34 replies to this topic

[Wallowa]

Probably missed it but why would you pick dual 6 volt batteries which I assume are in series over dual 12 volt batteries in parallel?  I did hear that the 6 volt batteries can deliver 30% more 'power' [Ahs?] than the 12 volt batteries; how I don't know.

 

If in series [6V] and you have one the batteries goes weak aren't you 'up a creek'?  In parallel [12 volt] you would still potentially have 12 volts if one of batteries craps out, correct?

 

I see the dual 6volt batteries are a $600 FWC option....ouch!

 

Phil

[Ace!]

It's just for more reserve (well, depending) and the ability to draw them down further.  The golf cart style batteries are designed to be drawn down further and recharged, at least more so than some of the other 12v options.

 

I killed 12v batteries by drawing them down too far and they wouldn't recharge.  I switched to dual 6s (with a different trailer) to get more reserve and a true deep cycle battery.  It was more hassle than it was worth (IMHO).

Edited by Ace!, 17 October 2018 - 04:56 PM.

[Wallowa]

Ace,

 

Thanks...I get it...but what about "series vs parallel"?  Did they fit existing battery box in camper?  How much more weight?  What brand/model did you buy?

 

Relevant since I met you at Tigard when we both bought our campers at the same time..

 

Thanks again...Phil

Edited by Wallowa, 17 October 2018 - 05:05 PM.

[Ace!]

I wired the 6v in series.

 

This was for a trailer I had prior to the Hawk and it had a single 12v battery that was supposedly deep cycle or a hybrid.  It was not a deep cycle in practical terms (it was a slightly better car battery I think).  The 6v batteries I swapped were much taller and I had to swap out my battery box to a different design.  They were much heavier as well.  They needed to be maintained regularly (water added).  Although they provided a better reserve and I ran them down more, I didn't like the cost, weight, maintenance and size.

 

In my Hawk I went with dual 12v batteries and I've added solar.  I've never had a problem with lack of power; although I will likely add another 100w solar panel.

[Wallowa]

Ah!  Now I see.

 

That actually is good news.  Your Hawk and your use is very similar to ours...and I also plan on another panel [currently with 160 roof and 80 portable]..

 

I doubt that I will ever go back to a vented, lead-acid battery...off-gassing, adding water and chance of acid escape is a no-go...all my motorcycles and vehicles use AGMs.

 

Let me know where you place a second roof panel [we have two roof vents], what brand you buy and how you wired it in.

 

Thanks Again,

 

Phil

[Vic Harder]

Phil,  I don't think there is any inherent advantage to serial over parallel in battery wiring.  I think it is more of a form factor and weight consideration.  Also "Golf Cart" batteries can be AGM or FLA.  FLA is more of a hassle than most of us are willing to put up with, so my assumption is we are all talking about various AGM battery shapes and sizes and AH capacities and designed purpose.

 

The reason "Golf Cart" comes up frequently is as a contrast to "Starting" batteries or marine/deep cycle batteries.  These are all designed differently for their different applications. 

 

Starting batteries are designed to deliver huge current to the electric starter for short periods of time.  They don't work well with low current loads over a long time, which is why a puny dome light left on overnight can kill your battery leaving you stranded.

 

Golf Cart batteries are designed for moderate draw over long periods... similar to your fridge/fan running for 48 hours.

 

Marine/deep cycle are half way in between.  Sometimes they are used to start the engines in the boat, and in between they have to run the lights.

 

As for size/shape, when I was planning my shell build, I knew I wanted 200AH or more of battery, and I looked for battery brands with a good reputation.  Typically this means their www sites have detailed spec sheets with charging profiles and such, and good warranties.  And then I looked a sizes/weights.  I could barely lift/fit my 250AH 6v batteries into place.  I did find a 12v 200AH battery, but I think it was over 160 lbs.  Ugh.  By then I had drunk the 6v cool aid and went that way, but two of these would do much the same

 

http://www.rollsbatt...ery/s12-128agm/

 

Only 73 lbs each.  

[Wallowa]

Vic,

 

Thanks that helps...FWC uses these 6 volt batteries..Model number is, US AGM2000 @ 66 lbs and about $400 each..my IOTA IQ4 and Zamp solar will work with them...FWC does not recommend lead/acid [off gassing] and only uses AGMs..

 

What brand/weight/cost of 6 volt battery did you buy?

 

Thanks,

 

Phil

Edited by Wallowa, 17 October 2018 - 07:37 PM.

[Dphillip]

Good info Vic, thanks for explaining things in easy terms.

[Vic Harder]

Vic,

 

Thanks that helps...FWC uses these 6 volt batteries..Model number is, US AGM2000 @ 66 lbs and about $400 each..my IOTA IQ4 and Zamp solar will work with them...FWC does not recommend lead/acid [off gassing] and only uses AGMs..

 

What brand/weight/cost of 6 volt battery did you buy?

 

Thanks,

 

Phil

Rolls - 6v 250 AH  

http://www.rollsbatt...tery/s6-275agm/

[esimmers]

I seems that a lot of the 6v vs. 12v comparisons are between batteries that differ more than in just voltage. Comparing two 12v starting batteries or two 12v dual-purpose batteries with two 6-volt AGM deep cycle batteries is a meaningless comparison since they are designed for different uses.

 

Let's compare apples to apples. That would mean comparing only same-technology deep cycle batteries, regardless of the battery voltage. Let's compare two 6v (in series) and two 12v (in parallel) where the battery technology, size and weight of each battery, battery type, and amp-hour rating are the same. 

 

If there is any difference, I'd bet it's because the two 6v batteries have larger cells, given that they have only half as many per battery as the 12v batteries. Having larger and fewer total cells means the 6v batteries are more sturdy with thicker plates that will last longer. Some folks say thicker plates may also help with holding a charge, better re-charging, and better handling deeper discharges. But in any event, 6v true deep cycle batteries are more common and in stock on the shelf and easier to purchase than true deep cycle 12 volt batteries.

 

My opinion only.