Invertor problem in my car...advice sought please.....?

I have a 400 Watt invertor in my car to run some equipment. Here is the link for it :-





www.maplin.co.uk/Module.aspx?


ModuleNo=227114





It is a 400W Black and decker invertor


Trouble is, if I turn off my car engine and restart the engine it goes into auto shutdown. The other problem I have is that if I use my laptop PSU with it, it also goes into shutdown.....have I just bought a bad invertor?...could anyone recommend a better more robust one ?


I am only using about 120 Watts in total so I have plenty to spare....it's driving me nuts....I have to sort it out today!!!





Thanks in advance guys





AndyInvertor problem in my car...advice sought please.....?
The trouble is that the voltage level in your car might routinely drop down to 10 volts or so while the engine is cranking. This is normal; it's caused by the high current load on the battery, but it will make your inverter shut down due to low voltage.





The fact is, there might not be a fix. The internal resistance of the battery means that when there's a very high-current load (like the starter) the voltage at the terminals will drop. Just about all inverters have a low-voltage safety shut-down. If you upgrade your battery to a model with a higher CCA rating, it won't drop the voltage as much when you're cranking; but it's hard to say if it will help enough to stop your problem. You should also make sure that your battery terminals are clean and tight, and upgrading the power/ground wiring between the engine block and the battery might help too.Invertor problem in my car...advice sought please.....?
The auto shutdown is to prevent you draining your battery. Are you using the cig lighter? Or is the inverter connected straight to the battery?





Try connecting it straight to the battery, turning off your ignition is maybe triggering the auto shutdown thru the cig lighter socket?





Just read on maplin site that you can only draw 100watts when using it thru the cig lighter socket