Dukester,
I'm not a soldering expert, but when the solder blobs don't stick, it's because the item that you were soldering to wasn't brought up to temp. I suppose the blobs that fell off can be compared to cold solder joints. The size of the blob has nothing to do with the solder sticking. It's just that the size of the blob had sufficient heat to transfer it to the battery to heat the area of contact enough to make it stick.
When you solder, it isn't a matter of melting solder and dripping it onto whatever it is that you are soldering. You shouldn't be using the iron to melt the solder. You should be using the iron to bring the item to be soldered up to a temp sufficient to melt the solder. In other words, when you are soldering blobs on a battery, you aren't supposed to be applying the solder to the tip of the iron as it touches the battery. You're supposed to be applying the solder to the top of the battery, which should be hot enough to melt the solder itself. If it isn't, then you aren't getting a good solder joint, so to speak.
Having to bring the point of soldering on the battery up to such a high temp is what makes putting solder blobs on a battery so dangerous.
When I solder blobs, I use a very broad tip to transfer as much heat as quickly as possible. That way I can get in and out really quick, to avoid heating the whole battery.
If I misunderstood what you said above, I apologize.