I’m new at this so please be kind…. I have 5ea 18650 flashlights, mostly clones. I ordered 4ea. Samsung ICR18650-30B batteries, they are too big to fit in one light, 3 others the light comes on but will not change modes. When I put the smaller UltraFires in they work perfectly. My question is when I reorder how can I tell if they will fit all my lights? I thought 18650’s are all the same size Maybe if you could just tell me which ones to buy I will order them.
Thanks in advance,
Bob
The protected batteries are longer. You may need to buy unprotected cells to fit your torch.
Ok, can you tell me a make and model of a good unprotected battery that will fit in all my lights? I have already spent $26 on the wrong batteries, I don’t want to make that mistake again.
Make sure it’s a button top, as flat tops may not work in your light.
Use the batteries you have now by slightly boring the battery tubes of the lights they won’t fit. Pretty easy to use a wooden dowel, saw a groove into one end about an inch or even two deep. Use this groove to start a piece of sandpaper and then turn the paper around and around til you get the appropriate size you need to fit snugly in the tube. Use a drill to turn the dowel thereby reaming out the battery tube. A grit of 220 should be sufficient to take a small amount of aluminum out of the tube allowing the batteries to fit. Simply remove the device and check the battery, rinse and repeat til you’re satisfied. Extra space can be taken up with masking tape between the layers of sandpaper to keep the fit tight as you proceed.
Enjoy!
Worked like a champ… This is why I asked the professionals. I hope I’ll be able to help someone one day.
Glad it worked for you. Sometimes problems are simple to solve. The age old question “Honey, do these pants make my butt look big?” now that’s a whole nother story! 
Dale
That was a width fix only…. but I’m very happy with that, not the length.
This is going to give me a reason/excuse to look at buying a Sunray King. Not sure if these batteries will fit “but” it’s an excuse, not sure if she will buy it but will give it a go.
The OP never said which way was to big. Everybody just assumed it was the length. Guess it wasn’t :bigsmile: must have been diameter.
Bcalvary member HKJ has tested a lot of 18650’s and he was also nice enough to measure and list the dimensions on his site.
For some reason the link I gave keeps adding 25 before the 20 in the link after the % sign. I have tried to fix it several times with no luck.
Here’s the url: Battery test-review 18650 summary
I have noticed the wrapper being larger on certain Panasonic 3100mah reseller’s like Callie’s Kustoms. The same battery from fasttech fits my light fine but the CK’s are to big even with the Callie’s Kustoms label removed. Some resellers must use a thicker shrink wrap causing the problem. Its the same battery. 
I have some lights that will only accept some 18650s. I have a Roche F12 that would only fit one brand of 18650 or I had to go to 17670. I haven’t heard any other members complaining about their F12, so I assume mine was just machined a little tighter than factory standard.
That strip that connects at the top adds some thickness, and they usually use a thicker shrink wrap to help protect against a short on that strip.
I have been working on an issue that required some boring and jumped to the conclusion the same problem existed here with the OP. Should have asked. Sorry if I misled anyone, I’m doing good to remember if the original question was mine or someone elses some days! 
Well, at least it helped in one way. There’s ways to get around the other issue too. Not as easy though.
Dale