New Battery

[mdlemieux]

I need to get a new battery for our FB22 Bambi sport.Been looking at the pros and cons of just replacing with the same Interstate lead acid battery it came with, or getting an AGM type instead. Would like to hear from you folks. We usually leave our AS plugged in all the time, but I guess that's the wrong thing to do, unless you turn the battery switch off and only charge the battery occasionally. We boondock on occasion and would like to do more, so would also like info on generator and solar, and if my battery choice would matter.

[Bill M.]

I favor replacing it with another flooded cell battery. I would put the trailer on a timer when stored.

[Caffeinated]

The interstates AS puts in the trailers are pretty much the cheapest you can buy, and you get what you pay for. They have a one year warranty. I replaced mine with the same type, but from Trojan, that had a three year warranty. The Trojans have worked well. You can spend more, and get more amp hours, which makes sense if you are doing a lot of boondocking. There are tons of threads on battery/charger/converter performance in the repair section you should read.

Mike

[uncle_bob]

Hi

One very valid option is "whatever deep cycle RV battery Costco has on sale this week". In a few years, you buy another one. Cost wise this one is a winner. The battery will have virtually the same capacity as a similar size flooded 12V battery from any of the "big guys".

Normally the next step up is to AGM. You get a bit more capacity and a few less maintenance headaches. You pay quite a bit more for the battery so bang for the buck goes way down. The 10% increase in capacity is in the "you will have a hard time noticing it" range. They *should* last longer so two / three / five years from now it will beat the on sale battery by more than 10%.

If you have room in the battery box, going to two batteries will .... errr ... double your amp hours. Some trailers come with one battery and will only fit one, others come with one, but will fit two. If indeed your trailer only has "a battery" going to two would be worth looking into.

Past that you head off into things that are a bit more DIY intensive. A pair of Trojan T-105's will give you another 10% capacity boost. They also are a bit larger than "normal" batteries. Fitting them in a stock battery box is a maybe will / maybe won't sort of thing. Lithiums are the "ultimate" solution. For a big pile of money, you effectively double your capacity over the AGM's.

All of the capacity numbers are open to debate. You *can* run lead acid's past the 50% point. How well they do depends on a bunch of things. To keep things simple, the comparisons above *assume* the 50% point is used.

So lots of answers, most of which come back to "what's in your wallet?"

Bob

[AirMiles]

I would suggest you start by reading this article: https://marinehowto.com/what-is-a-deep-cycle-battery/

Once you've read that article a couple of times and understand it. Then you can decide if you want a better battery than the stock Interstate.

If you decide you want a better battery, then you need to decide on a budget for a new battery. Installing a better battery in a 22' Airstream is not as easy as it is on larger Airstreams with dual batteries.

Options:

1) You could possibly fit a Trojan T-1275 in your original battery box at a cost of $200. This will give you a longer life 150AH true deep cycle battery.

2) You could modify your battery box and install two Trojan T-105 batteries (or Duracell EGC2 batteries) and get 230AH of true deep cycle batteries for $250.

3) You could decide to move your batteries inside your Airstream and use two Lifeline AGM batteries at a cost of $700 or a single or a number of Lithium batteries at the cost of $800 (Renogy) - $950 (Battleborn) each.

For a generator, it really doesn't matter which battery you get. I would get a generator that can run the A/C which could be a 2200W with a 22' Airstream.

For solar, I recommend installing as much solar as fits on your roof. A bigger battery bank is better with solar, so you can store all the power the solar produces. Therefore, you may want to consider the dual battery options.

Keep in mind that nobody ever complains about having too much solar or too big of battery bank. Have fun studying these topics. There's plenty of reading on AirForums to help you decide what is best for your needs and budget.

[BayouBiker]

To add to the great advice from Bob I'd say that AGM "gell cell" batteries are only good option if you add solar or are connected way more often than not AND the converter controller and solar charger controller are sophisticated enough to properly manage an AGM battery. If not, as Bob indicated it doesn't pay out to upgrade. Bob and I might argue even then it still may not pay out, but one big advantage of AGM when you have a smart type charger available most of the time is that they don't consume (much) water so you don't (can't) have to worry about checking them.

[azflycaster]

There is a big difference between an AGM and a Gel Cell battery. I have had great success with Lifeline AGMs. In my last trailer the GRP 27 was still working great after 10+ years of service when I sold the trailer. They are pricey compared to lead acid, but you get what you pay for. Never having to service is a big plus.

[BayouBiker]

Originally Posted by azflycaster

There is a big difference between an AGM and a Gel Cell battery. I have had great success with Lifeline AGMs. In my last trailer the GRP 27 was still working great after 10+ years of service when I sold the trailer. They are pricey compared to lead acid, but you get what you pay for. Never having to service is a big plus.

True AGM are a completely different design as the first generation Gel Cell batteries, but many people refer to them as "next gen gel cells' thus the mention. I suppose I should try to be more precise.

As long as I am, I should say a bit more about AGM (Absorbent Glass Mat) batteries. Because they are less prone to sulfation and stratification, they can be stored longer without a topping charge. I mentioned earlier they can be topped more frequently without water loss, but also they can be deep cycled to 80% depth of discharge vs. 50% for wet cells for the same service life, again because the absorbent mat tends to prevent plate damage modes. These advantages are partially offset by the lower specific energy and the earlier implied mention that they don't like being overcharged thus the smart charger requirement.

As far as service life goes, the more you avoid deep discharges, the more often you fully charge when a charge cycle is started and the better you avoid high internal cell temperatures the longer lead acid batteries will last.

[mdlemieux]

Thank you all for this valuable info. I have decided to go with the stock Interstate battery for now, and spend the next couple of years customizing for the next round.

[azflycaster]

I would strongly suggest upgrading to a better converter before you install a new battery.

[PKI]

Very good decision. As you research, look at a battery monitor. It takes a bit of installation effort, but the resulting convenience simplifies the management of power considerably.

Also - a suitcase solar panel can help with recharge and is whisper quiet. Pat