It’s a little early in the month for Battery Day, but yesterday afternoon was beautiful and not very cold so I decided to stop putting off fixing what looked like a looming problem with Landlady’s batteries.
Even with ALL NEW BATTERIES AND CABLES AND CONNECTING HARDWARE, somehow Landlady’s batteries still have more trouble with corrosion on the positive posts than anybody else I’m responsible for. Not as bad as before, but it’s still there.
Mostly just this green powdery stuff that washes away with a water bath. But I needed to know how much corrosion scum was building between the posts and cable connectors. It can insidiously cause a lot of resistance.
One thing I like about Landlady’s new setup is that I can completely isolate the batteries from the solar panels as well as the load, reducing arky-sparky to nothing. Uncle Joel is a macho man who fears nothing…
…I’m just being considerate to Torso Boy, who’s a scardie-dog.
Anyway…
Turns out that at least at this early stage the corrosion was only affecting exposed surfaces and didn’t seem to be building up between the connections at all. But I gave them a good scrape sandpaper anyway, and then went ahead and topped off all the electrolyte levels. So I’m done with the biggest Battery Day job a week early.
Would it help to coat them in Vaseline or something after you clean them?
My own experience with Vasoline does not suggest it’s invariably helpful but it does seem to work on my own connections. So yeah, I’ll try to remember to get a bigger jar when I’m in town on Monday. But it, and also specialized anti corrosion grease, has failed with Landlady’s batteries before.
It appears to be only on a couple of the terminals. Is it by any chance always the same ones, and if so does this mean anything significant?
Very likely due to over-charging and consequent acid vapor production. Check out the settings on her charging circuits.
This stuff works really, really well (but its messy if you aren’t careful):
https://www.amazon.com/gp/product/B004AWO4NI/ref=oh_aui_detailpage_o03_s00?ie=UTF8&psc=1
2nd the motion on overcharging.
Could it be that one of the batteries is bad, pulling down the string?
Know that budget is a thing, but there are automatic watering systems for T-105s. (I had T-105s on my boat, but the systems that work with stationary installs are better than what I had.) Basically replacement caps add distilled water from a reservoir whenever the level is low. They aren’t cheap, but they last a long time,and keep your batteries happy.
Joel, from a long time EE and automotive shade tree mechanic – the posts exhibiting the most corrosion likely have a very faint gap between the post and the plastic (or whatever material was used for the top/sealing of the posts). Dissimilar materials have different coefficients of expansion and since the posts and case get warm then cool with use of the system, that tiny gap allows gas and acidified humidity to escape/enter which leads to the corrosion happens on older solid post car batteries quite a bit. Clean the posts really well and around the base of same, then put some battery grease (not exactly the same as Vaseline but close, has some acid inhibitors in it) around the base of the post before putting the clamp and wire back on. This should reduce the incidence quite a bit. I will see if my local electronics supply has any of the grease and will toss one into the next care package.
Thankyou yet again for reminding me how much I DO NOT miss off-grid battery day.
Suspect overcharging. Ensure the afternoon float voltage with your meter to ensure that it agrees with the voltage displayed on the controller, and is within specs for those batteries.
They’re not overcharging. I have manually checked the float voltage and it’s lower than at the Lair. Also none of her batteries boil off a lot of water. It all seems perfectly fine, in fact. I’ve been over all 48 connections and they’re all nice and tight. This is an entirely different system than the one that used to drive me to drink; not just the batteries, the inverter and charge controller as well. Yet that’s the only location that gives me a lot of corrosion grief.
Just lucky, maybe.
I did some research on this corrosion buildup business after an annoying session with one of those side terminal bolts with the undersized 5/16″ head (probably made of pot-metal). The bolt would turn but the custom molded cable assembly was frozen to the bolt – so that after about a 1/2 turn the cables would start to twist and pull. I had a decent enough connection to start the truck and wasn’t rushed so I took my time and worked at it with baking soda and even Kroil after a while. Finally wedged the cable assembly with a piece of wood and went after the stupid bolt with the vise grips. Worked on the first attempt once I’d secured the fancy terminal harness to keep it from turning. After cursing the joker at GM that came up with this fancy, overcomplicated, and probably very expensive 3/4″ thick terminal with the molded insulative covering – I went and studied corrosion.
I agree with several comments that mention some aspect of off-gassing – for whatever reason. I also agree with the comment about the small gap around the post on the battery – or any other type of crack/breech in the case. I also think that if all that failed I’d look at the ventilation of the room itself.
I also recall that the color of the corrosion was an indication of the metal/s involved – green for copper and dull powdery grey for lead – iirc. Can’t recall what the cream colored cr*p represents – probably Zamak* (aka pot-metal).
* – that’s a funny forum to read – folks running those gats – enjoying it and admitting to it. The more the merrier!
Hi Joel – I find silicon grease works well on my Trojans. No corrosion in four years of use.
And of course you wore your full PPE, right??? Especially a full hood, elbow length gloves, boots, apron.
Maybe you have mice peeing on your battery connections.
Absolutely, Zelda. I can barely move about at all.
I think Zelda might be on to something with the mice using the battery posts as fire hydrants.
Strange they two corroded terminals are in close proximity but not on a pair of connected batteries.
Hmmm?
There’s a heave petroleum based battery terminal protective gunk called No-oxid iirc. When I was in the Sig Corps, we used it on massive station battery banks. Have to heat it up and brush it on clean terminals and wires. This if I’m not mistaken: https://www.illumn.com/miscellaneous/no-ox-id-a-special-electrical-grade-conductive-grease-2oz.html