Hello,
I have a MK 440 4 bank charger, guessing about 9-10 years old.
Has always worked flawlessly but this year at first start I am having an issue.
I have three brand new group 27 D/C trolling motor batteries and a 1 year old cranking/accessory battery. One of the banks, when plugged for charging, will show a red and green light lit simultaneously. If I unplug and replug however, the yellow charging light comes on and remains on for perhaps 20-30 mins before it turns to red/green. This particular bank is hooked up to one of my brand new T/M batteries. All 4 batteries tested and are fine. I have read the post on indicator light readout, I have taken all fuse holders apart and cleaned and applied dielectric grease and changed all fuses; fuse holder was getting hot on the problem bank as well, which would indicate resistance. If I charge this battery, with another car battery charger for example and correct settings, battery will charge just fine.
Thanks for any insight.