Risk in discharging an unprotected battery(s)?

[mikeeey]

Everyone is probably familiar with these:

They've always done me well in the past. But now that I have my Spartan 447nm I've wanted to use them in it. My current batteries die too quickly, and it only takes 20-30 minutes to recharge, so I'm considering these.
Is there a risk in completely discharging an unprotected battery? I'm really unsure if I should put these in my Spartan.

Also, what are some signs that a battery will blow up? Will it overheat first? I've already put these on the charger (for 3.0V cr123a's) and I plan on feeling them every 5-10 minutes.

 

[udanis]

If a battery gets too low in voltage it won't accept a charge.

 

[mikeeey]

I just had TWO battery scares. no not blowing up, I turned on my Spartan and it flashed blue for a second and turned off. So I tried putting the unprotected batteries in it but I noticed it didn't seem as bright. So I tried my other pair of batteries (that have horrible battery life) but it just flashed blue and then wouldn't turn on at all. I thought my spartan had actually died, but I put the original batteries back in when it flashed the first time and now its working just fine. Very odd..

I've contacted the seller whom I purchased the horrible life batteries from about a refund, hopefully I can get the better ones. These current ones die from sitting in my laser inside my drawer overnight.