My batterys got warm when I plugged them to my vape

[Thrasher]

With the whole box as the ground, any metal touching the box will cause a short (and I'm assuming that includes screwing in the batteries)

In the bomber the pos is a copper or brass bar that sits across the batteries. So it has to be in that area, maybe the button is stuck on and the insulator around the button is bad or something wrong with the 510 pin.

Maybe the bar itself shifted and is touching something

The whole case is ground, the battery positive is insulated by a nylon block, it has to be after that point, since pos contact is only movable piece and no Atty to complete circuit,

 

[Filfa]

In the bomber the pos is a copper or brass bar that sits across the batteries. So it has to be in that area, maybe the button is stuck on and the insulator around the button is bad or something wrong with the 510 pin.

Maybe the bar itself shifted and is touching something

The whole case is ground, the battery positive is insulated by a nylon block, it has to be after that point, since pos contact is only movable piece and no Atty to complete circuit,

Truetrue, ignore me, it's late ^__^

 

[Nomoreash]

Batteries should not be getting hot without a load(atomizer attached) no matter what batteries they are.

That being said you are using the wrong batteries for your application. Ultrafire is known for using low quality cells. Look for quality brands, AW, Sony, Panasonic, etc., you'll be more assured you're getting a quality cell more true to it's rating than with the lower tier brands.

Your other issue is you should be using IMR-High Drain batteries for your application. Protected batteries have a lower C rating and can't provide the amount of current required to power lower ohm/dual coil loads, especially when you get into sub ohm builds.

It sounds like an issue with the mod itself if the batteries are getting hot without the atty attached but you should really toss those batteries and get some that are capable of handling what you're doing with them.

You should also research, read up, study and understand batteries and the load/coil ohm that you're putting on them before you even consider using it.

Here's a link to some quality high drain batteries:
Sony 18650 VTC4 3.7V 30A 2100mAh Battery FLAT OR BUTTON | Lightning Vapes

 

[edyle]

1:
Putting in the 2 batteries the wrong way in a dual parallel mech mod will cause them to automatically drain each into the other; the two batteries should be facing the same way in a dual parallel mech.

2:
Most mods have a negative body, and the switch connects the positive of the battery to the positive centerpin of the 510 connector.
The cherry bomber has a negative body, but the switch connects the negative to the negative 510 threads of the 510 connector, and the 510 connector is insulated from the body; meanwhile the positive 510 centerpin is always-on connected to the positive of the battery.
Very easy to short circuit / bypass the switch on the outside when you put the tank on.

 

[WindyCityJoe]

I might be wrong, but I thought only unprotected batteries were to be used for vaping!!

 

[caferacer]

I might be wrong, but I thought only unprotected batteries were to be used for vaping!!

This is correct. Protected ICR batteries like OP's Ultrafires are low drain and should not be used for vaping. They're meant for use in things like high lumen LED flashlights.

 

[Strontium]

As I know only Orbtronic is selling real 3500mAh and 3600mAh 18650 batteries.

1. Get rid of any Ultrafire battery first (fake batteries, fake rating)
2. Send an email to somebody who actually knows about batteries, and is reputable seller: Orbtronic or RTD