Power Inverter Fault

**Skipjacks** · 10-25-2005, 04:02 PM

If this has been discussed before, sorry. I searched but I'm not really sure exactly what I'm searching for.

I've had my system up and running for about 11 months. It's worked great up until a few days ago.

I've narrowed the problem down to either the power inverter or some kind of electircal problem with the car. The PC works fine.

Anyway, the inverter goes right to FAULT (little red light instead of little green light) as soon as I turn the car key. Doesn't matter if the key is in the ignition position or accessory position. Same result.

If I keep the car off and just flip the switch on the inverter it goes on fine and runs the PC perfectly.

I have the standard relay set up so the car's accessory power triggers the relay and the relay sends the battery power to the inverter's power switch. But I took all of that stuff out of the circuit to test it and ran the car's accessory power right to the inverter switch. Immediately it went to fault. The computer was unplugged and out of the circuit completely for this test.

So the inverter doesn't like something about the car being on. There's no other noticable electrical problems in the car. Everything else on that same accessory circuit works fine.

Anyone have any thoughts? Could the inverter just be going bad?

What makes the inverter go to FAULT anyway? Is it always a short or can is just be that there's not quite enough power?

**DarquePervert** · 10-25-2005, 10:58 PM

Originally Posted by Skipjacks

What makes the inverter go to FAULT anyway? Is it always a short or can is just be that there's not quite enough power?

I think you've hit on it right there. It could be an issue with the battery not keeping enough power to suppor the carPC. The more electrical stuff in the car that's running, the more likely this is, even moreso if you've got a bad-*** audio setup.

**Skipjacks** · 10-25-2005, 11:05 PM

Nothing's changed though since I've had the set up. Nothing's been added to the car that draws more electricity. That's why I'm thinking the inverter is somehow going bad. I got the thing used so who knows how much abuse it's been through.

Like I said the PC isn't a factor here. I unpluged the PC and was doing my experiments with the inveter. By itself it's going to FAULT when the ACC line is connected to it.

It's because it does it even while using the relay that throws me for a loop. The ACC line doesn't actually send electricity into the inverter while using the relay, so that kind of eliminates the idea that the Accessory power system has a short in it somewhere.

I guess it could be a car battery problem now that I thin of it, if it's true that almost enough power but not quite will cause a FAULT.

I've got to get to it with a volt meter. Stupid rain is not copperating with my desire to work on this outside tonight.

**Bugbyte** · 10-26-2005, 12:41 AM

A good opportunity to switch to a DC based power supply!

**Haystack** · 10-26-2005, 01:05 AM

I dont think it is battery related, because then you wouldnt be able to start your car, and the inverter wouldnt turn on when the car was off. Sounds more like overvoltage to me. Check the voltage regulator at your local autozone.

**Skipjacks** · 10-26-2005, 01:15 AM

Originally Posted by Haystack

I dont think it is battery related, because then you wouldnt be able to start your car, and the inverter wouldnt turn on when the car was off. Sounds more like overvoltage to me. Check the voltage regulator at your local autozone.

That's a really good idea.

I hadn't thought of that at all.

**Skipjacks** · 10-26-2005, 05:41 PM

Allright I did some more experimenting. This problem is just getting weirder.

I have a kill switch on my relay. (Put that on there in case the relay ever hung up and I needed to kill the power manually)

Anyway....

With the car's power off, the inverter works perfectly.

With the car's electrical power on, it goes to fault.

Here's where it gets freaky.

I can hold the kill switch in and turn the inverter on manually and it obviously runs fine. (As far as the inverter knows in that scenario the car's power is stil off)

When I unkill the relay the inverter will STAY ON even though the car's power is engaged. Then I can turn the inverter switch to off (where it is normally using the relay switch) and it'll continue to work perfectly.

But if I hit the kill switch it immediately goes back to fault when teh power comes back on.

So it's acting like the car's electrical system isn't playing well with the inverter, but then it works fine under specific conditions.

Like it's enough to sustain the inverter switch, but not enough to trigger it.

Here's the short version of all this...

The car can supply power to the inverter and keep the it switched on, but the car can't seem to GET it switched on.

Does this sound like an inverter problem or a car's electrical problem?

I'm so confused by this it's not even funny.

**lez** · 10-26-2005, 05:48 PM

I think it may be a loss of voltage when you turn the key, not a drop but total loss as the keyswitch goes from the 'acc' to the 'on' position.

They usually discoonect the 'acc' when in 'start' position, but as they wear, some lose power between positions.

I had one that on some days would lose the 'on' position when in start so I could crank the car but not start it........(used to carry a length of wire with me)