On Tuesday, May 25, 2021 at 2:21:49 AM UTC-7, Jeff Layman wrote:> On 25/05/2021 01:13, Ed Lee wrote: > > On Monday, May 24, 2021 at 5:10:01 PM UTC-7, Ralph Mowery wrote: > >> In article <ih2pja...@mid.individual.net>, > >>> Those machines contain brush-type universal motors, probably with a > >>> compensation winding but not sure. Is is safe to run these with 40-60V > >>> DC over long periods of time or is there some sort of motor pathology > >>> that could hit? > > >> There are 2 problems with that. The motor needs to spin fast enough so > >> the fan in it cools it off. The other that may or may not be a factor > >> is that brushes are selected for a current density. That is the ammount > >> of current determins the size of the brushes and too little is almost as > >> bad as too much current as to the wear of the brushes. > > > > Also, DC tends to create spark and heat. That's why Edison beat Tesla (the guy, not the car). > It's the other way round, I think you'll find - Tesla's AC beat Edison's DC.Oh, yes. Of course.
Running garden tools on 40-60V DC instead of 120VAC?
Started by ●May 24, 2021
Reply by ●May 25, 20212021-05-25
Reply by ●May 25, 20212021-05-25
On 5/24/21 4:59 PM, Lasse Langwadt Christensen wrote:> tirsdag den 25. maj 2021 kl. 01.02.09 UTC+2 skrev Joerg: >> I dread all those extension cords when using the hedge trimmer and other >> stuff. I found that if I connect the E-bike battery of a friend to it >> the hedge trimmer runs somewhat slower but reliably. It had 53V DC. >> >> Those machines contain brush-type universal motors, probably with a >> compensation winding but not sure. Is is safe to run these with 40-60V >> DC over long periods of time or is there some sort of motor pathology >> that could hit? >> >> If ok I could build a stack of 12-15 Li-Ion 18650 cells which, at 1.5A >> to 2A, should afford me about 45min of runtime. Or maybe build three >> sets of 4S or 5S batteries I could use for other stuff and then connect >> those in series when bushes need to be trimmed 2-3 times per year. With >> reverse-polarity protection diodes, of course, so I won't fry their >> individual BMS'es. > > bite the bullet and buy a battery trimmer that runs on the same type of battery as your other tools >It's several tools and that would cost a bundle. My other battery tools are 21V Li-Ion and that's too weak for serious yard work. 2-3 of that in series, other story, then it works. I want to avoid having to nurse yet anoter battery system.> or something like this, https://www.amazon.com/Rockpals-250-Watt-Generator-Rechargeable-Emergency/dp/B075SSMR6K/6 >That would require also buying a big 12V battery and soon you are out north of $400 just for getting rid of extension cords. Nah. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●May 25, 20212021-05-25
On 5/24/21 8:01 PM, Don Y wrote:> On 5/24/2021 4:59 PM, Lasse Langwadt Christensen wrote: >> tirsdag den 25. maj 2021 kl. 01.02.09 UTC+2 skrev Joerg: >>> I dread all those extension cords when using the hedge trimmer and other >>> stuff. I found that if I connect the E-bike battery of a friend to it >>> the hedge trimmer runs somewhat slower but reliably. It had 53V DC. >>> >>> Those machines contain brush-type universal motors, probably with a >>> compensation winding but not sure. Is is safe to run these with 40-60V >>> DC over long periods of time or is there some sort of motor pathology >>> that could hit? >>> >>> If ok I could build a stack of 12-15 Li-Ion 18650 cells which, at 1.5A >>> to 2A, should afford me about 45min of runtime. Or maybe build three >>> sets of 4S or 5S batteries I could use for other stuff and then connect >>> those in series when bushes need to be trimmed 2-3 times per year. With >>> reverse-polarity protection diodes, of course, so I won't fry their >>> individual BMS'es. >> >> bite the bullet and buy a battery trimmer that runs on the same type >> of battery as your other tools > > +1 > > You're going to spend as much time and money trying to make a battery... > a commodity product that you can buy COTS mated to a specific trimmer. >I'll have to make those batteries anyhow for ham radio activities (SOTA or summits on the air). Got an old iWorx weed trimmer that has shot 18V NiCd batteries. I want to rework those into 16V (4S) Li-Ion, taking a slight power hit, and with a very small linear post regulator also use them for portable radio gear in the field. Now if I could use three of these in series to drive my other 120VAC garden tools that would be sweet. I've tried and it works, just not sure if that's ok for the motors longterm.>> or something like this, >> https://www.amazon.com/Rockpals-250-Watt-Generator-Rechargeable-Emergency/dp/B075SSMR6K/6 >> > > Personally, I prefer long cords as they can meet many needs and > eliminate the need for batteries (that fail and might not have > sufficient charge for the work you've set out to do, TODAY!)You probably don't have a property with steep rocky slopes and lots of prickly agave plants that latch on to extension cords like shark teeth.> as well as keeping fuel on hand (for gas powered devices). >And then it won't start, carburetor gunked up because of the #%^&@!! California gas. Plus if those run, you are breathing in 2-cycle exhaust for hours which can't be healthy. That's what I definitely don't want anymore.> Battery powered power-washer? Jackhammer? Air compressor? >Except for the jackhammer they make those. Too wimpy for me though. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●May 25, 20212021-05-25
On 5/25/21 6:34 AM, Ed Lee wrote:> On Tuesday, May 25, 2021 at 2:21:49 AM UTC-7, Jeff Layman wrote: >> On 25/05/2021 01:13, Ed Lee wrote: >>> On Monday, May 24, 2021 at 5:10:01 PM UTC-7, Ralph Mowery wrote: >>>> In article <ih2pja...@mid.individual.net>, >>>>> Those machines contain brush-type universal motors, probably with a >>>>> compensation winding but not sure. Is is safe to run these with 40-60V >>>>> DC over long periods of time or is there some sort of motor pathology >>>>> that could hit? >> >>>> There are 2 problems with that. The motor needs to spin fast enough so >>>> the fan in it cools it off. ...Yes, good point. Though it does spin almost as fast as with 120VAC, just doesn't have as much power and bogs down easier, so I have to avoid larger branches. I have a lot of 230VAC hand tools I brought over from Europe and I've used them extensively on 120VAC for decades now. Hammer drill, angle grinder, jig saw and such. No problems. The motors actually become less hot than they did on 230VAC plus they don't scream as much. I just don't know whether DC would also be ok over the long run.>>>> ... The other that may or may not be a factor >>>> is that brushes are selected for a current density. That is the ammount >>>> of current determins the size of the brushes and too little is almost as >>>> bad as too much current as to the wear of the brushes. >>>The peak current is 2A on 53VDC and 4A on 120VAC. If too little current causes issues that would be a problem but the current fluctuates anyhow all the time depending on what is being trimmed. Cutting ground cover barely raises the current, big sappy bushes do.>>> Also, DC tends to create spark and heat. That's why Edison beat Tesla (the guy, not the car). >> It's the other way round, I think you'll find - Tesla's AC beat Edison's DC. > > Oh, yes. Of course. >Edison failed to make cars and didn't have Bitcoin :-) -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●May 25, 20212021-05-25
On 5/24/21 6:32 PM, Cydrome Leader wrote:> Joerg <news@analogconsultants.com> wrote: >> I dread all those extension cords when using the hedge trimmer and other >> stuff. I found that if I connect the E-bike battery of a friend to it >> the hedge trimmer runs somewhat slower but reliably. It had 53V DC. >> >> Those machines contain brush-type universal motors, probably with a >> compensation winding but not sure. Is is safe to run these with 40-60V >> DC over long periods of time or is there some sort of motor pathology >> that could hit? > > It probably doesn't matter a damn in the end. If you really want to play > it safe with what's likely a disposable tool anyways, reverse the polarity > every battery charge so you get even brush wear.Now that is a good idea!> ... Just don't go too slow, > or you'll overheat the motor- too much current, not enough cooling from > whatever tiny fan is in there. Like with any appliance, there's not a > single part in there that's overdesigned or built to do more than just get > the job done. >I've used 230VAC tools on 120VAC for decades, never any problems.>> If ok I could build a stack of 12-15 Li-Ion 18650 cells which, at 1.5A >> to 2A, should afford me about 45min of runtime. Or maybe build three >> sets of 4S or 5S batteries I could use for other stuff and then connect >> those in series when bushes need to be trimmed 2-3 times per year. With >> reverse-polarity protection diodes, of course, so I won't fry their >> individual BMS'es. > > All that nonsense sound far more complex than a fucking extension cord, > but hey, have fun. You're in the electrocution danger zone at 40-60 volts > too. You won't be letting go of a DC tool running off some weird battery > pack wrapped around your leg and arm. >I'd carry them in a backpack but all well insulated and safe. I also never do such works when it's wet outside. Yes, making those packs and the chargers is a lot of work but I have to do that anyhow for portable ham radio purposes. The only extra work would be connecting three of them in series. And ok, I'd have to add in a reverse polarity Schottky diode each but that's easy. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●May 25, 20212021-05-25
On 5/25/21 4:41 AM, Chris Jones wrote:> On 25/05/2021 09:02, Joerg wrote: >> I dread all those extension cords when using the hedge trimmer and >> other stuff. I found that if I connect the E-bike battery of a friend >> to it the hedge trimmer runs somewhat slower but reliably. It had 53V DC. >> >> Those machines contain brush-type universal motors, probably with a >> compensation winding but not sure. Is is safe to run these with 40-60V >> DC over long periods of time or is there some sort of motor pathology >> that could hit? > > If you go much higher in voltage using DC on equipment designed for AC, > then the on/off switch may arc for quite a while each time you turn it > off, especially with an inductive field coil in series, and even more so > at higher currents, like if you stall the motor and really want to turn > it off. Same applies to fuses, if it has any. Perhaps 53V is still ok. > Otherwise, a device that makes the current go to zero periodically (like > an inverter) might help to extinguish any arc. >Good point. Might have to add in a TVS across the motor connection. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●May 25, 20212021-05-25
On 5/25/2021 10:59 AM, Joerg wrote:> On 5/24/21 8:01 PM, Don Y wrote: >> On 5/24/2021 4:59 PM, Lasse Langwadt Christensen wrote: >>> tirsdag den 25. maj 2021 kl. 01.02.09 UTC+2 skrev Joerg: >>>> I dread all those extension cords when using the hedge trimmer and other >>>> stuff. I found that if I connect the E-bike battery of a friend to it >>>> the hedge trimmer runs somewhat slower but reliably. It had 53V DC. >>>> >>>> Those machines contain brush-type universal motors, probably with a >>>> compensation winding but not sure. Is is safe to run these with 40-60V >>>> DC over long periods of time or is there some sort of motor pathology >>>> that could hit? >>>> >>>> If ok I could build a stack of 12-15 Li-Ion 18650 cells which, at 1.5A >>>> to 2A, should afford me about 45min of runtime. Or maybe build three >>>> sets of 4S or 5S batteries I could use for other stuff and then connect >>>> those in series when bushes need to be trimmed 2-3 times per year. With >>>> reverse-polarity protection diodes, of course, so I won't fry their >>>> individual BMS'es. >>> >>> bite the bullet and buy a battery trimmer that runs on the same type of >>> battery as your other tools >> >> +1 >> >> You're going to spend as much time and money trying to make a battery... >> a commodity product that you can buy COTS mated to a specific trimmer. > > I'll have to make those batteries anyhow for ham radio activities (SOTA or > summits on the air). Got an old iWorx weed trimmer that has shot 18V NiCd > batteries. I want to rework those into 16V (4S) Li-Ion, taking a slight power > hit, and with a very small linear post regulator also use them for portable > radio gear in the field. Now if I could use three of these in series to drive > my other 120VAC garden tools that would be sweet. I've tried and it works, just > not sure if that's ok for the motors longterm.And this is a better use of your time than buying a ready-made solution? I try to only spend time rolling-my-own when I can't find anything remotely suitable (e.g., electric wheelbarrow)>>> or something like this, >>> https://www.amazon.com/Rockpals-250-Watt-Generator-Rechargeable-Emergency/dp/B075SSMR6K/6 >> >> Personally, I prefer long cords as they can meet many needs and >> eliminate the need for batteries (that fail and might not have >> sufficient charge for the work you've set out to do, TODAY!) > > You probably don't have a property with steep rocky slopes and lots of prickly > agave plants that latch on to extension cords like shark teeth.No, we have a property littered with "landscape boulders" (large rocks that you pay to have delivered and placed on your land -- where they will never move!) and ~100 "plantings". The rocks very aptly bite into the cords as they pass, the larger plantings defy the cord taking the best "straight line between two points" and the smaller plantings are inevitably damaged if the cord passes by or over them (my cords are 12/3, 5/8" dia) OTOH, I know I can get to any place outside or inside the house (e.g., site the genset out in the back yard and run 100' cords into the house to keep the furnace running, refrigerator, freezer, etc.) and, barring an outage (which would then require the use of the genset), knowing that I can spend as long as I want trimming, cutting, washing, etc. It's much easier to drag an electric power washer up onto the roof than to also have to drag up "enough battery" to keep it running for an hour (no, I don't want to stop once I've started!). And, I never have to worry about dead (or flat) batteries. I have enough of them *in* the house running the 18 UPSs -- and they earn their keep *daily*! Though everything in my bug-out-bag is deliberately 12V powered so I can carry a battery pack and use it for any device -- assuming I don't have the vehicle's battery available to me (e.g., if we had to hike out).>> as well as keeping fuel on hand (for gas powered devices). > > And then it won't start, carburetor gunked up because of the #%^&@!! California > gas. Plus if those run, you are breathing in 2-cycle exhaust for hours which > can't be healthy. That's what I definitely don't want anymore.I *miss* gas powered tools (string trimmer, edger, hedge trimmer, power washer, chain saw, etc.) as they always had plenty of "oompf". But, the fuel (esp "mixed") was a PITA to keep on hand -- and wonder if I had to mix up more for today's workload). [I felled a couple of 18" dia trees with the neighbor's *electric* chain saw. Felt like I was digging a ditch with a tablespoon! :< ]>> Battery powered power-washer? Jackhammer? Air compressor? > > Except for the jackhammer they make those. Too wimpy for me though.A 20A outlet can do a lot of "work" for you -- and for an indefinite amount of time.
Reply by ●May 25, 20212021-05-25
In article <s8jmkp$f84$1@dont-email.me>, blockedofcourse@foo.invalid says...> No, we have a property littered with "landscape boulders" (large rocks that > you pay to have delivered and placed on your land -- where they will never > move!) and ~100 "plantings". The rocks very aptly bite into the cords > as they pass, the larger plantings defy the cord taking the best > "straight line between two points" and the smaller plantings are > inevitably damaged if the cord passes by or over them (my cords are > 12/3, 5/8" dia) > >You will not like it, but around some items I use Roundup or other grass and weed killer. I have never tried it,but there are lots of you mix your own out of kitchen items like viniger that is not harmful to you unless you decide to drink large quanities.
Reply by ●May 25, 20212021-05-25
On 5/25/21 1:28 PM, Don Y wrote:> On 5/25/2021 10:59 AM, Joerg wrote: >> On 5/24/21 8:01 PM, Don Y wrote: >>> On 5/24/2021 4:59 PM, Lasse Langwadt Christensen wrote: >>>> tirsdag den 25. maj 2021 kl. 01.02.09 UTC+2 skrev Joerg: >>>>> I dread all those extension cords when using the hedge trimmer and >>>>> other >>>>> stuff. I found that if I connect the E-bike battery of a friend to it >>>>> the hedge trimmer runs somewhat slower but reliably. It had 53V DC. >>>>> >>>>> Those machines contain brush-type universal motors, probably with a >>>>> compensation winding but not sure. Is is safe to run these with 40-60V >>>>> DC over long periods of time or is there some sort of motor pathology >>>>> that could hit? >>>>> >>>>> If ok I could build a stack of 12-15 Li-Ion 18650 cells which, at 1.5A >>>>> to 2A, should afford me about 45min of runtime. Or maybe build three >>>>> sets of 4S or 5S batteries I could use for other stuff and then >>>>> connect >>>>> those in series when bushes need to be trimmed 2-3 times per year. >>>>> With >>>>> reverse-polarity protection diodes, of course, so I won't fry their >>>>> individual BMS'es. >>>> >>>> bite the bullet and buy a battery trimmer that runs on the same type >>>> of battery as your other tools >>> >>> +1 >>> >>> You're going to spend as much time and money trying to make a battery... >>> a commodity product that you can buy COTS mated to a specific trimmer. >> >> I'll have to make those batteries anyhow for ham radio activities >> (SOTA or summits on the air). Got an old iWorx weed trimmer that has >> shot 18V NiCd batteries. I want to rework those into 16V (4S) Li-Ion, >> taking a slight power hit, and with a very small linear post regulator >> also use them for portable radio gear in the field. Now if I could use >> three of these in series to drive my other 120VAC garden tools that >> would be sweet. I've tried and it works, just not sure if that's ok >> for the motors longterm. > > And this is a better use of your time than buying a ready-made solution? > I try to only spend time rolling-my-own when I can't find anything > remotely suitable (e.g., electric wheelbarrow) >I am mostly retired and ham radio is one of my hobbies. So time investment is by different metrics just like it is when I spend an average of 5h to brew five gallons of beer. As I said, this is going to be a set of batteries that will serve at least three purposes. Plus likely serve during a power outage.>>>> or something like this, >>>> https://www.amazon.com/Rockpals-250-Watt-Generator-Rechargeable-Emergency/dp/B075SSMR6K/6 >>> >>> >>> Personally, I prefer long cords as they can meet many needs and >>> eliminate the need for batteries (that fail and might not have >>> sufficient charge for the work you've set out to do, TODAY!) >> >> You probably don't have a property with steep rocky slopes and lots of >> prickly agave plants that latch on to extension cords like shark teeth. > > No, we have a property littered with "landscape boulders" (large rocks that > you pay to have delivered and placed on your land -- where they will never > move!) and ~100 "plantings". The rocks very aptly bite into the cords > as they pass, the larger plantings defy the cord taking the best > "straight line between two points" and the smaller plantings are > inevitably damaged if the cord passes by or over them (my cords are > 12/3, 5/8" dia) >Then why cords?> OTOH, I know I can get to any place outside or inside the house (e.g., > site the genset out in the back yard and run 100' cords into the house > to keep the furnace running, refrigerator, freezer, etc.) and, barring > an outage (which would then require the use of the genset), knowing > that I can spend as long as I want trimming, cutting, washing, etc. > > It's much easier to drag an electric power washer up onto the roof > than to also have to drag up "enough battery" to keep it running for > an hour (no, I don't want to stop once I've started!). >With bush trimming it's different here. I have to clean up between cutting phases, snip here and there with the lopper, et cetera. Plenty of time to recharge. Most of the time other stuff such as the pool needs attention as well so I never run out of work out there. It's a matter of planning.> And, I never have to worry about dead (or flat) batteries. I have > enough of them *in* the house running the 18 UPSs -- and they earn > their keep *daily*! Though everything in my bug-out-bag is > deliberately 12V powered so I can carry a battery pack and > use it for any device -- assuming I don't have the vehicle's battery > available to me (e.g., if we had to hike out). >No UPS here, don't need that. At least not anymore.>>> as well as keeping fuel on hand (for gas powered devices). >> >> And then it won't start, carburetor gunked up because of the #%^&@!! >> California gas. Plus if those run, you are breathing in 2-cycle >> exhaust for hours which can't be healthy. That's what I definitely >> don't want anymore. > > I *miss* gas powered tools (string trimmer, edger, hedge trimmer, power > washer, chain saw, etc.) as they always had plenty of "oompf". But, the > fuel (esp "mixed") was a PITA to keep on hand -- and wonder if I had to mix > up more for today's workload). >The only way to keep that stuff going somewhat reliably is to make 110% sure the carburetor is dry after use, drain all fuel _and_ have Sta-Bil in the fuel.> [I felled a couple of 18" dia trees with the neighbor's *electric* chain > saw. > Felt like I was digging a ditch with a tablespoon! :< ] >18" diameter is a bit much for an electric saw.>>> Battery powered power-washer? Jackhammer? Air compressor? >> >> Except for the jackhammer they make those. Too wimpy for me though. > > A 20A outlet can do a lot of "work" for you -- and for an indefinite > amount of time.If you have one nearby. At a lot of place on our property that's just not the case. Main thing is, I like to be able to go out there and quickly do a couple bushes that look "unkempt", then do something else. -- Regards, Joerg http://www.analogconsultants.com/
Reply by ●May 25, 20212021-05-25
In article <ih5887FniirU1@mid.individual.net>, news@analogconsultants.com says...> I *miss* gas powered tools (string trimmer, edger, hedge trimmer, power > > washer, chain saw, etc.) as they always had plenty of "oompf".� But, the > > fuel (esp "mixed") was a PITA to keep on hand -- and wonder if I had to mix > > up more for today's workload). > > > > The only way to keep that stuff going somewhat reliably is to make 110% > sure the carburetor is dry after use, drain all fuel _and_ have Sta-Bil > in the fuel. > >I switched to the ethanol free fuel a few years back and have no problems with the small engines. I even put the Sta-bil in it just to be sure. The lawn mower is put up from about november to march with the gas in it and for the last 10 years no problem. I have a 5 kw generator that gets almost no use. I have had to clean out the carborator about 3 times because of the ethanol junk. I have learned to use the ethanol free gas and also drain all the fuel out and run it dry after each use. Bought a propane/gasolien fuel generator about 2 years ago and only use propane in it. For those that like to use the 120 volt tools there is a small (about 500 to 700 watt) generator that runs on propane. While you do have to contend with a drop cord, you can get by with one only about 25 feet long or less. I have a gasoliene only one from Harbor Freight that is about the same size. I carry that one near where I want to use the AC tools. If not too far,just carry it, if longe, sit it in the small wagon and use the lawn tractor to pull it where needed. It is sore of hard to start, but I use the spry starting fluid on it and it cranks right up. I don't like to run the 2 cycle stuff dry so I use the E-free gas and Sta-bil in it and start it once a month. It does put out a lot of smoke for a short period of time,but keeps the bugs away..
