12v to 110v inverter question

[Rob Tucker]

I am interested in installing a inverter in my truck to (hopefully) use power tools in the 15 amp range.

Does anyone have any experience in accomplishing this?

Mahalo.

[EightFingers]

They don’t work well for tools you’re asking about in my experience. 15a. Is about equal to 1hp. What tools you think you’ll be running?

[randomq]

You'll need one rated to surge to 2-3 times the wattage of your tools, and tied in directly to your battery posts. (Cigarette outlets are usually only good to 200w or so.)

[Hunt Stoddard]

Depends on where you will be mounting it. In the engine compartment, next to an existing battery, or in the cab, with its own battery; or running off the car battery. It will suck plenty of amps, since 15 amps at 120 is 150 amps at 12vdc. So consider the size of cable you will need for minimal voltage drop at 12vdc. Inductive loads will have significant startup requirements, so you will want something in the 3000 watt surge range, or more.

Not to rag too much on China, but there are a host of cheap Chinese made inverters that will last anywhere from zero to 90 days. Buyer beware.

[Royall]

I was thinking of doing the same thing at one point Rob. The main tool I needed to power was the worm drive. Couldn't find an economical solution so I bought an 18v Milwaukee circular saw this last April. It has a very high amperage battery and I believe a brushless motor. All other tools I normally use are also battery powered and I just keep extra batteries around. I do have a small inverter (about 750w?) don't remember, that I can use to power the battery chargers if out in the boonies. Only other thing I've used the inverter for was to run a shop vac to pull a string fish tape through a conduit. Hope this helps.....

[kalakoa]

1HP is ~750W at 120V pure sine.

I have a 1750W inverter that will push 3000W peaks. It's barely able to run a standard circular saw because its modified-sine output has less effective usable power.

You probably need at least 2/0 wire on the DC side.

Then consider: at 10:1, a 7A/120V power tool becomes 70A/12V (ignoring efficiency loss and modified-sine loss, for simplicity sake). A typical car battery will be drained flat in no time, so you kind of need a dual-battery system so the truck still starts after power tools have killed the aux battery.

The current crop of 18V (and higher, I think Milwaukee is doing 40V) battery-powered tools are impressive; even the cheap Ryobi does stuff that just wasn't possible a few years ago in the days of NiCD. MSW inverters are more effective driving the chargers for these tools because electronics don't suffer the same MSW loss factor as motors.

[kalakoa]

If you can still find a "cheap Chinese" inverter marked DESIGNED IN CANADA, they're using an old Xantrex design, mine still works great after many years of service, runs a fridge, power tools, small vacuum cleaner...

The originals are branded Xantrex, but I've seen the exact same unit called a Magnum Power, and there's at least one other badge, all have a claimed capacity of "1750 PLUS".

[Bullwinkle]

Ive cooked a few inverters .....but my Honda 2000i after ten years still runs my tools....dont forget to add in losses / resistance from extension cords....

[Rob Tucker]

Thanks everyone. I kinda pictured not running off a truck battery. In my naivete I assumed the engine would be running. Seems a truck engine should handle
the same load a 10 hp 5kw generator would put out.

Am I wrong?

[1voyager1]

I'm not very knowledgeable on this subject.
But, While the engine would surely have the capability,
I don't thing the battery/alternator combination found on most light duty vehicles would be up to the task.

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