Battery Bolt Corrosion
- Thread starter mzdrati
- Start date
bertsmobile1
Lawn Royalty
- Joined
- Nov 29, 2014
- Threads
- 65
- Messages
- 24,995
Sealed batteries ended a lot of that as no more acid fume to condense on the battery top
And yes a std service item done at every service .
And yes a std service item done at every service .
You are correct about galvanic corrosion. Two opposite metals in close proximity, with an electrolyte. In the case of battery posts, it's usually the difference between the battery post (Lead) and the electrical strap (Brass). Usually most new battery straps AND the clamping fasteners will be Lead plated, but the plating can be short lived. Electrolyte is supplied by humidity in the air, from wash water, and/or seepage from around the battery posts. Each is easy to come by; pick one. The chart below shows the compatibility of metals....
If "2 dissimilar metals and an electrolyte" sound like a battery, then you're correct. What's happening is that a tiny battery is formed. So the "corrosion" is the result of an electrical process. Of course, the additional presence of an acid (if your post is leaking) doesn't help one bit.
Prevention is easy: exclude the electrolyte. This can be done by coating the post and terminal with any type of thick grease. This could be a specialized battery post protector grease or a bulk automotive grease. If your posts are leaking then the felt battery post protectors can help.
If "2 dissimilar metals and an electrolyte" sound like a battery, then you're correct. What's happening is that a tiny battery is formed. So the "corrosion" is the result of an electrical process. Of course, the additional presence of an acid (if your post is leaking) doesn't help one bit.
Prevention is easy: exclude the electrolyte. This can be done by coating the post and terminal with any type of thick grease. This could be a specialized battery post protector grease or a bulk automotive grease. If your posts are leaking then the felt battery post protectors can help.
bertsmobile1
Lawn Royalty
- Joined
- Nov 29, 2014
- Threads
- 65
- Messages
- 24,995
Actually the metals do not even have to be dissimilar
When you bend a metal cold you create a stress in the lattice & that stress will form a galvanic cell between itself
If you have some old nails you will notice they always start rusting at the head & tip first .
As for mower batteries, I use a longer bolt and a shortened wing nut
When assembled the entire assembly gets painted over with a product called "Liquid Electrical Tape " leaving about 1/2" of thread uncoated so I can take measurements or clip on jumper leads .
Just done a mower I last serviced in 2014 and the LET was still in place & the battery was still fine
When you bend a metal cold you create a stress in the lattice & that stress will form a galvanic cell between itself
If you have some old nails you will notice they always start rusting at the head & tip first .
As for mower batteries, I use a longer bolt and a shortened wing nut
When assembled the entire assembly gets painted over with a product called "Liquid Electrical Tape " leaving about 1/2" of thread uncoated so I can take measurements or clip on jumper leads .
Just done a mower I last serviced in 2014 and the LET was still in place & the battery was still fine
shurguywutt
Well-Known Member
- Joined
- Jul 17, 2013
- Threads
- 29
- Messages
- 201
Clean tight connections and coat them with lithium or automotive grease.
