one vs two batteries

[IanC]

I see quite often that people pick 2 x 6volt batteries over one 12 volt. Is there a reason other than maybe the weight to lift? I'm just getting ready to head to Walmart - I going to get a 12 volt but perhaps I should hold off to see what folks have to say. Thanks

 

[ahh_me2]

True deep cycle batteries are usually 6 volts.

So your capacity based on 2 X 6 v will be far greater than 1 X 12 v

 

[Optimistic Paranoid]

A TRUE deep-cycle battery needs lots of very thick lead plates, and it's hard to fit them into a typical 12 volt battery case.  At best, you usually end up with one of the hybrid marine/rv batteries rather than a TRUE deep cycle.

A "cycle" is defined as discharging a fully charged battery down to 50% and then fully recharging it.  An engine starting battery is not designed for that - lots of very thin lead plates in order to maximize the square inches of lead exposed to acid - and you will be lucky to get 40 to 50 cycles from one before you kill it.  A marine/rv battery has thicker plates, and is usually good for 400 to 500 cycles.  A TRUE deep cycle battery has much thicker plates yet, and if properly cared for, will give you 1,000 or maybe even 1,500 cycles.

Plus, the 6 volt golf carts usually have 200 amp hours of capacity, whereas the 12 volt usually only has 100 to 125 amp hours.  You could parallel two 12 volts together to match the amp hours of two 6 volt golf cart batteries in series, but you'd still be dealing with the much lower cycle lifespan.

 

[Van Lady]

Thank you for asking this question. I am interested in learning from the responses.


Van_Lady

 

[AngryVanMan]

Already mentioned, but the difference is often in the style of the lead "plates." Deep cycle batteries have smooth, solid lead plates, which shed less material over time and with each cycle. Starter batteries, marine batteries, and other hybrid batteries are made with a lead 'sponge' material - this has a high surface area which gets you low resistance and higher peak amp output, but all those little intricate structures of the sponge break down faster, leaving junk at the bottom of the cell - that decreases the capacity and over time will short the cells. Some golf cart batteries use plates, and some are more of a hybrid. You can tell - the good manufacturers will sometimes use the plate thickness in their marketing materials (Trojan) and you can also tell by the weight of the battery - sponge has less overall lead quantity in it than a solid plate design.

 

[IanC]

A TRUE deep-cycle battery needs lots of very thick lead plates, and it's hard to fit them into a typical 12 volt battery case.  At best, you usually end up with one of the hybrid marine/rv batteries rather than a TRUE deep cycle.

A "cycle" is defined as discharging a fully charged battery down to 50% and then fully recharging it.  An engine starting battery is not designed for that - lots of very thin lead plates in order to maximize the square inches of lead exposed to acid - and you will be lucky to get 40 to 50 cycles from one before you kill it.  A marine/rv battery has thicker plates, and is usually good for 400 to 500 cycles.  A TRUE deep cycle battery has much thicker plates yet, and if properly cared for, will give you 1,000 or maybe even 1,500 cycles.

Plus, the 6 volt golf carts usually have 200 amp hours of capacity, whereas the 12 volt usually only has 100 to 125 amp hours.  You could parallel two 12 volts together to match the amp hours of two 6 volt golf cart batteries in series, but you'd still be dealing with the much lower cycle lifespan.

Ok, thanks . Glad I asked. So I'm guessing the batteries sold at Walmart as deep cycle are not true deep cycle batteries.

 

[Almost There]

Ok, thanks . Glad I asked. So I'm guessing the batteries sold at Walmart as deep cycle are not true deep cycle batteries.

Not likely - it's an advertising thingie as opposed to a true statement of fact.

I put in 4 Trojan 105RE's instead of 3 AGM top of the line 12V batteries because it gave me more amp hours for less money.

If you do decide to look at the 6V GC batteries, take a serious look at the difference between Trojan 105s and the 105RE.

Several dealers in Quartzite were selling the T105s for $125.00 exchange battery included which was useless to me since I didn't have any to turn in. I found the T105RE's which have quite spectacular ratings for longevity for only $30.00 each more on line. Yes, I had to wait a week and go get them but still!

 

[IanC]

Not likely - it's an advertising thingie as opposed to a true statement of fact.

I put in 4 Trojan 105RE's instead of 3 AGM top of the line 12V batteries because it gave me more amp hours for less money.

If you do decide to look at the 6V GC batteries, take a serious look at the difference between Trojan 105s and the 105RE.

Several dealers in Quartzite were selling the T105s for $125.00 exchange battery included which was useless to me since I didn't have any to turn in. I found the T105RE's which have quite spectacular ratings for longevity for only $30.00 each more on line. Yes, I had to wait a week and go get them but still!

I've been looking at some online - wow, that's some sticker shock. The batteries will be almost as much as the rest of the solar system

 

[WheelEstate USA]

We began with a 12V "marine deep cycle" from Wally's. After a couple solar upgrades, got 2 new 6V deep cycle...color me impressed at the difference. We have power to spare, even with a fridge and TV. A few days of bad weather won't be any problem.

 

[Almost There]

I've been looking at some online - wow, that's some sticker shock. The batteries will be almost as much as the rest of the solar system

Where have you been looking? Try http://www.thesolarbiz.com/Trojan-T105-RE-6V-Battery-225-AH#gsc.tab=0

I guess sticker shock depends on how you see your system. I saw 4 Trojan 105REs as only a slight upgrade from the 105s with much longer warranty (5 years as opposed to 18 months) and a huge improvement in cycle ratings. I fully expect to get at least the 5 years out of the batteries, probably longer.

Powering a vehicle for any amount of usage certainly isn't cheap. I don't even want to start adding up what I've spent on wiring, outlets, fuse panel, battery charger, solar and batteries but once I've got the system in place I'm free to boondock with total freedom from needing shore power and other than the gas I use on the generator when it's necessary, it will all be 'free'.

 

[IanC]

Where have you been looking? Try http://www.thesolarbiz.com/Trojan-T105-RE-6V-Battery-225-AH#gsc.tab=0

I guess sticker shock depends on how you see your system. I saw 4 Trojan 105REs as only a slight upgrade from the 105s with much longer warranty (5 years as opposed to 18 months) and a huge improvement in cycle ratings. I fully expect to get at least the 5 years out of the batteries, probably longer.

Powering a vehicle for any amount of usage certainly isn't cheap. I don't even want to start adding up what I've spent on wiring, outlets, fuse panel, battery charger, solar and batteries but once I've got the system in place I'm free to boondock with total freedom from needing shore power and other than the gas I use on the generator when it's necessary, it will all be 'free'.

You're right - I know whatever I spend on my build will pay me back 100 times

 

[Spaceman Spiff]

I see quite often that people pick 2 x 6volt batteries over one 12 volt. Is there a reason other than maybe the weight to lift? I'm just getting ready to head to Walmart - I going to get a 12 volt but perhaps I should hold off to see what folks have to say. Thanks

Reasons I went with two GC2 batteries:

• Golf cart batteries are cheapest of the deep cycle batteries due to the large number produced.
• They are true deep cycle batteries.
• Yes, it is easier to handle two 60+ lb. batteries than one 120+ lb. battery.  Unless you are very strong or have an easy, direct access to your battery box, it makes a difference.
• Batteries fit into a standard sized, sealed plastic bin; which made it easy to vent (I have FLA batteries).
• Easy to find replacements almost anywhere, if ever necessary.

I got my two Energizer 6 volt golf cart batteries at Sam's Club for ~ $170 two years ago.

 -- Spiff

 

[highdesertranger]

I really can't add anything, everyone here has given great advice. highdesertranger

 

[rvpopeye]

If you have the space (a 6v is roughly the same as a group 24 starter battery but a couple inches taller)
and can deal with the extra weight . Def get two of the 6 volts. You'll never regret the choice.

One more thing ,,,bring a scale and weigh them ! The heavier ones will have bigger plates .

It's kind of like my old shop teacher told me about buying table saws etc .
"Buy by the pound ,cast iron rules , it will out preform all others!
Divide the price by the weight and there you are !"
I followed his advice and was thrilled by the tools I got ,,well , until I went fulltime in an RV and had to sell them all for the cost of tin !