Question for the Solar Experts

[rotrax]

Three weeks ago I completed installing 400W of solar on our pilothouse roof. It has been performing exactly as I imagined - better in fact - and we have been running two fridges , lights, Webasto, and all other 12v uses since install. The batteries, 550AH of AGM,s, have not dropped below 12.9v in pitch darkness and have not been above 14.2v, the max setting for the EPEVER 30A MPPT for sealed batteries.

We have had shorepower, but only for the electric kettle, immersion and microwave. The battery charger has not been required.

We left Littlehampton at 1330 Saturday on non stop passage to Dartmouth. As we approached our destination after 18 hours of motoring - wind could not have possibly been more adverse - the Alternator charge light came on. I immediatly checked the drive belt, all fine. Shortly the Alternator charge light went out. This occured a couple more times.

The Alternator is a Balmar 110A fitted with the matching Balmar external smart regulator.

My question is, has the regulator sensed fully charged batteries due to the extra charge from the Solar and stopped the Alternator charging?

The light only came on/off during very bright sunlight when the Solar was giving maximum.

 

[LadyInBed]

I wouldn't have thought it likely, I've never seen the issue on my system, but my capacity is nowhere near the size of yours!
A possible way to check would be, when on shore power, to disconnect Solar, put mains charger on and when fully charged, run the engine to see if you get the same issue, as shore power charging and engine isn't a oft used combo.

 

[tillergirl]

My (unexpert) answer to your question is 'it would be very common'. I have a 24v and a separate 12v set-up with separate solar panels and controllers. Last Wednesday, before setting out, both solar panel controllers were flashing that they were 'dumping' charge because both systems were full. We then motored for 6 hours. On approaching our mooring, we obviously reduced revs and the 24v alternator light came on at 1500 revs. the 12v alternator light stayed off. If I increase revs slightly the light went out. Both controllers were 'dumping' charge during the whole day and the voltmeters were showing the usual good charge. The only burden on the 24v system is the starter motor and the anchor windlass (that wasn't used) so the 24v system was utterly full. On passage, we had all the nav instruments, water system, fridge etc on so whilst the 12v controller was dumping charge, the system wasn't quite so 'utterly' full, so the 12v alt light stayed off until right down to tick-over. The input into the alt light has to balance the overall charge on the batteries before the light is extinguished. That's the way I see it anyway. It was worked like that for 4 years.

 

[PaulRainbow]

Three weeks ago I completed installing 400W of solar on our pilothouse roof. It has been performing exactly as I imagined - better in fact - and we have been running two fridges , lights, Webasto, and all other 12v uses since install. The batteries, 550AH of AGM,s, have not dropped below 12.9v in pitch darkness and have not been above 14.2v, the max setting for the EPEVER 30A MPPT for sealed batteries.

We have had shorepower, but only for the electric kettle, immersion and microwave. The battery charger has not been required.

We left Littlehampton at 1330 Saturday on non stop passage to Dartmouth. As we approached our destination after 18 hours of motoring - wind could not have possibly been more adverse - the Alternator charge light came on. I immediatly checked the drive belt, all fine. Shortly the Alternator charge light went out. This occured a couple more times.

The Alternator is a Balmar 110A fitted with the matching Balmar external smart regulator.

My question is, has the regulator sensed fully charged batteries due to the extra charge from the Solar and stopped the Alternator charging?

The light only came on/off during very bright sunlight when the Solar was giving maximum.

Very likely. I get similar results and if the battery charger is on the solar controller sees that and doesn't charge much at all.

 

[rotrax]

Thanks guys, put my mind at rest a bit!

I went through the basic Balmar simple check - see if the field is magnetised - and that tested OK, suggesting the brushes were OK.