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3miles · 07-28-2021, 04:49 PM

Needed to replace the single twelve volt house battery in the '16 Grand Design 29RS and decided to go with two 6 volt deep cycle flooded lead acid made by US BATTERY. 230 amp/hr wired in series putting out 12 volts. Should run the lights and spin a fan from time to time.
$113 each plus a little tax and some cables and about $20 for a double box.

GrantR · 07-28-2021, 05:44 PM

If you are going to put in 2 batteries, I am curious why you would not put in 2 x 12 volt deep discharge batteries. That would provide more overall capacity.

3miles · 07-28-2021, 06:57 PM

This pair of 6 volt batteries supply 230 amp/hrs which is actually more power than most paired 12 volt systems. They are slightly taller than the 12 volt batteries. The series 6 volt system that I installed has much thicker plates than a parallel 12 volt system and offers many more charge/discharge cycles. When properly maintained the 6 volt system has a good chance of lasting 8-10 years.

xc-mark · 07-31-2021, 08:57 AM

Quote:

Originally Posted by GrantR

If you are going to put in 2 batteries, I am curious why you would not put in 2 x 12 volt deep discharge batteries. That would provide more overall capacity.

you are incorrect that 2 -12 volt battery have more power. Typical 12 volt (group 27 or group 31)battery are about 70 amp hours at 12 volt = 140 amp hours total

2 - 6 volt battery in series will be over 200 ~ 260amp(total) hour depending on the exact battery. you still can only draw a lead acid battery down to 50% without reducing the life expectance of the battery regardless of the brand or voltage so keep this in mind with your looking at your 12 volt battery needs.

the other issue with 2 -12 volt battery is if one of the two battery fail and have a internal short it kills both battery and you have nothing. If one battery has a bad cell your going to over charge that battery and it will end up being the cause of both battery failing. Its less likely with a 6 volt to have a battery cause both to fail from a internal short because its not wired the same way where one can feed current to the other .

treeoflib · 07-31-2021, 10:22 AM

Quote:

Originally Posted by 3miles

This pair of 6 volt batteries supply 230 amp/hrs which is actually more power than most paired 12 volt systems. They are slightly taller than the 12 volt batteries. The series 6 volt system that I installed has much thicker plates than a parallel 12 volt system and offers many more charge/discharge cycles. When properly maintained the 6 volt system has a good chance of lasting 8-10 years.

You chose well. We have 4x6 in our 29RS, and paired with inverter and solar, is serving us well. My biggest lesson was to keep an eye on the water levels, and they will last for years.

Cumminsfan · 07-31-2021, 11:26 AM

Quote:

Originally Posted by xc-mark

you are incorrect that 2 -12 volt battery have more power. Typical 12 volt (group 27 or group 31)battery are about 70 amp hours at 12 volt = 140 amp hours total

2 - 6 volt battery in series will be over 200 ~ 260amp(total) hour depending on the exact battery. you still can only draw a lead acid battery down to 50% without reducing the life expectance of the battery regardless of the brand or voltage so keep this in mind with your looking at your 12 volt battery needs.

the other issue with 2 -12 volt battery is if one of the two battery fail and have a internal short it kills both battery and you have nothing. If one battery has a bad cell your going to over charge that battery and it will end up being the cause of both battery failing. Its less likely with a 6 volt to have a battery cause both to fail from a internal short because its not wired the same way where one can feed current to the other .

Or if one 6V fails you only have 6V.

GrantR · 08-01-2021, 10:23 AM

Yep- also depends on the battery you are using, the class 31 AGM’s I have are around 110AH each.

3miles · 08-03-2021, 06:24 PM

Quote:

Originally Posted by treeoflib

You chose well. We have 4x6 in our 29RS, and paired with inverter and solar, is serving us well. My biggest lesson was to keep an eye on the water levels, and they will last for years.

That is a very nice set-up. Maybe someday when we go full-time I will build our up very similar to your rig. Enjoy!