The original one (without the thermo control) can get very hot, according to the thread on MaxBashing:
Originally Posted by
stot
i did post how to work it out lol
though mmm science must be wrong lol
right just little heads up warning
do not forget you have left these great little heaters turned on
did few tests on 12v sla battery
ended up with engine at 320 f after 13 min and the silver middle case at 140c ouch as i found out lol
the temp of the bulb goes well over 500 f so be aware dont leave on too long
this was on warm day ie this evening and on an old engine just in mounts not in car[fully aware chassis will heat sink some of the heat away from the crank]
head was at 104 celcius within 6 min
these are v powerfull do not leave unattended please
not knocking it at all does the job just great just use with care
As John has said, it is best to treat them with respect and monitor them.
If you are concerned about the high temps, your best bet would be buy the deluxe version with the thermo control.
However, it should also be noted that these temps were with the original design with both elements wired up. John has since modified production so only one element is lit which will keep the temps lower (although I believe you can easily change this to use both elements if required during the winter etc) and is probably why most people have not experienced these temperatures. The deluxe model has a 2 way switch to make switching from 1 element to 2 even easier.
RE: bulbs, I have seen/spoken to a couple of people at meetings that have had bulb failures. Whether this was down to high temps (with both elements lit) or being knocked around (bulbs in general don't tend to like being knocked around, especially when on...) I don't know - these were in the early days and I have not heard of any recent bulb failures. The simple answer is to carry a spare bulb if you are concerned about it.... John may not be aware of the couple of instances if the people have purchased replacement bulbs from a different source and haven't reported it... Bulbs in car headlights do not last forever and you shouldn't expect these to either...
I should add that I personally haven't used one of these heaters as I purchased a Comp Heat one before they were released etc and the info above is from following the product thread on Maxbashing with the development/progress of the product and from speaking to people that have actually used them. Personally I am very happy with my Comp Heat one - although the cost of importing them in to the UK with the shipping charges and import duty was significantly higher which puts alot of people off, together with the fact there was not a 12v one available (but is now!) which meant people had to have mains power/a generator and a drop down power converter...