AGM Batteries

[Jim Bennett]

Originally Posted by rbryan4

On the subject of venting AGM batteries: They don't off gas like flooded cell batteries, but that is not to say they can't off gas at all. Many AGM batteries actually have a small vent (very small hole) and come with thin rubber tubing that you route to a small hole that vents to the exterior. On my Miata for example, with the battery mounted in the trunk, the battery had two small holes on top, with two small rubber tubes connected, which merged into a small plastic junction. Then a single small tube went from the junction down the side of the trunk to a small hole that exited the wheelwell. The idea was to route any gas to outside instead of the trunk.

I haven't seen that yet, where they have a small vent hole. I wonder if this is one specific brand? Most of them tout that they can be placed in any orientation you wish, and I wonder if even a tiny vent hole would not allow this to be done.

Regardless, even if I was to ever forego the battery box in the future, I would take some kinda step to ensure should there be a problem, that the batteries were sealed and isolated from the interior of the trailer.

In my looking, and not hearing of an actual case where overcharging did occur, it leads me to wonder what would actually happen to a sealed AGM should overcharging and offgassing occur. Would the casing have to crack to allow the gasses to escape? Obviously in a flooded battery, these gases easily escapes from the caps.

[gocamp]

Good point, even an Optima Battery Rep posted this at FGRV forum, in the Parkliner battery burn up thread. Recommended to vent them exterior with that little tube.

Originally Posted by rbryan4

On the subject of venting AGM batteries: They don't off gas like flooded cell batteries, but that is not to say they can't off gas at all. Many AGM batteries actually have a small vent (very small hole) and come with thin rubber tubing that you route to a small hole that vents to the exterior.....

Quote "In my looking, and not hearing of an actual case where overcharging did occur, it leads me to wonder what would actually happen to a sealed AGM should overcharging and offgassing occur."

Example is in the parkliner battery burn up thread.

[Vermilye]

Originally Posted by Jim Bennett

I have done a ton of researching now, and though most battery manufacturers recommend that AGMs be vented, many users don't, and I have yet to hear of of one that was overcharged.

That was a problem with at least one individual with an early Parkliner - it was discussed at the Fiberglass Trailer forum.

[gbaglo]

Moved wiring issues posts to their own thread "Wiring".

[freespirit]

with regard to AGM batteries, I have made general inquires about availability in BC...seems like the going price is about $280 CDN...so what is the CDN taxes one must pay on this local purchase?

trying to determine if buying a battery in Canada with CDN tax and the exchange rate is a better deal than buying battery in states with sales tax. Thanks

[rbryan4]

Originally Posted by Jim Bennett

I haven't seen that yet, where they have a small vent hole.

Yeah, some do, some don't. They're all sealed, but sealing doesn't mean airtight. Just means no caps. The key is, if the AGM battery has a vent hole (or holes), then the tubing should be connected to route any gasses to the exterior, or the battery should be located outside.

[Brian B-P]

Originally Posted by rbryan4

Many AGM batteries actually have a small vent (very small hole) and come with thin rubber tubing that you route to a small hole that vents to the exterior.

All AGM (and gel) lead-acid batteries should have a vent, controlled by a valve... that's why one term for these batteries is Valve-Regulated Lead-Acid (VRLA). Only some of them have the vent designed to hook up a hose like that, but when they do it makes venting much easier - no extra enclosure required. The vent side is the only side that you can't mount facing down, because then it would spit acid when it vented.

From the Lifeline Technical Manual:

PRESSURE RELIEF SAFETY VALVE - Each cell in the battery employs a pressure relief safety valve. The valve is designed to release excess pressure that builds up over time to vent the small quantity of gasses that do not recombine inside of the battery. Once the pressure is release, the valve automatically re-seals The gasses that escape are mainly oxygen and some hydrogen, and these gasses rapidly dissipate into the atmosphere.

I looked at a typical Lifeline drawing (GPL-4CT.pdf) and the vents are not called out, but here are three circles on the top which are presumably the vents.

[rbryan4]

Originally Posted by Brian B-P

I looked at a typical Lifeline drawing and the vents are not called out, but here are three circles on the top which are presumably the vents.

Yep, I think so. Looked at some detailed photos of that battery and that's the only likely place.

[Santiago]

Hello everyone. I have RV'd with a GEL battery for 10 years under the bed and no issues. The terminals are as new and clean as they were 10 years ago. I forgot it's there for the most part.

On the classic 21 we will pick up late this year, I will install multiple Lifeline AGM 6 or 12 volt, TBD. One main advantage of the 6v is that you divide the weight per box which should help with the installation. Also 6v boxes are not as deep, most around 7 inches or less which helps in tight spaces. At 67 years young, I can appreciate only lifting 85 pounds ( twice ) instead of 170+ for a 12v of equal capacity. A decade later when replacing them as a 77 year old this will be a good thing. I expect at that time Lithium will be reasonably priced. Still overall weight and dimensions will likely determine voltage selected. Perhaps with 3 banks some will be 6v others 12v.

On the subject of venting in the cabin, I spoke to LifeLine and was told that their AGMs are designed to be used in the cabin. I brought up their document that states ventilation is required. He said yes, "do not place battery in a sealed container" an RV cabin is not a sealed container thus they have no issue recommending the battery being indoor as long as its not in a sealed box. In the cabin any slight venting should it occur will dissipate. This is not the case with flooded wet cell.

On the question of Escape allowing us to order a trailer without their flooded battery and allowing us to install our own AGM before it leaves the factory even if we have the AGM delivered to them ahead of time .... NO ! "As a certified manufacturer we have certain guidelines we have to follow during the production process"

So I will be bringing home my classic 21 with a flooded battery in a box venting through a large hole through the hull that I will later need to patch up.

[algonquin50]

Thank you for making people aware that even AGM batteries need to be vented. Remember that hydrogen is the most unstable element in the universe. I think stupidity is second.

[Jim Bennett]

Thanks for that follow up, Santiago.

I had suspicions along the lines you describe with the definition of a sealed compartment. This is good to know.

That is a bummer that Escape must install a battery box vent. Perhaps it could be done in a way and location that could be utilized for something else in the future, like an access panel for solar/wifi/TV connections.

[Jim Bennett]

Originally Posted by algonquin50

Thank you for making people aware that even AGM batteries need to be vented. Remember that hydrogen is the most unstable element in the universe. I think stupidity is second.

Actually, he said that LifeLine said venting was not necessary.

[algonquin50]

Santiago
I've been using AGM batteries for 16 years and you will realize the added cost by getting 3X's more life (at least). I typically get at least 5 years out of mine. You can also shop online as they are sealed and do not have to be shipped hazardous. Hope this helps.

[Santiago]

Originally Posted by Jim Bennett

Actually, he said that LifeLine said venting was not necessary.

That is correct Jim. Lifeline said their AGMs installed inside coaches is absolutely normal and acceptable. IF any hydrogen vents due to whatever reason, it's so slight its mostly undetectable and quickly dissipates.

Yes with full knowledge that a customer will discard the factory supplied flooded battery and box and still not accept a customer's preferred alternative, AGM, is disappointing. I would not seek credit for the factory battery and box just don't look forward to having to do fiberglass work on a brand new trailer. On reusing that hole, it depends on location of where they hole saw cut it and its not exactly a diameter with practical use.

[Santiago]

Originally Posted by algonquin50

Santiago
I've been using AGM batteries for 16 years and you will realize the added cost by getting 3X's more life (at least). I typically get at least 5 years out of mine. You can also shop online as they are sealed and do not have to be shipped hazardous. Hope this helps.

Yes they are the next best thing to Lithium at this time. My GEL is 10 years old and still works great. You are right in that due to the fact that they don't leak, GEL and AGM are UPS ship-able. AGMs are in airplanes since they often bank and roll. Can you imaging a flooded battery in an airplane ?

[Donna D.]

Originally Posted by Jim Bennett

............
That is a bummer that Escape must install a battery box vent. Perhaps it could be done in a way and location that could be utilized for something else in the future, like an access panel for solar/wifi/TV connections.

As of right now, this is where the vents are:
On the 21', standard dinette


On the 21', U-shape dinette... kinda hiding behind the spare tire

[algonquin50]

Originally Posted by Santiago

Yes they are the next best thing to Lithium at this time. My GEL is 10 years old and still works great. You are right in that due to the fact that they don't leak, GEL and AGM are UPS ship-able. AGMs are in airplanes since they often bank and roll. Can you imaging a flooded battery in an airplane ?

As a pilot/air traffic controller I can imagine what would happen.
Although I' not a fan of Gels or Lithium as Gels have charging restrictions and Lithium blows up when their polarities are crossed.
I had an interesting conversation with an EMT with reference to using the jaws of life on hybrids.

[Santiago]

Originally Posted by algonquin50

As a pilot/air traffic controller I can imagine what would happen.
Although I' not a fan of Gels or Lithium as Gels have charging restrictions and Lithium blows up when their polarities are crossed.
I had an interesting conversation with an EMT with reference to using the jaws of life on hybrids.

Oh WOW Richard, yes that is true, Lithiums are very sensitive to polarity among many other issues that will have them self destruct. It's scary knowing your $5,000 battery bank can be lost with one mistake. Second reason to not consider Lithium now, other than cost, managing them. Hopefully that will change over time. Meantime it's AGM despite the weight. Yes GEL plates won't allow the fast charge rate of AGMs which is great when filling up via Honda 2000 every 5-7 days in my case when boondocking. When on the road the truck will be charging them at a 40amp rate.

[Jim Bennett]

Originally Posted by Donna D.

As of right now, this is where the vents are:
On the 21', standard dinette
Attachment 16513

On the 21', U-shape dinette... kinda hiding behind the spare tire
Attachment 16514

The one at the back is nicely hidden.

[Santiago]

Originally Posted by Jim Bennett

The one at the back is nicely hidden.

Yes I could live with the rear vent, though I rather it didn't exist.
Jim I take it you are ordering a U shape dinette as well, otherwise it will likely be on the passenger side.