House Batteries — Confused

[Frank DeFeo]

Ok, now my rv repair shop has me confused, who is a Forest River dealer.
Took my 2016 369xl in today for new batteries and a check over before my Thanksgiving trip. Currently have 4 12v batteries which is how the rig came from FR. He strongly suggested that I replace them with 4 6v batteries. Said I will get better life and performance out of them.
Having trouble getting my head wrapped around this. Does this make sense?

[Tx2Stepn]

Yes it makes sense if you have the room for them. You will get more amp hours and they can be wired to give you 12v

[Tx2Stepn]

Watch this video might help you understand

https://youtu.be/Xt2igyyyNb4

[Frank DeFeo]

Originally Posted by Tx2Stepn

Yes it makes sense if you have the room for them. You will get more amp hours and they can be wired to give you 12v

Thanks for your reply. This is my 4th mh. I can do most repairs, services and mods myself, but when it comes to anything electrical my mind goes to mush.
Thanks again.

[67L48]

Originally Posted by Tx2Stepn

[...] You will get more amp hours [...]

Not necessarily true. Good quality 12 V batteries will be about the same as 6 V, when used in these multiple-battery circuits. For example, Trojan's group 27 12V is rated to 105 A-Hrs and the T-105 6V is at 225 A-Hrs ... so, about 15 A-Hrs more in the 6V than 12V, which probably is negligible. A group 29 will have even more.

There are some benefits to going with 6 V. Capacity generally isn't one of them ... unless you're comparing really crappy 12 V to good quality 6 V.

Good luck.

[SlowrideHD]

Originally Posted by 67L48

Not necessarily true. Good quality 12 V batteries will be about the same as 6 V, when used in these multiple-battery circuits. For example, Trojan's group 27 12V is rated to 105 A-Hrs and the T-105 6V is at 225 A-Hrs ... so, about 15 A-Hrs more in the 6V than 12V, which probably is negligible. A group 29 will have even more.

There are some benefits to going with 6 V. Capacity generally isn't one of them ... unless you're comparing really crappy 12 V to good quality 6 V.

Good luck.

I have eight of the Trojan T-105 6v batteries on my solar setup. All wired in series to give me about 50.6v to my 3600 watt pure sine wave inverter. Those batteries weigh 62 lbs each. Definitely some advantages to good 6 volt batteries over 12 volt.

[wrapperman]

Actually there are virtually no differences in 12 volt and 6 volt batteries. As long as they are the same weights and deep cycle. The room will generally dictate which way to go.

[clarkbre]

The 6v over 12v comparison does lead to the 6v being slightly superior in build quality for the purpose of RVing.

Vehicle and deep cycle batteries are build with multiple (3 or 6) 2v cells wired in series to obtain the needed voltage. While 2 6v batteries can be wired in series and 2 12v batteries can be wired in parallel to obtain the same amp hours, the 6v batteries will have 2 slight advantages over the 12v.

The 6v batteries are physically the same in size and weight to a 12v battery; however, housing 3 larger 2v cells, allows the battery to be charged and drained more evenly and consistently (balancing the voltage on 3 instead of 6 cells). 2 6v batteries wired in series forces the batteries to charge and drain and a very even 12v using the exact same amp hours out of each battery.

The 12v batteries have 6 2v cells to make 12v. Charging these batteries, the chargers have to do twice the effort to balance the 6 cells per battery instead of 3 cells per battery. This can lead to inconsistent charging where some cells will take more amperage over others....but, a battery is only as good as it's weakest cell. The other thing to be concerned with 2 12v batteries is wired in parallel, the batteries are both supplying 12v of power but one could be discharging faster than the other. This can also lead to shorter battery life as the 2 batteries will constantly be trying to balance each other in voltage.

Long story short, the 2 6v batteries will have 6 large cells and be wired in series to provide a uniform, single 12v power supply. The 2 12v batteries will have 12 small cells and be wired in parallel to provide 2 12v power supplies that are independent of each other but still try to balance each other out.

[bubbles]

If you don't expect to do a lot of boondocking your 12 volt batteries are fine.

[2manytoyz]

6V golf cart batteries weigh close to the same as a 12V regular lead acid battery. The reason being is the very large surface area of the plates on the 6V version. Half the number of plates as a 12V battery, yet close to the same weight. These 6V batteries were designed for deep discharges, and quite a bit of abuse by commercial golf course usage.

The benefit is when two 6V batteries are used to replace one 12V battery. As an example, one T1275 deep cycle battery is rated at 150Ah @ 20 hour discharge rate (standard used).

Ref: https://www.trojanbattery.com/product/t-1275/

The T105 deep cycle battery is rated at 225AH @ 20 hour discharge rate. Two of these in series would give you 12V and 225AH of capacity.

Ref: https://www.trojanbattery.com/product/t-105/

I have a solar setup at home, and have used 6V golf cart batteries for over a decade. I power part of my home with the energy collected/stored.

That said, I'm using 4 Trojan T1275 batteries in my golf cart. It actually has the option to use 8 T105 batteries, but the cost and weight isn't a big benefit for my application.

If you decide to buy Trojan batteries, check your local golf cart shop FIRST. I paid (with core exchange), state fees and taxes $772.54 for all 4 T1275 batteries. While this ain't cheap, it was a lot less expensive than having other shops order them for me. Furthermore, with the high turnover rate at a golf cart shop, all the batteries were fresh from the factory.

When my 4 RV house batteries die, this is what I'll be purchasing.

[MR.M]

Originally Posted by Frank DeFeo

Ok, now my rv repair shop has me confused, who is a Forest River dealer.
Took my 2016 369xl in today for new batteries and a check over before my Thanksgiving trip. Currently have 4 12v batteries which is how the rig came from FR. He strongly suggested that I replace them with 4 6v batteries. Said I will get better life and performance out of them.
Having trouble getting my head wrapped around this. Does this make sense?

you could get a couple trojan j185e-ac deep cycle 12 volt batteries at 175 amphr each , 4 of them would give you 700 amp hr . 4 6 v 225 amp hr batteries will only give you 450 amp hrs

[formerFR]

my question, though, is WHY are you getting 'new' batteries in the first place, with a fairly new coach?

[Toyman]

First, determine your needs...always stay with hookups = one cheap 12V

Infrequent overnight at Walmart = 2x mid range 12v.

Beyond that, YOU really need to know your application. Before I put 4 or more of any battery I would do Lithium. Look at the life cycle cost, weight & warranty.

4 T1275 = 340lbs, 300 MAXIMUM usable AHs, $ $1300. Did a search on the Trojan website for warranty info and found 18mo replacement, no extended prorate. Plus Maintenance requirements, additional cabling, space utilization.

Google is your key to information ... check out the equivalent Lithium numbers on https://battlebornbatteries.com & decide for yourself.

[SlowrideHD]

Originally Posted by 2manytoyz

Ref: https://www.trojanbattery.com/product/t-1275/


I have a solar setup at home, and have used 6V golf cart batteries for over a decade. I power part of my home with the energy collected/stored.

That said, I'm using 4 Trojan T1275 batteries in my golf cart. It actually has the option to use 8 T105 batteries, but the cost and weight isn't a big benefit for my application.

If you decide to buy Trojan batteries, check your local golf cart shop FIRST. I paid (with core exchange), state fees and taxes $772.54 for all 4 T1275 batteries. While this ain't cheap, it was a lot less expensive than having other shops order them for me. Furthermore, with the high turnover rate at a golf cart shop, all the batteries were fresh from the factory.

When my 4 RV house batteries die, this is what I'll be purchasing.

Good information for those that don't know. Good price and advice on using your local golf cart shop too. I bought my eight T-105 Trojans for under $1100, tax and all, loaded on my truck. No core exchange but this would have saved me $240 at $30/ea battery.

[camaraderie]

I'm with FormerFR... I'm fine with 4 6V or 4 12V as there is little to no difference in performance among good batteries...but ususally the 6V will be cheaper. Like FormerFR...the real puzzle is WHY you are replacing relatively young batteries and what are you doing that killed them early...and how can you get the best life out of the new ones.
We could have one more of many long discussions about this but IF YOU BOONDOCK... get yourself a true battery monitor like the Victron or Trimetric.
Use it to know when you've hit 50% charge and need to recharge....and use it to know when you've 100% charged up again. They are NOT voltage based...and a volt meter CANNOT tell you these two things accurately. Over discharging and under charging are the two biggest killers of batteries (other than running them dry!). Never run below 50% and never charge to less than 100% and keep the water up...
If you don't boondock...forget the monitor, forget the 6V's and just get cheap dual purpose 12V's at Walmart...since you don't cycle...you don't need deep cycle.

[Frank DeFeo]

Ok, here is the bottom line. Shop checked converter, that was working properly. Then checked batteries, 1 was ok, 2 were weak and 1 very week. Replaced all 4 12v with 4 6v. Washed tray out with baking soda and repainted tray. Installed new batteries and rewired. All for $742.
Forgot to mention what started all this. On my last trip tried pulling slides in and they barely came in at a snails pace, even stopped half way and all lights dimmed. Then fortunately started again and came in. Even awning came in extremely slow. All this while still plugged into 50amp shore power.
Hopefully all set now. Thanks to everyone for chiming in with suggestions. As we all know, great site for sharing and helping fellow RV’ers.

[garbonz]

Originally Posted by SlowrideHD

I have eight of the Trojan T-105 6v batteries on my solar setup. All wired in series to give me about 50.6v to my 3600 watt pure sine wave inverter. Those batteries weigh 62 lbs each. Definitely some advantages to good 6 volt batteries over 12 volt.

All this post does is confuse things although you are wonderful to have such an advanced system. So where does your 12 volt feed come from, a dc to dc converter? I presume you do this to use smaller wire to the inverter.

[garbonz]

Originally Posted by Frank DeFeo

Ok, here is the bottom line. Shop checked converter, that was working properly. Then checked batteries, 1 was ok, 2 were weak and 1 very week. Replaced all 4 12v with 4 6v. Washed tray out with baking soda and repainted tray. Installed new batteries and rewired. All for $742.
Forgot to mention what started all this. On my last trip tried pulling slides in and they barely came in at a snails pace, even stopped half way and all lights dimmed. Then fortunately started again and came in. Even awning came in extremely slow. All this while still plugged into 50amp shore power.
Hopefully all set now. Thanks to everyone for chiming in with suggestions. As we all know, great site for sharing and helping fellow RV’ers.

If you were plugged in then your batteries didn’t matter, your converter is bad, and your dealer is a kook. Run away. Your problems will be reoccurring soon.

[Whitnee1]

OK so I do a lot of dry camping and have a residential fridge. I currently have 4 12 volt batteries. If I converted to the 6 volt would I only do 2? Can I do 3 or 4 and if so would the wire be the same?

[clarkbre]

Originally Posted by Whitnee1

OK so I do a lot of dry camping and have a residential fridge. I currently have 4 12 volt batteries. If I converted to the 6 volt would I only do 2? Can I do 3 or 4 and if so would the wire be the same?

To maintain the same or more amp hours, you will need four 6v batteries.

No, they would not be wired the same. Currently, to give you 12v power, you have four 12v batteries wired in parallel.

In order to give you 12v power with four 6v batteries, you would need to wire two sets in series and then parallel the two series together. This would provide 12v with the maximum amp hours for dry camping.