# question

## twin motor boat with two alternator how it use for charge battery

Hello!

I need to know, how I must connect two alternators, charger, and battery.

I have two battery - single starter battery for both engines and single service battery.

I want to use battery isolator (smart relay) for isolate starter battery from service battery but what I must do with alternators? I think I can use simple parallel connection without any diodes.

But may be You can tell me best practice for twin engine boats?

Thank You!

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Very much depends on what alternators you have.

Joining both to the service bank may not yield twice the performance as one regulator will slave the other.

Hook up just from one, and consider if the alternator is large enough to supply your needs

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What You think about split charge? one alternator for starter battery and onther for service battery, but if one is broken we need to combine battery for charge by single alternator.

I make draft circuit, You can understand my idea from it (may be :-))

I make XOR element using two relay but I want to use electronic circuit (MCU+two channel ADC for sense voltage on L terminal from alternators).

I will use two channel AC charger or single channel charger with FET isolator.

blockdiagramm.png (124.5 KiB)

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I change circuit and want use FET isolator instead ACR because I do not like high inrush current when two battary carge is different but we connect it in parallel.

draftcircuit3.jpg (83.4 KiB)
blockdiagramm2.png (107.8 KiB)
blockdiagramm3.png (178.0 KiB)

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And one more method.

Using DC chargers like Orion-Tr

I will use remote on-off instead of power relay.

No inrush current when charge two battery from one source.

Good charge all batteries

draftcircuit4.jpg (89.2 KiB)
blockdiagram4.png (235.5 KiB)

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