Inverter

[SPYDERLK]

Watts are watts regardless of the source. Power in watts = Current times voltage. So power divided by voltage = current. 700W divided by 12VDC = 58 amps. Modern inverters are getting pretty efficient. Lightly loaded ones are less efficient. At full load, a modern inverter is probably better than 90% efficient. But that efficiency also needs to be taken into account, so instead of 58A to make 700W, you need closer to 65A to make 700W thru the inverter. At 12V, this ammount of current also takes really large wire.

Unless your alternator is greater than 60A output, it will see this load like a short, and do it's best to fill the hole this size load creates. The battery will buffer this load to some extent, but ultimately the energy has to come from somewhere. Alternators run beyond their max capacity don't live long.

What does a new alternator cost, plus labor to install it? I would guess that you can get a real nice cordless drill and a few extra batteries for that same cost. You will also not have to worry about cords and such, as well as properly wiring a 12V inverter to your tractor. The drill will also be usefull elsewhere. Once you have the batteries and charger, you can also add tools that use the same battery packs. I have a 19V sawsall that I am really impressed with. I even put it on a pole, and use it to limb trees...

Good Luck.

Larry, a voltage regulator in an alternator knows only one thing, and that is to make 14.5VDC. IF the load pulls the voltage below this point, the voltage regulator increases the field current to boost the output to get back to 14.5V. If it is unable to reach that voltage, the alternator will output at MAX capacity untill it does reach that voltage. There is a current limit circuit on the field circuit that keeps the alternator from frying immediatly and limits the output to the max rateing. Alternators run at their max output do not last as long due to heat and bearing loads...

V regs dont just slam the alt on and off they taper the field from near off to full excitation depending on the battery voltage. They do not go wide open up to 14.5, but taper to that as a max float voltage. The better ones go one better, charging to ~14.5 and then allowing the V to subside to around 14. This is healthier for the battery.

That however is not really very important to this conversation because this is based on long term experience using 1kW inverters on tractors with alternaters with capacities in the 15 to 35 Amp range. In a 4 year period each of them has tens of hours of inverter time. Not a single alternater has malfunctioned.
larry

No one said they slammed on and off. only YOU made that comment in your off reply.

I agree with the other poster.. the alternator running at max output for prolonged periods of use will not last long.

if it is a decent storage battery, the OP should be able to get some decent usage out of the small power tool with the tractor off and just using the battery, leaving enough for starting.. etc.

I've run parade routes with a couple inverters running xmas lamps and illumination lamps for the passangers.. I usually tie in an extra 'car' battery on the trailer tounge, and hookup marker lamps and flashers for the trailer. Don't have any problem in running a 1 hr parade with lamps going...

soundguy

Read it any way you want. The information - his and yours is alarmist. Many people put extra electrical draw on their systems with lights etc, that when all is totalled come near max alt capacity continuously. Inverters are intermittent use usually. NO doubt that the alt life is shortened some when asked for its full rating, but its not a death knell to run them at rated max output. You can expect to pay something for the great convenience of having AC for handtools on your tractor. My experience says this cost is small. So far, in 4 years of regular use I have paid nothing beyond the cost of the inverter. No alternator failures. No batteries replaced. So when one of these fails will we call it wearing out, or just blame it on the inverter and go to a much less convenient option.
larry

 

[Soundguy]

You post no data to base your references on...

We are talking about extreme situations. No doubt, limited, intermittant use will likely be no problems.

soundguy

 

[SPYDERLK]

You post no data to base your references on...

We are talking about extreme situations. No doubt, limited, intermittant use will likely be no problems.

soundguy

I posted experiential information. Data? What references?
larry

 

[Lloyd_E]

Wow...

All of this is beyond me. To think.. all I wanted to do was drill 4 1" holes in posts to hang my gates on. Guys... thanks for the info and take a deep breath. I am willing to take a chance. I have used this unit with my truck and no issues - running a skill saw - for limited periods. I was curious if I should consider NOT using it with my tractor... different wiring, electrically supply etc than my truck.

On my 'to buy' list is a generator... perhaps I should wait to do any work until the generator is purchased.

Many thanks.

Lloyd

 

[Travelover]

Wow...

All of this is beyond me. To think.. all I wanted to do was drill 4 1" holes in posts to hang my gates on. ...........

See how much trouble you stirred up?!!

Seriously, some on TBN would get into fisticuffs over the distinction between partly sunny and partly cloudy.

 

[mwb]

Maybe you should just use a hand brace... Makes a nice wall hanger when you are done.

 

[Soundguy]

I posted experiential information. Data? What references?
larry

you posted no data.. like AH draw, duration of time of draw, capacity of storage battery, specs on the alternator. % charge level battery was drained to ( specific gravity of cells, and / or static vs loaded voltage test.. ).. etc.

anything other than that is just 'ballpark figures'. IE.. take it easy and you should be good to go.. or.. if you don't take it easy and run it up to the wall.. continously.. you will hit problems... like some of us said..

it doesn't take much deductive reasoning to figure out that devices consistantly run at and past tolerance (for which there is a duty rating), and you exceed that duty rating... that you can expect problems..

soundguy

 

[Egon]

Hey, I got several Hand Braces. One is older than me.

From what I hear here I'd be getting worried about using the Starter to start the tractor!

 

[Treemonkey1000]

I would just use my trusty old cordless driver myself. Here is one link to Inverters.
All About Inverter

 

[Soundguy]

To think.. all I wanted to do was drill 4 1" holes in posts to hang my gates on.

Had you actually said that.. you would have likely gotten MUCH different answers.. simpler answers too..

For instance.. a 'normal' sized 3/8 drill with a 3/8 stem x 1" head 'spade' bit should do fine with an inverter of sufficient power and a storage battery even found on a lawnmower for 4 holes for gate hinge pins.

I've done this very job using a 500w inverter ( kinda small.. but worked ) and a variable speed drill.. I just took it a bit slow and cleaned the hole every few seconds.. used it powered from my pickup truck which has a same size or -smaller- battery than any of my 12v tractors.. though larger than a lawnmower/motorcycle battery of course.. ( though i have used the inverter from my lawnmower battery for a similar project.. short term.. etc.. )

this is an example of an intermittant / infrequent high load which, as said.. likely wouldn't be a problem.

remember.. the more precise info you provide in you question.. the more precise answers you will get.

asking a generic question about powering electric implements from an inverter and trac-battery for unspecified use and duration is much wider in scope than saying i need to drill 4 holes in a post...

soundguy