Start battery is not charged by charger on 1997 Hunter P42; is there a way to fix that.?

Don S/V ILLusion · 2026-09-28T10:12:08-0700

Not knowing the charging circuit makes this a guessing game. You need to map the system wiring and voltage readings. It’s also crucial to know if/how and where the two battery banks are interconnected.
Given the boat is 25+ years old, it’s likely some PO altered the original charge circuit and components. Step one is finding out how everything interconnects.

Stu Jackson · 2026-09-28T11:18:14-0700

Don's right, of course. In addition, I would add my experience, even though I don't have a P42. I do have a Freedom 1500, pretty much the same wiring to the house bank for this I/C. But what I did was to run the alternator output (AO) to the house bank and to ADD a Yandina combiner to charge the start bank. An echo charger would work just as well. If you don't want to reroute your AO to your house bank, you can use the Yandina but not the echo charger because the combiner will close the relay on voltage whereas the echo charger is a one way device, IIRC. Good luck.

PS m- Do you have a 1-2-B switch? If so B would charge both banks.

Making Sense of Automatic Charging Relays - Marine How To

Making Sense of the ACR WARNING: ACR's are not for use with LiFePO4 Batteries! What is an ACR? An ACR is nothing more than a fully automatic, voltage triggered, BOTH/PARALLEL switch that closes when charging voltage is present and opens

marinehowto.com

Terry Cox · 2026-09-28T11:50:19-0700

BBC16385 said:
Has any P42 owner solved this issue? How? Thanks.

Our 91 P42 has a power panel on the engine bay bulkhead that looks like this:

Sorry for the blurry picture.

Make sure both switches look like ours. Then come back for further instructions. We've never had a starter charging problem. Also, regardless of the house bank state, it should have no affect on the starter battery state.

P.S. The switches between the two Perkos is for the Genset.

BrianQ · 2026-09-28T12:37:13-0700

BBC16385 said:
I have a 1997 Passage 42. The Freedom 3000 charger/inverter does not charge the start battery. The alternator does charge it.

A friend's Passage 420 is the same way. If you dock the boat at a marina a simple solution is to add a small battery charger for the start battery. Alternatively, you could use a DC-DC charger to charge the start battery from the house bank.

jssailem · 2026-09-28T16:25:04-0700

You could also utilize an ACR (Automatic Charging Relay). Charge power to your House bank. When House bank full the ACR kicks the power to charge your starter bank automatically. Easy Peasy.

SI-ACR Automatic Charging Relay - 12/24V DC 120A - Blue Sea Systems

Automatically combines batteries during charging, isolates batteries when discharging and when starting engines.

www.bluesea.com

shemandr · 2026-09-28T19:35:23-0700

I don't understand why the OP can't move the entertainment center and bilge pump to feed off the House bank where they should be.

Terry Cox · 2026-09-29T04:39:26-0700

It seems we will wait for a follow-up from the OP. Our original configuration has worked great since we took possession in 2002. Never a charging or draw problem, unless here, the PO altered the system layout for some unknown reason. Although a complex electrical system with the Genset, Hunter did a class job on the original build layout. Other than making a few additions, I left the original intact, which means the starter battery is used only to start each engine, and that whether connected to shore power, Genset or alternator, all batteries get charged at the same rate, but as I mentioned earlier, draw from the house does not affect the starter battery, and vice versa..

Start battery is not charged by charger on 1997 Hunter P42; is there a way to fix that.?

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SBO Weather and Forecasting Forum Jim & John

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