Changing batteries from water to AGM

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esim134

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The following quote was written by Gary in a great article about changing your RV batteries. The quote fits me to a t!

"If you are one of those who can’t remember to check the water in the battery cells occasionally, or can’t access the batteries easily, an AGM battery provides freedom from those chores while also providing excellent performance and long life. An AGM battery also largely eliminates the corrosion that often afflicts the cables and terminals on the battery. Both 6v golf cart and 12v deep cycle batteries are available in the AGM" - Gary B.

I am the one who can't remember to check the water and when I do, I can't access it easily. So here I am with a 2021 24' Class C wanting to change the battery. I have one fairly new (to my knowledge) battery. I would like to change it to an AGM. Questions...
1. While I'm changing should I change to 2 batteries instead of 1? (I typically only travel to and from campgrounds but do plan on boondocking with solar in the future. That's another thread :) I will also have a 30 amp installed at the house in the near future.)
2. Which AGM would you go with?
3. Can I do this myself? I am fairly handy so I think I can.
4. Is there a video link somewhere to walk me through it?
 

John From Detroit

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Davison Michigan
Well to answer"
First. Normally I go on about the advantages of the GC-2 but since it appears you have two very good reasons for switching from Flooded wet to AGM.. We will skip that.
Do, however go for DEEP CYCLE. It is easier to find DEEP CYCLE AGM in both 6V (GC-2 format) and 2 volt (Group XX) batteries. Deep cycle (not MARINE/deep cycle) are better for RV use.
Now.. one or two.. In this case think of water
If you are on a long drive.. Do you want ONE bottle of water in case you get thirsty
Or two
Same with the batteries (Well technically.. naa I won't go there)

Two give you twice the run time (or more) before you need to re-charge
So if you feel you might run out of 12vdc when overnighting along the road.. Go with 2. In parallel
 

solarman

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I would suggest you go straight to Lithium and not bother with a lead battery. AGM are almost as expensive as Lithium these days and have inferior lifespan. it will actually be more cost effective to go Lithium now. If you are thinking of GC2 type capacity ( approx 225 A/hr ) and considering your possible future expansion then a 300 A/hr lithium would be a good choice. even though my off grid designs almost always specify FLA, I'm of the opinion now that lithium is a good replacement for AGM given the small price differential. for example, two 6 Volt lifeline AGM's at 300 A/hr will cost $1000. a commodity 300 A/hr lithium will cost $1200. not much extra for almost twice the lifespan.
 
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SpencerPJ

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I would actually wait and see what your RV habits are. Your current battery is fine for campground hopping. You say you are handy, adding distilled water a couple times a year is easy.
 

Larry N.

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adding distilled water a couple times a year is easy
Depends on how accessible the tops of the batteries are. On a previous coach, the batteries were in a tight area on slideouts, but they didn't come out quite far enough to easily fill the rearmost cells- it was a contortion.

On the other hand, it is even easier with certain remote fill devices such as:

I've got that setup now, and it takes me five minutes or less to top off eight 6V batteries, and another five to pour baking soda water on the terminals and rinse. On the previous coach, and without such a setup, it was a minimum of 30 minutes to fill the same number of cells (the rear ones took up most of the time) and a couple of hours was usually required because I had to also spend a lot of time disconnecting, wire brushing, and reconnecting batteries to clear corrosion off.
 

esim134

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Baton Rouge, LA
You hit the nail on the head Larry... the placement of this battery under the steps is not nearly as easy to fill as the two I had in my previous RV. I had the previous RV for almost 13 years and accessing the batteries was a piece of cake, it took no time to fill them. This one, not so much and it's only 1 battery!

Spencer
 

solarman

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You hit the nail on the head Larry... the placement of this battery under the steps is not nearly as easy to fill as the two I had in my previous RV. I had the previous RV for almost 13 years and accessing the batteries was a piece of cake, it took no time to fill them. This one, not so much and it's only 1 battery!

Spencer
another reason to consider a drop in maintenance free lithium..
 

Gary RV_Wizard

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Guessing that you probably have a single Group 24 battery (75AH capacity), an AGM deep cycle will likely cost about $100 more than a flooded cell type. And yes, that is about the same as a LiFePO4 battery of similar capability. However, depending on your existing charging system, there may be additional costs to getting the full rated performance from a lithium battery. I'll leave that debate to others.

Changing to AGM is a simple battery swap. You buy the same size battery with the same post configuration and move the wires to the new battery. Take pictures and label each wire before starting and it should go smoothly.

Which AGM? Lead-acid batteries are a commodity. Buy the lowest-priced one you can find that has desired AH capacity and has the case size (e.g. 24 or 27) and terminal post configuration that you need.

Install two now? Yes, if you are planning on expanding capacity in the next several months. But if that's a "get around to it" project, I'd wait till the time comes.
 

Zulu Kono

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The following quote was written by Gary in a great article about changing your RV batteries. The quote fits me to a t!

"If you are one of those who can’t remember to check the water in the battery cells occasionally, or can’t access the batteries easily, an AGM battery provides freedom from those chores while also providing excellent performance and long life. An AGM battery also largely eliminates the corrosion that often afflicts the cables and terminals on the battery. Both 6v golf cart and 12v deep cycle batteries are available in the AGM" - Gary B.

I am the one who can't remember to check the water and when I do, I can't access it easily. So here I am with a 2021 24' Class C wanting to change the battery. I have one fairly new (to my knowledge) battery. I would like to change it to an AGM. Questions...
1. While I'm changing should I change to 2 batteries instead of 1? (I typically only travel to and from campgrounds but do plan on boondocking with solar in the future. That's another thread :) I will also have a 30 amp installed at the house in the near future.)
2. Which AGM would you go with?
3. Can I do this myself? I am fairly handy so I think I can.
4. Is there a video link somewhere to walk me through it?
Have you looked into LiFePO4?
Superior to AGM.
I'll be building a 304 Ah LiFePO4 from SunFunKits.com once I receive it,
but there are lots of pre-built batteries out there to choose from.
 

Ray-IN

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North America-somewhere
I would suggest you go straight to Lithium and not bother with a lead battery. AGM are almost as expensive as Lithium these days and have inferior lifespan. it will actually be more cost effective to go Lithium now. If you are thinking of GC2 type capacity ( approx 225 A/hr ) and considering your possible future expansion then a 300 A/hr lithium would be a good choice. even though my off grid designs almost always specify FLA, I'm of the opinion now that lithium is a good replacement for AGM given the small price differential. for example, two 6 Volt lifeline AGM's at 300 A/hr will cost $1000. a commodity 300 A/hr lithium will cost $1200. not much extra for almost twice the lifespan.
That might also require an inverter/charger upgrade if the present one does not support lithium charging rates and voltages.
 

COCJ

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Jan 18, 2014
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61
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Montrose, CO
I have been using AGM batteries for years in my trucks and campers and I am sold on them. In my opinion swapping from lead acid batteries to AGM is a no brainer when replacement time comes around. I have been really happy with DEKA brand AGM batteries. They are not the cheapest but so far they have not failed. Plus they are made in the USA. Also, it is my understanding that switching to lithium batteries may require additional upgrades depending on your rig. AGMs are usually a drop-in swap. If you have a solar panel, you may need to change your charge controller to the AGM setting.
 
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Skookum

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I was looking at a brand new 2022 Newmar Super Star last weekend, just to see how the other half live. Awesome rig. But I was shocked to discover they come with regular lead-acid (not AGM) batteries from the factory. 8 of 'em!
 

Zulu Kono

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I was looking at a brand new 2022 Newmar Super Star last weekend, just to see how the other half live. Awesome rig. But I was shocked to discover they come with regular lead-acid (not AGM) batteries from the factory. 8 of 'em!
Makes a guy wonder what else they cheaped out on.
For another ten grand investment you can go solar/LiFePO4/inverter
and run your A/C all day long off-grid without using the generator.
 

Skookum

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Makes a guy wonder what else they cheaped out on.
For another ten grand investment you can go solar/LiFePO4/inverter
and run your A/C all day long off-grid without using the generator.

From what I could tell, I don't think they cheaped-out on much! The lead-acid batteries seemed to be at odds with the rest of the coach, though. Lead acid batteries and a pure sine-wave inverter? I would have thought they'd go AGM at least for the lack of a water maintenance requirement. Not that I'd imagine Newmar owners spend significant time off-grid, but I could see most people being adverse to the maintenance requirement. At that price point, why would you have to maintain the water levels in the battery? (Isn't that a job for the pool-boy?)
 

rldees

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Sep 1, 2021
Posts
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Location
Houston, Texas
Depends on how accessible the tops of the batteries are. On a previous coach, the batteries were in a tight area on slideouts, but they didn't come out quite far enough to easily fill the rearmost cells- it was a contortion.

On the other hand, it is even easier with certain remote fill devices such as:

I've got that setup now, and it takes me five minutes or less to top off eight 6V batteries, and another five to pour baking soda water on the terminals and rinse. On the previous coach, and without such a setup, it was a minimum of 30 minutes to fill the same number of cells (the rear ones took up most of the time) and a couple of hours was usually required because I had to also spend a lot of time disconnecting, wire brushing, and reconnecting batteries to clear corrosion off.
My batteries are under the step and impossible to reach without a couple of hours of labor. i will look into this idea. Anne else used this solution?
 
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