Coffeeholic:
If you want to make sure it will work in most trucks go for a 24 volt one. It will draw less current than a 12 volt one so more likely to work in the socket as the 24 volt sockets are usually rated higher than the 12 volt ones, 15 amps against 5 amps in a Daf for instance. If it is mainly for your laptop a 150 watt one will be more than adequate, if you go for a higher wattage one it will draw more current so will be less likely to work in all trucks - 150 watt, 24 volt inverter = 6.25 amps draw, 300 watt 24 volt inverter = 12.5 amps draw.
Finally buy a cigarette plug to Hella socket adaptor and that way you are covered whether the 24 volt socket in the cab is the cigarette lighter or Hella type. I use one of those adapters in a Daf with a 24 volt, 150 watt inverter and it works fine. Don’t be tempted by the cheaper adaptors that have a Hella plug, a length of wire and a cig lighter socket, they probably won’t handle the current, the cable is often very thin, and your inverter will just make squealing noises and not work.
Took me a while to track this down, but was exactly the info I was looking for. Very helpful. Cheers.
What sort of power inverter should i get which would work in most units? as I’m never sure what unit ill be driving either Volvo’s, MAN, ERF or Renault Premiums.
It will mainly be used for powering my laptop as things like my phone and ear piece i have a cigarette lighter charger for.
I did have a cheap Halfords special but it lasted about 10 Min’s before going pop with a cloud of smoke!! 
Also wheres best to get the best deal?
hi i was looking for an inverter the other day , found a decent offer in my local maplin , 300watt output with a usb output for charging phones i presume 
£24 obviously its 12 volt input not sure what voltage the cig lighters are in trucks?
cheers mike
Look on the power label on the lap top and it should say how many watts it uses. If not, the volts and amps are always shown on the label. Volts x amps = watts.
e.g my lappy says 15V 6A which = 90 Watts. Add up all the watts you are likely to use and sure the inverter can handle all the watts you need.
Also make sure the socket in the truck can handle the wattage. Most have a cap over the socket with either a wattage or amp rating printed on it. If you exceed this you could blow the fuse or start a fire!
If you want to make sure it will work in most trucks go for a 24 volt one. It will draw less current than a 12 volt one so more likely to work in the socket as the 24 volt sockets are usually rated higher than the 12 volt ones, 15 amps against 5 amps in a Daf for instance. If it is mainly for your laptop a 150 watt one will be more than adequate, if you go for a higher wattage one it will draw more current so will be less likely to work in all trucks - 150 watt, 24 volt inverter = 6.25 amps draw, 300 watt 24 volt inverter = 12.5 amps draw.
Finally buy a cigarette plug to Hella socket adaptor and that way you are covered whether the 24 volt socket in the cab is the cigarette lighter or Hella type. I use one of those adapters in a Daf with a 24 volt, 150 watt inverter and it works fine. Don’t be tempted by the cheaper adaptors that have a Hella plug, a length of wire and a cig lighter socket, they probably won’t handle the current, the cable is often very thin, and your inverter will just make squealing noises and not work.