I cleaned my battery posts 4 months ago and one of them is very corroded again. I cleaned them with CRC spray and then used another CRC spray to cover them (to prevent corrosion). As I recall they looked clean, but maybe not? Any suggestions on other ways to prevent the corrosion (besides switching to AGM batteries).

 

CRC isn't really a battery post protector/cleaner. Go to Auto Parts store and buy a REAL battery cleaner protector. Or at least some of the impregnated felt pads that fit over battery posts. Use a wire brush to clean the battery posts and connectors. DO BOTH POSTS ! Add water where necessary.

 

most of the time.. as your problem describes is a vent Leak at the battery terminal...

causing your stated problem.....

 

Ultimately what causes terminal corrosion is outgassing. Fix that. Keep it thoroughly charged, and make sure it's charging correctly on the road or whatever.

 

I've been using CRC spray on my other vehicles and haven't seen any issues there. I'm running dual 12 volt batteries. They came with the trailer. I don't know if it being a dual setup makes a difference. These are Interstate batteries and they have a lever operated gizmo that opens all three caps for water level inspection and maintenance. Of the four posts on my dual batteries, only one post has corrosion.

 

Check the voltage when the trailer has been plugged in for a day or two and if the voltage is over 13.6 you need a better converter
I use a Progressive Dynamics staged charge and after it brings the batteries to full charge it floats at 13.2.

Denny

 

Agreed....OR new batteries. Change both at same time!!!

 

Help me understand this. A bad converter can cause corrosion? I have a solar panel that uses a GoPower gizmo (converter?) to keep my batteries charged.

 

Check your batteries. An aging or failing battery keeps the converter working harder and increases gasing, so your batteries may be getting tired.

Most solar controllers provide better charge regulation than converters. Shut your converter off and see how your solar does. I just have Walmart batteries and haven't had to add water in over a year with a combination of my high-end inverter charger and my solar panels.

Steve

 

The first place to start is the battery voltage after they are fully charged, if they are floating to high it will cause the batteries to gas causing corrosion. It could be your converter or your solar regulator.

Denny

 

What you will find is differences in amperage, even at non-gassing voltages. My panel right now is showing over 14-volts with my solar, but only .1 amp output so much less than trickle charger. My controller throttles it way down. Check the amperage out of most converters when they are showing 13.2-13.4 volts and I think most folks will be surprised how many ampsthey are putting out, even on float. My inverter charger is also on a few tenths of an amp when floating. There is virtually no gassing at all until my batteries really start to age.

Steve

 

It has to do with the average state of charge of the battery, and the health of the wiring and connections near as I can tell. The regulator also "sees" corrosion/resistance as a battery that needs to be charged, even when it's full.

In order to reach a full charge, all batteries need to moderately outgas, there is no way around it. This is a good thing, but it needs to be minimized.

With infrequently used equipment I think what probably happens is it sort of hangs there in the absorption phase of the charge cycle, bubbling away... It wasn't charged to begin with. This causes even more corrosion on top.. and higher resistance... so more charging.. and.. Well you get the idea. This is why cheap small unregulated micro-amp chargers don't work very well. It takes a week and a half for a full charge, and the battery boils itself dry. A good charge(r) is properly "sized" for the battery ampere capacity. It's a compromise, quick enough, safe, minimizes outgassing.

Supposedly some brands of batteries are more prone to corrosion (Exide are blamed for this, I've no idea) and the OEMs have been known to use dissimilar metals in their terminals and connections. Oops. In recent years have been using chargers and tenders, keeping batteries plussed up whenever possible, corrosion is a thing of the past. YMMV.

 

I have been checking the water level in the battery since June 2016. I added water once around August of 2016. It's been fine since then.

I have never connected the batteries to a 120v AC battery charger. They seem to maintain a charge fairly well. I was leaving the stereo on (but not running anything) all the time but that seemed to draw down the batteries. I have yet to camp in my trailer so I don't really know how long the batteries will last under a "camping" load.

The batteries are in an enclosed battery box with a lid. Does the box need to vent?

 

the battery box should be vented. that gas is mostly hydrogen, which is explosive.

 

It won't hurt a thing to give it a good thorough charge with an AC charger once in a while, it's called an "equalization" charge. The amperes start out high and the voltage low. Monitor the volts as they come up. Outgassing starts around 14 volts or so as it approaches a full charge, and the current will continue to ramp down to almost nothing. This is where "dumb" chargers are actually good, so long as they are on a timer, don't forget. Let it cook for a while. Usually up to around 16 volts for about 3 or 4 hours. The end point voltage is temperature dependent. If you monitor the voltage during charging, you'll see how a standard old school automotive battery charger like a Shumacher follows the charging algorythm tables almost perfectly, they had this stuff pegged 65 years ago. In extreme cold (well below zero) the charging voltage has to be quite a bit higher to overcome the batteries internal resistance. The 4 amp setting in this situation is practically a float charge.

Batteries outgas hydrogen, and is definitely explosive. Also along with that, they give off a lot of other nasty chemicals you don't want to breathe. Plenty of ventilation is required. Once you know a battery is 100% charged, the battery tenders are worth their weight in gold, because they can be connected indefinitely and will keep it topped up. If it's real hot in your area bring the battery to an area that stays cool for longer term storage, they will hold a charge a lot longer. High temps kill batteries.