DC to AC power inverter to run electic tools?

GaryM · Oct 9, 2003

( I am confused? About the 17 amp thing. It takes over 167 amps DC to get 2000 watts AC right not 17 amps DC to get 2000 watts AC.

George )

Yeah, 167 amps at 12 volts is 2k watts. And that's not allowing for the inverter's inefficency.

But 2K watts at 120 volts input, rather than 12 volts, only requires 17 amps. In the case of the JD unit, is it an inverter, or is it using the AC produced by the alternator?

I'm going to go back and re-read a few posts.

Bob_Skurka · Oct 9, 2003

According to the JD website, it is using an inverter. I cut and pasted the actual wording somewhere up this thread.

have_blue · Oct 10, 2003

Bob,

I have a 1500 W inverter. It uses a 12 V trolling motor battery, which is charged by a 40 W solar panel. My 1500 W inverter regularly powers a honking big shop vac, an air compressor, a battery charger for my cordless drill, a disc grinder. It is good for tools up to 13 amps, which will work on a 2 HP motor. Every time I use the inverter, I am tickled to death. Yes, I believe it would be worthwhile to have one on your tractor on a large spread. You can now (DRAT!!) get a Coleman 2000 W for $200. This would be good for up to 18 A tools.

have_blue · Oct 10, 2003

Re: DC to AC power inverter to run electric tools?

(
I am still confused as to what the net effect of running a 1500 watt/3000 watt surge inverter would be off the battery, with the engine running on my tractor.
-- Will it draw down the battery too much?
-- Will it overload the alternator?
-- Would I be better off running it with the engine off for shorter periods of time?
)

Bob,

A 2000W inverter is not a big load on your battery unless you use honking big tools that draw above 15 A. Tools like a 4" disk grinder (8 A) can be run a long time without draining the battery too much. A 3/8 drill can run intermittently all day without problems. Most inverters produce 110 V, which reduces the wattage considerably from 120v, and thus the amperage drain on the battery.

As you indicated elsewhere, tools are normally used in short bursts. Constant use of a big tool can quickly drain the battery, but you can get a feel for this.

Always shut down the tractor when using the inverter, and crank it for a quick charge if you suspect the battery is getting below 75% capacity. Frequent deep discharging of a battery (below 75%) will shorten its life. Yes, below 75% is considered "deep".

Charging a battery will never hurt your alternator.

Inverters are cool. I'll never be without one again.

Bob_Skurka · Oct 10, 2003

Re: DC to AC power inverter to run electric tools?

Do the new Coleman units have an automatic shut down if the battery drains too low? I have been looking at a couple different brands and both of them have an auto shut down to prevent discharging the battery too much so that you are ended up stranded in the field with a dead tractor battery.

If the tractor is running will that cause the inverter to damage the alternator?

have_blue · Oct 10, 2003

Re: DC to AC power inverter to run electric tools?

( Do the new Coleman units have an automatic shut down if the battery drains too low? I

If the tractor is running will that cause the inverter to damage the alternator? )

Bob,

The Coleman units at least have an alarm, and I'm 99% sure they shut down when the battery voltage gets low. I would be afraid to run a larger inverter while the key is turned on, but I may be wrong.

LAGEORGE · Oct 10, 2003

Re: DC to AC power inverter to run electric tools?

Charging a deeply discharged battery will kill the alternator in time, trust me I know. Been there done that many times over. Take a look at your alternator it is a very small unit and if asked to produce maximum output it will generate lots of heat and wear out the bearings, brushes and diodes. My experience has been that the bearing or is it the lubricant for the bearing burns out and cause the unit to seize and bust the fan belt. On a modern Suburban it can be fatal if the engine is allowed to overheat after the fan belt goes south since it only has one belt for all. Here at work lots of guys have inverters in their own cars to watch TV and such. Common problems are dead batteries and done in alternators and oh yeah “dude can I get a jump”. On my NH TC 24D the alternator looks fairly simple to change out but I bet you the price is 200 bucks for the little thing. I have been tempted to hook up a winch to my tractor but know that the 200-275 amp draw might end up killing the battery and alternator but I have not ruled out installing a larger one but that would require letting New Holland off the warranty hook. So once again how about a cheap PTO gen? You get 5K and more and you can still run your tractor at high RPM’s. /forums/images/graemlins/grin.gif
Don’t get me wrong I like inverters and “inverter trucks” but they require lots of maintenance and can be problematic. Many of you are right about using them infrequent but heed this warning, run the tractor engine you will need all the power you can get to keep that inverter going or you will be buying new batteries often. We hardly ever run just off the batteries. Why because it kills the alternators and can be murder on the batteries plus it gets hot in the trucks /forums/images/graemlins/tongue.gif

George

DavidJ · Oct 10, 2003

Bob, I have 2 inverters.

1. Tripplite PV600. Used to run a TV and Satelite receiver. Not used on tractor but a few times.

2. PortaWattz 1000. Used on the tractor to power paint sprayer (Wagner) and small power washer as well as other small tools. It is not permanently connected to tractor battery. I use 2/0 welding cable with 400 amp clamps when connecting.

Using the power washer causes the most drain so I have to be sure and let it shut down periodically. I use it to clean fencing and such.

Soundguy · Oct 13, 2003

( a battery charger for my cordless drill )

Yikes... inverting dc to make ac.. to xformer it back down to dc to charge a coordless drill battery.. probably about the highest loss situation I can imagine.

Any chance you could get that cordless drill charged direct dc... cut out the middleman per se. Since something like charging that cordless drill battery is going to be a long process you are chewing up that storage battery capacity in the mean time. Even though the load from the charger is probably real negligable.. the onstate current draw from that inverter is still substantial. In other words.. just the inverter running, open loop, with no 12v appliances plugged in, there is still power being used, ...

Would be much more eccicient to rig up a dc charger either utilizing that high dollar 40w panel, or with the addition of a cheap add on solar charger available at tractor supply, or harbor freight....If your unit is 12v or lower it would be super easy.. if it is 14.4 or 18v it is still doable,... just need a bit more hardware. ( harbor freight has a panel that floats from 19$ to 9$ every now and then. It is rated at 12.5vdc @ 125ma... but will produce up to 22 volts in direct sunlight.. at a lower current.. like 45-65 ma... slow charge.. but if it has a week to set.. that's the ticket. Add a panel in parallel or series with a bit of support hardware from radio shack and you could have a still cheap and easy charger, for the 14.4 and 18v models ( A constant current charger using those panels and a handfull of diodes is real easy... ).

Soundguy

Spencer · Oct 30, 2003

Re: DC to AC power inverter to run electric tools?

I have a question relating to this subject. What if a person hooked a UPS (Uninterruptible Power Supply) after an inverter and plugged the power tool into the UPS? The new UPS system I just got has lighting and surge protection. I assume these units have some form of "power conditioning" also. If I ever had to power my computer off of my generator I always planned on hooking the generator up to the UPS and not directly to the computer.

Does hooking up a generator to the UPS and not the computer directly offer any additional benefits? Any downsides?

Would hooking up a UPS between an inverter and a tool offer any benefits? Any downsides?

Just wondering,
Spence