Battery issues for days

[2ball]

My battery bolts and terminals get corroded and then my mower won't start. If I clean then off it starts right up. below is a picture of the brass battery bolts I bought 2 weeks ago. What is making them so corroded?

full disclosure, when I bought the battery 2 seasons ago I left the mower on (not started just on) and drained the battery all the way down. I charged it back up and it worked perfect last season. This season it has never started on the first try.

battery tested at 12.57 V when I took it out.

 

[sgkent]

probably acid, can be overcharging, a bad cell, leakage of the seals at the posts, low fluid. Buy a new battery only thins time coat the posts and bolts with vasoline to keep the acid off.

 

[bertsmobile1]

The magic stuff is called "Liquid Electrical Tape" applied over the bolts & terminals .
any place where wo different metals touch there is a potential to create a galvanic cell when ever there is an electrolyte to complete the circuit.
The electrolyte can be dew, rain, acid fume from the battery.
The higher the conductivity of the electrolyte the faster the reaction .

 

[2ball]

The magic stuff is called "Liquid Electrical Tape" applied over the bolts & terminals .
any place where wo different metals touch there is a potential to create a galvanic cell when ever there is an electrolyte to complete the circuit.
The electrolyte can be dew, rain, acid fume from the battery.
The higher the conductivity of the electrolyte the faster the reaction .

Liquid Electrical Tape worked. 2 starts without issue. I kept the old battery also.