BMS questions - aluminium heatsink necessary?

ESK8 Electronics
1

Hey I’m going to keep this short…

The BMS from the group buy was massive so today I decided to dissect my battery pack. The main reason was to move the BMS in a different position and away from the battery because the BMS was so thick

But in moving and cable managing the BMS i accidentally pulled the switch out. So I decided to open up the BMS up unscrewong the metal plates that enclosed both sides of the BMS so I could solder the switch back on.

And I thought a couple of things

Is it important for me to put the enclosure back on? Does it act like a heat sink, i presume so since there’s thermal paste where the MOSFETs to

1491437781530225665932.jpg1840×3280 1.38 MB
14914378056941807794409.jpg1840×3280 1.43 MB

It will be great considering how thick the BMS with the casing and how thin it is without it

Ok thanks for reading and hopefully we can get some answers since everyone in the gb has had comments on the large bms

1491437522702257561652.jpg1840×3280 1.71 MB

2

Yeah if they put paste on it, it has to be a heat sink. How does the 2mm of aluminum make so much of a difference for you?

3

if you only used the bms for charging and not discharging I think it would greatly reduce the current it would see and then maybe you wouldn’t need it.
2mm is the world to me

4

I’m sure it makes a difference to a lot of people, for me not yet since i haven’t built a board yet

5

Well if 2mm is really an issue in your case, how about cutting out part of the bottom part of your enclosure, replacing with aluminum, and screw the bms to that piece of alu. Reduced total thickness, and the cooling of the BMS greatly improved because you now have forced convection from the bottom.

I may once do this for both the BMS and VESCs.

6

It’s like 1.5cm thick with the casing

7

Makes sense to me to do it that way too,cut what i need and mount

8

I pulled my group buy pack apart too. However I dumped the BMS and used a BesTech that I got from @Namasaki (thanks brother). The thing was just so massive that I was going to need a 2in deep enclosure by the time I padded the pack. I am using a 1.25in deep enclosure without it, and still have room.

1 Like
9

I’m going to do so said balance box. My enclosure is only 23mm deep so i will put that BMS in separate case and go without. When i want balance my battery i just plug it between charger and battery.

10

I did the drop down heat sink on my VESC’s today and currently looking around for BMS solutions as I’m tight on space and don’t want to drop down a third heat sink. I think I’ll simply grind down the one I have…what I did today is on my build thread. if you’re still looking at solutions.

11

IMG_3214.jpg3264×2448 1010 KB

This is what I ended up doing to the BMS… I have a fair amount of space (comparable) to work with but it wasn’t enough to fit the heat sink in at full size. So I cut the fins down lower and almost all the way off at the sides… when placed in the box this gives enough room for me to run wire over it (filed and sanded all edges to insure cables won’t get cut over time) and I can fit xt60s on either sid… I used some thermal paste on the chips and heat shrink to hold the thing down. I would have used a larger piece of heat shrink and then cut it back after instead of but this works well it doesn’t move unless I apply quite a bit of pressure