Vector 3,000 watt power inverter question

On Wed, 27 Dec 2006 11:16:12 -0600, Mike Has Frothed:

Looks like the unit is defective, return it for an exchange.

this is a repair newsgroup, not an exchange newsgroup you pain in the ass.

If you haven't already, make sure your source (battery?) doesn't drop drastically when you run the inverter under load. If the source of power is good, then it sounds like the inverter is defective.

Mike-

Did you look at your car battery voltage as well? It is possible that the battery's current delivering capability and the voltage drop in the connecting wires, does not provide sufficient voltage AT the inverter's input for it to work, even with a small load.

What size wire would you use to drive a 3,000 watt inverter? Even if it were 100% efficient, the input current would be about 250 Amperes at full load from a 12 volt battery. I think you would need heavy bus-bars connecting directly between the battery terminals and the inverter terminals.

In other words, it may not be practical to use this inverter for the applications you have in mind. High power inverters I've seen used, were connected to banks of large, high capacity cells.

Fred

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The owner's manual says the input cables are #4 AWG and they are 3 feet long (there are two red and two black ones).

I think you've helped me a lot Fred. I hadn't thought about running this battery off of a bank of batteries, but that may be what is necessary to make it do what I thought it was supposed to do.

Since my first post I have hooked the inverter directly to the car battery using the supplied cables (the first test I had merely used some 6 foot jumper cables from the input wires of the inverter to the battery, so there was probably a lot of loss there). With the inverter connected directly to the battery, a 100 watt light bulb load looks good and I can turn the electric heater on in either the 1200 or 1500 watt switch positions and it will come on and produce heat. Fan speed seems about normal. I only let it run for about a minute. I have a charger connected to the battery (plugged into the household AC) and I can see the heater is really loading down the battery. (Would be pulling around 150 amps I guess). I have also discovered that the fans only come on after about 150 watt load is applied to the inverter. That was one of my major concerns as I thought there was something wrong with the (4) fans since none of them would come on when I powered the inverter up. I am feeling a lot better about it now. I think I just need more battery power. The inverter itself seems to be doing what it should be doing.

Thanks.

On Wed, 27 Dec 2006 09:28:29 -0800, Malissa Baldwin Has Frothed:

Nobody gave you permission to poast here.

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Wowzer, that's a big inverter. Have a couple of small inverters and was thinking of getting a 1200 watt to run the gas furnace blower motor. Maintaining sufficient battery power for that wattage(several heating cycles) made me rethink the situations cost/benefit ratio. Multiple batteries won't last long with the kind of consumption you seem to be contemplating. Look at the amp/hr rating of the batteries. Average alternator output is ~55amp so it's not much help and has the same carbon monoxide hazard as a generator. People have died from carbon monoxide using generators the last 2 seasons in our county alone. Let us know how it works out and what kind of battery power you end up with to get a reasonable run time.

Hi..

But... your furnace blower is probably 1/4 horse, maybe 1/3.

Take care.

Ken

It is highly likely that the literature packed with the device (inverter) contained a pretty good description of how to get sufficient DC current into it. The OP's description seems to indicate this information was never read, never understood, never considered...which is normal, I guess. I attempt to help:

For a 3 kw inverter to be really useful, you need a BIG (300 CCA minimum, deep discharge) battery. It must be connected to the inverter with 6 (4 is better) gauge cables no more than 1 foot long. 20 Foot "Jumper Cables" WILL NOT WORK!!!!!! They are usually 6 to 12 gauge (bigger is not better, here). Jumper cables can be useful to charge the inverter's primary battery from a truck in between house-furnace runs. But again...learn some physics (Ohm's law, etc.)...good is big (small gauge numbers) wire between the source and the drain (truck alternater and inverter battery).

On Wed, 27 Dec 2006 19:00:30 -0500, T Shadow Has Frothed:

I bought a 3500 watt Coleman generator and got to use it once already. Our power went out for about 6 hours a few weeks ago after a windstorm toppled trees and lines. I have a disconnect that allows me to hook the generator up to my fusebox. 3500 watts was enough for enough 60 watt lights, the furnace blower and my fridge. My 51" Panasonic tv, the sat dvr and audio equip are on a 1500 APC but the APC sure didn't like the generator. Must have been noise or something because the output was 119vac but the APC didn't want to come off battery.

Run the blower at the lowest speed on inverter power. Let the burner cycle on the hi limit - you'll still get enough heat. That will reduce the blower motor power to maybe 200W.

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Motor options for the furnace also shows 1/2 & 3/4. From the info I got from motor the way it was wired it may have ran on a 750 watt inverter. Did the math at the time. The wild card was starting current. Has to have enough current to start or its worthless.

"T Shadow" wrote in news:459308f0$0$16732 $ snipped-for-privacy@roadrunner.com:

??? Because they ran them indoors? Or... ???

What size wire are you using to connect it to the battery? 3KW is gonna pull about 250A from the battery so you'll need some BIG cable like you'd use to connect to a starter motor. Also don't expect to pull even half that much for more than a couple minutes without the engine running, even with it, most cars have less than a 100A alternator so your continuous load will be much lower, probably around 500W for an average car.

Many are larger, mine is 1/2 HP. The run current is not too terrible, but the inrush is phenomenal, you need a bigger inverter than would first be obvious.

That happened around here in a recent storm that blew through. One guy ran a generator in his livingroom(!?) and a few others had them in a closed attached garage. Evolution at work.

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I am using the input cables that Vector provided with the inverter. I think I read in the manual that they are #4 awg and there are two positive and two negative cables. I didn't measure them but they are 3 feet in length or less.

What I was hoping to accomplish with this was to be able to run a 1500 watt electric heater when our electricity goes off. (I thought a 1500 watt heater would just sit there and coast on a 3000 watt inverter). I'd also planned to use a microwave oven, a toaster oven, some 60-75 watt lights, but I didn't intend to run more than one or two of these items at a time, and obviously had planned to run the toaster by itself and the microwave and the heater. I didn't realize I was going to have to have so much input current available to power the inverter. Kind of foils my plan because I had hoped to put a battery in a nice case, put that on the bottom of a two wheel dolly, mount the inverter to a piece of plywood and mount that to the dolly, wire it up and then have a set up I could wheel into the living room when the power goes out and plug in the heat or some lights, the tv, or whatever I needed. I was hoping someone who has such a set up would see my post and offer some suggestions on what worked for them. It appears I should have gone the route of the generator, but I opted not to do that because of the carbon monoxide and also routing a power cable from outside my house to the interior won't be easy (all brick home).

I like the idea of powering the furnace motor with a setup like this, but I have a heat pump so unfortunately, that isn't an option for me.

Thanks for your input.

Where do you live? You need to be able to keep pipes from freezing, but that does not take a 3000 watt unit unless you live north of the mason-dixon line, and there aren't very many heat pumps that far north.

H. R. Hofmann

Mike wrote:

Hi Mike...

Respectfully suggest that you might perhaps re-think your project... if you're looking for heat, even a fully charged new(ish) car battery is only going to deliver 1500 watts of heat for about a half hour, and that assuming that the inverter is somehow 100% efficient. Even then - don't know where in the world you are, but I'm in Winnipeg (sometimes called Winterpeg), Canada, and 1500 watts of heat is just teasing. I'm not sure, but I might also be concerned about off-gassing from the battery at that kind of load.

There are alternatives available - propane catalytic heaters or kerosene space heaters, with plenty of ventilation and safety barriers to protect youngsters work quite well, and the energy concentration of the source is much more dense than a lead acid battery. You might also consider putting in a wood burning fireplace, if you also enjoy the aesthetics and don't mind a little work.

You surely don't need the fridge; if it's cold enough to require much heat, it's also cold enough on a porch or in a garage to store your perishables. And you can do without the microwave, if the outage is long enough, you can (again, do it safely) use a camp stove burning propane or white gas. Another idea - if you have a baby or toddlers who need quick and often access to milk or formula, you might consider one of the peltier effect (Koolatron) 12 volt coolers. Mine draws about 4 amps at 12 volts. A side benefit is you can use it in your car for trips for soft drinks, sandwich makings, etc.

What you might like your idea for is a bit of lighting if you need it, but a 9 watt florescent (equal to 40 watt regular bulb) will run a long long time on a small inverter. Plug a small inverter into your cigarette lighter, and run a temporary extension cord outside.

Take care.

Ken