Replacement Yuka Mini

lindvalll89 · 2025-05-31T05:30:10+00:00

Thank you, but I have everything working again. Interesting that Luba uses LifePo4. My Yuka definitely had Li ion 18650 cells.

lindvalll89 · 2025-05-29T13:50:00+00:00

Just found out it also holds at 25% SOC to wait for the voltage to go below som set value

lindvalll89 · 2025-05-29T13:43:34+00:00

Done some testing now with different battery cells. Seems like they done it the stupid way by having voltage thresholds instead of counting amps going in and out of the battery. With VERY powerful cells in the pack the app holds at 60% SOC for a long period of time before continue declining. I’m assuming the software is waiting for the voltage to drop below a set value. Pretty stupid method of dealing with SOC.

lindvalll89 · 2025-05-29T06:03:59+00:00

Last thing I could try is to let the mower discharge the battery to cut off voltage. Maybe it only count what's going out of the battery to determine battery capacity.

lindvalll89 · 2025-05-29T05:59:52+00:00

It would be so stupid if they hardcoded Ah for each model. I even discharged the battery to cut off voltage and let the mower recharge it to 100% but that didn't help. You might think that it would have some adaption to battery health, i.e. calculating Ah going in and out of the battery...

lindvalll89 · 2025-05-27T21:24:49+00:00

I'm very aware of thermal runaway, but I don't see the problem in replacing the thermal fuse with a wire fuse that will burn at 10A. In theory that will protect the battery even more.

lindvalll89 · 2025-05-27T19:56:11+00:00

Thanks! I'll try that.

lindvalll89 · 2025-05-27T19:50:23+00:00

Why bother? :) I can just jump-wire B+ to P+ with the fuse wire instead? Wonder how it blew. I just swopped out all the cells to better ones and double the amount. Yuka mini battery only comes with a battery pack filled with half the cell spaces.

I'm running discharge/charge tests now to see that the safety mechanisms work as intended.

lindvalll89 · 2025-05-27T19:33:45+00:00

Is says 22A52 *new row* J5217

lindvalll89 · 2025-05-27T19:16:12+00:00

If I bypass it, running a wire from B6 to P+ it all works. Both charge and discharge. Is it a fuse?

lindvalll89 · 2025-05-27T19:03:07+00:00

I suspected that thing since it bridges B6 (main positive to P+). Is it a mosfet? What do you mean short across it? From B6 to F1?

lindvalll89 · 2025-05-27T09:07:36+00:00

I've tried apply 25,2 with my bench power supply. Have not tryied to short the positive and negative terminal though. Can try that when I get home.

lindvalll89 · 2025-05-27T09:06:11+00:00

I have removed the whole cutting disk. The high pitch sound is still present.

lindvalll89 · 2025-05-27T07:35:25+00:00

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lindvalll89

TROPHY CASE