@scoobiext great thanks for that I’ve just realised after ordering 40pcs of the Samsung 18650-26f that they are only rated to 5A discharge per cell. So that’s not going to work 
I’m thinking is it possible to attach a bms to the zippy lipo packs? Add another 3s pack for 9s and just connect the bms to the balance plug?
@scoobiext How did u wire the 12S BMS with the 10S battery?
G’day Jrocca122
My BMS is a 10S BMS. I’m fairly sure the same company do make a 12s BMS if that is what you are after.
@scoobiext I was only asking because the link you put early in this topic for your BMS is for a 12S BMS, and I accidentally ordered it
Easy fix, how many cells are you using?
@delta_19 i’m making a 10S
Yeah but you ordered a 12s bms. Depending on how many cells you have you can still use it.
@jrocca122 If you are making a 10S and you have a 12s BMS it will still work. Also allows you to upgrade at a later date.
ive explained quite often by now in various threads why I think a bms isnt super important really.
what do you want from your bms?
now, for charging I use my evolve charger, it cuts off at 41V on my 10S packs -> charging by single jack, no overvolt protection required! one off the bms list!
during riding, my battery is protected by the vesc settings. im using 32V soft off, 30V lower threshold, so when my board slows down I know that I hit 32V, then I got a few kilometers until it will be dead! another point off the bms list!
finally: drifting! I was aware and extremely afraid of this effect, I build up my batteries carefully and every pack equal, I have heat protection between vescs and cells but I still was afraid of drifting. the first battery I build was for my evolve carbon, 10S6P. I monitored the parallel packs on my balancer output every 2 weeks. then every 4, then finally just whenever I had the case open for whatever reason. in one year of heavy and daily commutes of 20km, I still had zero drift in the cells.
next was my 10S4P battery of LG HG2 cells. coming from my evolve battery, I just went without a BMS, since high current BMS are actually quite expensive and I wanted to use the 80A of the battery and not cut it down to 40A just because I couldnt find a small and powerfull BMS. so I went without a bms for now and started monitoring again. the battery has come a long way, probably 1500-2000km and just a week ago I hit 40km max range on my tesseract carbon build with a single motor. so the battery is still very healthy and again: ZERO drift of the cells.
and even IF the packs were drifting, there is still a headroom of 0.1V to 4.2V per parallel pack (charged only to 4.1V per cell/pack) since my battery is charged only to 41V and only discharged to 30V.
I started to believe, that if you buy quality cells and if you know exactly whats good and whats bad for lithium chemistries (and of course avoid the bad things), there isnt really a need at all for a bms! however, I would still add the balancer cables so you can check the parallel packs with your multimeter every now and then, just to be sure.
Do you mean series packs drifting? As when two cells are in parallel they will balance out with each other. Series packs will drift over time without being balance charged or without a BMS.
If you buy really good quality cells and they are all the exact same, chances are you can get away with not having a BMS, but after a while it would still be recommended to balance them out by adding a BMS or using a balance charger, or even remove the series connection and put them in parallel and wait a few days for it to balance.
So if i will have a setup like 10S4P based on SAMSUNG INR18650-25R, 2500 mph (decelerated 20A) i need to buy 80A BMS? When it’s like 10S3P = 60A? What about series number, if BMS will be dedicated for 12s, it’s still fine to use it with 10s?
the series number HAS to match the battery you are building but the max amp dis charge does not have to match your max discharge and would be better if it was lower. so you could use a 60A bms on a 10s4p set up no problem but not a 10s4p set up on a 12s bms.
I’m thinking of repacking/rebuilding a Yuneec 7s3p battery to hold 10s2p. Who can I trust to tab my battery?
I’m also looking for advice on 10s BMS. I might just do it myself because the Yuneec battery pack is tight on space.
@delta_19 A fair few BMS’ allow you to setup a battery with a lower cell count than what it is rated for
I’m making a 10S2P battery and have one 36V 10S BMS that can handle 80A discharge. How would I go about wiring the bms to the 20 cells? I’m trying to keep the battery as flat as possible.
You have to write your balance connectors to each pack of series.
Check this for more details. http://www.electric-skateboard.builders/t/connecting-a-bms-quick-guide-how-to/6122
You shouldn’t plan on an 80A discharge current on 2p if you’re running 18650 cells. 18650’s normally output about 20 per cell (40a in 2p) but you should really plan on using it for 10a per cell.
I’d recommend adding another 1 or 2 parallel groups in your pack. Even with a higher discharge pack you’ll probably need a 60A BMS at most, or just bypass the BMS for discharge.
will using the 80A BMS have a negative effect on the cells? I thought that getting a bms that can handle more than the 18650 cells output is fine.
There was a very helpful diagram on that thread, thank you
it’s fine but why spend the extra money and space? if you want a smaller pack getting a lower discharge bms will save space as well