Inside Batteries

[padlin]

My 2 6v batteries are under the rear dinette bench in the "U" configuration in the standard white PVC (?) vented battery box. During a charge cycle from Solar the voltage goes up to 15+ volts as it nears the end of the cycle, like it should. When it gets to this level I can smell the batteries. I've verified the single vent tube is clear and the seal looks okay. Has anyone else noticed this? I have not noticed it at the lower converter charge level.

As I type this I thought of the refrigerator seal dollar bill test, I'll give that a shot.

[fudge_brownie]

Yes, I have noticed the same thing. Only when using solar and only at those high voltages. I am not an expert on the chemistry of high voltages but at 15+ volts we are approaching equalization.

Equalization is defined as 10% higher than recommended charge voltage. Battery University (batteryuniversity.com) states during equalization:

The battery must be kept cool and under close observation for unusual heat rise and excessive venting. Some venting is normal and the hydrogen emitted is highly flammable. The battery room must have good ventilation.

My take on this is that it is normal, it occurs during the daytime only on a sunny day when the trailer is probably unoccupied and it quickly dissipates. Probably best not to do anything that might cause an open flame, such as: cooking or running the hot water heater. On the 21 that heater is pretty far away and probably not a good source of ignition.

The other thing is it is really hard for me to get to this stage with 120 watts of panel. I can say I have only achieved it twice and always late in the day,

[PGDriver]

If its the same battery box as used on my previous 19 the problem is they are not sealed air tight, there is even a hole for the wires. If you add some closed cell insulation and caulk around the wire hole it should fix the problem.

Cheers
Doug

[Rossue]

When I checked my battery electrolyte level I noticed the top of the box had a gray putty-like material used as sealant. Helps but certainly not airtight.

The 21 and 5.0TA are the first to have batteries installed inside aren't they? Haven't smelled hydrogen gas with the single 12V Group 29 yet.

[PGDriver]

Originally Posted by Rossue

When I checked my battery electrolyte level I noticed the top of the box had a gray putty-like material used as sealant. Helps but certainly not airtight.

The 21 and 5.0TA are the first to have batteries installed inside aren't they? Haven't smelled hydrogen gas with the single 12V Group 29 yet.

No we had inside batteries on our 19, they were under the passengers side dinette bench.

Cheers
Doug

[Jim Bennett]

I have never smelled anything in my 19 either, but have not been inside it when doing an equalize charge, as I don't do that while camping.

Like Doug said though, not greatly sealed, and it would be easy to do so as he described. This would definitely lessen any chance of gases escaping.

[J Mac]

I find that the real pain in the a$$ is checking that the cells have water in them. Being stored under the rear seat, with a full time mattress over it makes checking for water in the cells is a total drag. I know, I know, I've got to get an access panel installed. Even with an access panel those sealed battery boxes somewhat troublesome to re-seal. Do you guys think that with an access panel I would be able to get enough clearance to view the cells without removing them from the sealed battery boxes?

[Dave Walter]

Like some of the previous posters, I also have the dual 6V batteries inside the front dinette in a plastic box vented to the outside. We also have the factory solar. As of yet, I have not smelled any odors that could be attributed to the batteries, even though our battery box is not entirely sealed. There have been occasions where the trailer has experienced some unpleasant odors that could be attributed to other things besides the batteries.

[NJ Joe]

Originally Posted by J Mac

I find that the real pain in the a$$ is checking that the cells have water in them. Being stored under the rear seat, with a full time mattress over it makes checking for water in the cells is a total drag. I know, I know, I've got to get an access panel installed. Even with an access panel those sealed battery boxes somewhat troublesome to re-seal. Do you guys think that with an access panel I would be able to get enough clearance to view the cells without removing them from the sealed battery boxes?

I have been using AGM batteries on both my boat and slide-in camper because on both, the battery box is difficult to get to. There is no water level to check and they also provide an extra level of protection for an inside battery because under normal conditions, they do not vent anything when charging. You may want to consider an AGM when it is time to replace the battery.

[padlin]

Originally Posted by J Mac

I find that the real pain in the a$$ is checking that the cells have water in them. Being stored under the rear seat, with a full time mattress over it makes checking for water in the cells is a total drag. I know, I know, I've got to get an access panel installed. Even with an access panel those sealed battery boxes somewhat troublesome to re-seal. Do you guys think that with an access panel I would be able to get enough clearance to view the cells without removing them from the sealed battery boxes?

You could go this route. https://www.flow-rite.com/battery-watering

[fudge_brownie]

Bob,
Did you install the Blue Sky or the Bogart controller for your solar? Both of those units have the ability to charge the dual Interstate 6 volt at the proper rate. Owners with the GoPower controller provided by Escape or those using the WFCO shore power charger will probably never achieve the high voltage charge rates that the above two controllers can.

I think you are correct in that the sulfur odor comes with the high voltage charge and thus the only beneficiaries will be those charging at those rates.

I can sympathize with those having to move a queen or full size mattress to check fluids in the battery. I usually only perform such a task twice a year and for those so affected they could couple it with the vacuum cleaning under the bed.

[padlin]

Hi Paul, I ended up with the Bogart. Like yourself, it doesn't get up to the higher voltage very often, but when it does I get the smell. Was reminded about it today, and hence the question, when this am I used my standalone 10A charger on them in the basement, it goes up over 16v and I got the same smell. Obviously the venting in the trailer is not doing the job it is intended to do, question is what's the fix.
I read that the hydrogen gas rises, my battery boxes are vented on the side. Maybe that has something to do with it, I'll try replacing the closed cell foam and see if I can get a better seal. If that doesn't work I'll have to start looking for a replacement or better venting.

Thanks all.

[kvermeulen]

Originally Posted by padlin

Hi Paul, I ended up with the Bogart. Like yourself, it doesn't get up to the higher voltage very often, but when it does I get the smell. Was reminded about it today, and hence the question, when this am I used my standalone 10A charger on them in the basement, it goes up over 16v and I got the same smell. Obviously the venting in the trailer is not doing the job it is intended to do, question is what's the fix.
I read that the hydrogen gas rises, my battery boxes are vented on the side. Maybe that has something to do with it, I'll try replacing the closed cell foam and see if I can get a better seal. If that doesn't work I'll have to start looking for a replacement or better venting.

Thanks all.

How long is the smell there for.
most controllers will only equalize charge about ounce per month.
how about venting trailer with max fan when smell arrives.

[Brian B-P]

Originally Posted by Rossue

The 21 and 5.0TA are the first to have batteries installed inside aren't they?

The original 5.0 was essentially the same design as the 5.0TA in most respects - I don't recall external batteries, so I assume they are inside on that model as well.

[Brian B-P]

Hydrogen gas will certainly rise in air (there's no less dense gas than hydrogen), but it also won't smell... the smell is coming from a component other than hydrogen (presumably a sulphur compound), and may be carried up by the hydrogen.

Of course, that doesn't help at all to answer the question of how to better seal the box...

[cpaharley2008]

Take off the battery compartment cover on your battery box, I found that the foam seal had come off and it was not completely sealed around the top, check your for this issue.

[padlin]

Originally Posted by kvermeulen

How long is the smell there for.
most controllers will only equalize charge about ounce per month.
how about venting trailer with max fan when smell arrives.

The Bogart Controller has a pseudo equalize, not a real one. It goes into the higher "equalize" voltage as the 3rd stage of a 4 stage charge, the last being float, there is no schedule for it. In practice, the solar day is usually over before it gets that far. I've smelled it maybe 3 or 4 times since installing solar in July. And yes, the fan would get rid of it, but I'd like to prevent it.

[padlin]

Originally Posted by cpaharley2008

Take off the battery compartment cover on your battery box, I found that the foam seal had come off and it was not completely sealed around the top, check your for this issue.

I've done this and it was fine. It is kind of strange foam though, one side is stuck to the cover and the other has a rather hard plastic tape on it, kind of like 2 sided tape where they didn't remove the 2nd side. I'm have to look for some thing that will conform to the edge of the box better.

[Brian B-P]

Originally Posted by padlin

It is kind of strange foam though, one side is stuck to the cover and the other has a rather hard plastic tape on it, kind of like 2 sided tape where they didn't remove the 2nd side. I'm have to look for some thing that will conform to the edge of the box better.

That makes some sense to me, with a durable top surface and foam under it to conform to the top. If you're looking for better alternatives, there are rubber gaskets for automotive use that are available in bulk which might be suitable.

[rbryan4]

Originally Posted by Brian B-P

Hydrogen gas will certainly rise in air (there's no less dense gas than hydrogen), but it also won't smell... the smell is coming from a component other than hydrogen (presumably a sulphur compound), and may be carried up by the hydrogen.

Of course, that doesn't help at all to answer the question of how to better seal the box...

That's true - Hydrogen has no odor. The off-gassing is more likely Hydrogen Sulfide which has a rotten egg smell. Generally the more sulfated the battery, the stronger the smell.