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View Full Version : An inverter for my truck.



Dave Zellers
12-08-2016, 8:38 PM
I hope this belongs here. I do a lot of field work in my carpentry / cabinetry business so it seems like it does.

I would love to have an inverter installed in my truck (van) that could power my compressor (and other smaller tools). I have an Emglo dual tank (the smaller one that you can carry, but MAN has it gotten heavier over the years :eek:) and I also have a smaller Rolair JC10 which would be fine if need be.

My van is a Chevy Express 2500 cargo van with a V8 engine. It seems pretty capable. BUT- I have no clue about how this would work, and I certainly wouldn't attempt to install it myself.

I'm asking here because I don't even know where to start or even if this is financially feasible.

It would also be very usable when we lose power and I could keep the refrigerator from thawing. But that is a side benefit. I have no interest in buying a generator for that.

Would love some pointers from those that know about these things.

John Lankers
12-08-2016, 10:01 PM
Ouch, with a 400 Amp alternator, 3000 Watt inverter (preferably pure sine wave not modified sine wave), a few deep cycle batteries, it can be done but you'll be investing thousands and keep the engine running an hour for every 10 minutes you run your air compessor to keep the batteries charged. You would be better off investing in a self propelled air compressor or a generator.

Leo Graywacz
12-08-2016, 10:40 PM
I did this. I had a Campbell Hausfeld 1HP compressor that I could run off of it. I used a 3000w modified squarewave inverter running off a 105AH AGM battery. I had this connected to my alternator system that was 105 amps. With a fresh battery I could get about 6 starts out of the compressor. With the truck at an idle I could start it whenever I wanted. If I had two batteries I could probably start it quite a bit more. But a compressor isn't the best thing to try to run off an inverter with limited battery power.

That being said, it was one of the best additions to my truck for working outside. The best thing was if you needed to do something quick that required power it only took seconds. You always knew where there was an outlet.

I could operate my chopsaw for an 8 hour day plus use some other smaller tools. I used my DeWalt tablesaw on it. Most smaller tools operated without any issues.

http://www.fototime.com/7FB1EDB59A8639C/orig.jpg

Mike Heidrick
12-08-2016, 11:08 PM
Run a generator.

Leo Graywacz
12-08-2016, 11:20 PM
That's what several people told me. I'm glad I didn't listen. A generator has it's place. A constant need for power. More than one person using it. All day heavy duty use.

Inverter is great if you need quick power. It's quiet, doesn't need fuel or maintainance and works every time.

John Lankers
12-09-2016, 12:40 AM
My DeWalt Emglo twin cylinder draws 16 Amp when running in my heated shop (can't get a proper reading for start up draw), I know it will trip the 20 Amp breaker when the temperature gets close to freezing.
Even deep cycle batteries will die prematurely when discharged below 12Volt (50% SOC) frequently and this will happen when used this way. Using a rather small alternator will only add a small surface charge to the battery and will not ever fully recharge it back to 100% (12.7 Volt). A starter battery would be even worse because it is designed to deliver a short burst and is not expected to drop below 70% to 80% State of Charge (SOC)
The only advantage of Absorbent Glass Mat batteries is that they are sealed and don't lose electrolyte (low maintenance and no corrosion) and therefor don't need to be vented to the outside. Modified Sine Wave inverters are notorious for causing damage to anything with a circuit board from cellphone charger, battery charger to LED lights and won't even run some power tools, they are also less efficient than pure sine wave inverters. Regardless, inverters in the 3000 Watt range should be properly fused, the size of the wiring (awg) is definitely up there as well and cables must to be kept as short as possible to minimize voltage drop.

FYI, we have 960 Watt solar on our RV, 6 AGM batteries and 2 inverters (3000 Watt and 1800 Watt), we can run the fridge, tv, microwave, washer and dryer except the ACs, that would drain the batteries in a hurry (16 Amp each when running, the same as the air compressor).
Doing it right is a challenge, 'jimmying' something up when in a pinch can be done.

Martin Wasner
12-09-2016, 6:05 AM
Run a generator.

Run a generator.

Charles Lent
12-09-2016, 7:21 AM
Is there room under your hood to add one of these? I had one on my work truck with a hand throttle to set the engine speed. The mount was designed so I could throw a lever and remove the belt when not using it. Running the truck engine at 1000 rpm produced 60 cycle 120/240 volts AC to run my saws, compressor, radio, etc. I wired the truck with weatherproof outlets mounted outside on both sides and rear of the truck. I didn't need it often, but it sure paid for itself when I did.

http://www.northerntool.com/shop/tools/product_9040_9040?cm_mmc=Google-pla&utm_source=Google_PLA&utm_medium=Generators%20%3E%20Generator%20Heads&utm_campaign=NorthStar&utm_content=165913&gclid=CIjYuIaH59ACFchMDQodwoAAZg


A power inverter works OK for smaller 120 volt power needs, but converting your 12 volt DC vehicle power into 120 vac requires about 10 times the amperes from your 12 volt system that you get out of the inverter when it's converted to 120 vac (very rough calculation). Trying to get 20 amps at 120 vac is going to require a much larger than normal vehicle generator/alternator than comes stock in your vehicle, in this case about a 200 amp minimum vehicle alternator. In my opinion, leaving the vehicle 12 volt system alone and adding a 120/240 volt generator/alternator or a separately powered portable 120 volt generator is the smarter way to go.

Charley

Leo Graywacz
12-09-2016, 8:23 AM
My DeWalt Emglo twin cylinder draws 16 Amp when running in my heated shop (can't get a proper reading for start up draw), I know it will trip the 20 Amp breaker when the temperature gets close to freezing.
Even deep cycle batteries will die prematurely when discharged below 12Volt (50% SOC) frequently and this will happen when used this way. Using a rather small alternator will only add a small surface charge to the battery and will not ever fully recharge it back to 100% (12.7 Volt). A starter battery would be even worse because it is designed to deliver a short burst and is not expected to drop below 70% to 80% State of Charge (SOC)
The only advantage of Absorbent Glass Mat batteries is that they are sealed and don't lose electrolyte (low maintenance and no corrosion) and therefor don't need to be vented to the outside. Modified Sine Wave inverters are notorious for causing damage to anything with a circuit board from cellphone charger, battery charger to LED lights and won't even run some power tools, they are also less efficient than pure sine wave inverters. Regardless, inverters in the 3000 Watt range should be properly fused, the size of the wiring (awg) is definitely up there as well and cables must to be kept as short as possible to minimize voltage drop.

FYI, we have 960 Watt solar on our RV, 6 AGM batteries and 2 inverters (3000 Watt and 1800 Watt), we can run the fridge, tv, microwave, washer and dryer except the ACs, that would drain the batteries in a hurry (16 Amp each when running, the same as the air compressor).
Doing it right is a challenge, 'jimmying' something up when in a pinch can be done.

My AGM battery lasted 8 years, using it nearly every day and 1.2 the time I rained it down to the 10.5v level that it would shut down. I never used the alternator to charge the battery, just as a supplemental power source. The main charge was done by a 3 stage charger plugged into my house overnight.

If you want to go the inverter route, just do it. But it's really not going to worked satisfactorily for powering your compressor. And I would suggest that you try to get a true sinewave inverter. Back when I got my modified SW inverter the sine inverters were 10x more expensive, now they are about 2x-3x more.

Rick Moyer
12-09-2016, 9:17 AM
I don't know any of the specs but my friend's newer Ford Escape has an inverter. He ran Christmas lights on his roof rack last season :). I know you're needing more power but it certainly doesn't seem like your idea is unfounded.

Jerome Stanek
12-09-2016, 10:27 AM
I would get a generator that runs off the truck engine and use a electric clutch like on a lawn mower

Garth Almgren
12-09-2016, 10:46 AM
I like the idea of a truck engine-powered generator. All the power you can want, as long as you have fuel in your tank, and you don't have to run a noisy portable generator or invest in an expensive inverter and batteries.
When I installed my on-board air compressor in my Jeep, I needed to get a new magnetic clutch for it and at the time Ryder Fleet Products had the best prices for OE parts. I'm sure one of these would mount up pretty easily to the shaft of a generator: http://www.ryderfleetproducts.com/ac-compressor-clutches-and-pulleys-c-8589

Adam Herman
12-09-2016, 10:58 AM
if the primary use is air, I would run a 12v compressor. The Puma available on eBay is well liked in the overland travel market and comes with a tank and stuff all set up. I have a VAIR brand one that works well, but it does not come set up with a tank and pressure switch.

John Lankers
12-09-2016, 11:04 AM
I don't know any of the specs but my friend's newer Ford Escape has an inverter. He ran Christmas lights on his roof rack last season :). I know you're needing more power but it certainly doesn't seem like your idea is unfounded.

The maximum output is no more than 100 - 150 Watt which is enough to power the Christmas lights and maybe a laptop, but that's it.

John Lankers
12-09-2016, 11:23 AM
How about one of the following options.
A) Portable air tanks, cheap and very mobile but limited capacity and an air compressor is still needed within reach to recharge the tanks, could be inconvenient.
B) A 3000 Watt Honda/Yamaha Inverter type generator with boost function, very quiet (55 - 60 db I believe, the air compressor itself is much louder), much more fuel efficient than the truck engine and most likely less costly than going the inverter/battery route or engine mounted generator, yet still mobile.

Dave Zellers
12-10-2016, 9:16 PM
Wow- lots of great answers. Thanks to all.

I now have a much better understanding of this. It seems a bit out of reach. It just seemed like I could tap into the power of that V8 engine and make some AC power, and I guess I can but it would be more money that I want to spend.

So just when I was convinced to explore a Honda generator, I look at the manual for my RolAir JC10 compressor and it says specifically to not power it from a generator as the motor requires 3-5 times the full load amp draw to start up.

Oh well. Thanks for all the thoughtful replies. I will check out the 12v compressors mentioned.