ProMariner charger issue

[BartmanMN]

I have a 3 bank ProMariner charger on my boat.  I have been noticing that my starting battery, which is new, has been acting like the charge was low as it was impacting my Humminbird graph.  Tonight I plugged in my boat when I got home from an outing and the Red light came on as expected.  When I returned 3-4 hours later, no lights were on (usually green when charged) and the charger and 1 of the trolling motor batteries were Extremely HOT. 

Do I have a bad battery, charger, or both?

[h8go4s]

Have you checked the water level in all the batteries? Have you checked all the battery voltages with a multimeter? What accessories are you running off the starting battery? What size is the starting battery? Is it a dual-purpose, deep cycle or marine starting battery?

[BartmanMN]

Starting battery is 27 dual purpose. Volt 12.65, Trolling motor battery 1 (Hot one) was 10.44 volt and battery 2 was 12.44 Volt.

I am not sure if it is at 10.44 because the charger was in the process of discharging it before recharging it or if it would never get that low anyways.  Maybe it is just past it's time.    I checked the water levels at the beginning of the year, but will do that later today as well.

[h8go4s]

"I am not sure if it is at 10.44 because the charger was in the process of discharging it before recharging it"

I've never heard of such a thing. Chargers charge batteries, they don't discharge them. Sounds to me like battery 1 is bad. You could verify that by switching charger leads on the trolling motor batteries and seeing if the bad battery still won't charge, but hot battery is normally a bad battery. Replace both TM batteries. They need to be the same age and same size or the weaker one will continually pull current from the other to try to equalize.

[BartmanMN]

This is my thinking as well.  Thanks.

[delcecchi]

"I am not sure if it is at 10.44 because the charger was in the process of discharging it before recharging it"

I've never heard of such a thing. Chargers charge batteries, they don't discharge them. Sounds to me like battery 1 is bad. You could verify that by switching charger leads on the trolling motor batteries and seeing if the bad battery still won't charge, but hot battery is normally a bad battery. Replace both TM batteries. They need to be the same age and same size or the weaker one will continually pull current from the other to try to equalize.

​That is true if the batteries are in parallel (+ to + ) for a 12 volt system.  It is not true for a 24 volt system.

[BartmanMN]

ProMariner ProTournament 150 charger tested out fine on all three banks.  I will pick up new trolling batteries when the "boss" says it is OK.

I did more reading and my charger starts with Fast charge, then an absorption charge, then a float charge, so it definitely does not drain them down.  Battery one is just shot.