Twelve- or six-volt deep cycle RV batteries : What's best?

[windsunvolts]

I recently purchased two rolls surrette l16 series 4000 6 volt batteries and honestly I am a little disappointed , sure they are fine batteries and I'm sure they will last a long time. I'm just disappointed in the characteristics of 6 volt vs 12 volt batteries. now that I have a large bank of these batteries I can put a load on them for hours and they will still retain a higher specific gravity/voltage than pairs of 6 volt batteries will. My rolls bats rest at 12.6 but marine stay at 13.1-13.3

[windsunvolts]

Two Energizer deep cycle marine group 29 12 volt from sams club --84.00 each ---125 amp hours 3 year pro rated warranty. 125 X 2 = 250 amp hours @ $168.00.

Two Energizer deep cycle golf cart 6 volt from sams club --78.00 each ---225 amp hours

1 year warranty 225 6 volt + 225 6 volt = 225amp hours @ $156.00

I have purchased separately on 2 occasions banks of batteries of each type golf cart and

marine for me the large marine 12 volt has outperformed the golf cart batteries.--continued--

[Comfytees]

How many 12v batteries would i need to power a small ac unit for example 5,000 btu or a smaller unit for 5 hrs without draining the batterirs too low (dod)?

[jagsaiyan]

I dont get why parallel is bad. So if I was to setup my house with wind + solar, its better to use 1 giant battery with power then use an array of them?

[hoffinger]

Wiring 12 volt batteries in parallel will have a short life. The 12 volt wet cell batteries will last about 2 years or so.I have seen them last for 3 months.The plates are thinner and closer in 12 volt.The 6 volt battery has thicker plates and will laty 5+ years. I use AGM batteries now. I use Battery Corp, same used in cell phone towers.One 170 amp hour battery will do better than 220 amp hour 6volt pr.The AGM has much lower internal resistance. They charge 100 times faster than wet cells.

[1toomanyhobbies]

great vid. thanks for the info!

[sirmasterpimp]

Correction I meant to spell loose lose, my spelling sometimes.....

[sirmasterpimp]

Nice but it all depends on the battery. When wiring in series you loose capacity (is why your 6 volt batteries can make 12 volts in series, but can't double capacity.) For example, If someone were deciding between two 6 volt 100 ah batteries wired in series vs two 12 volt 100ah batteries wired in parallel, the 12 volt would win. With the 6 volt, you would have 12 volts and only 100 ah, but with the 12 volts you would retain 12 volts and now have 200 ah. The trojan t105 is rated at 225 ah for 1.

[crackermantim]

@sirmasterpimp bit confused/ your comment on making 2 6v batteries in series loses capacity..whereas the rv doctor guy in the video says it will increase capacity...which is correct?

[sirmasterpimp]

@crackermantim In his example he is right, because he is comparing a smaller 12 volt battery to a much larger and expensive 6 volt. If the batteries were the same capacity / price (how you would view in an actual retail store) I would be right.

EX his... (parallel) 12v = group 27 @ 105 ah x2 = 12 v @ 210 ah........(series) 6v = huge trojan @ 225 ah x2 = 12 v @ 225ah (6 volt better)

EX mine: (P) 12 v = 100ah x2 = 12v @ 200ah.........(S) 6 v = 100ah x2 = 12 v @ 100 ah (12 volt better)