@dzubot contacted me via PM, which is totally fine, but I prefer to give the answer here, so that others can profit from it as well.
I plan to build an 18650 pack now as I already have the same 300 amp bms you bought. Are you happy with the BMS?
It took me a while to figure out what is important.
You definitely need to use the App (with an android based smartphone, I think) to configure the BMS.
You need to set the amount of cells you have (13S in my case) and you need to reconfigure high and low voltages, at what voltage the individual cell is considered full - and at what voltage the battery is considered empty. For the LG HG2 this is 4,2V full and 2,5V empty.
I also had to reset the max amp to 360A instead of 300A - the BMS is only rated for 300A, but I haven’t had any trouble going full throttle for a couple of minutes, which definitely draws more than the 300A for which the BMS is rated.
What is really great, I don’t have to fiddle with the sparking or arcing with those switches. I just left them out, as a simple push of a button turns the battery on and off.
Happy with the LG HG2 cells? They are on sale now at IMRbatteries.com.
I don’t have any experience with batteries. I just did the math and found out, that for a minimum amount of cells (13S15P, which I later extended to 13S20P), the LG HG2 were the only ones that would have the correct technical specifications (Amp Draw). I purchased the cells for under 5 dollars directly in Asia. voltaplex.com or batterybro.com - they ship via UPS and DDP (delivered, duty paid).
I’m thinking either 14s18p or 14s20p battery, what are your thoughts?
when I decided to go for 13S15P only very little information and virtually no experience was available from the community - Today I know that the ESCs and motors would also support 14S. If I would build another battery, it would probably be a 14S - but 13S works as well.
Oh and i’ll be using a prototype vruzend connector
I looked at those back then, but decided that they would not support the amp draw.
Also the price was an issue - the price for a vruzend kit was about the same as for the spot welder plus nickel strips. The soldered connection is also better for higher amps, as “soldered connections” are really tight and good.
I don’t know about the new prototype, that you mentioned. I guess you just need to decide for yourself.
Any tips would be appreciated since you’ve gone through this process. Would you change anything, different cells etc?
I would still go for the high quality cells LG HG2, even though I would probably go for 14S, 20P or even 25P, which means there’s less stress for each individual cell.
The fans that I added are not really needed, the way I designed the case, the cells are very well ventilated even without the fans.
I would probably also go a different route for a case, the 600 Euros for the aluminum case are really killing it. With a little more time I would probably have been able to design a similar case made out of custom bent aluminum sheets or so…
I had a huge voltage drop on the battery from veconcepts, like 8v drop i’m assuming this is because they used cheap cells.
I don’t know, I am not experienced enough.
what I noticed is that after I added another 5 parallel groups (15 to 20p) the voltage drop wasn’t so significant anymore.
Curious where you got your cells and what price?
voltaplex/batterybro around 4.50 dollars plus shipping
Do you notice much heat on your 7mm connectors from battery to the openppg?
the connectors that I used are rated for 160A per pair, so I used 4 x 8AWG wire and 4 connectors (2 per terminal obviously - you can see that on my photos that I posted here:
Heat is no problem at all on the wires or connectors. Probably because everything is so well ventilated.
If I would build the battery again, I would probably search for different connectors - the anderson plug that you have from that veconcepts battery looks very solid, and probably much easier to connect to the cables then those RC Pro Plugs that I used…
How does the Bluetooth connection work to your bms through your battery box, is it solid?
No complaints on the bluetooth connection - the only problem I had when monitoring the cell voltages and temperature is that my phone kept switching off, and I was too lazy to find and change the appropriate settings. When you’re in the air, it’s a bit difficult to push the “on” button and enter the pin code 