Today, I started the engine off the LiFe house

[Guest 141]

Pretty mundane in terms of events but something I’d been putting off trying for years because I’ve never needed to. And, conveniently “forgot about it”.

I Switched start bank off and emergency on and yanmar started easily. VERY!  Quick return to normal and a check of each bms revealed 27A & 28A respectively max discharge during start. BMS’s are 200A max each for 5s so seems ok. I forgot to clamp the starter lead for the inrush current but bms’s didn’t complain so all must be good.
So I guess this is a green light for installing windlass & hooking to house bank.

Any fried mosfets  from pioneers out there?

 

[Guest 141]

I thought approx 60A was a bit low, but voltage sag would be minimal so is this possible?  1000/13=80A

 

[CarpeDiem 533]

It's not really measurable by us mere mortals.  You'd need calibrated laboratory grade equipment to be able to measure the actual power used.

The issue is the sampling rate across the shunt resistor.  It simply can't read the voltages fast enough to account for the coulombs used during the inrush phase.

I have been running our anchor winch off the Lithium-ion, (through the MOSFET BMS), for a long time now with no problems.  It's a 1000W/124A motor per the Maxwell label.  I observe the shunt meter reading at around 120A, but that's just spinning the winch in the marina with no weight on it, so I guess it's a bit more when it's actually fighting the anchor.

Our starter motor is anything from 1100 to 1400 Watts, depending on which Internet source I choose to believe.  I haven't tried it, but I doubt it would be a problem.