150 Amps on a 72v efoil enough?

efoils – Electric Hydrofoil Surfboards
41

My experience using a smart BMS (ANT or JBD) is that they do work well for short circuit protection. I have purposely shorted a battery, then powered on the battery and BMS detected the fault and cut power immediately. I repeated this test 50 times in a row with the same result. I’m still using the same BMS for testing now 1 year later.

One issue is that when mosfets fail, they can fail shut. Which means if the BMS mosfets fail you are unable to turn off the battery.

For a catastrophic failure during use your VESC would need to fail and cause a short, and then the BMS would need to fail shut.

Adding a fuse does add another layer of protection, but does add two extra join in the electrical system, which adds another failure mode.

1 Like
42

True, but the difference is that I would rather lose power then not being able to stop short circuiting :slight_smile:
What do you think about this?
https://www.aliexpress.com/item/1005005909395769.html?spm=a2g0o.detail.0.0.13bc5vGI5vGI4p&gps-id=pcDetailTopMoreOtherSeller&scm=1007.40050.362094.0&scm_id=1007.40050.362094.0&scm-url=1007.40050.362094.0&pvid=a7bc6339-ceec-4203-b7b8-19001fd781bd&_t=gps-id:pcDetailTopMoreOtherSeller,scm-url:1007.40050.362094.0,pvid:a7bc6339-ceec-4203-b7b8-19001fd781bd,tpp_buckets:668%232846%238108%231977&pdp_npi=4%40dis!EUR!13.03!7.43!!!98.40!!%402101c67a17018628356792162eeb10!12000034807130374!rec!HR!804175018!

It needs a little insulation on terminals and maybe cable gland (or marine silicone).

43

The cheap chinese ones all used to trip @ around 60A, no matter what they were rated for. Search the forum, there were some better quality that worked as supposed to.
200A Midioto fuse works well for me.