I’m building an inverter energy storage solution (think portable powerwall), based on 24v (7s) packs of salvaged 18650 cells. What’s the best BMS out there that won’t break the bank?
Display or bluetooth (or other monitoring) would be nice.
I know and love the Ant smart BMS, I’ve got one in my bike, but I’d like to go cheaper if possible.
That’s called a powerstation 
Do you want de BMS to control charge and discharge or only charge? And how many amps?
Shout-out to @Battery_Mooch for being an amazing new addition to our community, as well as providing wisdom and info for how to make our packs safer. Every time I weld the negative end of a cell, I’m going to think of you 
I want to give a huge thank you to this community for its incredible patience with my noob questions!
I’ve got my eye on a 3KW inverter so I figure I need about 130-150 amps at full tilt.
I don’t actually intend to run 3kw worth of stuff all at once, but I want that extra starting capacity to handle inductive loads.
Probably charge only. If I need discharge control (more than the inverter itself provides), I can make up a current shunt and contactor setup of my own.
If you’ve got the space, and you’re looking for cheap, I’d go with voltage meter/alarms and just balance them manually on occasion.
Is that a @Psychotiller pack? Ahh wait, they used too much nickel to be a tiller pack. That’s negative lead is the worst cold solder joint I’ve ever seen.
Did my ex girlfriend build that pack? Cuz that solder joint is cold as hell
Mboards pack?
What is that yellow sheet stuff? The battery looks like shit but that casing looks neat
Most likely, the do make a 10s4p with those nice square edges, and we know they are hella lazy about construction
It’s a very common casing they do for Chinese batteries for prebuilt boards
It’s lowkey a really nice way of making them 
I mean everything under is a no no but the outsides look 
C R I S P
I totally agree! Makes things nice and square. Electrically insulating. Makes the BMS part of the actual battery block. Aaaaaand it’s an excellent way to hide the shit underneath also
It’s such a shame that 95% of the time that extra volume makes it too big…maybe I just need bigger enclosures lol
And depending how you do it, you might also get a degree of water resistance from it…like an IP54 rating or something like that
I’m about 80% sure its fiberglass. Feels plasticity but bends and breaks fibrous if you snap it.
It does seems to be a pretty decent method of insulating but the way most of these Chinese packs come it’s almost definitely for rigidity.
Any idea how one would get their hands on that stuff?
It’s Verreal 10s4p samsung 30Q.
That yellow stuff if some kind of thin, semi- flexible sheet. Wrapped pack looks beautiful, perfect edges.
What bothers me here most is only one thin nickel layer for battery that could possible output up to 80 amps? And I mean every series connection is made out of that one layer. No wonder battery will sag on higher amps. Anyway, I guess it should be enough for stock Verreal esc?
Also, they wanted to be smart and they installed some fishpaper under balance tabs on negative sides of groups where is not actually needed, but no fishpaper between groups.
Those balance wires, chaos.
