Solar Panel and mains battery charger question

[Tony Cross]

I have two 80w solar panels connected via two Morningstar SunSaver-6 regulators to my 330AH service batteries. They keep the batteries topped up pretty well but if we don't move for a couple of weeks (ie. no engine) I need to plug into shorepower for 24 hours and let the mains charger top the batteries up. I have a Mastervolt 3-stage mains charger.

My question is; will the solar panels make the mains charger think the battery is in a better condition than it really is - because the mains charger sees the voltage from the panels which (in the daytime) is higher than the battery voltage? Should I disconnect the panels when charging the battery via the mains charger?

BTW. I'll be swapping the two Morningstar PWM controllers for a single Secca MPPT controller shortly (and wiring the panels in series) but the question still remains.

 

[GrahamM376]

I've wondered about this but, on the rare occasions we've been in a marina, I've never disconnected the panels and the charger seems to perform normally, even when solar is charging at maybe 6-8 amps.

 

[pathfinder]

I leave my wind genny (via regulator) connected all the time even with the shore power on, doesn't seem to be any problems and batteries are allways fully charged.

 

[Sandyman]

My question is; will the solar panels make the mains charger think the battery is in a better condition than it really is - because the mains charger sees the voltage from the panels which (in the daytime) is higher than the battery voltage?

Makes no odds if it does. If its an intelligent charger it will just sit on 'float' until the sun goes down.


Should I disconnect the panels when charging the battery via the mains charger?


Serves no purpose.

 

[Tony Cross]

Makes no odds if it does. If its an intelligent charger it will just sit on 'float' until the sun goes down.

And that's an excellent point which I hadn't considered.

Many thanks to all who replied, I'll leave the panels connected and stop worrying about it now - no doubt I'll find something new to worry about soon though.

 

[CaptainBob]

We've got 2 x 80 watt panels and live aboard in the uk. In two months we've needed a total of 3 hours generator usage to keep the batts full. Alternator has put in nothing in the same time.

Perhaps your fridge is working much harder than ours, but we are on laptops a lot... Maybe you should switch to led lighting and replace whatever other high power things you have running?

Keeping the depth of discharge as low as possible will increase the life of your batts as well as saving on marina visits/fuel.