Yet another battery question....

[Rocket1]

Hello all-

Having searched through the archives looking for an answer, I find myself still looking for answers and advice. Among my many winter projects are the replacment of the batteries and charger on our Hunter 340.

The PO had 4 6v GC batteries AND the starting battery crammed into the starboard aft lazerette, which not only caused the boat to list to starboard when at rest, but actually busted the floor of the laz, placing at least a portion of the considerable weight of the batteries on the holding tank below. Not good. As a temporary measure, I have reduced the house bank to 2 GC batteries, which still live in the same laz with the starting battery (after repairing the floor of the lazerette, of course). The batteries are about 8 years old, so I figure they're pretty much due for replacement.

What I would like to do is return to a 4 GC house bank (Sam's Club), plus a dedicated starting battery, with a new (smarter) charger. The current charger is the original 30A Newmar that came with the boat.

Here's where I run into some issues. Obviously, I can't cram all of these batteries back where the OP had them - lest I create the same problems that I had before. I would like to leave the starting battery in it's original location in the starboard aft laz, as there is a shelf built in there that seems to be dedicated to that purpose. There is no place on the boat that will reasonably house all 4 GC batteries together in one place. There is a nice space between the holding tank and the diesel tank where I could fabricate a shelf and house 2 of them (on the centerline of the boat - essentially under and between the lazerettes), with the other 2 possibly housed in the port aft lazerette (which would eliminate the "lean"). The run between the two locations would be around 5'-6'. The charger is currently located in the same compartment as the starting battery. The run from the charger to any of the proposed battery locations would be less than 8' (16' round trip).

So, all of that probably being clear as mud, here are my questions:

1. Are the GC batteries close enough to one another to wire them together as a single house bank, or would I be better off to utilize them as two separate house banks?

2. Are any of the distances from the charger to the batteries going to be cause for concern?

3. The Webasto diesel heater is also located in the port lazerette. Though there is plenty of ventilation and the heater is utilized infrequently, what are the potential issues with housing batteries in the same compartment?

4. Any recommendations regarding brand/model of charger/battery monitor would be greatly appreciated.

I know it seems like every third thread has someting to do with batteries/chargers/solar/etc. - and y'all are probably weary of talking about it. But, as this is one of the more critical systems on board - I want to get it right so I don't have to worry about it.

Thanks to all in advance for your help.

 

[Ralph Johnstone]

I've just completed exactly what you're looking at doing. The reason for it was eliminating the list to starboard. I had two 12V house batteries and one 12V dedicated starting battery in the starboard lazerette for a total of 180 lbs.

For balance, I moved one of the deep cycle batteries to the port lazerette and then added another 60 lbs of lead in 10 lb slabs in hidden locations along the port side of the boat. Now she sits upright all the time.

I did enough new wiring to bring it up to 99% good enough. The wiring between the two house batteries is 15 ft. (30 ft. total) connected with #2 wire. I left the wiring from the alternator and the battery charger where it was as I was not going to break my butt to rewire it so there was no imbalance. The 0.0047 ohm resistance caused by the 30 ft. of connector wire was not an issue. By the time it gets down to a float charge and minimum current flow, everyone will be happy.

As for a battery charger, the Xantrex 10 amp has more than enough capacity when we pull into a marina at night. My Balmar ARS-5 external regulator forces my 55A Hitachi alternator to get off its lazy ass and get to work charging the batteries up to 100% state of charge (SOC) right quickly. Not like before when the alternator was internally regulated and spent most of its time putting out 14.2V and never quite got the batteries to 80% SOC on a long day of motoring.

As far as a the batteries being in the same area as the heater, the batteries will give off hydrogen and oxygen in perfect proportions for an explosion, but if you're SURE there will ALWAYS be good ventilation .............................

I don't think you'll require anything more than a Link 10 battery monitor which will monitor your house bank only. No need to monitor your starter battery as you never discharge it. When you do want to look at how your starter battery is behaving, couple it to the house bank and see if you've got a current flow into the starter battery with no input from alternator or charger. Although I'm thinking of replacing the house batteries after nine years in service, the starter battery is still good after 14 years.

Although I like to spend money and work on the boat, that's all I felt that project was due.

 

[Bob 04 H260]

I did some of the same mods on my boat. I would suggest if an external regulator is used the battery and alternator temperature be monitored by the regulator . I used a Sterling regulator, it came with both temperature probes.

For a battery monitor I bought the Victron BMV-600. Very easy install and great price.

For a battery charger I bought the Sterling 50 amp model as I have a 400 Ahr AGM bank, also with temp probe on batteries. For flooded cell bank a much smaller charger would make sense.

I wired the alternator output direct to the house bank and an Echo charger to start battery. The battery charger also wired direct to house bank.

I would be cautious installing flooded cell batteries in a locker with a heater. Maybe look at sealed cells so no gas or different space.

Bob