Havasu Hangin'....

[SoundsGood]

I am getting ready to purchase the Guest 3 bank battery charger. What if I purchase a 40 amp charger? Will it cause a problem? Last question....how will I charge the fourth battery (starting battery on switch #1) Should I consider a 4 bank charger? It will be onboard mounted, and hooked to the inverter. Thanks for your help.

[Havasu Hangin']

Sorry, partner...didn't see your other question.
The Optimas are only rated for a 10 amp charge. You can charge them with more current, but you have to stop if they heat up. If it were me, I probably would put anything over a 30 amp charger (across all three batteries), because the extra 3 amps might be enough to heat them up in the summer heat (their max is 125 degrees).
I just don't think the benefits outweigh the risks...but that's just me. A 30 amp charger would be "fire and forget".
If you are running your engine on the starting battery, it will probably never need a charge (depending on how much you use your boat) since you aren't running it down with the stereo (and the alternator is keeping it charged).
But you could put a 4 bank charger on there if you want to be safe.

[SoundsGood]

If the 3 optimas are wired in parallel, why do I need three banks? Time is not really an issue. The boat is kept at a marina with shore power. It will be charged each night and all week long during the summers. What if I get a 2 bank charger with one linked to #1 starting battery and the second charger cables hooked to the 3 optimas in parallel bank (+) to (+ post) of 3rd battery and (-) to (- post) of 1st battery of parallel bank? I guess for my setup is a 3 bank system going to the 3 batteries overkill for 3 optimas linked together. Let me know about the advantages. Thanks again.....I won't know if I don't ask someone who does!

[Havasu Hangin']

If they are wired in parallel, you can charge them with a single 30 amp charger. Wiring the charger the way you mentioned will work.
The only problem with 3 in parallel is that if one goes south, the charger may continue to charge all three, and the other two may boil, because the charger doesn't know that they are full.
Unlikely...but possible. That would be the only advantage (that I can think of right now) to keeping the three batteries independent while charging.

[SoundsGood]

Do you think a single bank 30 amp charger as mentioned would be best or the Guest 2634 3 bank system 30A/5A/5A.
Can I hook both of the 5Amp cables to the starting battery for a combined 10Amp charge and then the 30Amp cables to each end of the parrallel bank? Sorry if I'm pesturing you. I guess a 2 bank charger with 30A/10A or even 30A/5A charger would be perfect for what I need . Does that exist?

[Havasu Hangin']

I'm not sure if the two 5 amp leads will be OK hooked together- you might want to call Marinco (Guest) and ask them.
I'm not sure if a two bank 30/10 exists...

[SoundsGood]

Will the 110V plug be placed in the inverter outlet just like an onboard microwave would be. My plans are to run a heavy extension cord from the inverter location (cabin) back to the engine compartment to the mounted charger. Can I simply use a 110V 'splitter' at the current outlet at the inverter? Is there a better way?

[Havasu Hangin']

Will the 110V plug be placed in the inverter outlet just like an onboard microwave would be. My plans are to run a heavy extension cord from the inverter location (cabin) back to the engine compartment to the mounted charger. Can I simply use a 110V 'splitter' at the current outlet at the inverter? Is there a better way?
Yeah...that's the easiest way to do it. Just run a switch in there so you can turn it off or on, and whenever your shorepower is connected, your batteries will be charging.

[SoundsGood]

Alright HH... 1st of all thanks for all your help. My boat is equipped with an onboard Guest pro 2 bank charger 2615 15Amp I guess that means 7.5 amps per bank. The charger has a (+), (-), and green switch wire from the inverter to the charger input posts. It has two (+) outputs that are connected to #1 and #2 Perko posts. The wires running to and from the charger are simply bolted on. I can use the existing wires. So, I need some help with the right charger for the 3 parallel optimas. I have decided to let the alternator and an occasional switch #1 charge take care of the starting battery. I guess I could use the Guess 2634 which has 30/5/5; but I would have to hook up power then run its output wires directly to the batteries. What would you do?

[Havasu Hangin']

I'm not sure I understand. You are replacing your existing charger with the 2634, right?
I would call Marinco and see what they say about wiring those two 5 amp circuits together. Worse case, you could premanantly mount it (just wire it off the shorepower 110V) and just not hook up one 5 amp circuit?