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**StuM** · 11-09-2016, 20:02

Quote:

Originally Posted by MVDarlin

Hmmm, I have converted my house bank to 6 golf cart batteries, 660 amps, I also have one 220 amp 8 d start battery. My mechanical advised I should upgrade my 30 year old 3 wire battery charger to a smart system. Any recommendations? I cruise and spend days at anchor, charger batteries wwith gen set/ charger for an hour am and pm, I only run refer and freezer when Gen set is on or underway.

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I presume that your golf cart batteries are 6V. Do you have 660 Amp hours at 6 Volts or at 12 Volts? (i.e. what is the rating of each golf cart battery in Volts and Amp hours)

MVDarlin · 12-09-2016, 02:20

I was advised 660 at 12 volts

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MVDarlin · 12-09-2016, 02:25

Yes, house bank 6 x 6 volt batteries wired for 12 volt output, total 660 amp hrs at 12 volts. I have a powerboat with 4.5 kw gen set. Also one 8d starting battery, 220 ahrs @ 12 volts.

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**StuM** · 12-09-2016, 03:31

What do you have in the way of alternator(s) on engine(s)

MVDarlin · 12-09-2016, 03:40

2 60 amp Motorola alternators

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MVDarlin · 12-09-2016, 07:02

That might be a good solution, I'll check the stats.

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**skipmac** · 12-09-2016, 07:12

Quote:

Originally Posted by MVDarlin

That might be a good solution, I'll check the stats.

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I have the same battery setup, 660 amp hours in six X 6V golf cart batteries. My main charger is 70 amps but wouldn't mind having a little more.

One thing to be aware of, if your batteries are already partially charged it doesn't matter how big the charger. They will only accept so much additional charge unless you really up the voltage of the charger which could be hard on the batteries. So if you routinely top off your batteries so they're not discharged too low you will seldom be taking advantage of the additional capacity of a high output charging system.

That being said, it could be very handy at times and it can't hurt (except in the wallet) to have additional charging capacity.

**a64pilot** · 12-09-2016, 07:20

I believe your initial thought of needing a BIG charger is correct as you want to charge in a short time of running the generator, smaller chargers are fine with shore power.
You can buy a couple of smaller chargers though and that is the same as one big charger, yet it gives you redundancy in the event one fails.

I do not believe using your main engine alternators is a good charge source, first it's inefficient and not the best way to put hours on your engines, secondly its my experience that alternators do not make rated power for long, seems they heat up and cut back on power, and most likely yours don't have good three stage controllers, they are most likely "dumb" regulated meaning they make 14V regardless of battery state of charge.

What I have done is I have this battery charger that is a 60 amp charger
Battery Chargers
And I have an inverter that will power my AC loads when the generator is off, but it is a 125 amp charger when the generator is on, this give me 185 amps of charging.
there are other ways of course, but I chose this way as I have redundancy and I have a source of AC power from my battery bank