1000w 12v Power Inverter on Gen 4 Prius

I have a Harbor Freight 750 watt inverter that I carry under the hatch. It hooks to the battery with jumper cable clamps. I will have to say, that my attempt to use a 600-watt one cup coffeemaker was a disappointment. The coffeemaker had electronics in it that were not happy with the modified sine wave. I have pulled wire (2 #12 combined) to the rear of the car to accommodate the inverter, again using the clamps on a couple of bare posts. I will also use the power for trailer lighting.

If you are going to use 1000-watt inverter the wire size will need to increase. Make sure you do a calculation. There is lots of voltage drop with lower voltages. If you want 110 volts at the hatch, it might be better to put the inverter at the battery and route the 110 through the cabin and to the hatch area.

 

Apparently, the Gen IV Prius 12v battery is in the engine compartment, and that's why he's asking about keeping it dry.

It's a challenge: If you permanently mount the inverter inside the engine bay, it will be exposed to a lot of heat and vibration. I'd devise a mount which I can quickly attach my inverter to, and then rig a 120VAC plug (capped off) which exits near the rear of the front right tire.

 

You live in Florida so I imagine you're planning on running a few lights during an emergency. Here in buffalo NY I need to run a furnace and sump pump. The pump is a motor that wouldn't care about a 6 step waveform, but the furnace has a computer board that's easily blown. I would get an inverter that produces a sine wave.

 

A sump pump is likely a very large load for a consumer-level 12 volt inverter, particularly since pumps usually use starter coils with very large initial loads. You'd pay less and get more with a Honda generator than a commercial grade sine-wave inverter.

 

A 750 watt inverter pulls about 65 amps from the battery. This is way too many amps for #12 wire. You should be using at least #4, depending on the insulation. The result of using #12 could be very bad.

 

Take a look at the table on this page:
Wire Gauges - Current Ratings

#6 wire should be OK for 65A, but #4 would give more margin.

 

What I did with our old Echo was use 1" particle board (plywood works too) as a platform to hold the inverter. I fitted the board with extra bolts that fit into 'holes' found in the engine compartment while making sure the inverter DC terminals, especially the B+, was close to the battery B+ terminal. Paint or treat the platform to make it water resistant. Then I mounted the inverter on the platform.

Electrical, I installed a solid ground wire, away from the battery, that is stored in the compartment and reaches the inverter ground easily. The inverter has B+ wire permanently mounted that just reaches the battery B+ connector/post. Lift the B+ cover to see the bold it will connect to during an emergency. Get a dedicated wrench that fits the bolt and wrap it with multiple layers of electricians tape. The wrench remains with the inverter and platform.

Operational scenario:

• Put the platform and inverter in the engine compartment. The platform has 'bolts' that fit in open holes to be mechanically stable.
• The B+ is connected to a battery terminal because we want maximum current for surge. Do not strike body of car with wrench or ratchet. A short handled wrench wrapped in multiple layers of electrical tape dedicated for this task is recommended.
  
• Connect the previously installed ground cable to the inverter ground (there will be sparks as it charges the caps.)
• Start the car and turn off all 12V loads (i.e., no AC, heater, lights, radios,)
  
• Turn on the inverter.
• Plug in extension cord without loads.
  
• Lower hood (add painter's cloth tent IF horizontal wind and rain are anticipated).
• Add the high inrush loads first: laptop, TV (just plugging them in solves the problem even if off)
  
• Fans are good, refrigerator should be tested BEFORE the emergency
• Cook food and heat water over outside grill

Bob Wilson

 

I've got the eu2000i. I can run my furnace, sump, and lights. I have switch hit between my two fridges.