Power Issues with inverter

kostyanj · 08-01-2007, 01:41 AM

I've been searching and researching non stop for the last 5 hours to no avail. I'm trying to use an inverter to power my laptop that's going to be used for my carpc. The issue that i'm having is the following. I hacked the inverter to connect it directly to a power line rather than plug into the cig lighter. When there's power, the LED comes on saying that the inverter is working. I plug the AC adapter for my laptop into the inverter. The LED on the brick lights up, meaning that the adapter is receiving power. Then when I plug the adapter into my laptop....nothing happens. Well actually let me clarify that. It seems that the inverter starts cycling, it goes on and off as if there's a power overload.

It doesn't always do that however, which baffles me even more. If it's been sitting for a while, I can connect everything and it'll work for a few minutes. Then as soon as I turn on my monitor (different power line), it goes back to cycling and my monitor goes crazy. Even if I turn off the monitor, the inverter won't charge my laptop.

I've measured voltage and wattage at different points on the line and everything is where it should be. There's about 12.26v going into the inverter. It's putting out 121v, and my ac adapter for my laptop is putting out 19.36v. All within the normal ranges.

SOMEONE PLEASE HELP!!!!

v8 scimitar · 08-01-2007, 05:00 AM

is it doing this with the engine running as well? Sounds like the inverter isnt getting enough power or it things it isn't. What size is the inverter? Is it a cheap one or expensive and finally did you check it worked before you changed it?

darkomen64 · 08-01-2007, 05:02 AM

My guess.. (and thats all it is) would be that the line you are running for the inverter is to small and its having a hard time pulling enough to over everthing and when you turn on the monitor it pushes that line over the amount that its able to pull.. i would try running a separate line for the inverter from the battery you might need to set a relay to allow power to the inverter only when the car is on..

but again like i said that is only my guess

greatwhite · 08-01-2007, 05:08 AM

Did you get the polarity right when you chopped off the lighter plug?

What size and brand is the inverter?

What size wire did you use to feed it and where is the power tapped off from?

kostyanj · 08-01-2007, 11:02 AM

It is a cheap inverter. Measured for 100watts. I used 14 awg wire to connect it.

http://www.compactappliance.com/xq/J...ters%3EVEC1040

I'm positive i got the polarity correct. The + has a fuse on the PCB and the - doesn't.

I tried drawing from several sources.
1) ACC line for rear cig lighter.
2) New line ran for Amp.
both to no avail.

It does this with the car running and not. I mean I have been running my battery down lately, but I start it up for a few min every once in a while to let it charge. Like i said I measured the voltage and everything seems fine.

greatwhite · 08-01-2007, 06:41 PM

100 w is pretty small............

ANd 14 guage wire is pretty thin...........

Is it 100w surge or constant?

I'm thinking you've gone "a little bit" too cheap..................

Also, starting the car and not driving it at highway speeds for around 20 mins or so is going to draw more power out of the battery than it replaces. Stick abattery charger on it for a couple hours.

You're either overpowering the inverter or you're not getting enough power to it.

A better idea would be to get a laptop car adapter rated for your laptop.

kostyanj · 08-01-2007, 09:18 PM

That's what I ended up doing after the inverter blew up this morning. I ordered a car adapter for my laptop. Should be here in a few days. Until then my car is on blocks anyways because I'm polishing the rims right now.

Hopefully i can hack open the adapter when i get it and connect it directly to the power distributor that i have for my amp. I'll let you guys know the results when I hook it up.