What is the appropriate amp draw on the SSG when tuned to perfection?

[Silver9]

I've built the SSG and having a great time learning this wonderful device. I was watching Aaron's video on youtube with the energizer able to get 15.67 or so volts to the charge battery and my build will do the same. I think I'm on the right track. I currently working on the matching transistors and resistors and will rebuild a new circuit. As for right now I just have the basic 470 ohm resistors in place. My amp draw is about 1.6 Amps which is think is too high. I will go back to do all the fine tuning as the intermediate book said and hopefully achieve a lower amp draw. What is everyone else getting?

[Tom C]

you can expect 1.5 to 2 amps depending upon the number of magnets you have.

Tom C

[Silver9]

Thanks Tom for your response, I've built according to the the SG Beginners manual with an 22 inch wheel and 24 magnets. I saw in one of your other post somewhere that we should expect to see at 12 volts about a 1 amp draw with the correct fine tuning correct? I've seen other post on the forum that said that their initial amp draw was 2 - 2.5 amps which seems really high.

[Tom C]

amp draw is a funny thing and unfortunatly there are many parameters. the first machines I built were tuned to 1 amp draw for some specific testing purposes. we also built the one we currently run which depending upon magnets will give you more. I have a 16 magnet wheel which draws 1.2 w/ 680 ohm resistors. you can tune your machine to match the C20 draw of your battery.

as a completly personal experience here, do not quote me or in any way imply this as something to be considered a rule..... I like between .125 and 250 milliamps per transistor depending upon the batteries. but even then it depends!!! I had a bifilar SG that ran best on a single transistor at 80 milliamps. whatever gives you good charging for the battery you are running. 470 ohms on the base is a great start. it opens the Base of the transistor fully using the coil John Designed.

Tom C

[romeo-kilo]

Silver,
I have a wheel for 26" and am using 22 Magnets - the rest was almost literally following the beginners book. My input current with 470 Ohm resistors was around 400mA, and the wheel turned 200rpm. After reading the intermediate book, matching the transistors, and buying a scope, the first sweet spot with a nice scope curve was with 465mA and 210rpm. The curves below that sweet spot didn't had the "h" form...
regards
Ralf

[Silver9]

So you decided to go less on the magnets increasing the spacing between, I'm curious why 22 instead of 24? My amp draw is huge then at 1600ma compared to your 400 wow! Can you tell me what your spacing is between your core and your magnets. I would estimate mine to be about 1/8 of an inch. I don't know how to use a scope but that would probably be next. I am working on testing transistors and resistors as well.

Paul

[romeo-kilo]

Paul,
I was using 22 because 24 were too narrow. As I'm living in Europe I did not get exactly the magnet size like explained in the book. Mine are a little bit larger and stronger. The spacing to the coil is 3-4mm (~25mm = 1 Inch), what gave me the highest rpm per mA. Like said before - the Speed is 210rpm at 465mA.

Ralf

[MrRonsen]

i have original twisted coil 8x20AWG + 1x23AWG 130 feet (ca. 40m)
with the original bedini SG 8 transistor board Kit
and a bike wheel 24 mags..
it took 1.8 Amps at first, now it takes around 1 Amp,
turning 230 RPMs

[Silver9]

There is such a wide variation amongst these energizers! Before I move on to the fine tuning should I be working with my coil spacing first before moving on to transistor matching and resistor matching? The closer I go to the magnets with my coil, I can see the voltage rise higher on my output battery. I get my best voltage on the output battery when my coil is almost touching the magnets but I am guessing that this is not suitable as well because of the attraction of the magnets to the iron core too strongly. A little confused I guess because I am looking for the highest rpms with lowest amp draw with my coil spacing? ( I have not yet done the matching or added the 100k resistor or Pot yet.)

[D Rhodes]

Each machine is different. I run mine with a gap of about 9mm, nearly 3/8". The closer you go, the higher the draw on the primary...or the more current you are pushing. We don't want more current, but less. After all, If it is just about the ability to charge a battery, we may as well use a standard charger. When we can charge a 90aH battery for example with only 300mA draw and 150mA input of current, something else is charging that battery.

[Yaro1776]

Silver9

I have the same basic 8 trans and coil arrangement as MrRonsen, but with 21 magnets. The alloy wheel Outside Diameter is ~ 22.5" and the magnets are very closely positioned on the wheel by using a plastic width gauge that was developed by trial and error. Since the wheel had 36 spokes I used 13 of the spokes to position 8 of the magnets over that 120 degree arc (The 8th magnet was the start of the next 120 degree arc). By trial and error I trimmed a piece of plastic to the appropriate spacing dimension (~2.6") between the magnets. Worked out very well for the rest of the magnet install!

The wheel spins at 245 to 250 RPM depending on the weather and other mysterious factors - the gap is at 1/8" between the magnet and teslgenx wooden coil holder. Best RPM with this gap +/- 1/8". The wheel has been balanced using steel BB's, though it does have a small bump in the diameter it seems to not impact its operation. The steel BB's were positioned ~60 degrees on either side of the resting heavy spot of the wheel. The wheel has not been tuned for maximum freewheeling - last trial gave 75 seconds of free spin, not great for sure. Will tackle this later as things progress.

Using teslagenx 8 trans board with standard 12 ohm final trigger resistor. Speed drops off about 10 or so RPM w/o this resistor. Amp draw on primary about 1.35 and it is charged with a Energenx 2A12 charger or at times w/ a 10A12. Able to run primary about 4.5 hours at this draw down to 12.2 volts - takes about 2.5 charges on primary to bring charge battery to 15.3 volts. I use an automotive bulb (6 watts and 0.48 amp draw) for now to discharge the charge battery to 12.2 volt - takes about 10 to 10.5 hours at this point. I am using my garden tractor batteries for the time being while I learn how this beastie runs. Later I will buy a new battery for the more serious effort.

Snowman

[Tom C]

yaro,

please get your freewheel time up..... don't even try to do any testing for cop with that low of a free spin time. the free spin test is done with the coil removed.

Tom C

[Yaro1776]

I am with you on this Tom - no intention of doing COP testing as is, just establishing some baseline information and getting a feel for the quirks.

Thanks for your reply and attention!

Yaro

[Silver9]

OK, well if my gap between the coil and the magnet is only 1/8 of an inch or 6.35mm I may be too close and drawing too much at 1.6 amps. I might work with backing the coil away from the magnets some and see how the draw is on the primary.

[Silver9]

Thanks Yaro! Still have a lot of learning to do, thanks for your input!