ZHIYU 60w Load - over temperature?

[Aragorn_84]

Hi folks,

A while back i bought one of the ubiquitous aliexpress/ebay "60w electronic loads", i believe going under the ZHIYU brand.

I've not used it much, until now mostly for testing 18650's and so running at fairly low power.

However i'm having a clear out/tidy up and decided to load test a bunch of 12v leisure batteries that i've got stashed in the shed. I know some of them are pretty knackered, so i figured i'd fully charge them all, capacity test them and keep the good ones and get shot of the junk.

Set up the load tester and almost immediately ran into thermal issues. Initially i started at full power, 5A, 11v cutoff in "FUN2" mode. It auto-limited itself to about 4.65A due to the battery voltage, which was fine. Except it only ran for about 2-3 minutes then shut down with "Otp" on the display.

Cranked it down to 3A and tried again, same thing, just took a bit longer. Maybe 10 minutes.

Took it down to 2A and it finally worked and got thru a load test on a fully charged 60AH battery. Ofcourse at 2A this takes quite a while.

I've checked some reviews of this unit and none seem to mention such poor thermals. Has anyone experienced this? Is it potentially a fault? Maybe i can modify it with a much larger heatsink?

Any advice greatly appreciated.

[tunk]

Does the fan turn on?
Faulty or wrong temp sensor?

[Aragorn_84]

Yep the fan runs, and cranks itself up in RPM when the load is applied.

I guess i need to check the temperature of the MOSFET and see if its a temp sensor issue or if it really is hitting 100c.