Tops of batteries are wet

[pasusan]

Hi folks - I've got a question on how to troubleshoot my battery problem.

I've got 2 6 volt batteries wired correctly and a Progressive Dynamics 4600 series converter with charge wizard. The batteries live in a galvanized box with a tray that slides in and out (from the factory).

While checking the water level before our last trip I saw that there was a little wetness on the tops of both batteries and there was evidence that it had trickled down the sides and made rust colored spots on the bottom of my battery box. I cleaned up those spots and dried the tops of the batteries and we went on our trip. No water was needed.

While camping I checked the batteries again and found wetness. Dried it up and turned off the converter for most of the trip and just ran off the batteries (which powered things fine for our week long trip) and just turned on the converter for a few hours at a time to keep the batteries charged up. That worked fine.

We got home and I didn't plug the camper in for a week or so and the batteries were still powering things fine - really have only used the lights. Last night I checked the batteries - the water level was fine and there was wetness on the tops and rusty spots on the bottom of the box again. So I cleaned everything up and plugged it in around 5 pm last night and by 8 there was a little bit of wetness around the front cell holes on the tops of both batteries (it could be that I didn't dry them up perfectly and I am now seeing wetness because of using my LED headlight which is really bright). The batteries did not feel warm to the touch and when I pushed them back into their box by pushing on the side of one there was a gurgling noise as the side pushed in a little.

I've got a remote display for the converter. Just before I unplugged last night the display said 13.7 volts which looks correct per the manual for normal mode and the green led on the converter is blinking fast (my manual says that means the battery has reached 90% of full charge)

This morning after 11 hours unplugged and zero load on the batteries the remote display says 12.96 and the green led on the converter is still blinking fast.

The batteries were new in 3/2009, the converter 11/2010. Before the new converter I had a Magnetek which I religiously turned off and on as needed to not over-boil the batteries or allow them to freeze.

Did I give enough information? :W

Anyway - what I'm hoping to get from you gurus is how to find out what is going on. Could both batteries be bad or is my converter not charging correctly? My other idea is that the water (acid) is spilling out from the top holes because of bad seals on the caps while bouncing over rough roads - possible? How should I go about tracking down the problem?

[DSchmidt_2000]

wilanddij wrote:
If you want to eliminate the mist out of the battery cells when charging, put an ounce of mineral oil in each cell. They will still bubble, but the oil controls the fizz.

Agreed. I just did this for my passenger car last Dec. Used to have a lot of corrosion (no, it's not overcharging - just horrible vent design). Added a tablespoon to each cell and even today the top is spotless.

Just had to replace the battery in the wife's PT cruiser - all dirty, wet and corroded on top (same battery mfgr). New battery got mineral oil before installation. Hope for a repeat performance of cleanliness.

[wilanddij]

If you want to eliminate the mist out of the battery cells when charging, put an ounce of mineral oil in each cell. They will still bubble, but the oil controls the fizz.

[Gale_Hawkins]

As batteries age they are harder to fully charge but the charger just tries harder leading to long charging cycles.

[RVUSA]

pasusan wrote:
It definitely isn't dew or condensation - it's acid.

Probably have too high a charging voltage when they ARE plugged in (being charged). You can get the special caps that capture the boil off water and return it to the cell. That will stop it.

[MNtundraRet]

If you are worried about Hydrogen, I would just replace the two acid/lead batteries with AGM batteries which are sealed.

The battery compartment is well ventilated to the outside and should not be a problem. The box was made of galvanized steel and can rust with age (23 years old in you case). If your converter/charger is overcharging the batteries you would be able to smell a rotten egg odor coming from the batteries and they would be warmer than normal if overcharging. Also; you should see a sulfate power forming around the battery-posts connected to the charger,

Our trailer was stored in a lot without access to shore-power so I added a manual battery-disconnect. A screw type that would clear the door opening when pulling out the tray. We took the batteries home in the winter.

If you leave the trailer plugged in and charging all the time when stored that can create the problem unless you upgraded to a decent 3-stage charger.

[pasusan]

Thanks for all the responses! Not that I'm feeling that much better. Especially because of you guys talking about the hydrogen gas that could explode. :E

It definitely isn't dew or condensation - it's acid. I guess what I will do is keep a close eye on it when charging and make sure that the charging volts actually drop down to 13.2 for the maintenance charge.

I will also put getting new heavier gauge cables on my to do list. (Thanks MNtundraRet and a friendly wave to you.)

[westend]

Pausan wrote:
We got home and I didn't plug the camper in for a week or so and the batteries were still powering things fine - really have only used the lights. Last night I checked the batteries - the water level was fine and there was wetness on the tops and rusty spots on the bottom of the box again.

This would mean that the moisture is not a result of charging the batteries. I think what you're experiencing is condensation within the box. Depending on the environmental conditions, there may be little you can do to prevent the moisture. Maybe some desiccant would help.
You may be able to reduce the maintenance of the box (i.e. less cleanup) by thoroughly washing the battery case and using one of these Acid neutralizing pads.

[Altern]

Altern wrote:

D.E.Bishop wrote:
If I remember correctly, the explosive level for hydrogen gas and air is 4%. Not very high and is easily reached near the battery during charging.

You are correct - The flammability range for hydrogen gas is one of the widest known . About 4 - 75%

HERE'S A CHART SHOWING VARIOUS GAS LIMITS

[Altern]

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[time2roll]

Seems reasonably normal. How full are the batteries? I recommend 1/8" to 1/4" below the split ring. Just touching is absolute max and can still get some water pushed out.

Otherwise test the liquid with baking soda to see if it is acid or condensation (see post above).

[D_E_Bishop]

If I remember correctly, the explosive level for hydrogen gas and air is 4%. Not very high and is easily reached near the battery during charging.

[RCMAN46]

Wipe up the moisture with a paper towel. Then put some baking soda on the wet towel. If it bubbles then the moisture is battery acid. If it does not bubble than it is most likely dew as previously mentioned.

[Norskeman]

Battery will off-gas hydrogen when charging - if the level is too high in the cells some moisture will come out too. The cells need to vent when charging or gas and pressure will build up. Remember hydrogen can burn and is explosive at higher concentrations.

[RoyB]

Maybe a check with a multimeter would put your mind at ease. About the only thing that will boil out battery fluids is having 13.6VDC or more coming from the converter/charger unit for a long period of time.

Your smart mode PD4600 series converter should drop your battery voltage down to 13.2VDC when nothing is going on. It will jump between 13.2VDC and 13.6VDC when being used.

When it needs to re-charge it will jump up to 14.4VDC for about two hours and then drop back to the 13.6VDC level.

I suspect some condensation is forming on your batteries since you have NOT noticed the battery levels dropping.

Something to watch however...

I originally had two GP24 standard issue 85AH Interstate batteries when I first got my Trailer. It was equipped with an older single mode ELIXIR charger and it wasn't no time before I boiled out one of the batteries making it unusable.

I then added two more standard issue 85AH Interstate batteries and replaced the converter/charger unit to a PD9260C and all has been well now for the past 5 years or so. I still check my fluid levels on a regular basis out of habit but always find them ok.

Roy Ken