Mike's Li-SAVER

[kulangflow]

Sure enough! I just got my EagleTree data and every time it hits 60 amps or greater, the voltage drops to 12V or below. To be a little fair though, they weren't freshly charged this time. They started at 3.9V/cell.

The peak current was 130A and that dropped the voltage to 9.1V. Yikes.

I have 4 total 2s 6K MaxAmps packs, so I'll have to test a few more combinations of them to see if I can narrow down one of them that might be causing the problem.

For this graph, I just averaged the voltages for everything under 110A.

[jhautz]

That'l do it. Glad to see you at least identified the problem.

I dont know if you have room, but try running 2 of those packs in parallel just to verify that a battery that holds voltage better solves the problem.

I think the reason the MM doesnt kick out is CC put a timer on the LVC in the MM. It needs to stay below the cut off voltage for a few seconds before it cuts out.

[kulangflow]

Good call. I'll give that a shot. Thanks again for your help.

[jhautz]

BTW... That really sucks that those lipos drop voltage that badly. I would be writing a letter or calling MaxAmps and looking for a refund if they were mine. a 20C battery should stay well above 3.0v at the 20c load. That isnt even constant, its just burst. the 6000mah pack at 20C should stay above 3.0v at the 120A load you showed. 2.3v/cell is useles at 20c draw.

Hell... Those arent even good numbers for a 10c cell.

[kulangflow]

I'm going to keep somewhat of a running diary here.

So, I have 4 total 2s 6k MaxAmps packs. Let's call them A, B, C, and D.

Last night's test was with packs A and B, but they weren't fully charged.

I did a 10 minute run with the A and C combo just now (fully charged). They hit the LVC at 80A or above.

Interesting observation is that pack C was 99F while A was only 85F. Motor was 113F and BK9920 was 105F.

My next test will be with packs B and D.

[kulangflow]

Another update.

Another 10 minute run with packs B and C fully charged.

The combo hit the LVC at 70A and above.

Both packs were 95F. Motor was 116F and ESC was 105F.

At 157A the pack hit 8.82V.



And here's both runs next to each other with a bit of smoothing: