Arcing sound when using charger

[Jcris]

I’ve got a Noco dual bank charger in my boat that I plug in Just to keep the batteries ready for the next outing. I usually plug it in the night before. Lately though when I plug it in I hear what sounds like something is arcing. It’s brief but sounds kinda loud. Something is pulling current hard enough to cause a jump in amp draw. Could this be a sign of an aging battery? I only have 2 batteries, 1 for cranking and all other accessories and 1 one dedicated to just the trolling motor. The only accessory on the starting battery is the fish finder. I’m thinking about putting the fish finder on the trolling battery as well to balance the load. I don’t think the finder draws much current but wanted to ask advise here.
I appreciate experienced input,
thanks

 

[GA_Boater]

Does the charger have a power switch? If no, then the chargers is doing it's thing and starting to charge the batteries and the snapping sound may the AC plug making contact.

How old are the batteries an are they holding a charge or are they drawing down faster than they used to? You can always yank 'em and get them tested.

 

[Jcris]

Thanks GA
no Switch on the charger but the sound definitely sounds like it’s coming from the plug when it makes contact. That doesn’t seem right to me? Both batteries have been tested and take a charge and seem to last normally.

 

[Jcris]

Also,
The cranking/starting battery is 8 years old. I pulled it and had it tested at Napa auto The voltage was good and the cranking amps were good. Do you think I should replace it just because of its age?
I have also noticed my fish finder shuts down when I start the motor. I was told that was due to the battery not holding at least 10 vdc when the motor is cranking. If that were true though wouldn’t there be other issues? What do you think?

 

[JASinIL2006]

My fishfinder/GPS also shut down when I started my boat, and my battery was fine. The solution was to just move the electronics to a house battery.

If my battery tested OK, I would not replace it just because of its age.

 

[GA_Boater]

Thanks GA
no Switch on the charger but the sound definitely sounds like it’s coming from the plug when it makes contact. That doesn’t seem right to me? Both batteries have been tested and take a charge and seem to last normally.

This sounds normal then because the charger starts to work as soon as the plug makes contact and for brief instant, the AC jumps the gap like lightning. SNAP! without the thunder. LOL

As JAS said, move the FF power feed from the starting battery to the house battery. That should solve the FF shutting down when firing up the motor.

I won't say you should replace an 8 year old battery due to age, but watch out for draggy starts and longer cranking times. My starting battery, the cheapest WallyWorld one, lasted 6 years until the starter began slowing down and it had to go on the charger. The guts wear out.

 

[JASinIL2006]

I would add that it's a little easier to be cavalier about hanging on to an older battery when you have a second battery (the house battery) available as a backup!

 

[Jcris]

Thanks guys,
I moved the fish finder to the trolling motor battery just to see what difference it makes. Again, I don't think it draws much current, but the next time I'm on the water should tell the tale. I'm tempted to put an amp probe on it just to see what the circuit is drawing.