Operational Toyota Echo - 1KW Inverter

August 28-30, 2005, we had a 28 hour power outage and we got to test the 1 KW inverter with Holly's Echo. We ran it from 5:20 to 12:00 midnight which took about 1/4 tank, ~$6. Compared to living in a dark house, this works.

The inverter now is in the Prius that provides double the run time for the same fuel at a full 1kW.

Inverter Battery Connection

The battery voltage stabalized after an hour at 13.65 VDC. This is well within the operating range so there was no need to increase the idle speed. The alternator was fairly warm but not hot. Although the alternator is rated at 90 A., at idle it doesn't spin fast enough to provide a full, 1 KW supply. The cables and connectors were cool to the touch. The inverter case felt slightly warm and we never found the inverter cooling fan running.

Inside, the last open outlet measured 98 VAC with the full load:

This voltage is lower than optimum but not unexpected since we were using ordinary extension wiring. Only the fan was a risk from the low voltage but after six hours, there was no evidence of over heating.

The only change planned is to look for a 15-20 ft. contractor extension cord with multiple outlets. The heavier gage wire and fewer connections will reduce the I(2)R losses and hopefully improve the delivered voltage. Unfortuantely this inverter does not have a remote voltage sensor which would aleviate wiring problems. Thanks to a note from Porter Clark, another solution would be to use a 1.5 KW mini-UPS to buffer from the inverter and provide power directly to the load.

Echo Throttle

Modern cars have to deal with commuter grid-lock and are well designed to handle periods of extended idle. Electronic spark and emission engineering have pretty well eliminated the idle problems of earlier technology. A well maintained car engine can pretty well idle until the tank is empty as long as it has no automatic choke or low oil pressure problems. Regardless, it is a good idea to check your owners manual if in doubt.

Preparing For Inverter Installation

These photos were used to plan installation of a 1kW inverter. The stock, 90 A. alternator has enough capacity to sustain the inverter at rated power if the idle speed is increased. At ordinary idle, provides about 400-500 W.

Echo Crash Test

While attempting to roll the window on the passenger side, the driver ran into another car: