Golf Cart Batteries

Mike B · Mar 13, 2009

Lots of discussion already had on this one but yes I had Trojan T105s in my last boat and was very happy with them. Good price, easier to fit, more total Amp Hrs, better recovery to name a few benefits. Just wire them in series and you're good to go.

Ron20324 · Mar 13, 2009

My take is you shouldn't use them if you only have one 12-volt house bank now. If one 6-volt dies, you got nothing to run anything with anyway. Two or more 12's make it feasable to go with 6's.

Don S/V ILLusion · Mar 13, 2009

Phil
So-called golf cart or 6V batteries are quite common on boats these days for a number of reasons, not the least of which are convenience and durability.

I have to disagree with Ron in that if a cell goes bad, it's a problem regardless of whether it happens in a 12V or 2x 6V batteries - you lose power regardless. When you consider the increased capacity ratings of a set of 2 golf cart batteries compared with one Gr27/31 battery which takes up the essentially equivalent space, the advantage becomes greater which is why most of the so-called experts suggest golf carts as a viable alternative for those seeking max power per unit volume of space required.

Chuckbear · Mar 13, 2009

Phil, We and many others we know have used 6V batteries as our house bank and even starter battery for many years with very positive results. We use Interstate 2200 batteries as opposed to Trojans since they are considerably less expensive. We get about 6 to 7 years out of a pair and since we cruise extensively the batteries get used and abused. Our friends that use the more expensive Trojans get the same usage we do for more money. Keep in mind that the 6V is a taller battery so be sure you have the clearance for them. The statement that one could fail and you have no power does not make sense since a 12V battery can also fail with the same results.

sailingdog · Mar 13, 2009

Don—

The problem is that if you have TWO 6V batteries as your house bank, as opposed to TWO 12V or FOUR 6V batteries, and one cell goes bad, you lose the ENTIRE HOUSE BANK. That means you have NO ELECTRICITY WHATSOEVER. If you're going to use 6V batteries, only do so if you're installing FOUR or more... If you can only have two batteries, better make them TWO 12V batteries for redundancy's sake.

Don S/V ILLusion said:
Phil
So-called golf cart or 6V batteries are quite common on boats these days for a number of reasons, not the least of which are convenience and durability.

I have to disagree with Ron in that if a cell goes bad, it's a problem regardless of whether it happens in a 12V or 2x 6V batteries - you lose power regardless. When you consider the increased capacity ratings of a set of 2 golf cart batteries compared with one Gr27/31 battery which takes up the essentially equivalent space, the advantage becomes greater which is why most of the so-called experts suggest golf carts as a viable alternative for those seeking max power per unit volume of space required.

Don S/V ILLusion · Mar 13, 2009

sailingdog said:
Don—

The problem is that if you have TWO 6V batteries as your house bank, as opposed to TWO 12V or FOUR 6V batteries, and one cell goes bad, you lose the ENTIRE HOUSE BANK. That means you have NO ELECTRICITY WHATSOEVER. If you're going to use 6V batteries, only do so if you're installing FOUR or more... If you can only have two batteries, better make them TWO 12V batteries for redundancy's sake.

I agree SD but the premise I'm operating under is that we're talking about a "house" bank which I infer you and Ron means to assume there is a separate "start" battery. In this case, there is an alternative power source available to preclude not having any power.

sailingdog · Mar 13, 2009

Yes, but if you're sitting at anchor, and need to run the anchor lights, cabin lights, and such, you probably wouldn't want to use your starting battery, as then you might not be able to start the engine... if you had two 12V batteries as a house bank, and killed the second one after the first was taken off line, you'd still have a starting bank to get the engine started with.

I have two banks, one is a starting bank and is never to be used for house loads if at all possible, and I can hand start the auxiliary on my boat in a pinch, which isn't necessarily the case with most diesels.

Don S/V ILLusion said:
I agree SD but the premise I'm operating under is that we're talking about a "house" bank which I infer you and Ron means to assume there is a separate "start" battery. In this case, there is an alternative power source available to preclude not having any power.

Stu Jackson · Mar 13, 2009

Single bank of (2) 6V golf carts

is a viable option instead of one 12 V battery.

Many times folks, when this regularly recurring subject comes up, do mention the possible failure of one of the 2 six volt batteries, thus depriving the skipper of any power whatsoever, as compared to (2) 12V which provide a fallback in case one of the two batteries fails - there's still 12V power. Usually (2) 6V can provide about the same amp hours as two 12V, in a smaller physical footprint.

Questions:

How often have folks ever actually experienced the complete physical failure of a battery, as compared to simply being drained too low by bad battery management? Too low battery bank drain is not the failure of the battery, but rather of the operator.

What quantity of actual battery physical failure rate have we been seeing?

Maine Sail · Mar 13, 2009

Anotehr question

Stu Jackson said:
Questions:

How often have folks ever actually experienced the complete physical failure of a battery, as compared to simply being drained too low by bad battery management? Too low battery bank drain is not the failure of the battery, but rather of the operator.

What quantity of actual battery physical failure rate have we been seeing?

Another question is how many boaters would actually know what to look for if one cell actually did go bad? I would argue that the vast majority would take either a 12V-2 battery house bank or a 6v X2 battery house bank off line either way. How many boaters other than a few here could accurately diagnose this and break the two 12V batteries apart and figure it out...

I know I speak of heresy here but my emergency battery is a 125 amp hour deep cycle battery not a start battery as in a real emergency I'd at least have some run time...

With all that being said I have owned, in my life, over 60 batteries between cars, boats, snow machine & motorcycles etc. and never once had a bad cell. I've had batteries wear out but not had a bad cell. I know it can happen but I have not physically seen it..

6V batteries represent the most bang for the buck in terms of amp hours..

Don S/V ILLusion · Mar 13, 2009

sailingdog said:
Yes, but if you're sitting at anchor, and need to run the anchor lights, cabin lights, and such, you probably wouldn't want to use your starting battery, as then you might not be able to start the engine... if you had two 12V batteries as a house bank, and killed the second one after the first was taken off line, you'd still have a starting bank to get the engine started with.

I have two banks, one is a starting bank and is never to be used for house loads if at all possible, and I can hand start the auxiliary on my boat in a pinch, which isn't necessarily the case with most diesels.

This is the fallacy in the argument SD. If, as in your scenario, you killed the 2-12V battery house bank, it's dead - both batteries in it are dead. You can't "take it offline" unless you:
1. have them switched (which is by definition not a house bank but two separate batteries in two separate banks), or
2. know in advance they are both about to be drained.

I think we went WAY off the original question but suffice it to say that anyone with the ubiquitous separate start battery should have no problem using a house bank of 2 golf carts.

Stu - don't know what conclusions can be drawn from anecdotal stories but I too doubt that total failure of a battery, regardless of type, is a common thing and particularly when it comes to those properly managed. As the cliche goes, batteries don't die, they are killed.

Mike B · Mar 13, 2009

Re: Single bank of (2) 6V golf carts

As I said earlier I replaced my battery with 2 Trojan T 105s 6Vs. I went from a single 4D to the Trojan's. I also had a seperate dedicated start battery which I would isolate while at anchor. I went from apx 180AH to 235AH and the added benefit of just overall better battery performance. BTW the cost of the T105s was less than a single 4D. Add in the ease of replacing a 115lb battery with 2 at 60 lb each and it was no contest. IMO there's no more risk in 2 6Vs than there is with a single 12V. And Stu to answer your question I've had batteries in the car fail but never in any of my boats. As I said it's not an issue in my mind.

Chuckbear · Mar 13, 2009

Stu Jackson said:
is a viable option instead of one 12 V battery.

Many times folks, when this regularly recurring subject comes up, do mention the possible failure of one of the 2 six volt batteries, thus depriving the skipper of any power whatsoever, as compared to (2) 12V which provide a fallback in case one of the two batteries fails - there's still 12V power. Usually (2) 6V can provide about the same amp hours as two 12V, in a smaller physical footprint.

Questions:

How often have folks ever actually experienced the complete physical failure of a battery, as compared to simply being drained too low by bad battery management? Too low battery bank drain is not the failure of the battery, but rather of the operator.

What quantity of actual battery physical failure rate have we been seeing?

Stu, We had an 8D short a cell on us in the DR about 7 years ago on our boat. I can tell you it was weird and scary and the reason we converted to 6 volts completely on the boat. It was the last of the 8Ds left on the boat and 6 volt batteries were readily available and 8Ds were not. In 40 years in the marine service industry this was the only time I have encountered this. I have gone aboard boats that have had batteries that registered no voltage. What caused this ultimately was never determined since the system was fine and replacement batteries showed no problems. Could a bad cell have been the cause? Who knows.

captain cajun · Mar 13, 2009

Thank for bring this topic up. As I get older, always looking to cut back on lifting. I think I am going to give this a try. I just order Don Casey's book "Sailboat Electrics Simplified". Thanks again for the heads up.

sailingdog · Mar 13, 2009

I'm saying if one of the two ended up with a bad cell, you'd still have one battery you could use for house loads, provided you caught it in time. If you only have two 6V batteries and a one has a dead cell, you've got nothing...

Don S/V ILLusion said:
This is the fallacy in the argument SD. If, as in your scenario, you killed the 2-12V battery house bank, it's dead - both batteries in it are dead. You can't "take it offline" unless you:
1. have them switched (which is by definition not a house bank but two separate batteries in two separate banks), or
2. know in advance they are both about to be drained.

I think we went WAY off the original question but suffice it to say that anyone with the ubiquitous separate start battery should have no problem using a house bank of 2 golf carts.

Stu - don't know what conclusions can be drawn from anecdotal stories but I too doubt that total failure of a battery, regardless of type, is a common thing and particularly when it comes to those properly managed. As the cliche goes, batteries don't die, they are killed.

Don S/V ILLusion · Mar 13, 2009

sailingdog said:
I'm saying if one of the two ended up with a bad cell, you'd still have one battery you could use for house loads, provided you caught it in time. If you only have two 6V batteries and a one has a dead cell, you've got nothing...

Yup! All good points. If there is no separate start battery, you'd have a problem but I can't see a scenario, without good monitoring, when someone would catch it in time. In any case, this discussion exemplifies another good reason to have a separate start battery as well as a good means of measuring battery performance.

Don S/V ILLusion · Mar 14, 2009

Phil V25 said:
I guess I should have added that I don't necessarily need a starter battery, its an outboard and easily starters with the pull rope. But you bring up a good point, what do you define as a good "means of measuring battery performance"?

Phil
It can vary depending on how extensive an electrical system you have or want. With one battery, the automobile mentality of a simple voltmeter should suffice for purpose of gross monitoring. The other extreme being someone who runs refrigerators, freezer, radar, full electronics, inverter, etc.. and has a large house bank with a correspondingly large charging system who needs to know the state of charge to figure out what might be intuitive to someone with a single battery and less gadgets.
To say it in fewer words, it depends.

Stu Jackson · Mar 14, 2009

Phil V25 said:
what do you define as a good "means of measuring battery performance"?

Phil,

It's called a battery monitor. Look them up in the West Marine or Defender catalogs.

Bill Roosa · Mar 14, 2009

Dead cells

As an auto mechanic in college, I saw a lot of dead batteries. The one thing all of them had in common was they where deeply discharged trying to get the engine started during the winter.
You can tell if you have a bad cell or are developing a bad cell by looking at the water in the cells while charging. The cell that is bad will have no bubbling going on in it because it is shorted and no charge is being accepted. If you take the time to check your cells while charging you will be able to check that all the cells are bubbling at the same rate. If you have one that does not seem to be bubbling as much as the others that battery is on its way out and WILL fail shortly.
ALL the failures I saw where directly related to deep discharges so you might want to check your batteries after such an event. I'd recommend that you check the bubbling 15 minutes after putting them on charge.
Another way to check batteries is to turn off all loads, take the caps off and using a volt meter set to measure 2ish volts test the water between each adjacent cell. Use the terminal for the end cells. If one tests low it is on its way out and you should take appropriate measures. DO NOT touch the multimeter probe to the battery plates. Only test the water in the cell.