Firstly, let me say thank you for all the responses. I appreciate it.
Further to my last, I today tried a little experiment - I ran my 3Ah 12v lithium polymer battery to a heating element through a variable voltage tester I made (basically a potentiometer with a voltage gauge attached). I also connected my multimeter to measure the amperage.
I found if I kept the voltage to around 5v, this kept the power consumption to about 2.8A and the element worked, although it didn't get very hot.
If I went to 6v, the power went to 3A and the battery overload protection kicked in.
Tomorrow I'm going to try using a regulator to output 5v and see if I can make it work that way. If it does, then in theory I could attach any battery to the system (over 3Ah) and not have to worry about the overload protection.
Thank you all again for the help - I'm certainly heading in the right direction.
First off, let me start by saying my speciality was automotive engineering and as such I am a hopeless duffer when it comes to the magical dancing pixies of electricity, so go easy on me.
Since I retired, I've been building all kinds of weird stuff in my workshop in the garden, one of which is smoke generators; specifically small ones, from a few inches on a side down to my smallest which is less than an inch square.
I've built loads of the things for various projects and it's all been fine. I power them from sealed 12v 1.2Ah lead acid batteries, the kind you get for alarm systems, and they work great, to a point. The trouble is, I want to improve the electrical side more. I'd like to use 12v Lithium batteries, add timers, Arduino controls and so forth, but the problem is whenever I try to do this, the inbuilt overload protection in the battery kicks in and shuts it all down.
I think I know why this is happening - the heating element in the smoke generator is basically shorting out the battery - I'm using resistance to turn the electrical pixies into heat (the element wire comes from a hair dryer), so what I need is a way to limit the current going into the generator (I think).
Now, as I mentioned, I'm useless with this kind of stuff. I can build basic circuits, solder and such but other than that I'm at a bit of a loss. I put a multimeter on it and it looks like it's drawing about 6v and 10A, which is kicking the snot out of it as it's a 1.2Ah battery, so I'd also like to do this to help save the battery as they have a very short lifespan because I'm abusing the heck out of them. I can use higher capacity batteries, but they're obviously bigger and heavier which kind of defeats the object of making tiny smoke generators.
Basically, I want to limit the output from the battery to avoid tripping the overload protection on the electronics. I tried using a 10ohm 10w resistor to limit the draw, which works on the multimeter (output is 11v 1.1A) but the resistor soaks up all the power so the element doesn't heat up.
Any assistance would be greatly appreciated.
For info, I've added a link to a short video showing one of the smoke systems in operation to give an idea of what I'm rambling on about.