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Discussion Starter #1
Ever wish you could plug in some 117V appliances into your E? :)

Here's what you'll need.
1,800 Watt Powerverter $200
Heavy Duty and very flexible rubber covered copper cables. $50

(Sorry about the white balance on two of the pictures.)
 

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Cheap inverters usually aren't very efficient.

I wonder how light it would take to run the E's battery flat -with no output load. :lol:
 

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Cheap inverters usually aren't very efficient.

I wonder how light it would take to run the E's battery flat -with no output load. :lol:
Well, do the numbers. Assuming absolutely no loss and 100% efficiency, it starts out pulling 150 amps from the battery at 12 volts. By the time that the oem battery has finished screaming in agony at around 8 1/2 volts (when the inverter shuts down from low voltage) it's pulling over 200 amps. If somebody can fill in the missing figure for how much current the teeny-tiny starter motor draws, we can get an idea based on how long you can crank the engine before it slows to a frustrated stop.

Okay, so you could just calculate the amp hours on the battery but this way's more fun. Or, you could try to claim that the engine was running so the alternator was adding current before it fried, or...

I liked the thread with the giant boat horns better.
 

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Well, do the numbers. Assuming absolutely no loss and 100% efficiency. . .
Assuming that, would give you an number that was meaningless. I'm an electrical engineer; I know how to do the numbers. The cooling fan load is a tiny fraction of the idle current load; the don't engage until the unit is loaded.

The only Tripp Lite unit currently in production is with this output is the PV1800HF. Here's its specs: http://www.tripplite.com/en/products/model.cfm?txtModelID=183 The spec I was interested in is: "No load - 2.7A at 12VDC", which is about twice the load of all the stock interior lights left on, so I figure that 4 hours idling would be more than enough enough to make it hard to start my Element.

Under load, low cost inverters like this one have efficiencies less than 50%, worse at low load. Their input draw current initially increases non-linearly with very small increases in output load. The inverter doesn't "shut down in agony" when input voltage is inadequate; it's input draws increases as the input voltage drops until it trips a current limiter. At 200 A that draw would look like a dead short to a nearly discharged battery, and high enough to blow the alternator diodes.

The Tripp units I've worked with aren't designed for vehicles, but high efficiency ones designed for computer applications. Their battery banks would have several deep discharge batteries, each larger than the Elements', just to get 15-30 minutes of run time for a 2KVA mostly capacitive load.
 

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Discussion Starter #6
1,800 Watt Power-verter

Yes the motor should be running and a second battery is recommended. There is no model # on it except for a serial #. New condition! It was mounted in a show car but was never used.

However I did find it on Dick's Sporting goods website with a picture of it.
Listed as: "Tripplite PV1800HF 1800 Watt Ultra Compact Power Inverter $340":)
 

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Assuming that, would give you an number that was meaningless. I'm an electrical engineer; I know how to do the numbers. The cooling fan load is a tiny fraction of the idle current load; the don't engage until the unit is loaded.

The only Tripp Lite unit currently in production is with this output is the PV1800HF. Here's its specs: http://www.tripplite.com/en/products/model.cfm?txtModelID=183 The spec I was interested in is: "No load - 2.7A at 12VDC", which is about twice the load of all the stock interior lights left on, so I figure that 4 hours idling would be more than enough enough to make it hard to start my Element.

Under load, low cost inverters like this one have efficiencies less than 50%, worse at low load. Their input draw current initially increases non-linearly with very small increases in output load. The inverter doesn't "shut down in agony" when input voltage is inadequate; it's input draws increases as the input voltage drops until it trips a current limiter. At 200 A that draw would look like a dead short to a nearly discharged battery, and high enough to blow the alternator diodes.

The Tripp units I've worked with aren't designed for vehicles, but high efficiency ones designed for computer applications. Their battery banks would have several deep discharge batteries, each larger than the Elements', just to get 15-30 minutes of run time for a 2KVA mostly capacitive load.
I think that's pretty much what I just said, but without the humor. :grin: Anyway, the efficiency is a bit better than that on the higher wattage models. I'm sitting beside a 2kw unit that provides constant power for this computer (a whole rack of them) and it uses 4 -large- 12v deep cycle batteries in series for the input power if the line goes down.

I have seen one of those 1800 watt models being used to run the blender, microwave, etc, on a floating snack bar down on the Intracoastal Waterway, running off of a bunch of trolling motor batteries in a Jon-boat. Because of their location, they're not allowed to run a generator.
 

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