Ok, so I have a 5 year old battery powered Craftsman weedwacker trimmer thingie. Here's a diagram:

It isn't working. The charger doesn't seem to be functioning at all. No light and no voltage at the DC end of the plug.
So I manually hooked up the batteries to my small car lead acid charger. I only let each charge for 45 minutes or so monitoring them from time to time. For some reason the negative connector from my battery charger heated up on the first battery significantly, but everything else was normal. I figured this would assist in delivering enough voltage to the charger to indicate if that part was bad also. So the charger still wouldn't work. The device would actually spin up a little- enough to indicate that I assume the rest of the device is working properly.
So, I'm assuming that I have 2 bad batteries (even if its just one both will need to be replaced) and I'll also need a new charger.
So batteries are $42.44 each and the charger is $22.08.
So to replace all the parts from Sears would exceed (I think) the original cost of the trimmer at $106.96. Even if I hunt down the batteries from another supplier I figure we could be around $70 for all the replacement parts, still dangerously close to the cost of a new similar model.
So basically I'm attracted to this Black and Decker 18 volt one:
http://www.sears.com/shc/s/p_10153_1260 ... ckType=G10
I've never had good luck with 2-cycle engines and the mix is a pain. However I would consider it. I usually only trim once a month or so but we do have a fence in our backyard so that does need trimmer assistance. Our yard is looking pretty dismal at this point.
I hate to be the guy who throws stuff out instead of fixing it but sometimes the economies of scale trend that way. I only paid $62 for my current lawnmower new and have used it for 5 years. If it dies it only cost me a little more than $12/year, which isn't bad either so sometimes I just find this easier and cheaper. I do not, however, plan in using this strategy on the generator or snow blower which are properly stored for the summer.