21 replies to this topic

[Vic Harder]

Well after a lot of research, I am really thinking about getting 2 6v batteries and connecting in series, I found some that will fit for about $200 each. They have the same footprint as the group 24, but are taller, and my battery cabinet has lots of space above the batteries.  This shouldn't pose any issues for the solar charger should it? 

Existing charger should have no problems.  Your batteries will appreciate the best, fully adjustable charger you can get.  Victron or Trimetric are good choices.  I have dual 6v batteries and they are awesome.  Which batteries?

[dharte]

Existing charger should have no problems. Your batteries will appreciate the best, fully adjustable charger you can get. Victron or Trimetric are good choices. I have dual 6v batteries and they are awesome. Which batteries?

Amstron GC2. I ordered them on Amazon.

[Vic Harder]

Amstron GC2. I ordered them on Amazon.

Good stuff, as it comes with spec sheets!  https://www.amstron....ation_Sheet.pdf

Does your solar charger have adjustable settings to accomodate the specific voltages and currents this spec sheet lists?

[dharte]

Good stuff, as it comes with spec sheets! https://www.amstron....ation_Sheet.pdf
Does your solar charger have adjustable settings to accomodate the specific voltages and currents this spec sheet lists?

I don't know if it's adjustable-it's the one FWC installed with the panel. I do know it currently charges at 13.4v, and that's close to what the specs list (13.2) on the new batteries (when hooked in series of course). Vic, is yours adjustable?

[Vic Harder]

Yes it is.  0.2v doesn't sound like a lot, and it might not make a difference depending on how long you want those batteries to last.  I have roughly the same setup, 2 6v 220 AH batteries.  Like yours, the cost a fortune, so I think spending another couple hundred bucks on a good charging system and monitors for it might be worth doing.

 

Like a few other folks here, I am using Victron gear.  Love it.

 

For reference, you have 165W of solar, and are now adding a fridge (2 way?).  With my 265W on the roof and my 130L two way fridge, I have NEVER discharged my batteries below 80% (OK, I have, but just once, during a test) in 42 days of camping.  

[Clemson]

Noob question - what is the advantage of 2 6v vs 2 12v batteries?

Edited by Clemson, 27 February 2018 - 12:33 AM.

[ckent323]

Clemson,

 

The answer is mostly due to weight of the individual batteries.

 

In a nutshell a 12 volt 220 Ah true deep cycle battery weighs about 120 pounds.  Two 6 V 220 Ah true deep cycle batteries can give you the same power but the batteries only weigh 66 pounds apiece.  Clearly the 6 V batteries are easier to move into a camper.

 

Similarly if you only wanted 100 Ah, each 6 V battery is about half the weight of the 12 V.  In the end the total Ah and weight is pretty much the same for one 12 V or two 6 V.

 

Now this is for lead acid batteries - i.e.  flooded lead acid (FLA), Absorbed Gas Matt (AGM) and Gel.

 

If you spend a lot more money you can get a Lithium Iron Phosphate (LiFePO4) battery which weighs about half as much as a lead acid battery with the same Ah and at the same time get a lot more and deeper discharge cycles on the battery than you can on a lead acid battery before you degrade the battery.  But LiFePO4 are still about 3x or more the cost of a high quality deep cycle lead acid battery.

 

I hope that helps,

 

Craig

Edited by ckent323, 27 February 2018 - 01:17 AM.

[dharte]

With the 2 6-volt batteries I'll have 210 amp-hours, as opposed to 150 amp-hours with 2 12v group 24 batteries. The 6-volts are about 20 pounds heavier and taller but have almost the same footprint so they will fit in the cabinet in my front dinette Hawk. Since I needed to buy two batteries anyways, I figured this is the time to switch. I will be installing a 2-way fridge this week and don't want to worry about running out of electrical juice (or cold beer)!

[ckent323]

dharte, et al,

 

You may already know the following but just in case and for folks reading who don't:  group 24 is a case size and group 24 batteries are frequently starting batteries not true deep cycle although they can be deep cycle (be sure to check and verify). 

 

There are significant differences among starting batteries, hybrid starting deep cycle batteries and true deep cycle batteries.  It is important to know the difference in terms of depth of discharging and lifetime.

 

http://www.wanderthe...battery-thread/

Edited by ckent323, 27 February 2018 - 06:46 AM.

[philos65]

https://www.amazon.c.../dp/B00S1RT58C/

 

100 ah battery for $165 and includes shipping - another option!