AGM Battery

[mcaslaon4449]

We are in the process of purchasing a 2017 25' FC. The new Airstream comes with the two Interstate batteries. We are thinking of purchasing two AGM batteries instead. We're wondering if it is worth the extra expense to go with these batteries. We understand they are maintenance free & they hold a charge & recharge better then the Interstate batteries. What are the pros & cons. Thank you for your input.

[cabinetmaker]

Unless you plan to do a lot of boondocking or use solar the factory interstate batteries are fine.

In a few years when you need new batteries then replace with what you want.

Be aware that the factory 12 volt converter will overcharge your batteries and might ruin those AGM's.

Before I went to those I think I would replace the converter with a upgraded one that cycles the charge as needed.

When camping the factory converter isn't too big a deal because your regularly using 12 volt power. During storage I strongly recommend against leaving the Airstream plugged in to shore power because the converter will overcharge and boil your batteries.

Use a "Battery Tender" or "Battery Minder" like you see mounted on boats. These will charge the batteries then float charge as needed. Your batteries will thank you and last many years.

Don't forget to check the water especially in hot weather and top off with distilled water as needed.

[PKI]

AGMs cost more and are reported to have a longer life. AGMs are also safe to be moved inside the coach to reduce tongue weight. In that position, larger battery size is also possible. The other advantage of AGM is the ability to discharge the bank to less than 50%. However, they have been known to die at less than the expected life span that makes them cost effective. Only you can determine if the cost of an AGM house bank is appropriate for your RV application.

We gave it some thought and ended up keeping the Interstates. We normally use full hook up RV parks, so bank capacity is of minimal concern. We have decided to use a LPG generator for the rare opportunities when we will dry camp.

You should look at a battery disconnect for storage, a converter upgrade for multi-stage charging, and a monitor for power management.

Good luck with your choice. Pat

[graysailor]

AGM's are the best. No maintenance at all. Be sure to upgrade to SmartCharger. Also the deeper battery box that Airstream now uses will accommodate two high amp AGM's.

[DaveP]

Discharging AGM batteries below 50% is not recommended. It will shorten their life. You can check this with a battery monitor kit. Talk to Randy at Bestconverter.com. He is an expert and can recommend the right equipment.

[AnnArborBob]

Are you an experienced camper who knows how they like to camp? Or is this basically new to you and you still don't know your "camping style?"

If you are an experienced dry camper (or boondocker if you prefer) then switching to AGMs right away makes sense. However, if you are new to this you may find that camping with electrical hookups is more your style in which case investing in AGM up front may not make as much sense.

Frankly, I would start with the Interstates and see how you end up using them. You can always spend the money for the AGMs down the road.

In any event, the first thing I would do is replace the Airstream supplied charger with a multi-stage (or smart) charger. Regardless of whether you use wet cells (Interstates) or more expensive Lifeline AGMs the stock charger will kill them in short order so the charger upgrade it a wise investment.

Finally, as previously corrected, AGMs should not be run below a 50% charge (about 12.2 volts at a resting state) or you risk damaging them as you do with wet cells.

[DKB_SATX]

We (and the rest of our unit) do a fair amount of boondocking, but I'm an irrational cheapskate. I say irrational, because if I were a rational cheapskate I probably wouldn't have bought the new 26U I'm going to fetch in a little over a week...

At any rate, I thought about this. If the flooded Grp. 24s turn out to be in good shape when I go to get the 26U, I'm going to use them 'til they drop and then replace them with AGMs. If they aren't in good shape (I'll be camping in the trailer on battery power the first night as a test) then I'll negotiate a credit towards AGMs instead of a swap to new flooded batteries.

I camped with a single (!) grp 24 in our vintage trailer for years, and could go several days without charging but all it was really driving was LED lights and the water pump. The new trailer has gadgets I'll want to use, and 12v control boards in the fridge and water heater and a propane detector that'll use battery capacity even when I'm trying to conserve. Even the toilet is electric!

[PKI]

My apology for the greater than 50% discharge statement. That was an error as additional discharge reduces life. Thank you all for correcting the thread. Pat

[AnnArborBob]

Originally Posted by PKI

My apology for the greater than 50% discharge statement. That was an error as additional discharge reduces life. Thank you all for correcting the thread. Pat

I assumed you were thinking of Lithiums when you made that comment.

[PKI]

No, it was my understanding that AGMs could be discharged below 50%. I broke one of my principle internet rules - "do not believe what you read without verification".

After seeing the correction in this thread, I did some basic research, which I should have done earlier, before providing incorrect information.

The Lifeline manual has a life cycle chart in the appendix. It shows the degradation in battery life with respect to discharge level. Degradation starts at 5000 cycles if the battery is only discharged 10% and goes down to 500 cycles if discharged 85%. The 50% discharge level yields a 1000 cycle life. So even going to 50% has a significant impact on life.

Thanks to all for correcting my prior error. More research pending. Pat

[AnnArborBob]

Originally Posted by PKI

No, it was my understanding that AGMs could be discharged below 50%. I broke one of my principle internet rules - "do not believe what you read without verification". Pat

There is indeed a lot of misinformation on the internet. And an amazing amount of misinformation even on AirForums! Fortunately, on AirForums I believe that those who misspeak have the best of intentions but are simply misinformed and just passing along what they believe to be the truth.

As some say: all information is worth precisely what you pay for it.

Also, I think that Ronald Reagan was quoted (or perhaps misquoted?) as saying: Trust but verify!

[gypsydad]

We had "bad" Interstate batteries when we purchased our 2014 new. Took us a couple trips to figure out why things were not working right...some of the 12vdc lights and water pump worked, and some did not, including intermittent stereo issues. Found out we had bad cells in the "new batteries". Interstate offered to swap them out free, since they come with a 3 year warranty. They also offered to give me 100% credit on AGM's, which they recommended. We went that rout and 2.5 years later, we have had no issues. I would stay with the original equipment till they fail, then make your decision. I would also look at some folks recommendation for 6V's, or Lithium also...in the end, its just money... We used original equipment 12V's in our first 2 AS's and never had an issue, so it really can vary on this.

[Caffeinated]

Originally Posted by gypsydad

We had "bad" Interstate batteries when we purchased our 2014 new. Took us a couple trips to figure out why things were not working right...some of the 12vdc lights and water pump worked, and some did not, including intermittent stereo issues. Found out we had bad cells in the "new batteries". Interstate offered to swap them out free, since they come with a 3 year warranty. They also offered to give me 100% credit on AGM's, which they recommended. We went that rout and 2.5 years later, we have had no issues. I would stay with the original equipment till they fail, then make your decision. I would also look at some folks recommendation for 6V's, or Lithium also...in the end, its just money... We used original equipment 12V's in our first 2 AS's and never had an issue, so it really can vary on this.

Pretty sure interstates that airstream uses come with a 12 month warranty. Which is why I was out of pocket when mine died at 13 months.

Mike

[gypsydad]

Originally Posted by Caffeinated

Pretty sure interstates that airstream uses come with a 12 month warranty. Which is why I was out of pocket when mine died at 13 months.

Mike

You may be right; could have been 12 month warranty, but Interstate did give me the credit toward the AGMs. If I had the room, I may look at those 6 V deep cycle they offer.
I just remember that when I took in my AS to the dealer after only owning it for 4 months with the "electrical issues", he had it for 3 days before they discovered the battery would not hold a charge and got Interstate involved. They tried to charge me for labor to trouble shoot the problems and also tried to charge me mileage to Interstate till I complained to the owner. I went to Interstate myself and got them to swap the batteries to the AGM's with full credit; no issues from Interstate. They recommended the AGMs at the time. I might look at their 6V models if I had room in my box up front, but these AGMs have worked fine for 2+ years now.

[AL’ UM- MONEY]

First time camping this year, tryed to use my jack and nothing happened. My two year old AMG was dead. I have a disconnect switch but forgot to open it so apparently I boiled it out and loss the battery. I guess I thought a new converter would float it but must be wrong. Guess I will replace and may go back to wet cell?

[graywhale]

I too am thinking about converting to AGM batteries (probably 6 volt) to replace the 12 volt wet cells in my new trailer. I'm thinking about this because I've had a really rough time of maintaining the wet cells over many years of trailering.

What I'm curious about is that I've seen several comments about upgrading the converter to a 3 stage model for proper charging/maintenance of the AGMs. According to my converter manual, the converter in my trailer is a 3 stage and designed to use those various modes of charging. Am I missing something???

Larry

[uncle_bob]

Hi

Ok, AGM's are a bit more durable than flooded cells. That's just a bit. The converters in the 2018's are a bit better than the 2017 versions, again just a bit. Neither one will compensate for battery abuse. Sorry about that.....

The real key is to baby your batteries. Pay attention to them. Care for them. Don't neglect them. You'll get four to six years that way. Do some bad stuff to the batteries and you will not get a year.

Best approach: (assuming you are paying for it and I'm not ....)

1) Get a good converter / charger
2) Put a temperature probe on it
3) Put a good current monitoring (battery shunt) capacity meter on the system
4) Go with the biggest AGM's that will fit in the space you have.
5) Put in solar, even if it's a single panel.
6) Wire up a "full disconnect" switch and a trickle charger

You still need to do things right. A setup like this gives you the best performance you will see with lead acid batteries.

Bob

[gypsydad]

Just took my 4 month old Interstate batteries back to Interstate to see why they would not hold a charge during this past 2 week camping trip. I did use my new Champion dualfuel propane powered generator in combination with my GoPower 80W solar most of the time to bring the low batteries up to use voltage, after running the heater a couple times in the morning. But one night near end of the trip, they went from 12.6 to 9.4 V and nothing would work except the converter fan. Interstate wanted to keep the batteries overnight to make sure they were being charged properly. They just called and said both batteries had bad cells so I have choice of new ones today or $113 credit/ each, against other types/sizes.
I am pondering this one for sure: 6V golf cart deep cycles are quite a bit heavier, though they will fit in the AS battery case, and offer about 4X capability of the stock wet cells. These are $160 each less the trade in ($113/ea). But the Interstate rep said if a cell goes out in the 6V, they are dead. Said this does happen to these also. AGM's also is a choice, but lower output than standard batteries, so not sure that is the way to go.
Any thoughts or suggestions are appreciated. I may just get the replacements and move forward to next time there is an issue within the warranty period...

[gypsydad]

Originally Posted by cabinetmaker

Unless you plan to do a lot of boondocking or use solar the factory interstate batteries are fine.

In a few years when you need new batteries then replace with what you want.

Be aware that the factory 12 volt converter will overcharge your batteries and might ruin those AGM's.

Before I went to those I think I would replace the converter with a upgraded one that cycles the charge as needed.

When camping the factory converter isn't too big a deal because your regularly using 12 volt power. During storage I strongly recommend against leaving the Airstream plugged in to shore power because the converter will overcharge and boil your batteries.

Use a "Battery Tender" or "Battery Minder" like you see mounted on boats. These will charge the batteries then float charge as needed. Your batteries will thank you and last many years.

Don't forget to check the water especially in hot weather and top off with distilled water as needed.

Thinking of replacing my converter also, since the 4 month old Interstates have bad cells and are being replaced today...could be from the stock converter on my 17'? AS service manager is recommending Progressive Dynamic replacement. Any thoughts?

[dmbecke]

I would opt for the most Amo hours you can fit in the box
I recently had the same decision and chose two group 31 batteries for a total of 240 Amp hrs
Barely fit in box and took a little force to get them in
May have to cut them out
They would also be an option