Does anyone have any info of the SONY US21700VC7 5000mAh 12A cells?
Well. That is not very usefulā¦
I am trying to cancel my order with them.
Do any of theirs do balancing that you could tell? I thought this one didā¦ But it is not really clearā¦
I would disagree with that. I have run my battery without balancing for about a year. Nothing got significantly out of balance. Then one of my P-groups started drifting. It turned out that one of the welds got loose, which effectively made the group a 4P instead of 5P. Balancing wouldnāt have helped here. In fact, it would have probably made things worse.
Li-ion cells normally donāt get out of balance a lot. Slight drifting merely causes that some cells wonāt be charged to full because others will reach the full charge earlier at which point the BMS disables the charge. Thatās not a big issue. You just loose a little of bit range and you should get slightly better battery lifetime in return.
Being able to monitor cell voltages is much more important than balancing. Helps you identify problems early. Smart BMSes all the way.
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It says that it does? Are they lying? Good excuse to get your money back if they are Raf.
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Well. It is not clear to me. I assumed they did. But I struggle with the specifications. On the data sheet on balance they just have /. What does that meanā¦
Same port. You can order direct from aliexpress too
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https://forum.esk8.news/t/the-battery-builders-club/720/3131?u=bwahl602
Anyone with one of these constant current dc load testers able to chime in on this issue Iām having?
Seems like you may have a faulty unit. Has it worked prior to now ?
Nope, always trying to draw. Seems like it.
If I plus a 5V 1a adapter to a usb mini and plug it in, it reads about 1V and 1amp. Knobs do nothing. Batteries it just yanks 10a and 0.97 V from. Weird
Iāve blown 2 of these up but it was my fault both times. One time is was because I plugged power supply into wrong 2.1mm jack 
and the other because I pumped too much juice on a 13s pack. But the issues you are having seem like there is either a short or something terribly wrong with the trim knobs. Iād just exchange it if possible
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They copy pasted that from another page or something. Look at the spec sheet, balancing voltage and current just has slashes through them. On the PCB it is also missing balancing resistor and transistors, only detection.
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I looked through a bunch of their data sheets and the ones I saw seem to have the slash on the balance line.
So annoying.
I canāt ever just clearly find the right stuff to buyā¦
Wish all esk8 parts were on Amazon primeā¦
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I fully agree being able to monitor cell voltages is the best way, I prefer to see a list of my P groups, and occasionally I take a volt meter and check them manually. BUT, imo, keeping the pack in perfect balance is the most important job of the BMS. I would run no BMS if I just wanted to let the pack be. I donāt see the point to charge only when the charger should be doing the cutoff. I will only run bypass with a variable top voltage charger (to get 80% charges if I feel like it), and BMS to keep my groups perfectly balanced.
On the little 12s3p pack I just build as my first battery adventure I got a smart bms with Bluetooth. It is really freaking cool to see what is going on. But it is freaking giantā¦
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It really doesnāt have to be. Evolve boards transmits P group voltages to the remote, including separate motor rpms, even sends battery error if one group drops voltage too low. And their BMS is relatively compact. In fact about the surface area of a d140 but thinner and longer. Itās just a matter of someone making one. Think theres a couple good ones coming out this year that is not gigantic.
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The charger assumes the cells are in balance, which may not be the case, at which point it may overcharge one or more P-groups. In case of a significant imbalance (e.g. you have a faulty P-group), this can lead to major damage including fire. The main reason for having the BMS is not to get the cells perfectly balanced but to prevent cell overcharge.
Some people may live under the impression (and I did, too, for a long time) that if the BMS balances the cells, thereās no need for it to be able to cut the charge. Thatās wrong though. Unless you charge very slowly, typical BMS wonāt be able to bleed the cells as fast as the charger is charging them and wonāt be able to prevent the overcharge just by balancing. Therefore itās critical for the BMS to be able to cut off the charge. This is the most important BMS feature.
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I think you are way over the rated voltage, all consideration of watts aside. I think peak voltage is like 24v.
10s?!
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Spec sheet says max 200V
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Ive had success with these on a couple of 12s packs. Although it took all day to drain them. Couldnāt go over 3A pretty much
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