Power Inverters

[JRP]

Why 2000 watt?

Inrush and capacity.
A 15 amp skill saw draws 15 Amp x 120 volt = 1800 watts.
This is before inrush is considered.

With a wall outlet the wiring and breaker can handle short periods above 15 amps without fire or trip. With an inverter you have very little extra. Only perhaps a second or less at "peak" ated power.

When you are mowing you might draw 10 hp from your tractor. Should you get a 10 hp tractor? No.

As far as the starter buring up the alternator my point is that you can power inverter loads from the battery only without risk to the alternator, just like starting a motor with your starter.

Ebay has lots of new Coleman 2000 watt for $170. I plan to order one this week. We will update this post after it has arrived.


I'm more likely to power a skill saw than a cumputer while working around my tractor.

 

[Soundguy]

This reminds me of the post about tractor lights, alternator ratings, and loads.

Someone was asking about installing lighting to their tractor, that. if all lights were on.. it would exceed the rating of there alternator. Some told them they couldn't do it.

I pointed out that they could but, the storage battery would be in a state of discharge carrying the load above the capacity of the alternator for the lights. As a temporary condidtion this is no big deal.. only till it runs the battery past ignition power 9 gas jobs ) or starting power ( or fuel cutoff solenoids... etc..diesels ) would it be an issue.

Soundguy

 

[Charlie_in_TX]

Your circular saw is a DC type motor with brushes. It is not like the induction motor in an air compressor. The starting current for your circular saw will pull no were near 15amps at startup. I have started mine from my 200watt inverter. Starting it is easy, it had a hard time cutting a twig.

You have made many comments along the lines of it is no different than installing a low battery in your auto to charge it. Been there done that to the price of a $500 120amp alt in my wifes car. Have you ever heard of surge rating? The surge rating of the diodes used in alts are 10 time there continuos rating. And that is only when properly heatsinked. In an alt they are not well heatsinked. If you want to take out the rather expencive alt in your tractor, thats fine. Recomending it to others is somewhat reckless.

The next consumer grade inverter to get anywhere near 95% effecent will be the first I have ever heard of. Do you think there is a reason they put fans on 400 watt inverters? I assure you it is not because the are disipating 20 watts of power.

You have stated you can prove me wrong. I await your proof.

 

[TBAR]

I had this one mounted to my tractor for a while. Heavy duty industrial type.

http://community.webshots.com/photo/111851761/111852069CrJecN

http://www.campsitevideos.com/rediline.html


TBAR

 

[JRP]

I think you are right. Many of my tools have universal motors so it should not be a problem.

At work we calculate available fault current for switchgear. It is amazing how much amperage a 2000 KVA transformer can generate during a fault, and how much amperage a 20 amp breaker will source for the short duration of starting an induction motor.

An inverter just can't compare. Another reason to get a larger inverter.

 

[texastomtom]

Use a True RMS meter,,,

it should show 110


The battery backup systems designed specifically for computers have a 12v lead acid batter and an inverter.

If you measure the output with a 'common' meter it will show 80-90 volts. Use the proper test equipment and you will see 110-120.

Perfectly normal and should be fine for your notebook.

I use an inverted in vehicle for laptop regularly...