Conner's Build

[conner85]

Hi everyone. I ve been stalking these forums for awhile and decided it's time to start a thread. Thanks for all the info everyone has shared here.
I have built the SSG according to the beginners handbook, then rebuilt the circuit to try to match the intermediate handbook. Everything seems to be running well. I had zero knowledge of electronics so the learning curve has been steep.
I have many questions. What is the exact procedure to measure the current draw from the primary batt?
I will also include a pic and video and if you see anything that needs to be changed please let me know. Thanks!

[BobZilla]

Hi Conner,
Nice work on your circuit! You can measure your current a few ways.

The easiest way is to just use a clamp on amp meter. Search google and you will see them. The advantage is that you can slip it on while running and take it back off while running and never needs to go inline with your circuit. The bad side of it would be that it is digital and you may get false readings.

Another option which is what I have done for most of my builds is to use a panel amp meter. This gets connected inline on the positive line between the battery and the machine. I have Anderson Powerpole connectors installed so that I can add or remove the amp meter but to do so you have to shut off the machine first. You could add in a throw switch to bypass the meter if you wanted to but I never bothered.

A third option is to use your multi meter in the amp meter position. To do this again like the panel meter it would go inline with your battery to the machine. Put your red lead in the socket marked 10ADC usually on the left side switch the dial to 10A and connect the meter to the positive of the battery and the other lead to the machines positive input.

[conner85]

BobZilla,
Thanks for the reply and especially all the details on the multimeter and where to place the probes. When I follow those instructions I get a reading of .01 on the multimeter. I take that to be 10 milliamps? This is at the highest rpm which is higher than it would run with the 470 ohm resistors.

[BobZilla]

Hi Conner,
Yes that would be 10ma. That seems a bit low for that many transistors though. You may want to try that meter on some other load just to make sure it is working properly. I would suggest a small light bulb, either a flashlight bulb or or an automotive bulb such as a turn signal or license plate bulb. You could use any small DC load like a PC fan or anything you may have already. Do not try to check anything that pulls more than 10 Amps, that is the limit of your meter.

Anyway now that you can take amp readings you can go a step farther and calculate your watts.

Watts = Amp * Volts

[conner85]

I discovered that the .01 reading was wrong. I now know that in line or in series is actually clipping the + in of the machine to one lead of the multimeter and clipping the other lead of the multimeter to the + of the battery. I'm drawing about .9 amps at the highest rpm. If I adjust the pot to where my draw is higher than 1.18 the wheel starts to slow. Also if I draw less than .8 it starts to slow. I adjusted it to draw .82 then removed the meter. The rpm increased when I removed the meter. should I be replacing the pot with a fixed resistor? Do I need a scope to make sure I am getting the proper spike?

[BobZilla]

Hi Conner,
That draw sounds about right for your setup, your in the ballpark at least. I am not surprised that you noticed a change when you removed the meter. The meter itself will introduce a little resistance and effect your tuning,, but not by too much so just figure whatever your reading with it in you will actually be drawing a bit more without it.

To your question about putting in a fixed resistor or keeping a pot in, I would suggest you keep the pot for awhile. This will allow you to really study how the machine runs by changing your resistance and observing the effects. You will quickly find that there are certain points you will hit that give you double spikes, triple spikes, single spike and other seemingly strange behaviors. With a fixed setup you will not get to observe these different conditions. It will be up to you to decide how you like to run your machine but don't miss out on the experience of learning what not only works well but what doesn't.

Now what you could do is get a double throw switch that you can install a fixed resistor on one side and have the pot on the other allowing you to switch between both ways. A fixed resistor will come in handy when you start thinking you know the resistance you want to run on but then you can further adjust by changing your gap between the coil and the magnets. For those adjustments it's helpful to know that the resistance is not changed from one test to another.

O-scopes are nice to have but you do not necessarily need one to have success with your project. You can learn a lot from just making a timing light from a few led's and a resistor which would only set you back a few bucks.

Anyway I think your off to a great start. Most of all have fun and take your time. Observation is very important, notice the little things that change as you adjust your resistance, or your gap, or your voltage, or the size of your batteries, and on and on. There are so many variables but just remember to really ponder the things you observe, seeing effects is easy but what you want to be able to do is understand the cause.

Good luck with your project!

[conner85]

Hi everyone. So I bought two new 7 ah batteries to do some test runs on my build. I had been using two garden tractor batts ( one 340 cca and one 35 ah) but I could not push them over about 13.5. I can push these small batts to 15.3 easily. I'm running at .83 ma input at my highest rpm. I'm trying to estimate the rpm using a strobe. The wheel spokes appear almost stationary at 195 and at 435. My question is about doing the test runs. According to Branch Gordon's thread I should charge the charge batt to 15.3 then immediately pull one amp from the batt for one hr? Or should I be discharging it at .83ma for one hr as this is my draw on the run batt? Also is there a good way to do the discharging with resistors and LED s? I'm currently using a small inverter with window candle lights for a load.

[BobZilla]

Do not pull 1A from those small batteries, that is way over their C20 rate. Generally speaking you never want to discharge any battery at a higher rate than it's C20. As a battery gets larger so does the rate. I would guess that your 7AH is probably about 200ma C20 but look it up. Get a data sheet for your batteries and find the C20, that is what you want to discharge at.

Even doing this will still be problematic to get exact readings because you will find that as you discharge the voltage is going down and to properly calculate your joules you need to know your watts and for that you do as I said before Watts = Volts * Amps, with the volts drifting down it becomes a moving target. You can however take note at intervals to get a close enough figure.

If you have some money to spend on it you could get a CBA which will run discharges at whatever rate you set and give you totals at the end of how many amp hours or watts you used. This is what many of us use.

Link for CBA:
http://www.westmountainradio.com/cba.php

For RPM's some people use bike speedometers others use laser pointed RPM meters ( I use one).

Example meter:
http://www.amazon.com/Handheld-Digit.../dp/B009T4REQG

[conner85]

Ok so if the C20 rate for my 7 ah batts is .35ma I realize that my batteries are too small. Should I run at a lower input draw than the .83 ma which is my highest rpm? Should I try to run it around the C20 rate for my input current? To correctly size my batt I could take my input draw of .83 ma x 20 which gives me 16.6 ah. So an 18ah batt would be a better size?

[BobZilla]

There are many things you could do but generally speaking you want to stay around the C20 rate or better for your primary battery. The way your machine is running it sounds like the garden batteries you started with would be more appropriate. If your machine is running nicely then I would just use the garden batteries for awhile.

You said you could not get over 13.5 and that was why you went smaller. Let me ask where is your primary voltage when you reach 13.5 on the back? The thing I am getting at is if your voltage sags too much on the front your back will not go high, even if it is fully charged. I would suggest that you get a charge on the back up to 13.5 and then recharge your primary, then put it back on and see where you can get the back too with a fresh battery on the front. It may go higher then you think it can.

Also keep in mind that these batteries need to be conditioned for this type of charging. You really need to do 15 - 20 runs on that back battery before making any determinations on the effectiveness of your system. As they get conditioned they go to higher voltages and get there quicker.

The two 7AH you have could be put into parallel to handle more current safely. The two of them together would be roughly the same as 1 garden battery.

[conner85]

Ok I'll give that a try. I discharged both of the bigger batts on a small load to see if they are about the same capacity since one is 340 cca and one is 36 ah. The 36ah batt (charge batt)ran about two hrs longer than the 340 cca (run batt)batt did. I'm also doing a discharge of the 7 ah run batt at .35ma to get a baseline so I can compare the runs. In the meantime I'll run the wheel on the bigger batteries and see if I can increase the voltage on them.

[conner85]

I have a few questions while I am doing test runs. I am alternating between my big batteries and the seven amp hour batteries. Would I get better results if I would recharge that 7 ah run battery on the wheel using the big battery for a primary instead of using a standard battery charger? Also a friend gave me some coils out of a machine from work. They appear to be in the configuration of a low drag generator. Could I use these coils as they are for a low drag generator? I will include a few pictures of the coil .

[conner85]

and another pic of the coil. It's actually two coils stacked together. One is about a 23 ga and the other is about twice as heavy.

[BobZilla]

Conner,

Your moving to fast.

What you should be doing is charging a garden battery on the back using the other garden battery on the front. When the front get's too low recharge it with your standard charger and continue the charge on the back. I asked you where your voltage was at on the front when you reached 13.5 on the back as you said that was as high as you could get but you did not answer the question. Have you tried what I suggested, recharge the front and keep going on the back?

I am trying to see if your machine will push the back up higher than the 13.5. I also mentioned that even if it cannot you need to do 15-20 runs on it because it may need conditioning.

To speed up the process you could use your 7AH in parallel on the front while your recharging the the garden battery that ran out.

You should not worry about pick up coils until you understand how to tune the machine for basic runs first. Those coils look like transformers to me and yes you could use them but in my opinion it is best to use the right size inductor without transforming so that you do not get any loss. Basically the thicker the wire means more current, the thinner the wire means more voltage. Depending on what you want to do with the energy you choose the right size to supply your external circuit.

As I said though if I were you I would not try to add coils yet. I understand it is exciting and you want to try all kinds of things but it takes patience if you want to be successful.

You should be focused on the right resistance and coil gap for example to get your machine running best.

[conner85]

BobZilla, thanks for the reply and for pushing me to understand the machine first. I feel pressured to have the machine be successful because of the $ invested and people keep asking me if it works. Patience is the key! I have been trying what you suggested along with test runs on the 7ah. I will try putting those in parallel and using them to get the 36ah to a higher voltage. I have done several runs but didn't keep my notes organized so I'm starting over with a clean chart.
I ran a few cycles with a 3/8 coil gap. This spacing runs slower and I feel charges slower. I moved the coil to a 1/16 in. Gap which is where I get my highest rpm.
At .98 ma input for 8:46 hrs/min
Starting voltage run batt Charge batt
13.23. 12.07
Ending voltage. 12.04. 12.79
I see that I ran this at about a C9 rate of discharge which isn't good. I recharged the primary and tuned to .40 ma input and am running another cycle without discharging the charge batt. I want to try to make the timing light like I saw in the forums to see how many pulses per magnet I'm getting at the diff resistance settings. Also should I be running in the common ground mode?