Cen-Tech 1000W Inverter Questions

[DerbyDad03]

I bought this inverter at you-know-where. I will be calling the tech support number given in the manual, but I thought I'd run my questions by you folks also.

1 -When I power it on, the fan starts, runs for about a second and then stops. Is this normal? Will the fan start again if required?

2 - When I plug in a lamp with a 72W bulb, it works fine. When I plug in a air mattress pump (120V, 1.0A) the pump may or may not start and the inverter chirps its alarm. Sometimes the pump seems to run fine, other times, not so much. The chirping is more evident and consistent when the pump is running at what appears to be full speed.

Shouldn't even a cheap 1000W inverter be able to handle the pump without breaking a sweat?

(I'd return it and try another inverter, but both of my local stores are out of stock right now.)

[trader_4]

It sounds defective to me. It's rated 1000W continous, 2000 peak. That should certainly be able to handle a small 1A motor. In the reviews a guy said he used it to power his impact wrench to change a tire......

[makolber]

O

to the op..

before we blame the inverter as being bad, please tell us how you connected the inverter to the 12V source.

You have to realize that 1000 Watts at `12 Volts is about 100 Amps. The cable and connections for the 12 V need to be like the wiring for the starter motor in your car.

Mark

[jamesgang]

Some of the cheap hi rpm motors are very noisy electrically. That might be why your inverter is unhappy.

[DerbyDad03]

I tried 2 different sources: One of those 12V "jump start" power packs and the 12V accessory port in my van. In both cases I used a 12V extension cord, probably 16g. Obviously not the right wire for this application.

If it's going to require those huge wire "starter motor" wires and end up as permanent installation, then this device is not what I want.

[trader_4]

According to the manual, you need 7 gauge wire to go 7 ft. That of course is to support the full 1000W cont, 2000W peak. So, if you're looking for anywhere near that, then you're not going to get it out of the aux outlet. If you're looking to just run small loads like the current one, then you could certainly get by with smaller wire. But you'd have to change the fusing. It says it's fused for 120A, 40A x 3. If you can refuse it to a lower value, then you could use say 10g, which is more manageable, but it would reduce your max 120V power accordingly.

The other question is what can that aux outlet support? 10A? 15A? If that's where you want to hook it up, then you're going to be limited to 120W - 180W input power, maybe 20% less output.

Can you try hooking it up temporarily to the battery, maybe with some jumper cables, etc?

[DerbyDad03]

...snip...

The aux outlet uses a 15A fuse.

I'll try jumper cables this weekend just to see how it works. I doubt that I'm keeping the unit.

[gregz]

Where does it say it's ok for motors ?

I would check basic operation with a heater 500-750 watts. It's going to draw a bunch of amps. I bought a sine wave inverter. Never tried a motor yet, but I've drawn a few amps. I can't say the brand name of mine. Got It on eBay. I think the fan shuts off.

Greg

[trader_4]

In the manual it has a list of devices and their typical power requirements. On that list are belt sander, chest freezer, blender, AC, vacuum.....

It would be pretty useless if it couldn't even power a small 100W motor.

[sms]

You could try another one, but it sounds like HF just rated the inverter way too high. Or else you're not using sufficiently thick gauge wire. The motor may be drawing more current when using a modified sine wave that the inverter puts out. Allowing for losses in the conversion you should use about 10AWG wire and connect directly to the battery. For higher loads look at 4AWG wire, i.e. or 2AWG i.e. .

You may need the proper gauge wire even when you're operating the inverter with a load that is far lower than it's capacity.

"Use an inverter" is often a stock answer in forums regarding running

120V devices off of 12V, but it's rarely a good answer. For laptops, an Auto/Air adapter, essentially a DC-DC converter is a much better option. For things like compressors, there are plenty of them with 12VDC motors. And of course there are plenty of 12V light bulbs, i.e. .

[trader_4]

Why would that be? Where would all the wasted power be going? Makes no sense to me that you need the same wire for 100W that you'd need for 1000W.

[Ralph Mowery]

Those bulbs have their own built in inverter circuit. The LED types could be a good way to go when the price comes down.

[bob haller]

on the gauge of the input cable. awhile ago harbor freight was selling some cheap ones were copper plated steel. i looked into this because if the cab les were real copper I could of bought them, stripped the connectors and in sulation and made a fortune. this when copper prices spiked so much a few y ears ago.

so if the input cables arent solid copper this too would explain the poor p erformance

[Vic Smith]

I looked into using an inverter to power my house a while ago. Instructions are all over the net, The first thing you learn is you need heavy copper from the battery to the inverter. I forgot the sizes, but it's thick copper, especially is you're coming from a car/truck battery, and have the inverter out of the engine bay. Like jumper cables, you don't go cheap. Lots of people do it right, and have no issues.

[clare]

But they are NOT running a house on a 12 volt inverter!!!!!! Running even 1000 watts on a 12 volt battery pack is not a terribly wize decision. 24, 26, or 48 volts makes a WHOLE LOT more sense.

[Vic Smith]

Some do, during outages. No big deal if done right. You're not going to run your central air, and you'd probably buy a bigger inverter. But for powering the fridge, some lights, etc., they work fine. Fridge doesn't kick on often. Typical car alt is 100 amps. Figure it out. I didn't do it because the outages are rare here. Not worth it. Some contractors have permanent installs on their trucks for 120v tools. You just have to know what you're doing.

[Arthur Conan Doyle]

I agree - the HF inverter is a square wave inverter, not a true sine wave inverter. You might try a few other motors with similar draw and see how they work before assuming you have a defective inverter.

[clare]

The typical 100 amp alternator will burn out in as little as 20 minutes at full load. Just look at the guage of the wiring in the alternator stators if you want to know why!!!! My dad, an electrician, ran his 1/2" drill and when necessary his skill saw off a belltronics converter installed on his old Dodge Van. Note it was NOT an inverter - it produced 120vdc directly from the alternator so there was never more than about 15 imps involved.

He got more "power" ot of the 38 amp Mopar alternator than you would get out of a 1000 watt inverter on a 100 amp alternator

I was also involved in the setup of an "off grid" system in Burkina Faso, west africa about 14 years ago. We converted from 12 to 24 volts with Xantrex tue-sine inverters and were able to run 2 inverters (1000 watts each) instead of just one, on lighter cable with less voltage drop and a whole lot less problems with primary connections due to the reduced current draw. This was a solar system, with emergency charging capability using the Toyota Diesel. - which was never required.

So I think I know what I'm doing.

[Vic Smith]

Like I said, you have to know what you're doing. You never pull 100 amps. Typical fridge pulls 3 amps running the compressor. That's 33 12v amps, assuming 120v AC, but only when running the compressor. Throw in some amps for lights, you're still ok. It's a viable emergency power source for some folks. Plenty of examples of people who do it.

[trader_4]

Not the typical fridge in the last 3 decades. Before replacing my old Frigidaire I used a Kilowatt meter to measure it. It pulled 180W. The new replacement pulls 90W. I also saw similar ~90W number from a 8 year old fridge and also a freezer at a friends house during Sandy.

That's 33 12v amps, assuming 120v AC, but only when running the

More like one quarter to half that.