Split alternators between 2 banks

[rob71]

My boat has 3 battery banks. All 12 volt. 2 4D mains, combined for starting. 2 8Ds for inverter and 1 group 27 for the generator. All banks charged by Victron smart charger. Generator has its own alternator. Currently the engine mains both feed to the start bank.
I am thinking it would be better if I split them so one charged the inverter bank while cruising with the generator off.
Is this a good idea ??
Capt. Rob

 

[Jammin']

I would certainly think so. I'm surprised your alternator doesn't charge it now. The inverter bank will get drained more than anything else. If you have an external regulator, I would install a temperature compensation sensor on the inverter bank too.

 

[Boatsb]

How big are the alternators and what's the battery capacities?

Does the inverter have a charger?

Hows the system laid out?

I just sent 2 balmar 24 volt regulator kits and a balancer to a customer with a victron inverter/charger as he upgraded to LiFePo. It's a cool package and can charge the inverter bank through the engine alternators along with its charger.

He also has 12 volt batteries and alternators for the start batteries.

 

[Captain Ralph]

Or, Ad some ACRs and both engines can charge all while running and the banks are separate when not running.

 

[Jammin']

I used this:

https://www.victronenergy.com/battery-isolators-and-combiners/argo-fet-battery-isolators

 

[Boatsb]

I'd suggest looking at the Cyrix-i intelligent combiner.

Then again what do I know.

Oh yeah that's right.

It makes sure the start battery is charged before charging the house (or inverter) and can handle 400 amps. Theres no voltage drop like the diode or FET systems and I've used them with LiFePo batteries ((LiCt) where the alternator charges the inverters lithium batteries.

 

[rob71]

Thanks guys.
No charger on the inverter, just the Skyla charger.
Alternators are 60 amp. Stock equipment on my Volvo diesels.
Both are connected to a pair of parallel wet cell 4Ds. 135 amp hr. Each.
Inverter batteries are also paired wet cell 195 amp hrs. Each
My understanding is only one alternator is actually charging at anyone time.
My gauges usually indicate one is at almost 14 volts while the other is 12.5.