Ego 900 mah issue

[dudeman2013]

I went on break at work on Tuesday and my I took a puff off my ecig and nothing happened. I figured it was the carto as the battery light was still working fine. When I got home and changed the carto it still did the same thing. I switched to a different battery and it worked fine. Now only having one battery, after just a full charge, I went to a friends place and during the visit the same thing happened with the other battery. I have had them for about 4 months and no prior issues with them. I tried recharging them and they charge super fast and only give me 1 puff before stopping, but the light still goes on with no blinking to indicate that it's dying. Anyway to fix this or do I need to buy more?