What Is the Best Way to Charge Two Battery Banks?

[bobfnbw]

Hi.
Installing the new engine and battery's and alternator and....

I have 2 battery banks.
1 is 600 ah of agms for the house. Charged via the balmar 120 amp alternator and 2 100w solar panels.
2nd is the start battery, currently is a optima spiral agm.
I need the best way to combine them for charging, but to isolate them otherwise.
I do not have a AB batt switch and do not want one. I have 2 separate on off bss battery switches.

So what is the best way.
Either the BSS ACR Blue Sea Systems #7620 Solenoid ML Series 350A 12V ACR
or the balmar duo charge Balmar Digital Duo Charge something else.
I do not want to use a isolation diode.
Your thoughts are appreciated.

Bob

[Hud3]

The Balmar Digital Duo Charge works fine on my boat. Since the start battery is drawn down so little in starting duty, having a regulated charging source from the house bank makes sense to me. I'm not familiar with the Blue Sea gear.

[fergie_mac66]

Quote from bobfnbw

What is the best way to charge 2 banks?

You could send them a bill but I dont hold out much chance of them paying up !!!

[barnakiel]

Newer Sterling chargers will charge the banks separately.

The solar connection as per Calder's book.

b.

[jdoe71]

Echo charger on the starting battery. Start batt needs minimal top up and this device has worked flawlessly for us with all sources of charging power. There are so many ways to do this though, it's more a matter of personal preference than anything else I think.

[Cacique]

On my boat (a circumnavigating Vancouver 27) I used to have a switch to allow me to charge the house battery and/or the engine battery. This was OK but the house battery never really got fully charged as I was allways worrying the start battery would be flat. Now I have installed a second alternator 90A, I purchased from a scrapyard for £15 (about $25). I have a Bukh 20 engine and the alternator I got uses a flat belt which is driven by the main flywheel, I used a simple relay so the indicator light was only energised when the ignition switch of the engine was on, also obtained from the scrapyard for £0.50 (About 75 cents). Now with two charging systems when ever the engine is started the engine battery is replenished stgraight away, and the house battery gets a good boost too. Also when running the engine to charge the batteries with the second alternator there is more load on the engine so it is less likely to glase bores etc, when we have been using the house lights and telly for some time when we start the engine you can tell it's working by the tone of the engine at tickover

[sailvayu]

I like the electronic battery combiner by BEP, I have had good luck with these units, For more money you could use the Xantrex combiner which has adjustable voltage settings.

Good luck

Wayne Canning, AMS
Projectboatzen.com

[CharlieJ]

I am partial to battery combiners and especially the Blue Sea Systems ML Series of Automatic Charging Relays m/n 7622. These are latching relays which means they take no power to hold them in position. They are remotely operable and they have a manual over-ride switch in the unlikely event that the electronics goes south. Complete the assembly with the Blue Sea Systems m/n 2145, a gated operating switch and you have a nearly bullet proof installation capable of some serious amperage.

[jerryprocter]

The draw to start your engine is minimal compared to its capacity. I would just add a solar trickle charger to your start battery and keep it completely isolated from your house bank charging system. Saves on money and is rock solid KISS in design.

[Beach Cruiser]

We have been using the Duo Charge. I like the fact that you can have different battery types in your battery banks. We use AGM for our house bank and wet cell for start and the Duo Charge can handle the different charging profiles.

Barry
s/v Beach Cruiser

[CharlieJ]

The Duo Charge is a great piece of gear that I have successfuly used to charge a battery remote from the main bank. It is, however, limited to 30 amps, unless you use a contactor, so you cannot directly use it to parallel banks for emergency starting.

[bobfnbw]

Great, thanks for all your suggestions.
I purchased a Balmar duo Charge on EBAY yesterday for 82 bucks with shipping. New.
So I am happy with that.
Bob