Dual battery questions and solar charger info…

[jcr159]

Ok, need some more help.

I have dual batteries onboard that were installed last year. I noticed yesterday that it seemed that the charge levels were a bit low. I show upper 13-14.1 volts when running so the alternator seems to be fine.

I usually run in the 1+2 switch position assuming this will ensure both batteries are charging. Is this a mistake? I switch off at the dock, but the boat stays in the water and has the bilge pump bypass the switch for obvious reasons. Boat gets used one pretty full day every week or two lately…. Sometimes two days on the weekend.

Is there anything I should check, or am doing something wrong?

That all said, I have a 25 watt solar panel(could get bigger), and wondered if I should set it up to charge the batteries while I’m away, but that likely needs some charger circuitry that I’m not sure how to connect. Anyone know if that’s a big enough panel, and a recommendation on a charger and wiring diagram?

Thanks!

 

[Potomacbassin’]

Check voltage on both batts in 1+2 while running to ensure proper wiring. I assume so otherwise one on your batts would be dead by now but you never know.

Check contacts for corrosion, give them a clean as part of general maintenance.

Check fluid levels if batts are flooded lead.

Bilge pump in auto mode?

Anything else drawing a small charge?

Solar charger at 25 watts is basically trickle charging but may be enough to offset your losses. I assume this also has a controller so you don't overcharged and start blowing acid.

 

[jcr159]

Check voltage on both batts in 1+2 while running to ensure proper wiring. I assume so otherwise one on your batts would be dead by now but you never know.

Check contacts for corrosion, give them a clean as part of general maintenance.

Check fluid levels if batts are flooded lead.

Bilge pump in auto mode?

Anything else drawing a small charge?

Solar charger at 25 watts is basically trickle charging but may be enough to offset your losses. I assume this also has a controller so you don't overcharged and start blowing acid.

Just checked everything last night and wiring looks clean and like new, so nothing funny there.

Bilge is in auto mode, thankfully. I’ll check levels next time I’m out, though I may be AGM. I never specify and they just matched the original battery when I asked for a second when buying the boat. I didn’t think to ask back then. No other draws that I can see, but I’ll take my meters to be sure next time.

I don’t have a charge controller or charger other than using the alternator. Any recommendations for something that works with solar and two batteries? I have no power at the dock, so it will never be on AC. I don’t store at home either, it goes straight to the dealer’s storage in the winter.

Thanks!

 

[Potomacbassin’]

I'm no expert on charge controllers, I would start with the manufacturer of the panel and see if they have something compatible. If not do a quick search on the many RV sites, those guys are huge users of PV and probably have countless articles.

OR - if it is some parasitic draw consider perhaps a smaller PV such as a 5 watt that doesn't require a controller and not overcharge your batts, but could do just enough to keep you floated until the next engine start.