wiring problem i THOUGHT i had

[bamabassman]

ok, as ya'll know, da cajun has been down for a week or so form what i ASSUMED (yeah i know what that stands for,lol) was a wiring problem. as it turns out, it's the BATTERY i jsut got a little over a year ago.
let me explain more for you. this is really weird i think. never heard of this happening.
i have 2 batteries for the troller and 1 for the cranking. i also have a 3 bank charger on my rig. jsut plug it up and ready to go in the morning.
well, on the day my troller conked out, the batteries were all charged and ready to go that morning. when i got home it showed ALL 3 batteries were still full. so i thought it had to be the troller. RIGHT? so, mad as all get out and dreading changning out trollers (which i have done now, got the 56# 12/24 on the boat) i called the guy i got the 80# from and asked if there was a warrenty on it. sorry he said, used trollers had no warrenty.so now i am really pissed i paid for a troller that is no good and swear i am a taken sucker. I AM SORRY, I WAS WRONG. wish now i had his number still so i could call him up and tell him in person.
anyway......i take a break form it all cause i really ain't got no money to put in the rig now anyway and it's hotter than hades out there too. got grass to mow, weedeating to do and so on and so forth. (i know, get on with it right?)
so thursday evening i plug in the cord to charge up the batteries. friday morning before i go to work i go to unplug it and check to make sure they charged. cranking batery and 1 troller was charged fully, but other troller battery is not. ow this is AFTER i have taken out all batteries and checked the wiring to make sure there are NO breaks or anything. and remember, BEFORE it took out the batteries, they would ALL CHARGE. weird right?
so i took it this morning to my boat shop and have it tested. 6.7 volts....bad battery. now i am thinking WTH?!? why did this happen? why wouldn't he onbaird charger CHARGE the batteries, then NOT charge them? i have 2 other chargers, they wouldn't charge the battery.
anyway, we hook up the 80# troller to 2 NEW bateries and ...........it works. yes i feel so small and stupid. after the phone call to the guy i bought it from got a really bad talking to from me.

but all this makes me wonder why;

if it charged up all battereis (green lights acorss the board) and troller didn't work. why did the onboard charger SHOW all were good if 1 was not?

shop owner and mechanic said it could do that sometimes.
have any of you folks ever seen or heard of this happening?

at any rate, by next friday i will be ready to hit the water. sweating like a stuck pig......but ready to hit the water with the "new to me" troller. hahaha!