To prevent and stop electrical connector corrosion this product
comes highly recommended. It's called PENETROX A
The electrical and electronic techs here at the Mack Trucks Power
Train manufacturing facility say that it makes the connector highly
water resistant and if moisture gets in the connector, corrosion
will not set in. I'm told that a little goes a very long way. This
product can be had at electrical supply places. I didn't check with
Home Depot or Lowes yet to see if they stock it.

Dielectric grease will do the same thing. Unplug and clean your connections then put a small amount of grease on them and then plug them back together.

With a sealed Battery there should be no problem with corrosion normaly.

Where can I by "PENETROX A" or "Dielectric" ? Sounds like a wonder
lubricant or sorts.

Dielectric grease is available at any parts store, such as Autozone. It is used on battery terminals and ignition parts. Should be a dollar or two.

I checked Home Depot, they have some other brand. Is dielectric grease a spray? I didn't get their brand, 'cause I thought grease means it's in a tube. They didn't have anything other than spray.

I have only seen it in a tube but if it is dielectric grease and a spray that could also work - I use to use lithum spray grease (until I got some water proof bearing grease).

I bought a can of dielectric grease at autozone that is pressurized and has a trigger. It's grease, but comes out like greased lightning if you hold the trigger too long. A little touch of the trigger and you get grease for about 20 seconds. I'd rather have a tube you squeeze yourself... But hey it works.