How long to recharge a 200Ah Lead Acid (sealed) Battery via alternator?

[DnK]

Returning from our last trip (running from French lockdown) I thought i had battery charging problems. On one particular day we were down to 85% SOC at noon despite good sunshine on the 300 watts (3x100 semi flexible) of solar we have from the previous couple of days. We are not heavy power users and have LED lighting and watch a bit of TV in the evenings, and we charge our phones and iPads during the day. We have no 240v devices and no inverter. In the afternoon we drove for 6 hours to next destination and when i arrived I checked the BMV we were at 91% SOC. So 6 hours to put back 6% charge state. I expected the batteries to be 100% SOC!

When we arrived home just prior to UK lockdown I decided to check the Solar panels. One failed completely, one was showing 9v and the other was showing the correct rate 18v. I had suspected for some time that we were not harvesting as much as when they were first fitted 3 years ago. On basis two were not performing and the third was likely to fail as it was same type I decided to replace them all with glass aluminium framed Victron Blue Solar 115 watt panels. Solar problems resolved. On a brief test on 100% SOC all lights, TV, Cooker fan, Maxair fan on we were pulling down 230 watts.

So now I turn my attention to the alternator charging. According to my EBL manual : …While driving charging current * simultaneous charging of starter and living-area battery by alternator, batteries in parallel by cut-off relay, maximum charging current of living-area battery by alternator must not exceed 50A.
See block diagram.

I know the Alternator is 120amp so it would seem the capability for higher charge is limited by the EBL and the wiring fused to 50amp. I don’t know what actual amperage is being fed and don't have the tool to check.

My question for those not gone to sleep reading this. Could I replace the leisure battery charging by alternator by fitting Victron Cyrix Batterry Combiner to enable faster charging?

 

[trevskoda]

Most alts will only charge to if lucky 95% where as a good solar sys will hit full and return to a float charge,semi flex panels have a short life due to overheating and no air flow under them,as a rule. 100w panel for 100ah battery.
It takes about a 50/60 mile trip just to get back what you used to start the engine,never mind the les batteries,unless you have a all sing and dance charge unit.

 

[DnK]

semi flex panels have a short life due to overheating and no air flow under them,as a rule.
It takes about a 50/60 mile trip just to get back what you used to start the engine,never mind the les batteries,unless you have a all sing and dance charge unit.

Would never buy or recommend semiflex panels. Disgusted I only got 3 years from them - they dont tell you this when you buy them.

I assume you mean a B to B charge set as being all singing set up. So no advantage going the Cyrix Combiner route then?

 

[trevskoda]

Would never buy or recommend semiflex panels. Disgusted I only got 3 years from them - they dont tell you this when you buy them.

I assume you mean a B to B charge set as being all singing set up. So no advantage going the Cirix Combiner route then?

Yes b to b charge set is good for smart alts,sort your panels out and that setup will be ok.

 

[mistericeman]

I'm part way through solar install in the Moho and went for a 315w (bi facial up to 400w) and a ring rscdc30 combined b2b and mppt solar regulator.

I've only fitted most of the solar side yet (still have to alter brackets on roof rack to bolt panels down)
BUT dropped the batteries down to 80% last night (left compressor fridge on -20 over night)

Then turned solar breaker on at around 13.30...
By 16.30 the batteries are back to 100%...

Looking like it's working OK so far

Just need to finish off the bracketry etc and connect the engine charging in.