I was looking at the fact that to carry a decent battery supply without breaking the bank I had to go sla.. So I bought two car batteries in very good condition used for 100 bucks. Now I had to build a trailer to carry them..and wow the trailer is big enough to fit one of those 900 watt generators... output ac.
I have been using a 350watt scooter motor as a pedal assist and it works great. I found on google last night.that a watt is a watt is a watt So if I thought a 500 watt ac motor rigged a roller. would be the same system I have now, only with unlimited range. I THINK lol.
rather than buy a 300 dollar lithium battery that still has limited range and will wear out and requires careful monitoring, this might be the way for me to go. I'm going to keep looking at it. I also have that horizontal ilfan with the lost compression I need to look into and yes that and an alternator would work wonders as well,.
To be honest the thing I like best about the e friction drive is at about 250 to 500 watts the thing doesn't need any electronics at all. Just a simple on off switch and you can go. It makes adding it to a bicycle very easy. I also like the grinder mine runs pretty darn fast and wasn't all that expensive. Could easily weld a pipe onto the nut that holds the wheel on. I think I will give that a try if I go that way.
Yeah I am still building just not inflicting it on others much, since the big accident of august 2011 lol.
The car battery thing is my latest experiment. My wife is much happier with me and pedal assist. Say it cuts down on the hospital visits.
One of the ideas here was a big fan. If you kept the hub and removed the blades and smoothed it off that might make an excellent roller. Lots of ideas once you move your mind out of the kit mode.
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From Measure Twice
Actually a Watt is a Watt is a Watt is not actually fully correct.
This is since there is with AC Current inductive and capacitive effects which are not as much a factor with DC Current except when powering on.
Look up the term Power Factor. With AC Current when there is an absolute pure Resistive Load (No Capacitance or Inductance) then Power Factor is 1 and the calculation Volts times Amps equals Watts holds true as it is for DC Current.
As either Inductance (like a Motor Winding) which is like a resistance to Alternating Current but passes DC Current or Capacitance (like a DC Power Supply Filter) which is like a resistance to DC Current but passes AC Current, both Inductance and Capacitance offset the Power Factor of 1.
What this means is that a portion of the wattage is not going to be able to be used in the load to do work as the value of Power Factor ranges below 1 toward 0.
What is for real…. Not joke…. Is that there is what is called Real Power and Apparent Power.
Apparent Power in a circuit where the Power Factor is less than 1 is greater than the Real Power measurement. Real Power is what does the work in the load. The difference is what is essentially wasted when you do not have Power Factor being 1 as it is in a purely resistive load.
What this all means is that you have to have a bigger generator not just for Inrush (Surge Current) at start up for a motor that is essentially an inductor, but all the time when running. It may not amount to much if the value measured for Power Factor is close to 1 just below, say 0.9 but as it gets smaller then is has a greater affect.
There are means to add Power Factor Correction circuits to try an null this out and get Power Factor as close to 1 as possible and large businesses use these methods since otherwise it also has adverse affect on the power companies transmission lines and the power company will charge the business extra or even demand that they do the correction circuitry.
OK all this gobbledygook I suppose, but I have though I would like to use a battery and an inverter to run a small chest freezer in remote location when camping and not wanting to have a generator running at night. I know a pure sine wave inverter not a cheap stepped wave inverter could be necessary as some circuits have problems with stepped sine wave, so I have the pure sine wave type. It is rated at 280 Watts. The motor for the compressor in the chest freezer is an inductive load, so the specifications on the label on the chest freezer when it states how many watts it uses after initial start up and is running is not the full amount for an acceptable minimum wattage necessary for the inverter to be used. It would have to be more. Apparent Power being more than Real Power is something to be aware of.
I got side tracked a while back and never got the math down to figure it all out and the chest freezer I think had said 240 watts, so if the Power Factor is just a little below 1, say 0.85 I am hoping that it might be marginal and be able to use the 280 watt inverter. Also many times the labels on like this chest freezer are over rated by a small amount to keep the manufacturer from having a liability issue if the end user has overload problems.
One thing you do not often see it mention of Power Factor on the labels, but if they are not listed, then you have to make the measurement and I will see what I can get using the Killawatt meter I got for cheap like $39.95 at a Radio Shack many years ago. Be careful though as the rating for the Killawatt model you get has a maximum amount current rating that is acceptable for your particular situation or you make smoke the meter.
The P4400 say 1875 Watts max rating so that is enough for my chest freezer at startup inrush current with extra to spare, but maybe not for a washing machine motor. That is where I have a friend loan me a 73756 - True RMS 800A Clamp Meter on ammeter that also measure AC Current up to 800 Amps. All I had to do is get a short extension cord that has thick enough wires and split the two conductors so I can loop the clamp onto just one wire so it can take a measurent.
http://en.wikipedia.org/wiki/Power_factor This wiki page has the information and graphs
MT
