Got mine from IMRbatteries
1 Like
Another question for you guys who could help. I am building a 12s6p battery, but I have batterys at 2 diffrent voltage levels, what are some things that I should consider before hooking everything up? I am also using N.E.S.E. modules for all this. Can I simply connect my p groups after ri have everything assembled and then let the BMS sort out the voltage levels? Or am I not understanding how this works. Appriciate the help.
If the difference is more than 0.2V you need a very good bms to be able to balance the packs out after.
I would suggest to get something like this
https://s.click.aliexpress.com/e/cP4Kpp26
And manually bring the cells up to nearly the same voltage. The closer the better.
Easiest way would be to just fully charge all cells, but I don’t like to build a pack with fully charged cells, because if something goes wrong it can go south pretty bad.
With the charger i linked you can also discharge the cells, so if you keep an eye on it it should be easy to discharge the cells with higher voltage to the same voltage as the rest.
5 Likes
Thank you! I will obtain this device!
I‘m sure you can get something similar somewhere close to you in an electronic store or from amazon without the long wait. Link was just an example, doesn’t need to be the same 
1 Like
Slowly coming along.
I’ve got 2 glitches to solve. I know this is some serious nerd talk, but there are some serious nerds here. 
- sometimes I get cell5 or cell6 with voltage > 40v or < 1v. Have to trap and throw those scans out
- sometimes the bluetooth stack locks up, and I have to
sysctl restart bluetooth.service. I can have the scan script do that, maybe with a sudo rule - one time, I think a glitch caused the bms to stay in some higher drain state. Resetting bluetooth on the pi and rescanning fixed the drain.
I’m sending to influxdb running via docker on the pi. Grafana does the graphing, and is also pi/docker. Docker on pi seems good, as it’s like a one liner to make it work, and this way the data backend can easily run on some virtual host in teh interwebs instead of the pi. Grafana can send alerts, which is the real goal.
I have a few improvements to make, and I need to package everything nicely, probably moving the scanner itself into a docker container.
The scan does use some power, as you can see in the graphs. I’m scanning at 1hr interval to generate some graph data, but once a day should be good for normal use. And yes this board has not been ridden in some time.
I’ll make a thread when things are all nice and neat.
6 Likes
@deucesdown Not sure if I’m misunderstanding. You made a sniffer for voltage readings off other devices? If so, damn daniel
Yeah the smart bms units with bluetooth. I had a moment. pi have bluetooth, bms have bluetooth, someone reversed the protocol already. I have multiple boards with smart bms and it’s annoying checking in with the phone app once a month.
5 Likes
Sweet. Could it sniff on the go? Could be fun to go on a ride with friends and be like " okay you have 47v left, you 46.7, and you 48. You guys ready for another round?"
Lol for sure. You can do this with the phone app already – the bms will talk to any app if it’s not already already talking to one.
For me, I noticed these bms have some passive drain, so I wanted to quantify that drain, and I want a “yo charge your shit” alert.
2 Likes
But your take on this would allow to grab multiple signals simultaneously rather than connect to one, check, disconnect and repeat
1 Like
If I only had phone app skillz.
1 Like
12s13p to go in a top box on a mountain board… any ideas for insulation between p groups? Ive got adhesive fish paper but it doesnt hold real well to the curves of the battery.
Was hoping to silicone the whole pack together honeycomb layout
7 Likes
Wow lotta cells.
First thing that comes to mind is plastic cell holders, maybe 3d printed. But they’re glued already. Next thing that comes to mind is thin abs sheet. You can cut the abs sheets to match subpack size, and glue. Kinda like the PCBs.
1 Like
Woah damn you beat the new LaCroix’s battery in capacity 
1 Like
It is quite a tight fit, JUST enough room. Not @deckoz level of mad scientist on Master Evo, but tight.
I am curious if the Unity will handle it. And if not, what will fail first.
My guess would be the switch.
5 Likes
Good shit. Let us know how it goes!
2 Likes
Is this the one going on the collab deck?
2 Likes