Battery not charging

I have had a HP ipaq rx1950 for about 2 years and last month it has stopped charging the battery. I bought 3 batteries and each one does not charge. I put these batteries in another person's ipaq and they charge. When the charger is plugged into my ipaq the light blinks 10 times and then stays on solid for about 10 seconds and this repeats and does not stop unless I unplug the charger. After about 24 hours of charging I disconnect the charger and the ipaq shows that the battery has charged to 100% but after about a half hour the % drops to the original low state. I noticed on my friend's ipaq that the light blinks constantly until it has charged, then stays on solid. Is there any fix for this problem or is there such a thing as an off line charger for these batteries? If I use a battery that is correctly charged it lasts for a good amount of time and the ipaq works fine.