I'm getting a lot of corrosion on one of my two 6V batteries, enough that I've had to replace the terminal nuts twice in the last year or so.Since I bought my Fleetwood Storm a little over three years ago, I've kept the batteries topped off with distilled water. They occasionally appear like they're low on water, but the level has never gotten so low that the plates are exposed. When I park it in storage, I hit the disconnect switch so they don't run down, and I only plug into shore power when at campgrounds with 30A hookups or when parked in my driveway (15A) when getting ready for a trip, probably 10-20 days a year.Some more background: Last time I checked, the battery with corrosion read about 0.05 volts less than the other battery on my voltmeter, and my cheap hydrometer gave a slightly lower reading on one of the three cells. Also, I'm my Storm's power converter is a WFCO 55-amp model WF-9855.What could be causing all this corrosion?

Battery boiling from overcharging.

Parasitic draw(s) followed up by excessive charging

OldBlackWater wrote:I'm getting a lot of corrosion on one of my two 6V batteries, enough that I've had to replace the terminal nuts twice in the last year or so.Since I bought my Fleetwood Storm a little over three years ago, I've kept the batteries topped off with distilled water. They occasionally appear like they're low on water, but the level has never gotten so low that the plates are exposed. When I park it in storage, I hit the disconnect switch so they don't run down, and I only plug into shore power when at campgrounds with 30A hookups or when parked in my driveway (15A) when getting ready for a trip, probably 10-20 days a year.Some more background: Last time I checked, the battery with corrosion read about 0.05 volts less than the other battery on my voltmeter, and my cheap hydrometer gave a slightly lower reading on one of the three cells. Also, I'm my Storm's power converter is a WFCO 55-amp model WF-9855.What could be causing all this corrosion?Too much water causes them to gassify and boil out acid. Use new nuts and then installed apply a liberal coverage of plain old VASOLINE and they wont get cruddy after you do. Keep water at the proper level.

You need to diagnose whether this is a battery with a bad cell. That is where to start.Use a hydrometer to recheck both batteries. With batteries fully charged and charger turned off, check SG. If OK (no bad cells) then the next thing to check is the voltage your converter or charger is putting out. Some are adjustable, some are not.If the charger is not adjustable in terms of output voltage, an inexpensive alternative while in storage and plugged into shore power is to by a HD 120 VAC timer (20 amp) from any box store. Plug your converter into it and let it run for 20 minutes a day. That should certainly keep up with the self discharge rate.

Put one or two pennies close to each battery post & they will keep the posts clean.They will soak it all up.Yes really!!Could get kind of pricy tho,could use up 5 or six pennies a year.

Excessive battery corrosion | Good Sam Community

10forty2
Explorer
Jul 22, 2015
DOtte wrote:
to clean off corrosion, use plain Coca-Cola and rinse with water. leave it sit a while before rinsing

And if you don't want to waste a perfectly good Coke that could be mixed with a wonderful Kentucky bourbon, :B, just use some baking soda/water. When we bought our coach, the house battery compartment was very corroded...especially the battery tray. I removed the batteries, and added the baking soda/water solution and watched it fizz. Then rinsed with plain water and it looked like brand new.
Mr_Mark1
Explorer
Jul 22, 2015
tratterboy1 wrote:
Put one or two pennies close to each battery post & they will keep the posts clean.They will soak it all up.Yes really!!Could get kind of pricy tho,could use up 5 or six pennies a year.

--Side note---

Before you put a penny out to be destroyed, make sure it's not a 1943 copper penny. They are worth about $80,000 each. One sold for $200,000 in 2004.

In 1943, only steel pennies were issued. A few copper pennies got through and are worth a fortune. They say about 40 copper pennies were produced, 12 confirmed to exist (per wikipedia). But, you never know, you might find one.:D

Safe travels,
MM.
RayChez
Explorer
Jul 22, 2015
Batteries require maintenance and one very important thing to do is to wash the batteries every two or three months. Just get a water hose and hose the batteries real good and you will never have a corrosion problem.
DOtte
Explorer
Jul 22, 2015
to clean off corrosion, use plain Coca-Cola and rinse with water. leave it sit a while before rinsing
MrWizard
Moderator
Jul 22, 2015
if you do the oil thing
besure the cells are full and charged before you do the oil
if low you will get oil on the plates
Jim
Explorer
Jul 22, 2015
Sounds like something going on there isn't normal. But, whatever, one way to reduce the corrosion is to put 2 oz of 3-in-1 oil (mineral oil) in each cell. That keeps the 'bubbles' that boil off the plates from casting acid into the air space above the liquid level, and escaping out of the vents.

Tada! No corrosion.
OldBlackWater
Explorer
Jul 22, 2015
tratterboy1 wrote:
Put one or two pennies close to each battery post & they will keep the posts clean.They will soak it all up.Yes really!!Could get kind of pricy tho,could use up 5 or six pennies a year.

I'm pretty sure I have a bad cell in the battery that is getting all the corrosion. My hypothesis is that the good battery is constantly trying to charge the bad one to bring it into equilibrium, and the excessive "charging" is causing the gassing. So far I have spent eight cents preventing the terminal nuts from getting too corroded (the penny trick works great, BTW).
OldBlackWater
Explorer
Jun 05, 2015
Thank you everyone for all the replies.

I didn't know about the possibility of having too much water. I'll be careful not to overfill.

The two times I cleaned the terminals, I used a wire brush and lots of paper towels. I couldn't find my DeOxIT electrical connection cleaner this last time, so I just used some dielectric grease instead. I've been scared to get liquids on the terminals for fear of arcing, but maybe I'll try using water next time. I'll also try the Vaseline and penny tricks and switch the caps around to see if that makes a difference.

But I have a feeling that I have a bad cell. I'll double-check next time I get a chance. I'll also check my charger voltage at some point.

And regarding over-tightening the terminal nuts, I torqued them down a little extra this last time, thinking maybe loose connections could cause corrosion - maybe not the best idea!
tderonne
Explorer
Jun 04, 2015
Could be leaky caps. Swap the caps around. If the corrosion moves around, it's the caps.

I had to take my caps apart (remove the rubber sealing washers) and file off some casting flash so the washers had a nice smooth surface to seal against.
time2roll
Nomad
Jun 04, 2015
What do you do to clean the terminal?

I recommend lots of water followed by a spray on cleaner from the autoparts store. Then use a spray on protectant.

Since it is one battery I doubt it is the charging system or the usage. Probably the terminal has broken the seal as it comes up through the case. You may need to just deal with it until you get new batteries. Careful how much torque is applied when tightening the terminals.

Weak battery will also gas more and be prone to corrosion.

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