If this has been covered before, a thousand pardons . . . Disclaimer: if you don’t know what you’re doing or aren’t comfortable with this, disconnect the ground cable before servicing the battery. You already know this: use a small amount of baking soda dissolved in warm or hot water – pour and/or brush a little on the corroded terminal(s) with a garage grade tooth brush, watch it fizz, repeat the process once or twice more till fresh solution doesn’t result in any fizzing, rinse off with a little straight water, paper towel it dry, remove the cables (ground first) and clean the terminals / posts with a wire brush style terminal cleaning tool. Put it back together (ground last), and, if you’re feeling ambitious smear some grease on the exposed terminals / posts. End of story. Simple, huh? I ran into a bigger problem the other day – the terminals / posts were visually perfect – no need for the above, but the ground cable in the last inch and a half adjoining the terminal end that goes on the battery post was corroded between the wire strands, causing the wire strands to have bulged out and forcing part of the insulation back. This is in a finished, carpeted trunk, so containing the entire cleaning mess was a requirement, the opposite of what I might do in the engine bay of a daily driver. Also, since all the corrosion was between the copper wire strands, I felt a different method was required. I surfed and I found: So tip #1 is the white vinegar / 2 part solution: Solution A – white vinegar with a small amount of table salt dissolved in. Solution B – the afore mentioned hot water and baking soda. Solution A does an amazing cleaning job, leaving the wires looking brand new with approximately all the corrosion gone. Solution B neutralizes A and, if it fizzes to any extent, is an indication that it is dissolving any corrosion that may have been missed with the first solution soak. I keep a quantity of clean, empty 1-quart plastic milk or juice containers around the garage to hold fasteners or little things when I’m in the middle of repairing something around the house or on the car. I took two of them and cut 6” off the bottom, using those to hold the solutions. I stripped another 3/4" of insulation off of the offending cable, dipped it in the first solution, gently agitated it for a minute, gently brushed it, pulled it out, blotted it dry, and moved on to the second solution. Same procedure there. Cable was perfectly clean with no corrosion left between the strands. Success. Next the cable repair: it was obvious that any piece of heat shrink tubing that was big enough to go over the terminal was going to be too big in size to shrink down to the cable diameter, so I taped the cable with shrink electrical tape. This tape shrinks only slightly when the heat gun is applied to it, but it bonds to itself in the process, so the result is a sealed cable. I’ve had that stuff sitting around for several years; I was wondering when I was going to use it. Next comes the cable ends that go on the battery posts: I spent 45 seconds or so with the battery terminal cleaning tool, wire brushing the cable terminals and battery posts. I smeared di-electric grease on a pair of those red and green felt washers that go between the top of the battery and the bottom of the cable terminals, which I then put in place. So tip #2, to stop oxidation, is to use electrically conductive grease on the terminal / post junction only: NOT on the felt pads. The di-electric grease is there on the felt pads to make sure that you are not leaving an easily conductive path after putting conductive grease on the inside bore of the battery cable terminals ONLY. I didn’t feel like buying specific grease so I used Copper Coat Gasket Sealant – the same stuff you might use on head gaskets, water pumps, and in other assorted places. It conducts electricity. I carefully wiped off the tiny excess on the top of the battery posts and I was done. As these particular terminals have some kind of a prior coating on them that caused them not to corrode in the first place, I saw no need to apply grease to the exposed parts of the terminals. Job done.
I've been known to remove the battery from the rig it was in to clean it on my rigs and on customer rigs. On batteries under the floor or in the engine compartment you can have a serious voltage loss across the top of the battery if the battery is dirty on top, enough in some cases that it will drain the battery in a couple of hours.
A car guy should have his own tube of dielectric grease. And use it on every terminal on his car. Way easier to install it when the wire is installed than to track down a bit of corrosion giving you problems later.
What I noticed is a battery that is serviced and maintained won't corrode externally the way a neglected battery will. The corrosion on the terminals is a symptom. Keep battery clean and thoroughly charged. Once a lead-acid battery approaches somewhere around an 80% charge it starts to outgas when charging. This is wha (mostly) causes terminal corrosion. OEM likes to use dissimilar metals now and then. Outgassing is part of the charging process and is unavoidable. It continues moderately outgassing up to a 100% charge. It's necessary but the time spent in this state should be minimized. Keeping a battery topped off to the high side with a charger is the way to go. Once the corrosion sets in too, it starts to wick up and attack the cables internally, where it can't be seen. Then the resistance of the charging and start circuit increases, so now the alternator is constantly shortchanging the battery, though also constantly boiling the battery electrolyte. More corrosion follows, rinse lather repeat. Clean tight connections - Happy Electrons.
To stop battery corrosion cold, I always coat the post/terminals with Permatex Aviation sealant. https://www.permatex.com/products/g...x-aviation-form-a-gasket-no-3-sealant-liquid/ There is a trick.... and it can be a bit messy... For this to work, you have to have clean 'bright' metal with absolutely no existing corrosion. Ideally, start with a new battery and terminals, but you can clean up used ones in most cases. If starting with used, replace the terminal clamp bolts/nuts as a matter of course. Then make sure you have every last bit of oxide off, in the bolt hole, between the terminal clamp ends, everywhere. If there's 'hard spots', that's oxide. I'll use wire brushes, sandpaper, files, utility knife, whatever, to make sure all the lead is spotless. Do the same for the battery post. Even new ones should be scuffed until 'bright'. I then paint all the hard-to-get-to spots with the sealant; the base of the post, underside of the terminal, hole for the bolt, bolt, etc but keep it off the inside of the terminal and outside of the post. Assemble the terminals to the battery. Make sure you've got a good connection, then heavily paint the whole terminal. Do a minimum of two coats, three is better. Make especially sure you get the post/bottom of the terminal sealed to each other. If you did it right, the coating should 'flow-out' into a smooth, deep ruby red coating. You probably won't need to touch that connection again until you replace the battery. And even if you do, the only corrosion you should find will be on the actual contact areas. Now, just like rust under paint, any corrosion left will come back. And this stuff never fully dries, so it won't crack. It does remain sticky though, even 'dry', so it does attract dirt. And I'd recommend masking the surrounding area; this doesn't come off easily. If you nick it with jumper cables or something, touch it up promptly.
When I want to have a battery with no corrosion issues on the posts or cables, I just buy a side terminal battery, and it's good for five years. The cables will last for decades, with little or no corrosion. But this makes the car non-traditional, by about 5 years. If I want the battery to look traditional, I use a post type battery, and it corrodes, and it looks just like they all did back in the day.
I have used coca cola in a pinch when I was on the road, works like a champ. I have also just happen to own a tool for cleaning battery terminals, its a kind of s brush thingamabob that you can buy in any autoparts super store for about 5-10 bucks. You just stick it over the post and spin. Oh by the way I failed to mention, @Was 196 #'s this is good information.
I just take my Bat. in the House & wait for Spring or a Nice Warm day to fire up my Car. That way if it Need's any work I will play with it.! P.S. if you are Playing with a Batt. Always Disconect The Plus Terminal in the CAR. Just my 3.5 cents Live Learn & Die a Fool
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