Your charger might be junk. Had that happen with my LG car charger.
I have an LG AX8600 and I am NOT impressed with it at all. I paid $200 for the thing and I had to replace the battery when it was 7 months old. The extended life one I bought is wearing out now too after about the same amount of time, I'm glad I only paid $12 for it on ebay. The hinge on it sucks and moves a lot. It has a huge delay receiving text messages (though that may be the service). Its a little over a year old and I'm so sick of it.
My last phone was a Sony Ericsson I paid $50 for and it lasted 2 1/2 years with absolutely no problems, and I beat the crap out of my phones.