Does inverter draw power when the computer is turned off?

phoTToniq · 08-13-2003, 09:01 AM

Hi -

Do inverters draw power from the car battery even when the PC is off?

300watt inverters have a fan so I am assuming they always draw some power whether the PC is on or off. However, does the fanless 150watt inverter draw power when the PC is off?

osirisdon · 08-13-2003, 12:03 PM

The PC does not power the inverter. It works the other way around. The way you are asking your question, make me think that YOU think the PC powers the inverter. It does not work like that.

I have never worked with inverter, I prefer NOT to. But if the inverter has a remote line, once the ignition is off it should turn off.

Sorry for not being of much help, but I had to clarify that for you. On the inverter issue, maybe someone who has used inverters know much better than me.

hijinks21 · 08-13-2003, 12:11 PM

it all depends on how you wire your inverter. Mine is right from my battery so if the inverter is on and the car is off it will keep drawing power. Even if the computer is off. if you hook it up to a line thats hot just when the car is on then it'll turn off when you turn the car off. In my experience you should wire an inverter right to the battery.

kosala · 08-13-2003, 12:13 PM

If you have the PC off but the inverter on, the inverter will draw some current, regardless of whether there is a fan or not. You can check the specifications for the inverter you are looking at. For example, the Statpower 150W inverter has a "no load current draw" of < 0.1 A.

It's probably not a good idea to have the inverter on all the time, so use a relay or something like that to turn it on only when the car is running

Defiler · 08-13-2003, 12:48 PM

When I had my RX-7 a while ago, I was using the same 300W inverter I use now. I went to a hotel one weekend and turned the carputer off but forgot the inverter...Three days later my battery was almost dead. Thank god for the auto cut off at 11V. So, to answer your question, yes.

phoTToniq · 08-13-2003, 06:01 PM

Quote: Originally Posted by osirisdon

The PC does not power the inverter. It works the other way around. The way you are asking your question, make me think that YOU think the PC powers the inverter. It does not work like that.

Not sure what I wrote to make you think this. I know that power goes from the inverter in to the PC. Thanks for taking the time to reply though.

I figure I want the inverter (which I will only resort to if I can not get my head round dc-dc power supply) connected to the battery even when the ignition is off. I will use a shutdown controller for the pc - and will try to figure out how to get this shutdown controller to also flip a relay which will cut power to the inverter.

P.

Ricky327 · 08-13-2003, 06:32 PM

Thats what I thought too...theres nothing wrong with what you wrote there. Battery > inverter > PC. Dunno how osirisdon got that one wrong

Yes the inverter is going to drain your battery in a few days even if theres no load. Your PC is going to drain some current even when switched off...PC is never switched off unless you unplug it.

So you do need to disconnect your inverter with a relay, up to you how you wanna wire it all up.

osirisdon · 08-13-2003, 07:41 PM

I have never used inverters. That said I should have not replied, oh well no harm done.

phoTToniq · 08-14-2003, 04:49 AM

osirisdon - i dont really want to use an inverter either. I'm going to try and find ways of making a cheap power supply. I'm not hardware minded though. I'm waiting for sproggy to reply to my email.

Guys - thanks for all the advice. You have saved my battery

P.