Inverter Question

[TheScarab]

Just purchased a boat with a 3,000 watt coleman inverter.

The boat has 2 banks of 2 batteries.

When I switch on the inverter, it shows 13.2 volts so i'm assuming the batteries are fully charged.

The inverter works for very low wattage. For instance, I can charge my laptop and cell phone. However, I can't run a small electric fan, small heater, small stereo or small refrigerator. When I plug these items in, they simply do not run.

What could cause this?

[CharlieJ]

When the inverter is on line, have you checked for power at the outlet or outlets that you are plugging the appliances into?

If the answer to the above is "Yes", then check to see if the inverter is a modified sine wave type. Depending on how "modified" the sine wave is, many appliances will not run at all or will run more inefficiently then when being supplied with pure sine wave power.

Hope this helps.
Charlie

[TheScarab]

Originally Posted by CharlieJ

When the inverter is on line, have you checked for power at the outlet or outlets that you are plugging the appliances into?

If the answer to the above is "Yes", then check to see if the inverter is a modified sine wave type. Depending on how "modified" the sine wave is, many appliances will not run at all or will run more inefficiently then when being supplied with pure sine wave power.

Hope this helps.
Charlie

not exactly sure what you mean by that.

i can say this: there are 4 110 type outlets on the side of the inverter. when i plug my cell phone charger in, it charges the phone. same with my laptop.

but when i plug a little fan, fridge etc in...nothing happens.

[CharlieJ]

I didn't know if the inverter was hardwired into the vessel's system, thus the first question.

That leaves the second issue; is this inverter a MSW or pure sine wave?

Charlie

[DeepFrz]

What is the voltage at the batteries when you plug the fridge in to the inverter? The voltage should drop only a little.

Also does the cell phone charger continue to work if you plug one of the other devices in at the same time?

[TheScarab]

i found a manual for the inverter today online.

it's a coleman, 3000 watt.

the inverter shows that the batteries (both banks together and separate) are around 13.2 - 13.5 volts. yet, the inverter itself is only producing around 200 watts.

evidently the inverter isn't producing enough wattage to run the devices; even though the batteries are fully charged.

not sure what could cause this.

[atoll]

try pluging in something that doesn't have windings like a heat gun,or filament lamp

[donradcliffe]

The wires from the inverter to the batteries should be massive--at least 2/0, or quite a bit thicker than your car's battery cables, and the connections should be tight and secure. If it was installed with regular boat wires or has a loose connection, it might run a small load, but the voltage drop across the cables would be too much for it to run larger loads. You should also measure the DC voltage at the back of the unit and see what happens when you turn on a larger load.

Does the green led come on with no or low load?
Does the red led come on when it doesn't work?

[TheScarab]

Originally Posted by donradcliffe

The wires from the inverter to the batteries should be massive--at least 2/0, or quite a bit thicker than your car's battery cables, and the connections should be tight and secure. If it was installed with regular boat wires or has a loose connection, it might run a small load, but the voltage drop across the cables would be too much for it to run larger loads. You should also measure the DC voltage at the back of the unit and see what happens when you turn on a larger load.

Does the green led come on with no or low load?
Does the red led come on when it doesn't work?

yeah, the cables are massive. there does appear to be a bit of corrosion at the ends of the cables on the battery side.

perhaps that's the problem.

[44'cruisingcat]

I'd say you have a "modified sine wave" inverter. Which really means not sine wave at all, but square wave. Inductive loads, motors etc often won't run off this type of inverter.

[Wanderlust]

Corrosion at the terminals is a high probability of the cause. Often a small device will get enough power, but a larger draw will not.

But then as said before it may be your devices simply won't run on modified sine wave inverters. The AC house power is sine wave .... i.e. there is a smooth ramp up and smooth ramp down. A MSW inverter is cheaper to produce, and it just switches from one direction to the other with minimal ramp up or down. Many devices will not run at all on MSW while some may be less efficient or be damaged.

[donradcliffe]

Originally Posted by Wanderlust

Many devices will not run at all on MSW while some may be less efficient or be damaged.

This is an urban myth--99% of what I plug into my MSW's run just fine, from TV's to computers to power tools to microwave ovens. For example, the OP's fan would have run if the inverter was working properly.

[colemj]

Originally Posted by donradcliffe

This is an urban myth--99% of what I plug into my MSW's run just fine, from TV's to computers to power tools to microwave ovens. For example, the OP's fan would have run if the inverter was working properly.

If 1% of your devices do not work, then it is not an urban myth. And your microwave is definitely running at less efficiency, just like Wanderlust said. I have had several wall wart chargers and power supplies burn up on a modified SW inverter (in other words, damaged - like Wanderlust noted), while others work just fine. This was on a high-quality marine MSW inverter.

So, MSW inverters work fine for a lot of things, but it is not urban myth that many pieces of equipment will run less efficiently or be damaged. This is completely true.

And yes, the OP's problem is unrelated to the type of inverter. As you noted, his fan would have certainly run on a MSW.

Mark

[AnchorageGuy]

We have used modified sine wave inverters for 15 years including right now. We run fans, tools, TV, DVD Players, water heater, 110 fridge and everything else possible with no ill affects and everything works just fine. It is hardwired into our electrical system. I too suspect a bad connection either from a bad connector or corrosion. There is also the possibility that you have an internal problem with the inverter that will require a trip back to the manufacturer, not uncommon. Check EVERY connection carefully. Many inverters have a standard three prong outlet on the inverter. If you have this try plugging the appliance directly. Chuck

[sww914]

That's what my cheap (bought used) inverter did after a few weeks. My very expensive Magnum MSW inverter will run everything I have. I think I fried the cheapie when I tried to run my heat gun, slightly more than half of the rated watts. You may have a fried inverter there but I don't know how to test one correctly.