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williamwright williamwright is offline
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Default Regarding charging (batteries, not customers)

On 26/04/2021 15:43, Dave Plowman (News) wrote:
IMHO. 14.6v is far too high a voltage to float a 12v battery at. But if
this was accurate, I'd expect more than 30mA to be flowing.

The voltage readings come direct from the battery, rather than from a
point on the general circuit. I think that voltmeter might be reading a
bit high actually. They all read very high in winter when the van isn't
in use. I put this down to damp across the the very high value resistors
in the PD networks. So that might still be a factor.

Incidentally a late addition was a relay that links the two 24V supplies
when the 24V microwave oven is in use. This was to reduce the discharge
rate from the circuit A pair of batteries. The micro is connected
directly to Battery A because its current draw far exceeds what the
ammeters could cope with. So when the micro is in use Battery A shows a
charge of about 10A and Battery B shows a corresponding discharge. It's
interesting that the wiring and relay resistance of the link means that
Battery B only contributes 10A whilst Battery A (very thick short wires
direct to the micro) contributes 30A. I didn't think it was worthwhile
to improve this because it would mean moving Batteries B from the back
of the van to the middle.