One controller to for solar and AC charging and two battery banks?

[Bigjim]

I'm going to install some solar panels on my boat and replace the AC charger for shore power situations. So, the question is: Is there one controller that can handle the duties of charging two separate battery banks for both?

I read someplace that if the panels are balanced to the output rating of the batteries that you don't need a controller at all.

Is that true? And, how do you figure out whether the panels are balanced?

[Bigjim]

Does no one have knowledge or an opinion about this topic?

I see plenty of charger controllers that can handle two banks on shore power, but none of them mention solar panels in their literature.

[sailingunity]

Are you saying you're wanting a charger that can handle input from either the solar panels or the shore power?

[Bigjim]

Yes, that would be the idea. I have a solar panel controller that will charge one bank of batteries. I have seen charge controllers that can handle shore power and charge 2 independent banks of batteries.

But I'd like to have one device that could handle the input from multiple sources to keep the batteries charged without damaging any of the inputs or the batteries.

The other option would be to have a switch in the system that would disconnect the solar panels or shore power once the ignition is switch to the start position.

[wiekeith]

QUOTE=Bigjim;2661039]
I see plenty of charger controllers that can handle two banks on shore power, but none of them mention solar panels in their literature.[/QUOTE]

I suspect (but don't actually know) the reason is because shore power controller electronics derive their power from the shore power, and solar panel controller electronics drive their power from the boat's battery. Hence they are two separate systems, which is possibly why manufactures, such as Victron, sell them as separate units?

[sailingunity]

As far as I'm aware, most charging sources won't damage other charging sources because they determine how much to charge by the battery voltage.

On my boat, I have a wind generator (own controller), solar panels (own controller), alternator (on a balmar regulator) and a victron battery charger. None of them talk to each other. Good or bad, this is the way the boat was when I bought it, and the PO was an engineer. So far nothing has fried!

[Bigjim]

Originally Posted by wiekeith

QUOTE=Bigjim;2661039]
I see plenty of charger controllers that can handle two banks on shore power, but none of them mention solar panels in their literature.

I suspect (but don't actually know) the reason is because shore power controller electronics derive their power from the shore power, and solar panel controller electronics drive their power from the boat's battery. Hence they are two separate systems, which is possibly why manufactures, such as Victron, sell them as separate units?[/QUOTE]

I read in another post on this site that one person put the system after his inverter so that it was always powered no matter where the power was coming from. I know basic electricity, but I do know you want to keep your two banks isolated from each other and wiring one controller to both banks is probably not a good idea. The literature I've read about the shore power controllers keeps the banks isolated but charges them them both simultaneously.

[Bigjim]

Originally Posted by sailingunity

As far as I'm aware, most charging sources won't damage other charging sources because they determine how much to charge by the battery voltage.

On my boat, I have a wind generator (own controller), solar panels (own controller), alternator (on a balmar regulator) and a victron battery charger. None of them talk to each other. Good or bad, this is the way the boat was when I bought it, and the PO was an engineer. So far nothing has fried!

Do your wind and solar charge both banks?

[sailingunity]

We have 2 house banks that are joined all the time (but can be isolated in case of a short in one of the batteries), and a starting bank. The starting bank is connected to the house via an automatic charge relay.

[sailinglegend]

Originally Posted by Bigjim

I'm going to install some solar panels on my boat and replace the AC charger for shore power situations. So, the question is: Is there one controller that can handle the duties of charging two separate battery banks for both?

The answer is no, because solar controllers are basically DC to DC convertors.

Originally Posted by Bigjim

I read someplace that if the panels are balanced to the output rating of the batteries that you don't need a controller at all.

The answer is yes you must have a solar controller, no matter what the size of the battery. Under no loads even a small panel that has an open circuit voltage of maybe 18v will slowly get up to over 15v when the battery is fully charged - i.e. left alone for even a week.

[MikeFergie]

If you have no generator on your boat and only one source of Ac input, dc input (solar) and want to charge batteries and have AC on the boat you need a Victron Multiplus unit.

If you have a generator and shore power input for Ac and dc input (solar) and battery charging and AC on the boat you need a Victron Quattro unit

The issue of balancing the battery banks you would need a balancer unit between the batteries

[john61ct]

The above is very specific.

The question was very general, and shows a lack of knowledge that OP should overcome before spending money.

The most effective, and cost-effective solution is

buy panels and quality solar controllers that match each other for efficient solar charging

buy a quality mains charger, solar does not replace that need in caring for your bank.

As soon as you need AC power from your bank, the whole system is likely to need to be more expensive and complicated.

We would need more details on your needs and sailing patterns, genny, alternator setup etc to advise more specifically.

[Bigjim]

Originally Posted by MikeFergie

If you have no generator on your boat and only one source of Ac input, dc input (solar) and want to charge batteries and have AC on the boat you need a Victron Multiplus unit.

If you have a generator and shore power input for Ac and dc input (solar) and battery charging and AC on the boat you need a Victron Quattro unit

The issue of balancing the battery banks you would need a balancer unit between the batteries

The boat has shore power and connections for a shore power charger. I have not found the charger yet, and think it has been removed in the past. I have two solar panels from my old boat that I was going to use.

The engine has an alternator, but I have not confirmed it is charging the batteries when running.

Basically, i'd prefer to minimize and simplify the number of cables and connections running around the boat.

[john61ct]

How often and for how long are you away from mains?

What are your load consumers?

You need to figure out an AH/day energy budget.

[Bigjim]

Originally Posted by john61ct

How often and for how long are you away from mains?

What are your load consumers?

You need to figure out an AH/day energy budget.

The boat is new to us and our old boat we had for one year and only stayed aboard overnight.

At the moment, the boat has an VHF radio, instruments, running lights and interior lighting, which I'm converting all over to LED. I'm also going to install an FM radio with bluetooth entertainment system (4 speakers) this summer. We have only stayed on board one night so far and haven't even sailed at night, yet.

The goal is to be able to cruise at least a week or more off shore power, without having to run the engine to top off the batteries. My family all have cell phones that will also need to be charged.

I have four batteries divided into two banks wired in parallel.