Key left on all winter while batteries hooked to trickle charger. Any damage?

[I B Dead Eye]

Can you cause any damage to a 1991 90hp Mrec. By forgetting to turn off the key at the end of last season. The batteries have been on a trickle charger. This is my brothers boat. He noticed the alarm/buzzer making noise while starting to prep it for Spring. Thanks for any input you might have.

 

[alldodge]

If the bat will show 12.3V or more after being off the charger for a couple hours, and it does not drop below 10V while cranking, you might be OK. The 12.3V is the low end and would be better at 12.5V minimum

 

[I B Dead Eye]

Would any of the Electronics get damaged being left on for 3-4 months, this is what he is worried about. Not worried about the battery's so much.

 

[alldodge]

Would any of the Electronics get damaged being left on for 3-4 months, this is what he is worried about. Not worried about the battery's so much.

Normally no, once voltage goes below the cut off for the unit it just turns off. Leaving something on like a depth sounder, maybe. That said, there are to many unknowns and I cannot say

 

[I B Dead Eye]

Ok thanks. Just wondering if any of the engines electronics like coils and sutch things would get damaged. I guess he will have to wait till he comes back from vacation and just try starting it and see what happens. Thanks again.