I have built a few lights now, and a few of them have issues shorting out for some reason with certain batteries. For instance, my one light works like a charm every time with my ultrafire, but when I put my Panasonic in, it doesn’t work the first time every time. If it has a bad connection, I am able to shake it, and it changes modes without hitting the tail button. I usually have to loosen the tailcap, retighten it, and then its ok. Can someone explain what’s going on here, and why this is?
Compare battery lengths and whether one is a button top and the other a flat top battery. Some lights need long protected batteries for good contact and some need shorter unprotected batteries to fit properly and this is not usually clearly listed in the specifications. Also some need button tops while others will work with flat top batteries.
I’m not sure if the UltraFire is protected, but the Panasonic is and is a bit longer. Their both button top. You think if it was longer, it would make a better connection? Idk?
I have a few lights where the longer cells don’t work. A Sunwayman S10R is OK with a short (but still protected) Nitecore 16340, but doesn’t work with a longer Trustfire flame. Same with Jetbeam RRT-01 - a Trustfire 18350 doesn’t work, but a shorter efest one does.
I suspect this is your problem - the light needs to be tightened to make the connection between the head and the body properly, and the longer cell restricts this.
It is annoying when a crappy *fire cell works, and a quality Panasonic doesn’t.
I have two recently bought 18650 brass lights that cannot use protected batteries due to length. They warned of this in the description though. In some cases trying to use too long a battery can actually be dangerous as tightening down the tail cap can be trying to crush the battery with potential damage to the protection circuit or the battery itself.
Try tightening the retaining ring in the tailcap.
What flashlight? As others have already stated, it likely doesn't support longer protected batteries. Just in case, check that the battery wrappers are intact...
They were a blank host flashlight that I nodded with a nanjg 105c driver and xm-l emitter, so thry are no specifications on which batteries to use or not because they were a diy light