Auxiliary batteries - Golf buggy 6v in series vs 12v AGM's

[Fubar]

I'm just planning out the last of a long list of upgrades and came across a recommendation to run a pair of 6v golf buggy batteries in lieu of the 12v options for auxiliary power.

A pair of 6v 225ah wired in series beats the snot out of a pair of 105ah 12v batteries. Both set ups would weigh the same.

Seems too good to be true....costs aside what's the catch? There has to be one.

Looking at what I need for our long term touring/camping set up and I'm leaning towards more batteries than solar to keep everything going. We don't hang around camp all day and almost will always be on the move every few days.

[Tombie]

A serious combination of Solar and battery reserve will outdo battery banks hands down.

Here’s my experience with this.

2x 6v will have slightly thicker plates so may well work a bit better at deep discharge.

However for a long term tourer (offroad) redundancy is king... if a 6v dies that’s it you’re done.
If a 12v dies in a parallel you can just drop it out of the system.

Other than that it all comes down to packaging.

[drivesafe]

While I have used two 6v batteries in series, to get a 12v setup, I have to be honest, I a not a fan.


Potential problems are:-


If you have two 12v batteries in parallel and one dies, your still have a LIMITED 12v supply.


If a 6v dies, you have lost the lot.


If you are in the middle of nowhere and you lost one of your 12v batteries, any 12v battery, including substituting a deep cycle with a cranking battery, will get you back up to the capacity you need and you can get cranking batteries at most outback servos.


If a 6v battery dies in the middle of nowhere, you not only have no battery power, but you may find it near impossible to get a replacement and the freight may bankrupt you.


And the replacement MOST BE IDENTICAL, making getting a replacement that much harder.

[p38arover]

I'm running two 12V 45Ah deep cycle AGM batteries (as used a mobility scooter) in parallel in my dual battery setup in the L322 - they fit in the space available under the floor whereas a 12v 100Ah battery wouldn't.

[Homestar]

Where did this info come from? - 'A pair of 6v 225ah wired in series beats the snot out of a pair of 105ah 12v batteries. Both set ups would weigh the same.'

Energy density in a given format is similar, so the 2 x 6 volt batteries if they ran identical design, etc would be slightly heavier, and give you a little extra capacity, but that's because they are bigger batteries, so in series you end up with 12 volts and 225Ah, (remember your Ah capacity doesn't double to 450 like this, but remains the same at 225 - you only double your voltage when you connect them in series) but in reality not - they wouldn't discharge at an identical rate (close) but you'd lose a bit there, then as mentioned you lose one battery, the whole show is gone. Both batteries would need to be identical and of similar age too to even work to start with and not stuff one in a few hours of driving. If you are after the extra 20Ah, why not buy 2 x 12 volt, 110Ah batteries then you have exactly the same capacity with redundancy built in.

[Fubar]

Where did this info come from? - 'A pair of 6v 225ah wired in series beats the snot out of a pair of 105ah 12v batteries. Both set ups would weigh the same.'

Energy density in a given format is similar, so the 2 x 6 volt batteries if they ran identical design, etc would be slightly heavier, and give you a little extra capacity, but that's because they are bigger batteries, so in series you end up with 12 volts and 225Ah, (remember your Ah capacity doesn't double to 450 like this, but remains the same at 225 - you only double your voltage when you connect them in series) but in reality not - they wouldn't discharge at an identical rate (close) but you'd lose a bit there, then as mentioned you lose one battery, the whole show is gone. Both batteries would need to be identical and of similar age too to even work to start with and not stuff one in a few hours of driving. If you are after the extra 20Ah, why not buy 2 x 12 volt, 110Ah batteries then you have exactly the same capacity with redundancy built in.

Buy Trojan T-105 - Trojan Deep Cycle Batteries (https://www.everybattery.com.au/proddetail.php?prod=T-105&gclid=Cj0KCQjw-JvaBRDGARIsAFjqkkpbOYsId0DPGMtHWLME26AhmTYxGGhrUn4 Gs71H0_wxr7gUnBLpuaUaAmBQEALw_wcB)

Well that's the nail on the head.

Bloody hell I should know better! That's the 'catch', need to smack myself up the side of the head....I'm a moron. I got way too excited at the outcome and not the why.

ah @ 12v = wh/v

ah @ 6v =wh/v

1200/12=100ah

1200/6= 200ah

[donh54]

Also, 2 x 6v @ 28 kgs each = 56 kgs
Most deep cycle AGM types are around 30 kgs +/- ~4 kgs

Big difference!

[Homestar]

Buy Trojan T-105 - Trojan Deep Cycle Batteries (https://www.everybattery.com.au/proddetail.php?prod=T-105&gclid=Cj0KCQjw-JvaBRDGARIsAFjqkkpbOYsId0DPGMtHWLME26AhmTYxGGhrUn4 Gs71H0_wxr7gUnBLpuaUaAmBQEALw_wcB)

Well that's the nail on the head.

Bloody hell I should know better! That's the 'catch', need to smack myself up the side of the head....I'm a moron. I got way too excited at the outcome and not the why.

ah @ 12v = wh/v

ah @ 6v =wh/v

1200/12=100ah

1200/6= 200ah




Correct - power is power - the wattage of a given load stays the same - the current drawn is a different story. No free lunches here unfortunately. [wink11]