The battery builders club

How-Tos & Esk8 mechanics
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#18458

It’s okay until one of your cells goes into thermal runaway. Then you have a bomb if hard potted. If flexibly potted then the jet of flame could come out anywhere and maybe send some potting chunks (possibly flaming) flying.

The chances of that happening are verrrry low but the consequences are quite severe if it does. Best to leave the top vent, and bottom vent if there, out in the open…just in case.

IIRC there is a fully potted commercial pack (e-bike?) being sold but if that’s true IMO that is an insane practice.

3 Likes
#18459

I’ve heard it’s really strong. Is there a specific place to get the good stuff?

1 Like
#18460

Yeah it’s listed on amazon

I have these, someone bought a box before and reshipped them to people

#18461

Nice, will keep an eye, really weird, but checks out by having lower capacity, when charging it gets above the others

I might test each p group for capacity, what could have happened is one group has a bad weld and is 4P instead of 5P, I would say high unlikely, I guess the difference would be even bigger in that case.

What sucks is that my balance changer can only discharge at 1 A, so more than a week to check each group

1 Like
#18462

WowGo AT2 has a nearly fully potted pack.

1 Like
#18463

Thanks. Found a video that showed the potting. Looked like the cells were immersed in it though?

#18464

I believe so. I haven’t opened mine up yet (they sent me one), but I’m going to ask them for an empty enclosure so I can ultimately redo it.

I imagine it’s for water resistance, but I’m not a fan.

1 Like
#18465

image

2 Likes
#18466

Well then its fucked, thats a dead giveaway. Mine didn’t do that, it was just lagging behind a bit.

1 Like
#18467

20211101_105735
20211101_1057351920×2560 575 KB

20211101_104943
20211101_1049431920×2560 383 KB

20211101_104730
20211101_1047301920×1440 170 KB

Anybody ever come across this bms before, and know where I can acquire?

2 Likes
#18468

looks like this one

1 Like
#18469

Haha nice it does look exactly like that.

I found this one

AU $389.00 | 16S Li ion battery battery BMS with 50A constant discharge current for 67.2V or 60V PCB Lithium ion Battery Pack

2 Likes
#18470

just 2 mins of aliexpress search lol

why the heck do you need 10pcs of this bms? xD

1 Like
#18471

Local scooter distributor is having issues with batteries. I think i have just realised why.

The heatsink has been removed and there is no way for the mosfets to shed heat except open air

3 Likes
#18472

yeah when running anything close to 50A battery, these fets will get toasty in no time. These already are low quality fets. They need the cooling

1 Like
#18473

It all makes sense now! This is an excellent revelation.

3 Likes
#18474

Has anyone a link for a 8S BMS? From Daly I can only find 8S BMS for LiFePo cells. Amp rating as small as possible, will be charge only.

#18475

If you contact them, they should be able to get you a lipo one.

#18476

Where would I contact them? On AliExpress?

1 Like
#18477

Yep you can message them on AliExpress, or on Alibaba, or you can talk to @dickyho and see if he can set you up.

1 Like