On Sun, 28 Jun 2020 14:13:42 -0400, Paul
wrote:

T i m wrote:
On Sun, 28 Jun 2020 12:38:16 -0400, Paul
wrote:

It operates in its saturated mode (full on), and the losses
are a function of the channel resistance (I^2*R).

https://www.mouser.ca/datasheet/2/38...f55-956481.pdf

Rds-on = 0.018 ohms

At 10 amps, loss = 1.8W, while the load receives 12V*10A = 120W.

Then in the absence of a better alternative, that's part of the deal.

If you were obsessed, you could put ten MOSFETs in parallel :-)

;-)

And perhaps use a series resistor from the 8212, to limit the
peak current into the gates.

A 12V 5W (~.5)A should provide enough wetting current to keep some
relay contacts happy and a latching relay might be a 'simpler'
solution to at least protect the battery from over discharge than
anything then needs actively driving.

It could re designed to re-energise the load with a suitably large
hysteresis, if 'battery care' is important.

I know the controller I have had on the panels in the Workshop for the
last 10 years has a very low parasitic load but not insignificant, if
running a battery that matches the rating of the panel and especially
during the winter months.

The battery feeds some low power flouros (sorta emergency /
convenience lighting) and I have left them on by mistake several
times. 'Luckily', the charge controller has a LVD built in but it
still take a log time to get the battery anything like charged again
to be able to support the lights for any time.

Cheers, T i m