I had a recent power outage that lasted for 3 days. Not having a generator on hand, I decided to try using what I did have for short term power purposes. The items consisted of the car, 500 watt inverter, and I had an extra car battery available.
I hooked up the inverter directly to the car battery in the car. With the car running, I was able to run the 46" LCD TV, and a couple of CFL lights which was all I really needed to do. However, I ran into some problems. If the car wasn't running the entire time, the items connected to the inverter would start flickering on and off after a period of time. If off of the car battery inside the car, this might be within an hour, but with the separate battery, maybe 10 minutes unless it was coupled to the car battery in the car with the car running.
All in all, I was disappointed. I'm wondering why the items wouldn't operate correctly unless the car engine was running. There certainly wasn't a lot of wattage being drawn.... the TV uses like 100 watts with the lights maybe 10 watts each, and there were 2. I had hoped to just use the battery in the car to occasionally "jump" and charge the separate battery when it got too low, but never got to that point as the attached items would start flicking on and off.
I see portable power packs with internal battery and inverter at places like Walmart. The inverter is usually 400 watts or so, so I know this method should have worked. Any ideas as to why my set up didn't work well would be welcomed. If it had worked this time, I had planned on maybe a 1000 watt inverter at some point which I had hoped maybe if this happened in the future to be able to run the house refrigerator from the inverter/ car battery set up, but not if I have to have the car running the entire time.
Thanks for your help.