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yacht charging system

PostPosted: Sat Jul 04, 2015 4:41 pm
by MikeS
On my liveaboard yacht I run a solar panel (150watt) system through a 20watt regulator (dingo) into a 120 amp/hr LiFePo storage battery and a small LiFePo starter battery for the 14hp Beta diesel auxiliary. The diesels 40 amp alternator charges through a Vitron battery isolator. All good except the pathetic charging from the alternator. .18-20 amps at very best dropping rapidly to less than 10 amps ( I have a Vitron monitor) I guess caused by the relative high voltage of the LiFePo batteries.
Any thoughts on a simple fix.mikes

Re: yacht charging system

PostPosted: Wed Jul 08, 2015 1:52 pm
by Coulomb
With the space available on the Kubota engines fitted with a heat exchanger, there is much room for a larger alternator.

You might post a picture so we can see the actual space.

Re: yacht charging system

PostPosted: Fri Jul 10, 2015 11:05 pm
by MikeS
Thanks for that. Beta have a 70 amp alternator as an option.but
surely that too would go into " float " mode after sensing the LiFePo batteries high voltage
I, d be happy with 20 amps + if the charge could be maintained

Re: yacht charging system

PostPosted: Mon Jul 13, 2015 11:38 am
by Coulomb
Isolators cause more problems than they solve.

Alternators with built-in regulators are not appropriate for charging deep cycle batteries. They cut back output current to keep the alternator from overheating. A true hot rated alternator does not need current foldback.

You need a hot rated alternator with a multistep regulator, such as the SARV3 which does allow current limiting when at the engine power is needed for propulsion.

You might want to look at the Ample Power Primer: