Why aren't my NIMH receiver packs lasting?

[srusinek]

So just a little history. I've owned my Baja since 2010 and I ran the stock pack for awhile and then I upgraded sometime in 2012 to the Venom 5000 mah pack. That pack lasted until midway of 2013 and had a dead cell. Then I purchased another one last year which lasted until today. I last ran my Baja June 7th and I charged the pack prior to running. Today I check the battery at the house and it seemed fine. So I went to the field I run to, filled up the tank and then I checked the servos. The battery was so dead when I turned on the radio and checked the servos the fail safe would kick in. I'm running the stock radio and stock servos. So I went to charge the pack today when I got home and it went until 273mah and it said full to capacity. I running this charger:

http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXXLH3

which charges my lipos, nicads and other nimh packs I have. So how do I prevent this from happening? I charged the pack at the end of last season and I topped it off when I brought it back out this year. I run about 2 gallons a year which runs from around late April until it's too wet to run in the fall. I would go Lipo but I don't feel safe running a lipo on 6v servos without a regulator and money is tight at the moment.

 

[hamz9561]

How about a LiFe RX pack. It's close enough in voltage that a regulator isn't needed.

 

[srusinek]

I was looking at a life pack at my lhs around April that was made by killer rc but it had a weird balance plug on it so I passed. I was looking at a life pack from tower that's made by hobbico but looking at the dimensions compared to the pack I have, it won't fit into my receiver box. So I bought another venom pack expecting a season out of it and next season when I have the coin I'll get the killer rc lipo pack and regulator. The thing that I don't get is I have other stick packs that I use made by Venom and Duratrax that I use for my electrics and my nitro starters (roto start, pro start) that I usually never touch and they're fine. Go figure.