My first pcb: 48v 14S1P 18650 powerwall

Because i bought a 5048MS i had to use a 48v system.

I was going to do a hbpowerwall style system but because i don'd have many cells i wanted a more modular system.

Inspired by jehu's pcbV1 but not happy about the 7s system i was looking for a better solution that would also fit in the

under 22 euro limit for tax customs.

On Fb there is a group calleddiy powerwall - easywith14s2p gerber files and pics,ut i wanted only 1p and a smaller factor.

Searching on the internet i stumble onWeb learning youtube channel and his 7s pcb done on easy eda.

AlsoLeaf Rex yt channel tested many pcb fuses and was very interesting to watch.

A fewmonth later i decided to learn easy eda, so after one week this is what i came um with after several prototypes.


i know i sould have waited for the pro's opinions but i was so exited i had them made and are now in production...



Problems:

If the metal cell holders touch each other heat shrink tube has to be added to avoid shorts

Hey, thanks for the mention, that's my Youtube channel for the cell fuse testing. I'm also the layout/PCB designer of the "Jehu" 7s PCB. I assume you are using the all metal clip type cell holders? I'm sure you've read that they're not ideal for 18650s, especially used since any nick or damage in the cell wrap could short the cell (positive side from the positive terminal to sleeve of the cell which is all negative). Some people have gotten around this by using the full clip for the negative terminal, but only a positive center spring contact for the positive terminal. Anyways I still prefer the full black plastic + leaf spring holders from Blossom (clone)/Keystone that are used for the SMD version of the Jehu PCB. They carry a good deal of current (I use them up to 6A in my cell tester) and are much safer in terms of accidental shorts. I still added silkscreen underneath each cell because one user was using an old version of the PCB which had exposed copper, and inserted a damaged cell which shorted to the exposed copper and caused quite an accident (thankfully no harm to the user or their property, they threw it outside and let the fireworks happen).

i have to confess i only used the metal holders on the design because they are the only holders on easyeda and were useful to align and show how much space was needed, i want to use cell level fusing to hold them like your v1 pcb.
btw on facebook a user said that if i blow a balance fuse the cell stays rogue in the circuit and could be dangerous, what do you think?

Tax limit for the eu was in general 45 euro, but they seem to make there own rules.
Some orders up to 150 euro get free access while others like 33 euro not and you have to pay 26 euro tax....
Mostly with electronics they make a fuss about.
I don't know the precise story but with that 33 euro thing i got 18 euro's back after i payed, and after i made a claim.

CrAzYDr1veR said:

i have to confess i only used the metal holders on the design because they are the only holders on easyeda and were useful to align and show how much space was needed, i want to use cell level fusing to hold them like your v1 pcb.
btw on facebook a user said that if i blow a balance fuse the cell stays rogue in the circuit and could be dangerous, what do you think?

Click to expand...

Yeah that's somewhat true, it would be the unusual instance where a balance connector fuse breaks (breaking current ~6A) but the main PCB fuse doesn't (4A rated fuse from the official kits, not sure the real breaking current though). The other way is true also, if the main fuse breaks but the trace fuses don't, the pack will still provide power through the balancing connector up to 6A or so. Above that, the trace fuses will break also. The fuses are mostly to prevent large failures like a cell shorting or going full open circuit, which would likely break both sets of fuses.