AGM Batteries: Ruined upon Slow Discharge?

[Rgentum]

When I park my AS in its barn, I always hook it up to 110 VAC to provide AC, among other things to keep its AGM batteries charged.

The AS, however, has been parked at its local AS dealer since September for warranty service. I don't know but I fear that throughout this time, it's never been connected to 110 VAC or its batteries checked or charged. In reading this forum, I recollect that AGM batteries, if slowly discharged over months, for example, by sitting as my AS has been since September, go dead and cannot be recharged.

Question: When I pick up my AS from the dealer, how can I check to see if its AGM batteries are in working order or, more to the point, are shot from having been discharged passed the point where they can be successfully recharged?

[n2916s]

They will discharge a small percentage each month, say 2%. So they should be down no more than 10% by now. If you aren't going to pick it up soon, drive down there with a 50' extension cord and ask them if you can plug it in for a day or two...

[alano]

Basically, you'd want to perform a load test - discharge the battery with a known current and make sure the stated amp-hours of your battery is somewhat in agreement with the discharge test.

You can take remove your battery and take it over to AutoZone or equivalent and they might perform the test for free, or you can purchase a cheap load tester from Walmart for $20 among other solutions.

[alano]

Originally Posted by n2916s

They will discharge a small percentage each month, say 2%. So they should be down no more than 10% by now. If you aren't going to pick it up soon, drive down there with a 50' extension cord and ask them if you can plug it in for a day or two...

The propane detector draws approximately 70 mA. This means in a month it will consume about 50 amp-hours. I'm assuming the OP has about 200 amp-hours of total capacity, so in two months he'll discharge his batteries from 100% to 50%.

It's also not clear whether or not the dealer kept the batteries in "store" mode or not, so it's not a bad idea to verify the batteries and make a claim if you find them damaged.

[gypsydad]

Originally Posted by Rgentum

When I park my AS in its barn, I always hook it up to 110 VAC to provide AC, among other things to keep its AGM batteries charged.

The AS, however, has been parked at its local AS dealer since September for warranty service. I don't know but I fear that throughout this time, it's never been connected to 110 VAC or its batteries checked or charged. In reading this forum, I recollect that AGM batteries, if slowly discharged over months, for example, by sitting as my AS has been since September, go dead and cannot be recharged.

Question: When I pick up my AS from the dealer, how can I check to see if its AGM batteries are in working order or, more to the point, are shot from having been discharged passed the point where they can be successfully recharged?

Are you reading any of these current threads about how the existing OEM converters on AS's 2017 and earlier models come with only a "single stage" converter and are ruining batteries? There are several threads on this. The stock converters do not regulate the charge going to your batteries, and can easily over charge them. As your question relates to "keeping your AS always plugged in" when you have it in storage, you may be asking for trouble.. sorry if I am intruding in your discussion..

[rperrym]

That brings up a question I have been wanting to ask, can you change over to the AGM batteries if you have the stock Airstream charger? Ours is a 2017 model. And are there any other modifications I would need to make besides just changing the batteries other than perhaps installing a multi stage charger later?

Thanks,
Rick

[gypsydad]

Originally Posted by rperrym

That brings up a question I have been wanting to ask, can you change over to the AGM batteries if you have the stock Airstream charger? Ours is a 2017 model. And are there any other modifications I would need to make besides just changing the batteries other than perhaps installing a multi stage charger later?

Thanks,
Rick

I switched to AGM's with my 2014 25'AS with no issues. There are some sharp folks on this Forum in this area, but I believe AGM's are better than wet cells in my opinion. No real issues with changing over, except cost of the AGM's, and you gain some features that wet cell batteries do not have, like draining and re-charging without major damage to the AGM capabilities. The converter change is important if your not willing to watch the charge voltages on the OEM single stage charger...I am not. Insurance...

[rperrym]

Thanks gypsydad. I plan to change mine out soon.

[billrector]

Originally Posted by gypsydad

I switched to AGM's with my 2014 25'AS with no issues. There are some sharp folks on this Forum in this area, but I believe AGM's are better than wet cells in my opinion. No real issues with changing over, except cost of the AGM's, and you gain some features that wet cell batteries do not have, like draining and re-charging without major damage to the AGM capabilities. The converter change is important if your not willing to watch the charge voltages on the OEM single stage charger...I am not. Insurance...

I thought the only advantage to AGMs is that you don't have to maintain them (i.e. continue to fill with water)? AGMs are not like lithium batteries where you can discharge them completely without damaging the cells. In fact, AGMs are just like wet cell batteries except they are sealed. You need to keep AGMs above 50% for good battery life. Please correct me if I am wrong!

[rmkrum]

AGM batteries are just as touchy about deep discharge as a flooded (conventional) lead-acid battery. Deep discharge will damage them, and it is harder to recover from. They DO NOT tolerate deep discharge well at all because of their construction. Once sulfated, they are pretty much useless. They also need different voltage settings for a multistage charger.

Yes, the advantage is limited to they don’t spill, and can be mounted on their sides. Beyond that, they are expensive, and still a lead-acid chemistry. Not that much better on discharge characteristics. Overcharging can cause them to vent, permanently losing water and acid, hastening their demise, and you can’t fix that like you sometimes can with a flooded battery...I have a very expensive AGM that I accidentally deep discharged. Not recoverable, so I’m out big bucks now....I have a set of flooded golf cart batteries that adding water and some dirty charging tricks have recovered some capacity for now. I could do this because I could add water....and have a very smart, temperature sensing solar charger doing the charging.

[gypsydad]

When I researched the AGM's for my 2014 Airstream, it was the Interstate dealer I spoke with and an article I read that convinced me to get the AGM's at that time. They worked fine for me. Here is the article I read. I am sure there are other more recent reviews also which may dispute this article. Wet cells can work fine if you keep an eye on them when charging and maintain them properly. The AGM's don't seem to require that much attention, work great for RV applications, but cost more, is my take.

http://www.rvdoctor.com/2011/02/agm-...motorhome.html

As I said earlier, there are many "experts" on the Forum who have more "perceived" knowledge about this technology.

[lewster]

Just count me as an AGM proponent! I install Lifeline AGM batteries in every application where our lithium batteries (Victron, to be precise) are too expensive for the client.

My feeling is that you can't go wrong with a Lifeline, as they have a 5 year pro-rated warranty and typically last for at least the warranty period, often much longer. They don't like deep discharges, but will accept drawing to 60-70% every once in a while.

My thoughts are that you should go with Lifelines, as you will get much more usable time with your batteries.

[VAtom]

Originally Posted by lewster

you can't go wrong with a Lifeline, as they have a 5 year pro-rated warranty and typically last for at least the warranty period, often much longer. They don't like deep discharges

Of course, none of the warranties cover a dead battery caused by deep discharge. Ask me how I know.

It seem that most AGM battery-cide is committed by dealers, repair shops and storage yards who don't care much about keeping your batteries above 50% charge. Although I have murdered two because I was unaware of a power outage.

I had an Airstream dealer/shop assure me That my unit had been kept plugged in.

"Where, how, since it's been over in that vacant lot for three weeks?
"Uh.....well, uhhh"

You should disconnect the battery if it is going to be out of your control.
I would guess that on your model the store/use switch still has some drains when set on "store" so disconnecting is the safe choice.

[jcanavera]

Different model year trailers have different discharge levels dependent upon the position of the Master Disconnect switch. I did some different tests on older Safari to get a handle on the discharge levels occurring when my trailer was stored. I am unwilling to keep it plugged in since I did ruin a set of batteries keeping the trailer plugged in continuously in storage.

It depends on your trailer vintage. With the master disconnect on, my 2001 Safari for example showed a draw of .1 of an amp hour. With the master disconnect off, it drew .01 of an amp hour.

The problem is with the master disconnect on, your furnace, water heater, propane detector, refrigerator are all drawing power, even though they are turned off. With master disconnect off, you still are pulling power to the propane detector.

It's just a matter of how many amp hours your battery(ies) can support, the master disconnect switch position, and the length of time that the trailer sits without an electrical connection.

Jack

[crestonrv]

a minor solar panel 15/20 watts is the real answer .
a 7amp charge controller for you fancy guys or a 7 amp diode for the poverty stricken will work fine 15 watts gives you a nominal charge of 1.1 amps all day , diode/controller prevents draw down at night = maint. chrg.
the 7 amp controller I use is 25.00 I get panels for less than 50.00 ea. I buy quantity as this is a common application with my client base .
harbor freight tools currently has a 100 watt system on sale 140.00 comes with a controller ( throw controller away ) that's 4 x 25 watt panels 1 will handily protect your agm batt with nominal 2 amps output ! put 2 on and you are actually charging batts . sell other 2 to someone else ( nice people could split cost )
the 7 amp controller I speak of is the size of a cigarette pack the 1 I now stock is a strongway 12 amp , retail in my shop is 29.95 ( I make about 5.00 on 1) butt simple to install and functions very reliably.

[malett]

I have found that many battery chargers will not charge a battery if the battery voltage is below a certain voltage. This is built into the battery charger.
I bought several new batteries just because they would not charge, when the battery was ok and the charger just wouldn't charge ! Check your charger. Mine won't charge if the battery voltage is below 10.8 volts

[billrector]

Originally Posted by jcanavera

Different model year trailers have different discharge levels dependent upon the position of the Master Disconnect switch. I did some different tests on older Safari to get a handle on the discharge levels occurring when my trailer was stored. I am unwilling to keep it plugged in since I did ruin a set of batteries keeping the trailer plugged in continuously in storage.

It depends on your trailer vintage. With the master disconnect on, my 2001 Safari for example showed a draw of .1 of an amp hour. With the master disconnect off, it drew .01 of an amp hour.

The problem is with the master disconnect on, your furnace, water heater, propane detector, refrigerator are all drawing power, even though they are turned off. With master disconnect off, you still are pulling power to the propane detector.

It's just a matter of how many amp hours your battery(ies) can support, the master disconnect switch position, and the length of time that the trailer sits without an electrical connection.

Jack

Don't forget the inverter! Even when off, it draws power continuously and is not connected through the "use", "store" switch.

[m.hony]

Dead AGM batteries can be recharged.
You can trick the charger into charging dead batteries.
Hook the battery charger to the dead battery.
Then hook the dead battery to a good battery with booster cables.
I had the brake light switch fail on my old Pathfinder and the battery drained to nothing.
The battery even tested bad or showed no voltage or no results on the parts house battery tester.
I can't remember when that was- whether it was in March or June, but sometime in the spring.
I attached the charger to the dead battery, attached it to a good battery and went to work.
After work- 10 hours- I disconnected the booster cables.
The dead battery was showing 10 or so volts and charging.
Another hour or so after that, the battery was showing like 11 volts.
I put the battery back in the car and started the car.
The battery was showing 12.83 volts in the car with the car idling.
The car still starts today.

[gypsydad]

"Pay me now or pay me later", as the saying goes. If you have been following these posts on chargers, converters, inverters, and battery issues on the Forum past several weeks, you may have learned a few things. (maybe) Here's a recap from what I have learned:
1) The single stage converters on 2017 AS's or older, were/are single stage converters. They will fry your batteries if left on all the time.
2) Have your batteries checked. Interstate has replaced many batteries on newer AS's within a few months of owning, due to either bad batteries, or more likely because we inadvertently ruined the batteries due to leaving the converter on for long periods of time.
3) AS dealers and many "experienced" AS owners, have replaced OEM single stage converters that came with their AS's, with new multi-tage or 4 stage converters. Progressive Dynamics and Boondocker seem to be very popular choices for both 30A and 50A AS's. These new converters have "intelligent" charging features built in. They will properly charge and maintain your batteries and you do not have to worry about overcharging. Just make sure the wet cell batteries water levels are full.
4) We know even in "store" mode, there is still some small current draw on batteries by the LP detector, thru the Inverter. Perhaps other "gadgets" may also draw small current. Only way to prevent this is to install a battery disconnect switch and use it when you want to make sure your batteries are not discharging.
5) AGM's work well as replacement for wet cell OEM batteries; however, wet cells can last a long time if properly maintained.
6) Multi-stage converter replacement for OEM is an important upgrade/investment on 2017 and older AS's.. The new 2018 models now include this change.

[franklyfrank]

Originally Posted by gypsydad

Are you reading any of these current threads about how the existing OEM converters on AS's 2017 and earlier models come with only a "single stage" converter and are ruining batteries? There are several threads on this. The stock converters do not regulate the charge going to your batteries, and can easily over charge them. As your question relates to "keeping your AS always plugged in" when you have it in storage, you may be asking for trouble.. sorry if I am intruding in your discussion..

We are on our second Airstream, 2013 and now a 2017. I keep my As plugged in 24/7/365 with the store switch on at all times. I sold the 2013 with the original batteries still going strong. All I do is keep them clean and check the water level regularly. I read these comments about the substandard converters AS installs and they don't make any sense to me.