Small genset
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From: D Yuniskis on 2 Feb 2010 17:29 Hi Joerg, Joerg wrote: > D Yuniskis wrote: >> I want it to be smaller than the battery. > > It can't be too small or you can't hold/mount it properly anymore. My original plan was to mount it and battery in a single enclosure. Saves connectors, etc. Remember, size + weight aren't your friends when you don't have transportation available and have to carry everything! :> >> I tried running a battery powered hedge trimmer "backwards" >> and that seemed to work OK. A few amps into a dead short. >> About 18-20V open circuit. But, since everything is made >> out of *plastic* nowadays, there would be no way to remove the >> motor and site it in a different (size/shape) container. >> (i.e., the motor itself relies on the plastic to keep >> armature in place -- PoS). >> >> But, that's given me ideas as to other battery operated >> devices that I might try to cannabilize... > > If you have the time, yes, This is s.e.d... :> > but it takes quite a bit to equip it with > handles, holders, enclosure etc. Might be better to just buy one. > However, I don't know the prices. I think a crank from a bicycle would be effective and sturdy as all hell. OTOH, the "two crank" version you mentioned could lend itself to "foot power" that way.
From: Joerg on 2 Feb 2010 17:31 D Yuniskis wrote: > Hi Joerg, > > Joerg wrote: >> D Yuniskis wrote: >>> I want it to be smaller than the battery. >> >> It can't be too small or you can't hold/mount it properly anymore. > > My original plan was to mount it and battery in a single > enclosure. Saves connectors, etc. Remember, size + weight > aren't your friends when you don't have transportation > available and have to carry everything! :> > Sure, but you've got to mount it somewhere or it'll flip-flop all over the place when you try to crank. Case in point: A guy from a TV station told me that the camera men strapped 5-7 lbs of dead weight onto their new CCD cameras so they would be up to the weight of the old ones. To be able to keep them steady. >>> I tried running a battery powered hedge trimmer "backwards" >>> and that seemed to work OK. A few amps into a dead short. >>> About 18-20V open circuit. But, since everything is made >>> out of *plastic* nowadays, there would be no way to remove the >>> motor and site it in a different (size/shape) container. >>> (i.e., the motor itself relies on the plastic to keep >>> armature in place -- PoS). >>> >>> But, that's given me ideas as to other battery operated >>> devices that I might try to cannabilize... >> >> If you have the time, yes, > > This is s.e.d... :> > Doesn't mean lots of time :-) >> but it takes quite a bit to equip it with handles, holders, enclosure >> etc. Might be better to just buy one. However, I don't know the prices. > > I think a crank from a bicycle would be effective and sturdy > as all hell. OTOH, the "two crank" version you mentioned > could lend itself to "foot power" that way. Yep. Arms get really tired, really fast. Legs can pedal for hours and hours. Unless you are on a row boat team :-) -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: Michael A. Terrell on 2 Feb 2010 21:24 D Yuniskis wrote: > > The idea of mounting it on a tree is interesting. I had > envisioned something (with *one* crank) that I could hold > between my knees/ankles. The two cranks are also an interesting > approach. > > I tried running a battery powered hedge trimmer "backwards" > and that seemed to work OK. A few amps into a dead short. > About 18-20V open circuit. But, since everything is made > out of *plastic* nowadays, there would be no way to remove the > motor and site it in a different (size/shape) container. > (i.e., the motor itself relies on the plastic to keep > armature in place -- PoS). > > But, that's given me ideas as to other battery operated > devices that I might try to cannabilize... A cordless drill with a dead battery comes to mind. -- Greed is the root of all eBay.
From: D Yuniskis on 3 Feb 2010 14:18 Hi Ed, ehsjr wrote: > D Yuniskis wrote: >> I want to hack together a *small* "hand powered" genset that >> I can use to charge a 12V GelCel to power a SW rig when I am >> in the field. >> >> I should be able to use a DC PM motor with a suitable >> gearbox and crank. Any suggestions as to how to go about >> spec'ing the motor for such an application? I figure I >> should be able to easily generate 20-30W "mechanically" >> without resorting to "pedal power" > > Your arms are gonna fall off, real quick, at 20-30W. > How long do you figure you'll have to crank the thing? I don't expect to need to generate 20+W. Rather, I think *sizing* for that will put the "sweet spot" of the genset in a more comfortable ergonomic operating point. I think the rig uses about 5-6W during Rx. Tx obviously is the killer :> But, that's what you have a battery for :> (i.e., store the power you are generating for those times when you key the rig). Even at 20W, I think it is doable for "reasonable" stretches provided you have enough mechanical advantage. E.g., a short crank will kill you a lot quicker than a long one.
From: D Yuniskis on 3 Feb 2010 14:21
Hi Michael, Michael A. Terrell wrote: > D Yuniskis wrote: >> I tried running a battery powered hedge trimmer "backwards" >> and that seemed to work OK. A few amps into a dead short. >> About 18-20V open circuit. But, since everything is made >> out of *plastic* nowadays, there would be no way to remove the >> motor and site it in a different (size/shape) container. >> (i.e., the motor itself relies on the plastic to keep >> armature in place -- PoS). >> >> But, that's given me ideas as to other battery operated >> devices that I might try to cannabilize... > > A cordless drill with a dead battery comes to mind. Yeah, I started looking through my "collection". Unfortunately, the ones with dead batteries are the "toys" that were ineffective hence they were unused and batteries left to die. There is some advantage to a *non-dead* battery as then the battery storage is implicitly taken care of (though the batteries on cordless drills tend to be on the small side :< ) <shrug> I will have to play some more... |