6v serial vs 12v parallel for House Power

[snu164]

I recently purchased a new-to-me Jayco Alante. Before the sale, the previous owner replaced the house battery with a single 12v 100Ah marine deep cycle battery (less than one month old).

Based on the use of my old RV, I suspect that 100Ah isn't quite enough; however, it's a brand new battery. Would I be better off scrapping the brand new battery and replacing with two 6v in series to get 200Ah? Or purchase another new identical 12v battery to connect in parallel?

Option C is to swap the 6v batteries out of my old RV with the new 12v before selling it. They're only two years old.

[Brunnie]

Putting 2 six volt batteries will give you 12 volts, but it won't give you 200 Ah.


If you want 200 Ah, then you are better off getting another 12 volt battery and putting it in parallel with the first battery.

[Olyteddy]

Originally Posted by Brunnie

Putting 2 six volt batteries will give you 12 volts, but it won't give you 200 Ah...

Yes it will, provided that both 6 Volt batteries are 200 Ah. GC2 batteries, for example, are typically 225 Ah. Amps are the same at any point of a series circuit.

[Brunnie]

Originally Posted by Olyteddy

Yes it will, provided that both 6 Volt batteries are 200 Ah. GC2 batteries, for example, are typically 225 Ah. Amps are the same at any point of a series circuit.

That isn't what the OP said, though. The assumption is that the 6 volt batteries are 100 Ah each (since the OP didn't say how many Ah they were or what group they are). My answer still stands.

[twinboat]

Originally Posted by Brunnie

That isn't what the OP said, though. The assumption is that the 6 volt batteries are 100 Ah each (since the OP didn't say how many Ah they were or what group they are). My answer still stands.

Find me a 100 AH , 6 volt battery.

The least AH rating out there is 190 AH AGM from Sam's Club.

You can't assume something that isn't out there.

[wolfe10]

Yup, I would replace with two approx 225 amp-hr 6 VDC golf cart batteries (I prefer AGM) wired in series and use your almost new 100 amp "multi-purpose"/marine battery for something else or sell it.

[Persistent]

Cost:

Shop around for a matching replacement. Choose same brand, model, size, type, and voltage. Amp hours are the specification you are working on. A matching 100 amp hour battery will bring your total to 200 amp hours.

Shop around for a pair of 6 volt flooded cell gulf cart batteries.
Compare the price difference. Again amp hours are important. A pair of 225 amp hour batteries will give you 225 total amp hours.

AGM compared to Flooded cell.

If the 12 volt battery you have is an AGM battery, then of course you would pair it with another 12 volt AGM battery. AGM batteries generally cost more than flooded cell, but have features that are desirable for use as deep draw house batteries.

They charge and discharge faster.
They do not require maintaining water levels.
They do not emit acid mist or spit acid.
They do not emit flammable gas.
They are more protected if you draw them down flat. They stop discharging before damage is done.
They can be installed in occupied spaces. They do not need to be outside in an open compartment or box.

Many people have a seemingly religious belief that flooded cell 6 volt gulf cart batteries are better in all respects. This was true 30 years ago. It is not true today. Technology has changed.

12 volt AGM batteries are better than 6 volt flooded cell batteries in many ways except cost. Like wise LiPO4 batteries are better than AGM in most ways except cost.

[Winemaker2]

Originally Posted by Brunnie

Putting 2 six volt batteries will give you 12 volts, but it won't give you 200 Ah.


If you want 200 Ah, then you are better off getting another 12 volt battery and putting it in parallel with the first battery.

I'm with others... wrong assumption... find a 100AH 6V batty that isn't meant for toys.

This is why a pair of 6V GCs is your best bet. Worth the read as it covers the topic very well.

https://marinehowto.com/what-is-a-deep-cycle-battery/

Sent from my SM-T878U using iRV2 - RV Forum mobile app

[JMynes]

A pair of 6v golf cart batteries in series is better than two 12v group 24 batteries in parallel only on days that end with Y.
I recently traded a travel trailer with 2 GC batteries for a new class C with batteries under the entry steps. The tape measure says GC batteries will fit into the tray, barely, but they’re too tall for the step to go back on.
Now I’m back to two group 24s, and the difference is obvious. I can’t drip a cup of coffee using the inverter like I used to…

[Kayakist]

My class A came with two 12v Group 24 FLA batteries. When I looked at upgrades the dimensions of the battery compartment limited my choice substantially.



Larger capacity 12v batteries wouldn't fit. Luckily, two higher capacity 6v batteries would (just barely due to bigger height). Bought two Trojan's, am very happy.

[snu164]

Thanks all for the replies. I think I will pull the 6v LAs out of my old rig and put them in the new rig. I’ll look into the AGMs once the sticker shock has worn off from purchasing the new rig.

[bill06447]

I have two 6v 220ah sealed group 27 batteries on their side in my battery bay. 6v batteries are GENERALLY better made with stouter plates than 12v and SHOULD last longer. (Mine are 8 years old and still give us 2-3 days before you notice they are getting low yet will still crank the genny)

[twinboat]

Originally Posted by bill06447

I have two 6v 220ah sealed group 27 batteries on their side in my battery bay. 6v batteries are GENERALLY better made with stouter plates than 12v and SHOULD last longer. (Mine are 8 years old and still give us 2-3 days before you notice they are getting low yet will still crank the genny)

Group 27 batteries are 12 volt.

Group GC2 are 6 volt .

[Ludo]

With two 6v in series you'll will notice directly when one battery fails. With two 12v on parallel you'll find out only that both are dead.


But I'd propose you install a balancer to insure that both batteries are always on the same Soc. Or install a Victron battery manager like the bmv712 to at least be able to check them regularly.