Greetings,I have 2 Concorde 6V AGM batteries in my TC which are almost 10 years old. These batteries have been used continuously for the last 8 years as I live full-time in my rig. Batteries are charged with 200 watts of solar panels. I've been extremely happy with the performance of these batteries and plan to replace them this year with the same brand/model (at twice the price!).Since the batteries are nearing their end-of-life, performance is gradually declining. All is well if days are sunny but when I have a cloudy day the charge declines faster than before and it takes longer to charge-up on the next sunny day.Anyway, my simple question is - should I add distilled water to the batteries? I've opened one of the "plugs" and did not see any water.The manufacture states that these are no maintenance batteries and no water need be added. They also state these are "sealed" batteries which obviously is not true since the 3 plugs on top of each battery can be pried open.So, has anyone ever added water to an AGM battery? And, if so, was there any negative results? I can't imagine there would be since an AGM battery is in fact a lead-acid battery with exactly the same chemistry as any other lead-acid battery. Only the internal construction is different.Any advice or comments welcome. Thanks, Rob

There are lots of google hits on 'add water to agm'. Nothing definitive I could see.

More than likely your loss of capacity is due to sulfation not necessarily low water levels. You might be able to get some capacity back with a conditioning charge but IMO they're just old and need to be replaced. BTW, those plugs are there so the batteries can vent if they're overcharged.

Here is Concords conditioning instructions. www.concordbattery.com/extenderservice.phpI have never heard of anyone adding water but there is nothing to loose. I would try conditioning first.

I have read 2 maybe 3 posts on adding water. All seemed pleased with the results. No long term report so it may not last. Nothing to lose on 10 yo batteries.

Yes add distilled water. My owners manual says to peel the label off for checking and adding water. Give those batteries a nice send off. You are about double their life. At this stage the plates could be very fragile and may fail after a ride down a bumpy road. We don't really buy batteries, we rent them. About 95+ % of all batteries get recycled according to a tv show the other night. Very interesting show.

Adding water to AGM battery? | Good Sam Community

full_mosey
Explorer
Sep 25, 2013
Gale Hawkins wrote:
TechWriter one the ones I have opened after finding the hidden door just have a little rubber like cap over the fill hole open that 1-2 PSI would let them vent I expect. If they did vent they would not draw air back into the cells I expect.

That is exactly what I found in my dead APC UPS. Six rubber caps under a glued on cover that at best might hold back a spill, but clearly allowed the battery to dry out while on standby. I tried refilling the cells with a syringe but could not charge/recover the batteries. Definitely not VRLA.

HTH;
John
full_mosey
Explorer
Sep 25, 2013
TechWriter wrote:
full_mosey wrote:

There is no pressure component to recombination. The valve is there to maintain the chemistry. The valve prevents contamination in/out of the battery.

Lifeline AGM manual -- see page 5. Those are pressure relief valves for venting. I'd say that's part of the recombination process as opposed to just keeping contamination out.

Recombination is a chemical process unrelated to pressure.

Lifeline 1.2 Overview of Lifeline ® AGM Technology wrote:
The cells are sealed with a pressure relief valve that prevents gases within the battery from escaping.

I searched the pdf for 'pressure' and I don't see anything that explains that pressure acts as a catalyst to cause or enhance recombination.

HTH;
John
Gale_Hawkins
Explorer
Sep 25, 2013
TechWriter one the ones I have opened after finding the hidden door just have a little rubber like cap over the fill hole open that 1-2 PSI would let them vent I expect. If they did vent they would not draw air back into the cells I expect.

Any battery that you find needing water and lot of water, even the FLA type is SHOT from my experience. The six T-105's started drinking water two year ago in the GC. Before that they were good for 20+ miles. Now it is like two which is like four trips to the church so they are OK. Just trying to get to next Spring to get new ones. :)

Adding water to a AGM may get you a few more minutes of run time IF you have time to waste or want a project to mess with. :B
TechWriter
Explorer
Sep 25, 2013
full_mosey wrote:

There is no pressure component to recombination. The valve is there to maintain the chemistry. The valve prevents contamination in/out of the battery.

Lifeline AGM manual -- see page 5. Those are pressure relief valves for venting. I'd say that's part of the recombination process as opposed to just keeping contamination out.
full_mosey
Explorer
Sep 25, 2013
TechWriter wrote:

...
An AGM battery works by recombining hydrogen & oxygen under pressure, hence no watering -- opening an AGM up stops this.

There is no pressure component to recombination. The valve is there to maintain the chemistry. The valve prevents contamination in/out of the battery.

Deka wrote:
How does a VRLA battery work?

A VRLA battery is a “recombinant” battery. This means that the oxygen normally produced on the positive plates of all lead-acid batteries is absorbed by the negative plate. This suppresses the production of hydrogen at the negative plate. Water (H2O) is produced instead, retaining the moisture within the battery.

It never needs watering, and should never be opened as this would “poison” the battery with additional oxygen from the air.

Opening the battery will void the warranty.
.

HTH;
John
Gale_Hawkins
Explorer
Sep 25, 2013
pianotuna wrote:
Hi,

My brother recently bought an AGM motorcycle battery. It came "dry" and there were caps to seal it once the acid was added. They are not intended to be pulled out again, but it could be done.

I guess the answer is that "some" AGM batteries can be modified to allow additional distilled water to be added.

We got ours like this at WM. We had to fully charge it WITHOUT caps before 'sealing'.

Look and the fill holes will be hidden somewhere. :)
pianotuna
Nomad III
Sep 25, 2013
Hi,

My brother recently bought an AGM motorcycle battery. It came "dry" and there were caps to seal it once the acid was added. They are not intended to be pulled out again, but it could be done.

I guess the answer is that "some" AGM batteries can be modified to allow additional distilled water to be added.
beemerphile1
Explorer
Sep 25, 2013
FWIW this thread is eight months old and was a silly topic to start with.

Any AGM or Gel battery I have owned did not have caps. They are technically VRLA (valve regulated lead acid) otherwise known as 'dry' batteries and the vent/valve typically consists of a small vent on the side. The battery would have to be upside down to add water.

A so-called AGM that has caps is not a true VRLA battery but is a 'maintenance free' battery. Not the same thing. You can add water to a maintenance free battery, not an AGM of Gel.
Gale_Hawkins
Explorer
Sep 25, 2013
TechWriter wrote:
unbob wrote:

The manufacture states that these are no maintenance batteries and no water need be added. They also state these are "sealed" batteries which obviously is not true since the 3 plugs on top of each battery can be pried open.

Mmmm . . . there are no plugs on my AGMs but I suppose I could drill through the tops and make them un-sealed.

An AGM battery works by recombining hydrogen & oxygen under pressure, hence no watering -- opening an AGM up stops this.

You have to look again. There are no AGM 'sealed' batteries as such in that all that I have seen can VENT before they blow.

I thought like you at one time so have that second look. :)
TechWriter
Explorer
Sep 25, 2013
unbob wrote:

The manufacture states that these are no maintenance batteries and no water need be added. They also state these are "sealed" batteries which obviously is not true since the 3 plugs on top of each battery can be pried open.

Mmmm . . . there are no plugs on my AGMs but I suppose I could drill through the tops and make them un-sealed.

An AGM battery works by recombining hydrogen & oxygen under pressure, hence no watering -- opening an AGM up stops this.