Following the suggestion here that the charging voltage for Circuit C was too high ("C: 14.6V, +0.01A") I checked with an accurate meter. The voltage was 13.86V. That accords with the very low residual charge rate. As I suspected, the van's voltmeter is reading a bit high.
Bill
williamwright pretended :
My caravans limited range analogue voltmeter is in the panel, by the door - some way from the battery. It's reasonably accurate for an analogue, but the daft part is that they have shared it's supply with everything else - it measures across the main feed. Absolutely anything you turn on, will cause voltage drop and the reading to decline drastically. The only way to get a true reading, is with the main isolator on, the rest of the isolators off and use a torch in the dark to read it.
That's still high for a float charge. Should be more like 13v.
But the charge rate is 0.01A
Bill
That suggests the battery is fully charged and the current is there to offset the self-discharge current.
Assuming the ammeter is as good as the voltmeter? ;-)
13.8v is a nominal fully charged lead acid battery. I have one or two PSUs kicking around that output that voltage for powering kits that is designed for lead acid accumulators from the mains.
It probably is a bit on the high side for a float charge. A silicon diode in series and a 1k resistor in parallel might help.
13.8v is the standard for a car, engine running. So tends to be the output of a PS designed to be used with things like a car radio, etc. A fully charged battery, left to settle, is under 13v.
For most people, car engines don't run for much of the time. They do need to top up the starter drain reliably, it's not really a float charge regime.
Quite. A car is unlikely to run continuously for more than a few hours. Given the driver will want a comfort break of some sort, or indeed fuel.
A float charger could be running for weeks on end.
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