PTO Gen, chainsaw, or ...

[SPYDERLK]

Rob-D. Yes, I know about the modified sine/square wave output of these inverters. They do work well with brush motors like you say, and I find induction motors at less than their rated load are ok too - - I have run a sump pump to empty post holes and puddles. I would never attempt to run a welder on what is available from a normal size 12V battery, even if I was using a true sine inverter.
With your apparent knowledge of the subject Im sure you know that you wont deep cycle a normal capacity/size tractor battery with a 1kW load while having the 10.5V cutoff voltage sensed at the load(inverter). At the required 90 to 100A draw for this power, the voltage drop across the batterys internal resistance, combined with the drop in the wires and connections going to the inverter will cause the inverter to "see" 10.5V well before the battery deep discharges. Where you would run into deep discharge problems is with lower amp loads where the inherent battery and conduction losses are not so prevalent. A load that drains the battery slowly will deeply discharge it before the inverter cuts out. You dont want to be running a 100W lightbulb for hours with the engine off. That battery will be pretty dead before the inverter sees 10.5V.
Larry

 

[Soundguy]

Spyder,

As for inverters. The cheap inverters that you buy in Wally Mart or other outlets are called ‘modified sine’ inverters. This is basically a square wave and square waves do not run certain things very efficiently. I could go into the harmonics of the wave and losses incurred but there is a lot of info on this floating around the net.

.

If you are an EE.. be fair.. modified sine wave is not the same as square wave. Similar yes.. square wave.. no way.. the steps do make a difference.

Soundguy

 

[Soundguy]

I would never attempt to run a welder on what is available from a normal size 12V battery, even if I was using a true sine inverter.
With your apparent knowledge of the subject Im sure you know that you wont deep cycle a normal capacity/size tractor battery with a 1kW load while having the 10.5V cutoff voltage sensed
Larry

If welding.. why waste power thru an inverter.. just use 2-3 batteries in series, and weld DC.

As for battery discharge.. 10/5 is way discharged.. heck.. 12v is working on discharged..

Soundguy

 

[patrick_g]

Today I had to remove a fallen oak tree that was across a fence. Luckily the trunk divided into three branches just short of the fence so I didn't have to cut the full sized portion, only the three branches. The smallest of the 3 was about 18-20 inches. My old beat up Husky with 32 inch bar fired right up (38F) and zipped through the oak like a knife through hot butter. I then fired up a Mac 16 inch to trim things a bit. My only complaint regarding the Husky is that it seems to get really heavy really fast but it does a fantastic job. I have two Macs that are OK but are only 16 inch. OF course a good 16 inch is fine on any smaller cuts.

I have friends who have fallen for the lowball price and have Poulans (Wally World quality not any special industrial line) that didn't last and didn't hold a candle to any of my saws even when they were new. Low price can and will bite you.

If you are only pruning and cutting the once in a while windfall and maybe have a buddy with a good larger saw then you can get by with a cheapie, maybe.

The cheapest price is often not the most economical buy.

Pat.

 

[SPYDERLK]

If welding.. why waste power thru an inverter.. just use 2-3 batteries in series, and weld DC.

As for battery discharge.. 10/5 is way discharged.. heck.. 12v is working on discharged..

Soundguy

Yeah, thats how Id weld from batteries.
10.5V under heavy load does not indicate a significantly discharged battery. Check out what your battery terminals quickly drop to when starting on a cold morning - - maybe as low as 9V even tho the battery is fully charged. Voltage at the starter is even lower due wire and connection resistance.
Larry

 

[SPYDERLK]

If you are an EE.. be fair.. modified sine wave is not the same as square wave. Similar yes.. square wave.. no way.. the steps do make a difference.

Soundguy

Modified sine includes square, but does not necessarily mean square. I dont know how many steps the cheap ones use - - maybe just 2.
Larry

 

[Egon]

Have you fot some oak boards in the future Patrick_G ?

In most cases it seems you get what you pay for.

 

[Soundguy]

Yeah, thats how Id weld from batteries.
10.5V under heavy load does not indicate a significantly discharged battery. Check out what your battery terminals quickly drop to when starting on a cold morning - - maybe as low as 9V even tho the battery is fully charged. Voltage at the starter is even lower due wire and connection resistance.
Larry

I was talking static voltage.. not load.

Soundguy

 

[Soundguy]

Modified sine includes square, but does not necessarily mean square. I dont know how many steps the cheap ones use - - maybe just 2.
Larry

I havn't seen a really crude inverter that dropped square or just a couple steps since back in the early 90's / late 80's. Some of the newer ones are dumping some pretty pure looking sine wave on a scope.

I have seen more ring noise with some of the cheaper units.. but you can do a whole lot of clean up an output depending on the componets you stick between the plug and the output.

I've got a couple inverters that are nice large beefy units.. Packed with emi/rfi and then have a 1:1 xformer at the end. Makes utility power look 'dirty' when you compair them.

Ditto with some of the more high dollar ups systems.

Still.. my 3 old trusty inverters that i use around the farm, a 100w, 150w, and 750w run electronics fine.. even stuff with flybacks and colorburst.

i think you'd have to look hard to find a company still selling a square wave inverter or a crude stepped unit. ( unless you built it, or specifically asked for that type of unit from an industrial supply house ).

Soundguy

 

[JKNY]

Here's my 2cents worth. I,m not sure what you mean by oak wilt or how big/tall the oak trees you will cut are - if the they are trees and not saplings or brush I'd go with a gas saw. I have cut wood for heat for close to 30 years and own 3 gas saws and 2 older electric saws. Electric saws have a lot less power than gas saws. Their advantage is no rope to pull and they are handy for a pole saw or light use around the house. You dont get the rpms or torque from an electric saw so I wouldnt want one for felling or any large tree work.I also think it 's a real bad idea to use your tractor or vehicle in the woods near where you're felling trees for safety reasons, so I'm not keen on the inverter or generator idea. Sooner or later you'll have a real expensive day when a tree lands on them. It isnt always the tree youre cutting, it can be limbs or a dead tree that get knocked loose during tree felling that go where you dont want/expect. That being said I have a cheap McCullough I bought 3-4 years ago for $75 right around this time of the year at Home Depot.14" bar-36cc engine. I bring it with me in the woods to limb and do light cutting and its a decent little saw. I also have a larger John Deere saw made by echo and an Echo (both onver 25 years old), and occaisionally use one of my Dad's Stihls so I'm familiar with better saws but if you forsee limited use I wouldnt be afraid of a lower price saw . If you store a gas saw for long periods with no use store it with no gas in it, that will solve alot of problems, or use a gas stabilizer. Lastly as otheers stated , if you dont have experience felling trees get some help from someone who does.If you are cutting very small ,not too tall light stuff in relatively open areas thats a different story and one of the other solutions should be ok as you wouldnt need a couple hundred feet of extension cord to work safely.

 

[SPYDERLK]

Thanks for the good info on scoped inverter waveforms - - I had been wondering about that.

Regarding, "I was talking static voltage.. not load." : Looking back at post #41 you will see that I alluded to something like that when I talked about heavy and light load conditions having different states of discharge at 10.5V.

Regarding voltage on an idled (no load) 6 cell lead acid battery: Healthy battery chemistry will sit at 12V with essentially 0%charge. 10.5V would lead one the expect that the battery was "sick" - - bad or shorted cell,etc.
Larry

 

[Soundguy]

I have to disagree slightly on a couple points. The "gas is stronger than electric / electric has less torque" And "sawing near a tractor is not a good idea"

First.. I'll assume that you aren't aware of devices that are now sold in stores called 'extension cords' Due to advances in technology since 1900 you can now get HD cords in the 50' and 100' range. We have many HD contractor grae 50' and 100' cords that are high gauge, low loss on 15a circuits at 100' and 20a circuits at 50'.

As for low/no torque. My electric saw(s) outcut my stepfathers green poulans and a homelite (spelling?) of similar or slightly larger size.

I think it is all in the make of the saw... One of my electric saws was more expensive than a cheap gas saw...

Soundguy

Here's my 2cents worth. I,m not sure what you mean by oak wilt or how big/tall the oak trees you will cut are - if the they are trees and not saplings or brush I'd go with a gas saw. I have cut wood for heat for close to 30 years and own 3 gas saws and 2 older electric saws. Electric saws have a lot less power than gas saws. Their advantage is no rope to pull and they are handy for a pole saw or light use around the house. You dont get the rpms or torque from an electric saw so I wouldnt want one for felling or any large tree work.I also think it 's a real bad idea to use your tractor or vehicle in the woods near where you're felling trees for safety reasons, so I'm not keen on the inverter or generator idea. Sooner or later you'll have a real expensive day when a tree lands on them. It isnt always the tree youre cutting, it can be limbs or a dead tree that get knocked loose during tree felling that go where you dont want/expect. That being said I have a cheap McCullough I bought 3-4 years ago for $75 right around this time of the year at Home Depot.14" bar-36cc engine. I bring it with me in the woods to limb and do light cutting and its a decent little saw. I also have a larger John Deere saw made by echo and an Echo (both onver 25 years old), and occaisionally use one of my Dad's Stihls so I'm familiar with better saws but if you forsee limited use I wouldnt be afraid of a lower price saw . If you store a gas saw for long periods with no use store it with no gas in it, that will solve alot of problems, or use a gas stabilizer. Lastly as otheers stated , if you dont have experience felling trees get some help from someone who does.If you are cutting very small ,not too tall light stuff in relatively open areas thats a different story and one of the other solutions should be ok as you wouldnt need a couple hundred feet of extension cord to work safely.

 

[patrick_g]

Welding with batteries: use two each 100 AH or better batteries in series. Three would be OK, sort of, with cut rod.

The two batt setup is marginal but will work. If you can put a fraqction of an ohm in series it will tame it a bit.

I helped develop a battery operated arc welder. It used two 12 volt batts in series and the heat was controlled with a variable duty cycle pulse train output from the inverter. Continuously variable output from about 2-3 amps to over 100 amps, all with full open circuit voltage so it was easy to strike a low power arc.

RE extension cords: I have an extension cord I bought used and cut into two pieces. I use 50 amp male and female dryer connectors to put it back together. It will handle 50 amps at 240 volts and lets me operate my stick welder at 33 ft, 67 ft, or (when put together) 100 ft from 240 volt outlet. I have a quad 120 volt outlet on the back side of the 240 volt outlet for running grinders and such.

Electric chainsaws: There are powerful electric chainsaws and there are electric chainsaws sold through standard consumer outlets. These are NOT the same chainsaws. An industrial type electric chainsaw is much more expensive than a Husky, Stihl, Johnserd or whatever top of the line (loggers make a living with them) type gas saws. I have never seen a consumer grade electric chainsaw that I would want to try to cut logs in excess of 2 ft diameter. If you have the time and long attention span, like to sharpen chainc loops, and are easily entertained then use an electric to cut trees up around 3 ft in diameter.

Pat

 

[Soundguy]

Not saying i would use an electric for huge jobs.. but for cutting medium duty and light dute stuff.. like 1' and down.. they work just fine for a homeowner ( not a logger... ).

Speaking of big dob chainsaws.. anyone ever use a hyd operated one?

Soundguy

 

[JKNY]

Hi Soundguy, if you would take a look at the end of my reply which you quoted you would see I mentioned extension cords- but thanks for the tip - as far as electric saws - I have seen a Stihl electric saw at our local dealer which would probably keep up with a small gas saw. Not sure why you seem to take an attitude with my answer to the original question, my primary concern was the heretofor unmentioned safety aspect of using either an inverter or pto generator which would involve a tractor or vehicle potentially in harms way when felling trees. If the original poster has/wants to invest in enough heavy extension cord to do the job safely thats up to him. I stand by my opinion that a gas chain saw would be my tool of choice for the job given the facts at hand , and you are certainly entitled to yours. I guess I better stay over on Yesterdays Tractors where I feel welcome.

 

[Soundguy]

My point about the extension cord is that you can put your tractor or genny.. ( or inverter .. if you really want to use one ).. in a safe place by using extension cords. with 50'-100' of extension cords.. you should be able to keep the expensive gear far enough away from anything that is being cut down with an electric saw.. especially a consumer grade one.

It's pretty common for people with pto gensets to use them around the farm where there is no power.. that includes all kinds of uses.. not just the easy ones. If you've got gear.. you might as well use it... The average inexperienced / non pro tree cutteri s probably just as likely to drop a tree on your truck, using a gas saw..

I didn't see anyone here make mention of you not being welcome.

I have no attitude either.. I just felt your message was 'locking' a person with an electric saw into some kind of non-arbitrary hard and fast minimum distance from their power supply.. seemingly precluding the use of extension cables that would allow the electric saw to be used at fairly good distance from the power source. Also.. since this power source is mobile.. like a pto genset or portable unit.. then it should be easy to reposition it to be out of the way of falling trees.

I hang out over at ytmag..read virtually all the forums there.. and I can tell you... these forums here at TBN are -much- more content edited and user friendly than at ytmag.. that is.. I've seen harsher comments over there in the 'tales' section.. etc. So I'm not sure what your point was with the moving comment.

We've all got opinions.. Obviously if you are posting your opinion on an open forum.. there is going to be discussion on the points it contains...so I wouldn't get worked up at someone (me ) disagreeing with you...

have a great thanksgiving. I got to get back in the kitchen.. I've been baking since just after lunch. I've put out a cornbread and 3 apple pies and 3 pumpkin pies.. I'm whupped... glad someone else is doing the main courses...

Soundguy

Hi Soundguy, if you would take a look at the end of my reply which you quoted you would see I mentioned extension cords- but thanks for the tip - as far as electric saws - I have seen a Stihl electric saw at our local dealer which would probably keep up with a small gas saw. Not sure why you seem to take an attitude with my answer to the original question, my primary concern was the heretofor unmentioned safety aspect of using either an inverter or pto generator which would involve a tractor or vehicle potentially in harms way when felling trees. If the original poster has/wants to invest in enough heavy extension cord to do the job safely thats up to him. I stand by my opinion that a gas chain saw would be my tool of choice for the job given the facts at hand , and you are certainly entitled to yours. I guess I better stay over on Yesterdays Tractors where I feel welcome.

 

[JKNY]

My point about the extension cord is that you can put your tractor or genny.. ( or inverter .. if you really want to use one ).. in a safe place by using extension cords. with 50'-100' of extension cords.. you should be able to keep the expensive gear far enough away from anything that is being cut down with an electric saw.. especially a consumer grade one.

It's pretty common for people with pto gensets to use them around the farm where there is no power.. that includes all kinds of uses.. not just the easy ones. If you've got gear.. you might as well use it... The average inexperienced / non pro tree cutteri s probably just as likely to drop a tree on your truck, using a gas saw..

I didn't see anyone here make mention of you not being welcome.

I have no attitude either.. I just felt your message was 'locking' a person with an electric saw into some kind of non-arbitrary hard and fast minimum distance from their power supply.. seemingly precluding the use of extension cables that would allow the electric saw to be used at fairly good distance from the power source. Also.. since this power source is mobile.. like a pto genset or portable unit.. then it should be easy to reposition it to be out of the way of falling trees.

I hang out over at ytmag..read virtually all the forums there.. and I can tell you... these forums here at TBN are -much- more content edited and user friendly than at ytmag.. that is.. I've seen harsher comments over there in the 'tales' section.. etc. So I'm not sure what your point was with the moving comment.

We've all got opinions.. Obviously if you are posting your opinion on an open forum.. there is going to be discussion on the points it contains...so I wouldn't get worked up at someone (me ) disagreeing with you...

have a great thanksgiving. I got to get back in the kitchen.. I've been baking since just after lunch. I've put out a cornbread and 3 apple pies and 3 pumpkin pies.. I'm whupped... glad someone else is doing the main courses...

Soundguy

Maybe I took your original reply/comment on extension cords as sarcasm instead of humor - thats where I percieved an attitude. I have no problem with people disagreeing with me . I feel an advantage to seeking advice on these forums is the diverse pool of ideas and experience that are drawn from make it likely that many perspectives of a topic will be discussed . I was mainly trying to make a couple points I felt hadnt been addressed in this thread. Must be getting too close to my bedtime - maybe that explains my being too thin-skinned. You havre a good Thanksgiving too, at least we know you'll get desert!!BTW thats a fine looking 7610s.

 

[patrick_g]

Soundguy, Did I mention that I have had electric chainsaws? I have had a couple in the past (big disapointment) and I have one now (love it.) My current electric is the cheap, under $100 (I shop), Remington telescopic pole with electric chainsaw on it. It is very aggressive for such a small saw and makes pruning lower branches to have tractor clearance pretty easy. I cut up to 8-10 inch branches, with some patience.

I prefer using it rather than being up a ladder with a gas saw even though I have to use the generator to power it. Lately I have just left the 6KW genset in my smaller (Dakota) 4X4 since I have been removing limbs within 8-9 feet of the ground and welding on gates and such.

Since I have the electric power available most of the time an electric chainsaw (consumer grade) would not pose too much logistic difficulty. One big downside with an electric is the cord. There just is no easy way to manage the cord. If cordless chainsaws were not so terribly anemic they would be an option but corded are a real hassle as the cord will get tangled and burried under the limbs you are felling.

Just a couple days ago I needed to get a fallen tree off the fence it destroyed because I needed that 40 A pasture for some new heifers. Luckily the 3ft + trunk fell short of the fence and I only had to cut off the three main branches (each nearly 2 ft in dia.) As you wander around cutting it up to facilitate removing from the vicinity of the fence line a power cord would get hopelessly tangled.

I don't have the budget for an electric chainsaw that can replace a good Mac 16 inch and I don't have a generator that could support an electric motor powerful enough to replace the gas saw.

For light and infrequent medium duty an electric saw might be just the thing if electricity is available and the sort of work to be done will not create a nightmare of tangled extension cord. There are plusses such as no gas storage, no gas oil mixing, no hard starting. I have tendonitis in my right elbow and am really glad my saws all start pretty easy even in cold weather but I can see how electric would be ideal for someone with worse problems.

Electric saws have a zone of applicability but it does not overlap very seriously into the zone covered by gas saws. This is certainly so if you are talking consumer grade electrics. For me there are two issues, HP and the cord problem. For the next guy, electric might be a perfect fit in every task he can imagine ever doing.

I have hearing losses induced by noise exposure (OK and maybe age too) and I have to wear muffs to run a saw or even a 20 second run to cut a single limb will make my ears buzz for a WHILE. So there is another plus for electric. They aren't so loud and obnoxious or dangerous to your hearing and won't disturb the neighbors. Luckily my nearest neighbor is over 1/4 mile away because the 32 inch bar Husky sounds like a dirt bike with loud exhaust.

Pat

 

[Knotbored]

Nobody mentioned an old fashioned bow saw with a fresh blade. Any 10 trees under 8" would be a snap to cut by hand, anything over needs a gas saw unless you have unlimmited time. I have a (cheap) electric chainsaw but unly tried it twice, finished each cut with a bow saw, the chain dulled almost immediatly. I now have a Husky and love it. (I have 20 acres mostly huge maples) anyone want some cord-wood?

 

[Egon]

Yes there are hand tools that have downed what were probably the biggest trees in the country.

I have a double bitted axe, 5 foot swede saw. a 3 foot sweed saw and an 18" swede saw.

And yes, for those so inclined one of the hand saws and axes will be perfectly adaquate for logging.

But the good saws are also expensive as are the axes and must be kept sharp. The saws are sharpened differently for frozen wood.

The hand saws can also get jammed in the tree.