27 group & 24 group batteries

OK, I can’t go with 4 6v batteries due to space, so that leaves me back with 2 12v’s. It seems that our battery compartment is 24.5″ wide and 2 group 27 batteries will be 24″ wide and that just isn’t enough space. 2 of the group 24 batteries are only 20″ wide and that is what we have had for the past 4 years. Does anybody know if I can mix the 2 groups? In other words, can I do 1 group 24 and 1 group 27 hooked in parallel?

I’m not sure about yours, but my battery compartment will accommodate either two group 27 end to end OR 3 group 24 side by side. The 4th would have to placed in the forward basement very near the others. I will probably be doing this due to installing a new residential fridge and inverter. The one placed in the forward basement can easily be done by using a sealed battery box vented like the other batteries.
On the subject of mixing battery group sizes, I have read that it is ok as long as they are all of the same voltage and age but it depends on who you ask. I personally would not. Below is a link to the question. Good luck, Phillip
http://www.altestore.com/forums/Renewab … 268.0.html

Mismatched batts will charge each other at night, with solar or when your rv is not plugged in, causing a short battery life. Check out HandyBobs web site. Lots of info on batts and solar.

Lillyputz

2 good quality 6 volt golf cart batteries = 2 group 27 and will fit. They are heavier duty.

Thanks, I will not mix groups. As far as the 2 6v, several battery companies have replied to me that if 2 batteries is my option, I am better with 2 12v’s. If there is first hand experiense, I would love to hear it. I trust members of this site more than corporations trying to sell batteries.

6volt, deep cycle batteries, such as Trojans will give you better performance over a long life cycle. Most 12 v “deep cycle” batteries are designed as multifunction units – starting and providing longer term use. It is a compromise. Just look at the weight of deep cycle 6 volts versus a 12 volt and it get ones obvious. I’ve her seen a golf cart with 12 v batteries. Always six volt and there a fee applications more demanding than a golf cart.

Well given that I only have room for 2 batteries, I went with 2 of the 27 group NAPA 12v deep cycle. Thanks for all of the input and if I had the space, I would have gone with 4 6v Trojans.

Just an FYI. Two 6 volt Trojans would have provided 220 Amp hrs of 12 volt power.

Any idea what I will get out of what I purchased? All I could learn before I made a decision was that if I went with 6v, I needed 4 of them. Also, the closest Trojan supplier is almost 2 hours away.

To obtain 12 volts using a pair of six volt batteries requires that two of them be wired in series: the positive terminal of battery A is your hot lead, the negative terminal is attached to the positive of battery B and the negative of battery B goes to ground. This then becomes a twelve volt unit. Attaching two 12 volt units in parallel would double the amp hour capacity, etc. the batteries you have should indicate the amp hour capacity on the label.

Unless you do a lot of dry camping I would use 2 12volt batteries. If one of the 12volt batteries goes bad you can take it out and use only the other 12 volt battery. I have done this before. If you use 2 6volt batteries and loose one you have a bigger problem. JMO
Don

Moo,

With 12 volt batteries, you just add up the amp hours of each; do two that say they are 185 will give you. 370 amps at the quoted draw rate. In rv applications you will likely average a higher draw rate, but 370 will work for minimalistic boon docking.

With 6 bolt batteries, you don’t get more amps when you combine 2 batteries, you do double he voltage. So two of the cited 220 amp Trojan provide 440 amps at six volts if wired that way, but only 220 amps at 12 volts when wired in series. Adding a second set of 2 Trojan will give you 540 amps at 12 bolts.

If your 2 12 volt batteries had exactly the same amp rating as four 6 volt batteries, you would not likely see any difference in performance unless you are a heavier boon dock user. All acid flooded batteries need to be kept properly watered. I suspect that the 12 volt units will dry out faster, but do not know this. The 6 volters will deal with heavy draw downs (below 40 percent) much better than the 12’s; but neither really like it unless fully recharged very soon thereafter. By deal with, I mean last for more such cycles before needing to be replaced.

moo2613 wrote:Any idea what I will get out of what I purchased? All I could learn before I made a decision was that if I went with 6v, I needed 4 of them. Also, the closest Trojan supplier is almost 2 hours away.

Thanks. There is no way they are comming back out in order to look at the labe, it’s all l could do to make 24″ of battery fit through a 23″ hole. I may try a mirror.

The last pair of 12v’s lasted us over4 years, so apparently we can survive just fine with them. With the solar panel, we do just fine for the 2 weeks of boonedocking we do each spring, this includes the breathing machine that runs on 12v. I have high hopes that with the 27 group batteries, we can make it through the cloudy days without staring the generator to charge.