Yes I do
OK great. The most important thing here is the Bluetooth BMS. If you can monitor your voltages, there should be no fuck ups. You need to post as many photos as you can along the way so people here can double check everything over.
If they are really strict, leave the board in the garage.
1 Like
Oh no, I’ve made a whole rack that’s in my room that I got boards on
also lipo bags probably wouldn’t be a bad idea @Red_souls ? for storage before the board is built/if it needs to be left for a while/someone goes on holidays or whatever
What does the bags do?
and @mutantbass if you feel like answering more lipo noob questions I left a couple over in the replies to pictures thread
:joy They are supposed to help incase of a battery fire but really not needed. Dont do anything stupid and you will be fine. All battery fires I have read about come down to user error. They don’t just spontaneously combust. Otherwise, we would hear about these warehouses with thousands of batteries in them catching fire.
1 Like
basically just flame retardant bags, it’s allegedly best practice to charge them in the bags because charging is when an issue might turn into a fire, and to store them there for medium-longterm if they’re not in use
Isn’t that what the BMS does, has a limit on battery charge so they don’t overheat?
yeah the issue is more if you fuck up a battery in use, don’t realise, and then charge it it can let the magic smoke out. But as I said, lipo noob so I’ll defer to them probably not being necessary
Over charge I mean
yeah a BMS prevents you from causing an electrical problem (most of the time anyway) by controlling the electrical conditions like charge and discharge levels. If you don’t overcharge or short the terminals you’re probably not gonna start a fire. A flame retardant bag is a safety measure in case all that doesn’t work and a fire does start regardless, it contains it better and makes it less catastrophic.
But would make it overheat faster cuz it’s incased
You wont have room in your encosure anyways.
technically yes but charging doesn’t generate dangerous levels of heat unless you’ve already done something very wrong. Like a difference between 25C and 30C isn’t gonna kill the pack
Agreed.
Many people don’t use a BMS too but that would never make it a good idea IMO. 
I would suspect that they are using a significantly more reliable BMS than any of us would though and use cells of known grade and condition, lowering the risks of cell failure.
Excellent.
IMO we can’t apply anyone’s individual testing to all cells. There are too many variables. I agree that LFP cells are a lot less susceptible to runaway, and the reactions a lot less violent, than other cell chemistries but it is still a pretty big risk to seal off a cell’s venting disk. This can significantly increase the pressure the cell bursts at and also force side wall ruptures which can raise the odds that other cells could be forced into thermal runaway.
We definitely all can choose what level of risk to take but I’m always worried about when we say that it’s okay to do because some related thing someone else did hasn’t blown up yet.
Potting does make for one hell of a durable pack though!
1 Like
oh yeah I meant like for the garage, not in the enclosure. Sorry didn’t specify
How would I figure a discharge rate for the lipos so they don’t exceed that while charging and riding it without problems
So lipo manufacturers specify the charge and discharge capabilities as a C rate, where 1C for a 2Ah pack is 2A. Your pack claims a 30C discharge on a 4.5Ah pack, so theoretically that would be 135A but that’s nonsense. They usually make continuous and peak discharge claims, but even the continuous ones are not reliable.
I’ll let one of the others give a better guideline for what the real number, but I’ve heard ~1/3 of the stated manufacturer number. That’s still 45A, pretty damn good for a cheap pack, but I’m not very confident in that number. Go through that thread Mutant linked way above, there’s some good resources on voltage sag (basically how much the pack struggles to keep up with high current draw), and I think some on other bits like how much heat gets generated or how much heat is ok. Even if it’s not all in that, it’s a good starting point
Would I find that In the description of the lipos