Loosing battery life

[Captin840]

So I have a 1990 comanche 4.0l inline 6 renix. I have a snow blade attached, and has been attached     (During the winter months) since 1998. Never had an issue with it until just recently, I know when you use something like that the the battery will be drained to an extent, but the other day while I was plowing I stop and then all of a sudden the truck died. Sounded like the battery was drained, checked it and it had 12.31v. Went to jump it with another truck and it wouldn't start until we moved the ground wire around and it fired up. Then when lifting the blade up it almost completely drains the battery and wants to die. When the truck is running the battery says it has 13.58v. So I'm confused, and my question is, is it a bad ground wire because I know there garbage on the renix style engines, is it the small alternator not having the power to keep it going? Please help, I live in eastern washington and it loves to snow over here. 

[Classy Comanche]

That is fairly odd for sure. My battery in my '88 Comanche is over 9 years old and pushing strong. Is your connections clean and tight/refreshed? How old is the battery?

[Captin840]

The battery is about 5 months old, and yeah battery connections are good and tight.

[Classy Comanche]

Maybe to much load is being put on the battery from the plow? I know some vehicles when to much load is applied or say if you put to much of a electricity load on one circuit of a house it will shut off and flip a breaker to keep from overloading and blowing up/shorting out. I'm not extremely knowledgeable about this kind of stuff I will admit. But you mentioned you moved your ground and it fired right back up. Maybe it's not keeping a stable connection?

[pizzaman09]

Probably the easiest thing you can do is have your alternator checked by an auto store, most have tools that can perform a load test.  Also high on the list is the check that you have good grounds to the chassis and alternator.