Replacing onboard charger

[Dawgvet98]

I need to replace the onboard charger on my 2006 Sailfish. I have 3 batteries onboard, 2 in parallel for starting starboard engine and house, and 1 battery for port engine and gauges. Can I use a 3 bank charger and run 1 bank to each of the starboard batteries or do I use a 2 bank and use1 bank for starboard and 1 bank for single port battery?

Looking for a charger that will do low amp charging and maintaining.

Recommendations for a charger? I am running Interstate AGM marine batteries.

Thanks in advance for any help.

Rick

 

[Hookup1]

I'm using the ProMariner 3-bank 20 amp charges. There are probably newer modes from ProMariner. They are "smart" chargers that do a great job of charging and maintaining your batteries. Old style chargers tend to overcharge and "cook" the batteries.

I'm curious why you have two batteries paralleled on the starboard side instead of putting the engine on one and the house on the other. The engines will charge their own batteries thru the starter wiring. Typically there is a separate charging shunt wire from one of the engines (starboard on mine) that connects to the house battery that will charge a third bank. Maybe they did it that way because they only had a two bank charger. If you go to a three bank charger your could separate it.

I never liked parallel battery setups but when you change a battery both should be replaced with the same brand/type. I would consider separating them and optionally add a A/B battery switch for the house.

There is another brand of battery charger I would look at for my boat next time around. NOCO Genius battery charger line. They have a 4-bank 40 amp version. I bought a single bank for my bow thruster installation last year. Smart charger technology.

 

[Dawgvet98]

I can't answer that, but here is the wiring diagram from the manual.

 

[wspitler]

I talked to engineers at Promariner and they recommended a separate charge lead for each battery. Therefore a 3 bank charger would be, in their opinion, the recommended size for your setup. I have four batteries, two in each bank. They recommended a four lead charger, but said a two lead could be used but would not be ideal.

 

[Dawgvet98]

I talked to engineers at Promariner and they recommended a separate charge lead for each battery. Therefore a 3 bank charger would be, in their opinion, the recommended size for your setup. I have four batteries, two in each bank. They recommended a four lead charger, but said a two lead could be used but would not be ideal.

I looked at Genius' website and they show 2 banks, 1 to each battery, in a parallel connection. Good to know.

NOCO - Batteries In Parellel And Series - Support

Learn the difference between batteries in series and in parallel, and examples of NOCO products in each scenario.

no.co

 

[Hookup1]

I converted the wiring diagram so its easier for others to see. It looks to me like GW only offered a 2-bank charger and paralleled the starboard motor and house. The A/B/both switches allow you to switch engine/house to either side or parallel if necessary.

I have had problems with the ProMariner fuses (separate post) and putting two leads to a set of parallel batteries does help. Each lead carries half the amperage and doesn't burn up the fuse. But here is the gotcha. Two leads to parallel batteries doesn't charge each battery separately and the fancy finishing charge the smart charges do their best to average


While not ideal it should work fine for you. Get a three bank charger and set it up as above. If you decide to separate them you have the right charger. Maybe add a A/B switch. Just remember that if you need a new battery on starboard side replace both and make sure they are the same brand/type.

Side note: I just bought two Duracell AGM Group 34's for my boat engine batteries at Sam's Club. Great price great battery. I did my house battery earlier this year - same battery but Group 27. And my bow thruster battery is also same but Group 34.

 

[seasick]

For three batteries, I would expect, 2 starter batteries, one per motor and a separate house. I am not sure I see the reasoning behind the wiring logic in the drawing.

 

[dogdoc]

ditto what seasick said. house and starter together could lead to problem if something is left on and drains battery. could be dealt with if happened with bat switches but not ideal. my set up is 3 bats, starboard start, port start, house with 3 bank 30 amp promariner distributive charger. each bat gets own 10ga lead with 40 amp fuse

a bit pricey but worth the peace of mind