Hi,
I have added a lithium battery to my boat to run all the domestic loads. I still have my original AGMs connected to the bow thruster, electric winches and windlass. An Orion XS is charging the AGMs from the Lithium. I have a Multiplus and solar MPPTs that are charging the lithiums. I am now looking at using a 2nd Orion XS to charge the Lithium from the starter battery and alternator.
The standard Hitachi/Yanmar 80a alternator appears to be set up to primarily charge the AGM bank. With the engine running I can see 14.4v on the AGMs, but only around 13v on the starter battery. I don’t understand how the wiring to the starter battery from the alternator works. There are just two battery cables to the starter battery that go to the starter motor and ground, plus a third cable from the multiplus for trickle charge. How does the starter battery get 13v from the alternator?
I tried disconnecting the cable from the alternator to the AGMs, started the engine and measured18v coming out of the alternator, which is too high for the Orion. I assume the alternator needs the AGMs to help regulate down to 14.5v. Is my assumption correct?
So now I’m thinking about connecting my 2nd Orion XS’s input to the AGM and output to the Lithiums. So I would end up with two XSs connected to the AGMs and Lithium; one going one way and one going the other. All I’d need to do is figure how to switch one off while the other one is on.
Is there a simpler way to do this? Am I missing something?
I’d appreciate any help and guidance on this.
