock balance connector/wiring. I’m building a quart pack right now and crimping those small ass connectors is a nightmare. I wish I could find one preassembled.
How hot can ion cells get before they degrade?
I’m about to pour expanding polyurethane foam on a battery to make it a solid block for safety but worried the heat from the curing could damage the cells.
Ironic going under 2v seems acceptable with those who told me I was a hazard for talking about it
It depends and different manufacturers say different minimum voltage they can be resuscitated from
i read the curing process can reach up to 170deg F. why not cut foam blocks to form
Easier just to pour it in and would get a better result with a harder foam that is stiff and nothing can move. It’s like potting in resin but lighter
arent u worried about it being completely unserviceable
I checked the voltages after they sat around two months n all looked good. I assume the best. I’ve never serviced a battery other than some beat up lipo long ago. It’s pretty easy to cut into the foam with a ceramic knife if I did need to replace a cell. But getting it all apart, and having to probably take a lot apart, sounds like an awful experience.
