What battery type to purchase

[newRVer]

I could use some input from the group here to make sure my decision process makes sense for purchasing new batteries. My original flooded lead acid batteries are on their way out mostly due to long durations of time not being charged either because it's been sitting on a dealer lot for weeks at a time waiting for repairs and/or been in storage between trips or over the winter. I thought I knew what direction I was going to go in but the dropping costs of Lithium batteries has caused me to take another look. Here are some of the facts which will influence my decision.

• I am just finishing up a 200W solar panel install which was mostly intended to keep my batteries charged while not on shore power.
• We do not boondock at all when we are together although I have taken the RV out for a couple of tailgating functions and overnight/weekend biking trips myself where there is no power available.
• I would like to minimize generator use mostly not to disturb the neighbors and reduce noise but will run it when I need to.
• I will only be keeping this RV another 3-5 yrs before upgrading to something different when I retire.
• I’d like to reduce the need for battery maintenance.
• I do not have a lot of carrying capacity so weight consideration is a factor.

Right now I am leaning towards replacing my flooded batteries with AGM models. The Lithium batteries are attractive because they would be half the weight, charge quickly, can discharge deeper and hold a charge significantly longer. That being said, I doubt that I would get the return on them that would warrant the additional cost. I.e. Even though AGM’s are more expensive than flooded and for now quite a bit less than lithium, with the solar panels and my type of RV use I can see them easily lasting the 3-5 yrs which I intend on keeping this unit. If AGM is the best option here then my next decision is to go either 12V parallel or 6V series. Adding 12V AGM’s of similar AH capacity would add about 30lbs of weight. However, using two 6V batteries in series would actually provide a slightly higher AH capacity but at about the same weight as my current batteries (51lbs ea)
PS. This could all change in a few years when we upgrade. At that point we might be in a larger Class A and Lithium batteries will probably be an option on most new RV’s.

[A32Deuce]

Originally Posted by newRVer

I could use some input from the group here to make sure my decision process makes sense for purchasing new batteries. My original flooded lead acid batteries are on their way out mostly due to long durations of time not being charged either because it's been sitting on a dealer lot for weeks at a time waiting for repairs and/or been in storage between trips or over the winter. I thought I knew what direction I was going to go in but the dropping costs of Lithium batteries has caused me to take another look. Here are some of the facts which will influence my decision.

• I am just finishing up a 200W solar panel install which was mostly intended to keep my batteries charged while not on shore power.
• We do not boondock at all when we are together although I have taken the RV out for a couple of tailgating functions and overnight/weekend biking trips myself where there is no power available.
• I would like to minimize generator use mostly not to disturb the neighbors and reduce noise but will run it when I need to.
• I will only be keeping this RV another 3-5 yrs before upgrading to something different when I retire.
• I’d like to reduce the need for battery maintenance.
• I do not have a lot of carrying capacity so weight consideration is a factor.

Right now I am leaning towards replacing my flooded batteries with AGM models. The Lithium batteries are attractive because they would be half the weight, charge quickly, can discharge deeper and hold a charge significantly longer. That being said, I doubt that I would get the return on them that would warrant the additional cost. I.e. Even though AGM’s are more expensive than flooded and for now quite a bit less than lithium, with the solar panels and my type of RV use I can see them easily lasting the 3-5 yrs which I intend on keeping this unit. If AGM is the best option here then my next decision is to go either 12V parallel or 6V series. Adding 12V AGM’s of similar AH capacity would add about 30lbs of weight. However, using two 6V batteries in series would actually provide a slightly higher AH capacity but at about the same weight as my current batteries (51lbs ea)
PS. This could all change in a few years when we upgrade. At that point we might be in a larger Class A and Lithium batteries will probably be an option on most new RV’s.

I have a SunSeeker. Two of the biggest AGMs that would fit in the step and 305 watts of solar on the roof. Does all I want and sounds like what you want. Did change the converter to one thats 4 stage.

[newRVer]

Originally Posted by A32Deuce

I have a SunSeeker. Two of the biggest AGMs that would fit in the step and 305 watts of solar on the roof. Does all I want and sounds like what you want. Did change the converter to one thats 4 stage.

Yes, being able to fit in the stairwell is also a consideration and our 3011 came with a 4 stage converter from the factory so that is not a factor here. Also, one of the reasons that I'm going with 200W vs something higher is weight and additional PV install cost. The Sunseekers that I looked at had much more carrying capacity so that would have been a benefit if I had gone in that direction.

[JLeising]

Several people on the forum have reported issues with the height of 6 volt batteries in the step mount.

[UT_Grandpa]

Remember that lead is lead. Flooded and AGM are both lead based. The AGM batteries will last 5-10 years and I replace flooded cells at 5 years but any battery not being maintained will go flat on you. Also that if you have two 12 Volt batteries in parallel with no charge being applied will run themselves down just by being coupled together. Solar on the roof is a great way to keep them up and it doesn't take much. One percent of the capacity will maintain them, e.g. 200 Amp/hour of batteries need only a flow of about 2 Amps of float charge (average so a higher charge rate if you don't have night solar cells :^). Only a couple of things are critical: water, lights, and a working toilet. Everything else is optional.

[ependydad]

Lithium and take them with you when you move out of this rig. I'm hoping to sell this rig in the next 6-12 months and plan on transferring my Battle Born lithium batteries over when I get the new rig. If you're willing to take the price- the benefits outweigh everything else.

[newRVer]

Originally Posted by ependydad

Lithium and take them with you when you move out of this rig. I'm hoping to sell this rig in the next 6-12 months and plan on transferring my Battle Born lithium batteries over when I get the new rig. If you're willing to take the price- the benefits outweigh everything else.

That's a good idea and actually caused me to pause, but 3-5 years from now I have no idea on what type of RV/trailer I might be buying or the age/type of the batteries that will already be installed. Lets say I buy two 6V batteries now and then buy a class A in 4 yrs which has four 6V batteries. I know with Lead Acid its not a good idea to mix and match but is that also the case with Lithium? Most of what I have read says to always start with the same model/type and age of battery just to make sure their are no issues. Now, if I knew that whatever I was buying later was going to require the same battery configuration, then your suggestion might be the winner!

[newRVer]

Originally Posted by JLeising

Several people on the forum have reported issues with the height of 6 volt batteries in the step mount.

For the most part that is what I have also found. However, I have come across a couple of manufacturers that have models in the 9+ inch height range vs the 11+ that I mostly see. If that is real and the terminal options don't require connections that add another inch or two, then it may work. Just don't know enough yet.

[trees]

I think your on target with thoughts. I saw a life cycle chart with lead acid battery discharged to 65%. Wow, they lose capacity. It only takes about six of these to lose a big percentage of your capacity.

Battery manufacturers are zeroing in on AGM technology to power the mild hybrid. The cost has come down and selection up. They are can take hundreds of 65% DOD cycles. They do better in cold and recharge about 40% faster. Lithium will self destruct in hot temperature. You can't charge below 30 deg and can't use them below zero. Other than their temperamental environmental requirements and cost a great battery.

[Granny K]

Originally Posted by trees

Lithium will self destruct in hot temperature. You can't charge below 30 deg and can't use them below zero. Other than their temperamental environmental requirements and cost a great battery.

Good points "Trees". Here is what Battery University has to say. Charging Batteries at High and Low Temperatures – Battery University

No one here has brought up the subject of converters. Progressive Dynamics in partnership with FR designed the converter specifically for the lithium batteries in our MH. The charging profile and float voltage of lithium batteries is completely different from lead acid batteries, so AFAIK you can't simply swap battery types without also changing the characteristics of the converter.

[camaraderie]

Lithium drop ins are not ready for Prime Time yet and there are extremely high failure rates when used with conventional 3 or 4 stage chargers.
I think AGM's would be a good choice for your stated needs but with solar since they are very sensitive to overcharging and temperatures...suggest your charging system have a battery temp sensor to totally shut down charging if the case temp hits 120.
If 6V will fit then I suggest those since you will get true deep cycles...not dual purpose. If you need to go the 12V route...get a DEKA INTIMIDATOR AGM's in the largest size that will fit your space.
Cheapest route is sticking with Deep Cycle flooded batteries and getting a profill or flowrite system to make watering a one minute chore.

Lithium may be a great choice for your next camper... but I wouldn't do it just yet.

[HangDiver]

Following this thread as I am in a very similar position as the OP with similar thoughts ~ 200W panels and two 12v batteries that are going on 4 years old. I'm leaning towards AGM but still have much to learn.

[Wobbles]

Originally Posted by ependydad

Lithium and take them with you when you move out of this rig. I'm hoping to sell this rig in the next 6-12 months and plan on transferring my Battle Born lithium batteries over when I get the new rig. If you're willing to take the price- the benefits outweigh everything else.

Just price checked. Wow! Take them with you is an understatement. I have not done the research (since I do not have the requirement) and I now have a wow factor eyeball expression. Must be a lot to learn about this...

[ependydad]

Originally Posted by camaraderie

Lithium drop ins are not ready for Prime Time yet and there are extremely high failure rates when used with conventional 3 or 4 stage chargers.

Based on what?

[sailski]

FWIW I faced the same condumrum earlier this year and decided to replace the batteries in my motor home with a couple of Chinese 12 volt AGM batteries I found on Amazon that fit in the box under the steps. I have 300 watts of solar that can keep up with our battery use when we get days of full sun.
Most importantly I have a Trimetric BM 2030 battery monitor to let me know how much juice has been used and help prevent draining the batteries down too low. The 4 leds from the factory do not provide enough information to keep tabs on what's happening.

[carlsbad]

I’m using two 31AGM on solar and it’s perfect. No venting. No maintenance. 110ah usable at 50%.

[CaptnJohn]

I have been running flooded batteries in boats and campers for over 50 years (boats) and over 40 (campers). Have run 3 or more in boats and 2 for the last 20 years in campers. All are regularly checked for water level. Never used a charger or maintainer. Only have had 1 go bad and that went within the 1st 4 months. All are deep cycle and cannot recall how long ago a 24 was used instead of 27s. The boat is out of use 4 months while we snowbird and the 5er is down over 3 months as we do not use it during summer. A real battery shut off always used now, used to disconnect batteries long ago and brought them in when I lived up in the tundra area of PA. Boat and camper batteries are replaced every 5 years.

[DavidBo]

I've been considering replacing my flooded house battery with a marine grade lithium. There are several well known advantages (size, weight, charge retention) and a few drawbacks, mainly cost and an unfortunate tendency to burst into flames. Since the battery box is right behind 2 large propane tanks, I think I'll stick with an AGM upgrade.

[babock]

Originally Posted by DavidBo

a few drawbacks, mainly cost and an unfortunate tendency to burst into flames.

Never heard of a Lithium(LiFePO4) burst into flames. Have any links to this?

[DavidBo]

Originally Posted by babock

Never heard of a Lithium(LiFePO4) burst into flames. Have any links to this?

I guess I'm thinking about the lithium-ion batteries that have had this issue. That's the type of battery I was considering, not sure if that's the type that would be used as a house battery.