6 volt vs 12 volt?

[rleslie]

I feel that if the batts are from the same manufacturer and you want to achieve the same AH, weight is a component to consider.

East Penn AGMs
2 - 6V @ 186 ah = 72 lbs ea. = 144 lbs
1 - 12V @ 186 ah = 135 lbs

A 9 lb difference is negligible in the overall vessel wight, but there is a huge difference when you start trying to move them around the boat by yourself.

[hellosailor]

"but there is a huge difference when you start trying to move them around the boat by yourself."

What, you don't have the remote controlled hydraulic operated battery elevator trays? You push the button, the tray come up and out, you have the deliveryman put the battery in, you push the other button, and the new battery goes below deck and links up, all without human touch except on the buttons? [weg]

[rleslie]

Originally Posted by hellosailor

"but there is a huge difference when you start trying to move them around the boat by yourself."

What, you don't have the remote controlled hydraulic operated battery elevator trays? You push the button, the tray come up and out, you have the deliveryman put the battery in, you push the other button, and the new battery goes below deck and links up, all without human touch except on the buttons? [weg]

We had one, but it wasn't marinized and only lasted 3 weeks....darn chinese products!

I then got something that works much better.....my wife!!!!!!

[mestrezat]

The original question still stands--Am I better to have two 6 volt-golf cart batteries or switch over to one 12 volt deep cycle battery? Not sure the amps of the batteries that are there but would be immaterial to the final installation if I matched the amps of what is there to what I am putting in. Would take up lots less space under the boards of my boat.

[Pblais]

Am I better to have two 6 volt-golf cart batteries or switch over to one 12 volt deep cycle battery?

No better or worse. They type of battery does however matter a lot. All batteries are not even close to the same. The fact that they were 6 or 12 volts wouldn't say much. You need the charger and regulator setup to handle the appropriate battery type and you should adjust all the voltages with a good digital multimeter.

[rleslie]

Originally Posted by mestrezat

The original question still stands--Am I better to have two 6 volt-golf cart batteries or switch over to one 12 volt deep cycle battery? Not sure the amps of the batteries that are there but would be immaterial to the final installation if I matched the amps of what is there to what I am putting in. Would take up lots less space under the boards of my boat.

Perhaps a over simplification but, a 12V batt is just two 6Vs in one case. In regards to AHs, it makes no difference. If it saves space, go with the 12v.

[David M]

If you can get two 6 volt batteries in the same space as that of one 12 volt battery AND the stored energy of the two, six volt batteries is greater than that of the single twelve, then do it.

Has anyone ever tried lifting a 12 volt, 8-D battery into an awkward space? At 47, I'm too old to do that now. It's much easier to haul 2 batteries at half the size than a single enormous 12v 8-D battery.

Also, a charger cant tell the difference between two 6 volts in series or one 12 volt...electrically it is the same thing. The internal resistance is the SAME. Modern 3 stage computerized chargers do a pretty good job of it and you don't have to fuss with a digital volt meter to tweak them.

If you have an older ferro resonant charger then get rid of it..they are garbage and will only destroy your batteries prematurely.

[kr6cq]

without knowing the amp hour rating no one can give you a reasonable
answer. you first need to know the ah rating of the six volt and 12 v
to make a comparison. If they both have the same ah rating, you will
get the same number of watthours either way. If you have the space
using 6v generally means you can use larger and heavier battery and
get more amp hours. Something most people don't know is that wet
cell lead acid batteries like to be slow charged. when you get over a
ten amp charge it is considered a fast charge. Over kill is the last thing
you want in your system. 6 volt batteries are primarily for electric motors
because of the high amp draw and amphours needed. So unless you have
heavy loading and need more time between charges, I would stay with the
12 volt. It will definitely save space and weight.

I hope this has helped

[hellosailor]

David-
"Has anyone ever tried lifting a 12 volt, 8-D battery into an awkward space? "
I think it was a couple of Group 30 Trojans that I last argued with this year, something like a paltry 75# each. Does the phrase "Let the Force move through you!" sound familiar?[g]
SIngle 2.2V cells are starting to sound more logical every year.

[roverhi]

6 volt golf cart batteries are built to take a lot of crap for a price. They are made in great quantities so you get economy of scale. Since they have to built to take the abuse of a golf cart fleet, they are built well. Doubt that you will find an equivalent quality battery cheaper per amp hour than them. Since practically every golf course in the world has them, they are available world wide should you need a replacement. When push comes to shove, however, it's the weight of the batteries that makes the decision for me. A 12 volt, 200 amp hour battery is one humongous battery. Wouldn't want to ruin a cruise with a back operation.

If your batteries date from 2005, they are getting close to the end of their expected life. They could go tomorrow or last for another 2 years or more. You need to make a decision whether to save the money and stick with them or replace them locally where you can probably get the best deal. FWIW, It seems many cruises don't seem to last more than two years so you may have a chance of them lasting as long as you need them.

I would consider breaking up the single 8 battery bank into two 4 battery banks. Batteries can fail at any time. It would be best to have all the batteries in a bank close to the same age. A lot less painful to replace 4 batteries than 8.

Aloha
Peter O.