That is considerably more difficult with some chips than others.
Using two separate 16S controller setups in one pack, and handling all that in software, adds up to a chunk of extra work too.
A BMS of any s-count is, of course, possible. My post was only to suggest that it’s not as simple as just tossing another chip on the board and we’re ready to go. As you mentioned, just adding CAN is a three month effort.
With you being confident about an 18S+ solution though I look forward to you hopefully bringing it quickly to market!
Assuming 15A is “absolute max” and there is significant heat nearing that limit, i would say it’s quite low. We’re slowly progressing towards chargers that can output the full 2000W limit from the wall into the pack. Won’t happen within a year, but that is roughly 35A accounting for losses. 30A charging isn’t uncommon already, and ltt smart bms has the 30A version most commonly sold.
What i’m suggesting is to double that 15A, even if it means bigger pcb. Also thermal design is important! 95°C parts boiling in the battery pack = no good
Something something the balancing chip is limited to that and there isn’t much out there that can do more. Alternative is 2 chips and 32S but that complicates things. Just saying what i read on another bms thread on this forum.
CAN is good enough imo. Most people have a bluetooth dongle for their ESC already. If the BMS can relay cell voltage info via CAN, then people have all they need imo I’d happily pay 15$ extra for that.
This is really cool nonetheless! Being able to program a cheap, non-smart BMS to the user’s liking seems really valuable.
Looks very interesting, i’ve been looking for a BMS for my builds, some other BMS build on the STM32 are not available and probably won’t be for sometime because of a IC shortage(maybe, it would seem)
Be nice to have a feature just to monitor each cell, and just balance charge?
I don’t use a bms and just balance charge only, like lots of people here.
I’d be interested if it was low cost
IMHO, 15 amps is more than enough for the average rider. What I consider important for myself, small, vesc compatible BMS, cell monitoring, 18s or more. Trampa is about to release () a 18s BMS and Flexibms another 18s.
Fancy features cost money, and @SimosMCmuffin must be compensated for his work, imo the price is just right for what you get.
Other stuff comparable on the market is almost double the price, and not halfway made to work with vescs and metr for example. Plus his support is above and beyond.
I’m sure that if @x-bms makes a “smart” bms it will be in the similar price range, or that he will work hundreds of hours for free
He must use similar components to achieve a similar result, and the cost should be roughly the same in bom I guess
I’m happy to pay more for the features and also have a cheaper option. I tend to put the more feature packed units in my personal builds, but when I give someone for whom I’m building the options, they tend to not want to pay as much.
Granted, I don’t build as many packs as most of the builders here who take clients, but so far I haven’t incurred the kind of situation where I couldn’t diagnose an issue and fix it. Granted, all my builds are local, but either way.
I’m really just saying that I’m happy to patron the various offerings here. I have a FlexiBMS for my fancy build, two ENNOID 18S Lites that are going into Onewheels, and several Daly BMS units that go into other eskates. I appreciate their strengths and values they offer.
I never said that it’s not fair that Simo gots money for his awsome work, but 70 bucks + 20 of shipping to the other side of the world is already a serious amount of money that isn’t spent in more “fun” parts
If @op says he could make something maybe less smart and fancy but for half the price, i’m sold.
It won’t replace the flexy that is on my “fancy build” but it will def replace the two aliexpress bms i have in kg other boards
I’d happily pay 15$ extra for that.
) a 18s BMS and Flexibms another 18s.