AGM 6 volt versus AGM 12 volt

[camaraderie]

BobA... if I may just simply answer your question.... YES... it is better to have golf cart AGMS than 12V agm's as the MAJORITY of name brand AGMs are dual purpose rather than true deep cycle. You can count on deep cycle thicker plates with 6V AGM's.

AGM's are about double the price of wet cells AND more sensitive to fully charging whenever used and charging in hot climates. They have lots of advantages IF you need those advantages...but they do not last longer or have more cycle life than wet cells.
Why are you considering them?

[Bob2019]

I just bought 2 new 12v batteries to replace the ones that came with my Forester. I was considering 2 6v batteries and decided against it. Why? If one of the 6v batteries go bad, I then have only 6v to work with and I will not have anything work in the RV with 6v. Much sooner have less capacity AmpHrs with 12v and manage my electrical use then be dead and can't run the slides and awning in, etc. Might never happen with 2 6v batteries, but why take chances.

[Jay2504]

Camaraderie, can you please list the advantages and disadvantages of AGM vs FLA? My 2 reasons for considering them were the ability to put them inside the camper like with a Lithium and a small percentage of performance gain. Thanks. Jay.

[camaraderie]

Sure. If you need to put them inside the camper then that is one big advantage as you must vent lead acid to the outside. I had 500 amp hours of AGM's under my bed in a prior life for that reason!

There is no performance advantage in cycle life vs. properly cared for lead acid....but of course not everyone properly cares for their wet cells so not needing care is an advantage of AGM's.
AGM's are much better at retaining a charge. Disconnected they lose only about 1/10 as much to self discharge in storage as wet cells. If you leave your coach unattended for months and unplugged you can come back and find everything still works.

They wont leak and can be mounted sideways which can be an advantage.
If used at sharp angles (i.e. boats on a heel or off road) the plates stay covered and don't sulfate.
They are generally able to accept higher charge and discharge currents than the wet cells if that is needed. NOTE this does not mean they can be charged much quicker to 100% but it does mean they'll get 80% there.
But you never want to go long without getting AGM's back to 100% or they will ramp down in capacity in a slow death spiral.

BTW... I agree with the notion that 6V pairs are less redundant than 12V pairs and would stick with a couple of 12V TRUE deep cycles over a pair of golf carts ...but 4 golf carts over 4 12V since redundacy is not an issue in that case.

Hope that answered your question.

[TitanMike]

Perhaps those who install agm's inside their RV's should read this.

AGM's can still release hydrogen gas.

https://rvnerds.com/2017/11/01/elect...%20be%20vented.

Just because one hasn't had a problem doesn't mean it can't occur.

[Jay2504]

Thank you camaraderie. I notice that car maker’s put AGMs in those ridiculous start- stop applications. Recharging quickly would help there, as would a boost in total charge-discharge cycles. Now that (at least right now ha ha) my need for a battery inside the camper has fallen by the wayside, I’m leaning back towards FLA. Jay.

[camaraderie]

Originally Posted by TitanMike

Perhaps those who install agm's inside their RV's should read this.

AGM's can still release hydrogen gas.

https://rvnerds.com/2017/11/01/elect...%20be%20vented.

Just because one hasn't had a problem doesn't mean it can't occur.

True dat Mike but AGM's are valve regulated and typically don't vent except in overcharged high heat situations. Nevertheless it IS standard to NEVER fully enclose AGM's inside...and to provide flow through ventilation to prevent any build up of hydrogen in an enclosed space.
ABYC standards allow them to be mounted inside in ventilated space.

[dward51]

The 6v GC2 Platinum batteries at Sam's Club are AGM 6v (Duracell Platinum). Duracell is made by East Penn Industries who is a well known USA battery maker. Here is the spec sheet: https://www.driveduracell.com/pub/media/wysiwyg/1688.pdf

Sam's also has regular lead acid GC2 batteries which are less expensive and just fine for a trailer/RV.

[Leadbouncer]

Originally Posted by SlowrideHD

The math works for BB or other LiFePo batteries if you really plan on several thousand cycles of your battery bank. I don't think 99% of rv folks are ever going to approach that level of battery bank use.

A main attraction for me is how fast they will recover a full charge from solar and their ability to maintain 13 volts until 10% SOC, or thereabout. Currently I have sixteen Trojan T-105 in a 8s/2p bank for a remote cabin. If I could find a 48 volt LiFePo battery with the technology and performance of the Battle Born 12 volt batteries, I'd take a serious look. The BB don't seem to play well in series to make a 48 volt system and that's what I want to continue using.

How fast THEY.... which battery are you referring to? Im curious, what is the application of 48 volts?

[NavyLCDR]

Originally Posted by mjbenedict

These can be wired up to 6 in series based on the specifications: https://relionbattery.com/products/lithium/rb100

Lifeblue states they can wire in series as well. I have a single 300AH lifeblue low temperature version battery in my rig.

So, if you wired 6 12 volt batteries in series you would get 72 volts. Who has 72 volt systems? And at the rated voltage of 12.8 volts, it would actually be 76.8.

[TitanMike]

Originally Posted by NavyLCDR

So, if you wired 6 12 volt batteries in series you would get 72 volts. Who has 72 volt systems? And at the rated voltage of 12.8 volts, it would actually be 76.8.

You are overlooking the fact that RV' aren't the only place Lithium batteries are used.

Home solar systems can use much higher voltages than we use in our TT's and MH's.

For that matter, the main battery in my Chevy Volt is a piddling 360 volts. Higher the voltsge, the smaller the wire size needed for the same number of watts delivered.

I personally think we should be using the 24 volt automotive standard today. We're starting to overload the 12v systems just like back in the 50's when "Detroit" realized that the 6 Volt system was inadequate.

[NavyLCDR]

Originally Posted by TitanMike

You are overlooking the fact that RV' aren't the only place Lithium batteries are used.

Home solar systems can use much higher voltages than we use in our TT's and MH's.

For that matter, the main battery in my Chevy Volt is a piddling 360 volts. Higher the voltsge, the smaller the wire size needed for the same number of watts delivered.

I personally think we should be using the 24 volt automotive standard today. We're starting to overload the 12v systems just like back in the 50's when "Detroit" realized that the 6 Volt system was inadequate.

Since most people on this forum would be talking about batteries for RV's though, I would hate for them to think they could connect 6 12 volt batteries in series to their RV 12 volt systems.

[pgandw]

Originally Posted by Jay2504

I have the camper at the fairgrounds inside storage right now. I think the real number of my WFCO 100% sure. I do know it’s 55 amps for sure. It doesn’t make sense to me that 2 6volts in series would not look like a big 12 volt battery to the converter. I did experience water loss that I thought was excessive, but I didn’t treat them any differently than the “sealed top” 12 volt FLA batteries that I was running before. I never pried the top off the 12 volt batteries to see if they needed water or not. I still have 2 of the 12 volt batteries and one is still in use. I should pry off the cover and check the water level. Jay.

The converter does NOT see the 2 6V batteries any differently than a 12V battery of the same type.

What is likely causing the water consumption is your WFCO converter doesn't shift down to trickle mode, and therefore your batteries are being overcharged (cooked). I had this happen with 2 consecutive WFCO converters; it apparently happens more frequently in the WFCO 8735P than in the larger WFCO converters.

It's easy to check - plug your camper in and measure the voltage - should be 13.7V or thereabouts. After 2 days of being plugged in, if you are not using the batteries much, the voltage should drop to about 13.2V. Like I said, neither of my WFCO converters ever dropped below 13.7V - even if I left the camper plugged in for weeks. This causes the water to slowly "boil" away.

I replaced the WFCO converters with a "drop in" Progressive Dynamics 4135. The PD converter readily goes into all 3 modes as needed by the battery - I can tell by checking voltage. Water consumption has dropped considerably - I might have to add water once or twice a year.

If you have 2 12V batteries in parallel, and one fails, you have less than 30 minutes to detect the failure before the bad battery sucks the good one down. In other words, both 12V batteries will be dead before you realize what happened. Don't ask me how I know this. 6V golf cart batteries are proven reliable commodities and are usually less expensive than 2 12V batteries. And give you more capacity, too. I have been using 2 6V GC-2 batteries for the past 6 years without any problems.

Fred W
2019 Flagstaff T21TBHW A-frame with 2 Costco/Interstate GC-2 batteries, PD 4135 converter, no generator, no solar
2008 Hyundai Entourage minivan
camping Colorado and adjacent states one weekend at a time

[bikendan]

Originally Posted by boondocking

I would personally never buy a Lithium battery for my trailer.
Cost vs life expectancy.

My flooding GC2 batteries are 8 years old and still going strong. For the cost of one LiFePO4 (100AH) I can buy 6 pair of GC2 batteries (230 AH/pair). That would give me at least 48 years of service.

Totally agree.

[Jay2504]

pgandw, the 6 volt batteries that used a lot of water were on a camper that I no longer have. Both that camper and my current one have a WFCO 55 amp converter. In the 4 years that I owned the old camper, I only seen it hit the bulk charge rate 2 times. None on this unit so far in one year of ownership. The old camper did drop to 13.2 volts but not often. The new one drops down to 13.2 volts in about 48 hours like it’s supposed to. Maybe that was a contributing factor in loss of water. I will pry off the cap on the bad 12 volt battery that I have(used in both the other camper and my golf cart) and check the water level. I would think that if this was a problem, there would be a lot more people on here talking about it, like people do about weak rear bumpers and China Bomb tires. Jay

[Keystoner]

Has anyone researched Carbon Foam batteries?

My limited understanding is that they are an AGM variant that hold more energy and charge faster than a lead acid/AGM; with better cold weather performance and less expensive than a Lithium.

[BobA]

Originally Posted by camaraderie

BobA... if I may just simply answer your question.... YES... it is better to have golf cart AGMS than 12V agm's as the MAJORITY of name brand AGMs are dual purpose rather than true deep cycle. You can count on deep cycle thicker plates with 6V AGM's.

AGM's are about double the price of wet cells AND more sensitive to fully charging whenever used and charging in hot climates. They have lots of advantages IF you need those advantages...but they do not last longer or have more cycle life than wet cells.
Why are you considering them?

Good question. I guess the quicker recharging time is the main draw to me.

[MR.M]

Originally Posted by BobA

Many folks have chosen the 6 volt flooded lead acid battery (~golf cart) versus 12 volt batteries for a variety of performance reasons, including capacity and longevity.

Does the same reasoning apply to AGM 6 volt versus 12 volt batteries ?

Thanks, Bob in Grand Rapids

The only real difference is a few amp hours and you need 2-6volt as opposed 1-12volt . you can find very good deep cycle 12 AGM as you can 6v

[BobA]

Originally Posted by MR.M

The only real difference is a few amp hours and you need 2-6volt as opposed 1-12volt . you can find very good deep cycle 12 AGM as you can 6v

Thank you. I am a newbie, so let me be more practical. Here's the scenario:

I'm out boondocking for 2/3 days and have drawn down our batteries to close to 50%. I pull into an RV park for ONE night to fill up on water, dump my tanks, take a shower (cuz my wife orders me to), and charge my batteries. Perhaps I'm on shore power for ~14 hours.

Am I more likely to get close to a full recharge with FLA or AGM batteries? I realize they would not be at 100%, but enough of a charge to head out again for more multi-day boondocking. Perhaps this is wishful thinking ?

Thanks........

[chriscowles]

Originally Posted by Jay2504

... Has anyone ever heard of a WFCO converter having trouble with 2 6volt batteries? Jay

The converter knows nothing about what kind of battery it is, only that it's nominally 12V. It doesn't matter if it's 2 6Vs in series or a single 12V or 2 12Vs in parallel.