Bedini current difference between run and charge battery

[Dieselship]

I have build a bedini motor with an 8 filer cable with one wire acting as a trigger. There are 8 transistors that are pulsed. The motor works well in terms of charging the charge battery or a capacitor bank. I use a 12v deep cycle battery as the primary/run battery and a 12v capacitor bank or a 12v lead acid battery as the charging battery.

What I don't understand is the current usage/generation ratio between the primary battery v/s the charging battery. There seems to be a constant ratio maintained between the current usage when I check with a clamp on meter.
Eg. When I clamp on the positive cable of the primary battery, the current shown on the meter is around 80 milliamperes. At the same time the same meter shows around 39 to 40 milliamperes on the positive wire of the charge battery. When I change the trigger resistance using the potentiometer, it seems to follow a similar pattern. Eg. 17:40 milliamperes ratio. I don't understand why this ratio is happening. Isn't this ratio supposed to be flipped where the "current used < current generated" rather than what I am reading using the clamp on meter. Any help would be appreciated.

[BobZilla]

Hello,
Generally speaking your observation is typical although 80ma seems quite low for 8 tranny's.

You will see much less current on the back than the front however and that is why I say it is typical. The reason for this is because the output is HIGH voltage and not current. Current and voltage have an interesting relationship when you really look closely. The energy is there either way you look at it but one is potential and the other is velocity. Also understand that your front end is a closed loop, you are not passing the source energy through the circuit, what you see on the back end is a different source ;-)

You may want to get an analog amp meter for your experiments. Digital only shows you an averaged sample. You can get by without one but I prefer a needle.

[Dieselship]

Thanks Bobzilla. I agree you may have a point on my clamp meter. I'll change it to an analog meter and check the results. The clamp meter shows "ac" when in current settings. I was not 100% sure if it can read DC current also.

I was able to charge a capacitor bank from 0v to 12v in less than 6 hours. It's actually a 3000farad cap x 6 bank. My rotor is 22 inches in diameter and has 16 neodymium magnets in it. The setup is capable of 16 independent spools. I have only put one 8filer spool at this point. Right now it is able to achieve only around 300 rpm. I guess I need to go a long way to get it tuned properly.

On your comment on current v/s voltage, I always assumed that you need high current to charge a battery along with voltage. I also noticed that when I charge a 12 volt battery instead of a capacitor bank, I am not effectively able to use that charged battery as a run battery. The voltage dives down from 12v to around 10v as soon as I switch on the system. If I switch it off, it again comes back to 12v. My current experience shows that the charged battery is not very effective when charged using bedini. I am planning to pulsable the charge to a battery using a smaller capacitor instead of direct charge.

[BobZilla]

Ok so sometimes it is easy for me to take for granted all of the stuff I already know about this technology so I do not want to start tearing your experiment down but let me offer a few pointers.

First off there is no need for neos. If you are running the same circuit as is common to most of us the magnets are only there to induce a small bit of current into the trigger wire which in turn opens the transistor base which closes the power rail (emitter & collector). Neo's will do that but they are way stronger than you really need to do it. The other thing the magnets are doing is of course providing a pull force on the wheel to keep it spinning, again you do not need extremely strong magnets to accomplish that. In fact the neo's will slow things down because of the force required to break free of the coil.

Now about your run battery falling down to 10v. You must be pulling MUCH more current than you think. Also what size is the battery AH wise? When you charge it where are you letting it charge up too in voltage? You should charge it to at least 15v while it is charging and when you remove it and let it rest, it will drift back to 13v or so, maybe 12.8, maybe 13.2 but somewhere around 13v.

[Dieselship]

Bob, Thanks for the advice on the neodynium magnets. Actually I used neodymium instead of ceramic magnets since my plan was to mix the 8 filer Bedini spools with generator coil spools also. As I mentioned earlier, I have made space for 16 spools in my design. I.e. 8 inner and 8 outer spools in two concentric circles. I assumed that the neodymium magnets would be better for the generator coils, and I can try make it work for the Bedini coils also. I think that's where I went wrong as you noted. As you correctly pointed out, the neodynium magnets are really powerful. I have my rotor made of polycarbonate with neodynium magnets glued in two concentric circles on it. So it will take me a while to switch them with ceramic magnets. Meanwhile, I have designed my system where I can easily increase the distance between the rotor and the stator that holds the coil spools. I did that today and has started to perform some initial tests. I even could add some generator coils without a lot of cogging. Thanks to you, I thought of increasing the distance between the stator and the rotor. Earlier I was not able to add the generator coils without slowing the system considerably. Now since I increased the distance, I was able to add a few generator coil spools for a test. There is slight degradation in the RPM, but I am only running one 8 filer spool at this point. I was planning to put equal number of Bedini and generator coils in the system. I was planning to test them in various combinations, like mixing them alternatively or keeping the inner circle with 8 generator coil spools and the outer circle with 8 Bedini coil spools.

On your question on batteries, I was using 12v 12ah sealed lead acid batteries where I experienced the issue with the charged batteries of not holding the charge when in run position. I have since then got some marine deep cycle 100 ah batteries that I have not yet put into a charging position.
I didn't think the 12v batteries could be charged up to 15v without destroying them. Is that safe to do for marine deep cycle batteries also ?

Again, Thanks for your advice.

[BobZilla]

Your build sounds interesting. I can tell you have really thought a lot of things through. On the subject of voltage levels to charge too, you want to take it to at least 15v, this is common. Even a normal off the shelf charger will take them to 14.7. In these experiments it has been found that taking it to 15.3 is optimal and that is where most people shoot for. It will depend on the strength of charge you are appliying (current) but I don't want to confuse the situation because I do not mean current as you would normally think of it. What I mean really is the movement of those spikes at high voltage. We can get into the finer points later but yes around 15v is where you want to be.

Watch out using sealed batteries. They can dry out. I have used some for years but many others cook them in short order. You are best off with a wet cell that you can top off.

Moving your gap out for those neo's was the right way to go. I would experiment more with your gap and see how far you can go and how it runs. Nevermind about the generator coil for a moment, just talking about the primary circuit.

On my machine I mounted my wheel on an axle. I have the main wheel which has ceramics and another smaller wheel that has neo's. This way I can tune the machine how I want on the ceramics and the generator function is on another wheel so I can move those coils in as close or as far as I want.

[Dieselship]

Bob, Thanks for the advice and information on the voltage levels of the batteries. I like the way you have designed a separate wheel for the generator circuit.

I have seen some posts about capacitor dumping into the charge battery using some kind of comparator circuit. I used to think it is because the charge battery cannot be put into the run position if it is charged directly without a capacitor dump. Could you please comment on what is the need for a capacitor dump when the battery could very well be charged directly ? When I couldn't put my 12h Bedini charged batteries to the run position effectively, I was almost convinced that I'll need to make a cap dump circuit. I don't understand its need that well. I would like to switch the batteries as needed without worrying about loosing efficiency. Please advice. Thanks.

[BobZilla]

There is some truth in what you say about running from a back end battery. This effect is not immediate however, it takes doing it over and over in a constantly running system to become a problem (in my opinion). It certainly is not the reason for your test going south. It depends on how you want to run your machine if this would be a problem or not. If you intend to just swap the back to the front as soon as they are charged to sort of keep the machine going all the time then it would probably come into play. If you take the charged battery and set it off to the side over night before you use it again it will most likely be fine. I use back end batteries on the front all the time but usually with a little rest period. The flip side of that is that a battery coming right off the charge will loose a lot of it's juice if you let it sit. What I mean is if you were going to take and run that battery on some other system like an inverter or to run a motor you would get a bit better performance from it if you use it fairly quickly right off the charge but if you want to put it on the front of a Bedini machine it is best to let it have a little rest.

As you have mentioned there is another way around it by using a capacitor dump circuit. By dumping through a capacitor you are converting the energy back into normal positive energy what can be used right away. For example a guy named Rick used to build Bedini circuits into small DC fans and switch the front and back around when the front got low. He used a cap dump so that he could switch them instantly. In this way he was not so concerned with charging batteries but rather the mechanical output of the fan. Sure he was charging batteries but only for the purpose of keeping that fan running.

I would suggest that for now you just work on the machine in normal operation, learn to tune it and get what you want from it. Adding a cap dump later will not change much about how you run the machine, you will just be outputting to an intermediate device instead of directly to a battery. In other words you want to have your machine running the best it can before adding complexity to the back end.

*EDIT*
I wanted to add a comment on the actual difference between the two methods. In a Bedini circuit going directly to the battery we call that "mode 1".

Mode 1 charging is done with very little current but very high potential. It is this potential that does the charging. Your spikes are somewhere between 100v - 150v showing to a 12v battery. That huge potential difference is what charges (with a smidgin of current).

Cap dumping however collects this potential first in a capacitor and then periodically dumps it to the battery in the form of high current with only a little potential difference. A good guide line is to dump at double your battery voltage when it's full so for a 12v you would want to dump around 30v. You can go a bit less or a bit more but that is a ball park number. It is not the voltage but rather the current doing this charge.

Changing your dump voltage will also change your frequency, less voltage will mean faster dumps. There is a lot to play with in frequency as well and that can add a lot of complexity. It will also depend to some degree on the size of the capacitor. I have found that between 18v to 35v can be very effective at charging depending on other factors.

[Dieselship]

Bob, Thanks for the explanation on the characteristics of the batteries while working with the Bedini circuit. It was really helpful for me. When I think back on the issues that I faced while flipping the batteries, it kind of makes sense now.

Also, Thanks for the details on the usage of cap dump. In fact, I tried it on a small scale and it works well. I had a 50v 33k uF capacitor and a Solid State Relay handy. I used my Arduino micro controller to pulse a cap dump into the charging battery using the Solid State Relay. I wrote a small Arduino code that switches on the Solid State Relay for a few microseconds to dump, and then switches it off until the charge in the capacitor reaches around 24v. I had to time it a bit to understand the timing needed for the ON and OFF state of the Solid State Relay. I had connected the +ve end of the capacitor to the +ve of the charge battery. The -ve were connected via the Relay. I'll probably park this cap dump circuit for the moment, to take care of some of the mechanical and tuning issues that I am currently facing in my system. I may also need to put some kind of fuse in this circuit to prevent overcharging of the capacitor as a safety measure. That's going to be a challenge, because the fuse may fail even before it is used because of all the radiant voltage ..lol

Looks like I'll need to get an oscilloscope to tune my system properly.

[BobZilla]

That's funny, I have built many cap dumpers and solid states with Aurduino at the helm myself ;-)

I started out using FET's but lately I have been using SS relay's also. Mine are actually FET's inside as well but in a better package because they are opto switched.

*EDIT*
(After reading your post again I see you already know this, leaving the comment in for the benifet of others reading)

Something to keep in mind when cap dumping is that you want to switch on the negitive rail not the positive. In other words connect the battery positive to the cap positive directly and then put your switch/aurduino in the negative rail.

Be careful with the power to the aurduino when wiring this way. It is tempting to use the same power as the primary or even the distribution side with a regulator or something but the common ground will cause you to over supply the board, i have fried quite a few myself discovering it. You are best off to just use an external supply for the arduino like a USB phone booster or sometimes I use a 6v 4.5AH battery like you find in emergency signs for backup.

I will try to shoot a little video for you of my setup.

[Dieselship]

I appreciate your explanation on the Cap dump Bob. I like your idea of using the Opto switched SS Relay. Mine is a cheap Chinese version. But it works well though.

Bob did you ever try using a fuse with a cap dump circuit ? I have a concern on what if the arduino fails and the capacitor overcharges.

[BobZilla]

No i don't have one installed. I'm not sure where I would put a fuse to prevent that because the MC failure would not cause a surge. The cap would just build up and up.

I do have an idea however. What if you used an normal-closed relay instead of normal-open. The timing would be reversed but if the MC failed it would just become a pass-through.to the battery.

[Dieselship]

Bob, I think attaching the cap to NC Relay position may work. I need to try it out and see if it works. It is also possible that the Solid State Relay can also fail.

[BobZilla]

Another safety feature could be to attach a load across the cap but it has to be something that will not activate until a certain voltage is obtained. Perhaps a string of neon's I think they generally activate at 65-85v. I have never tried it, just thinking out loud. The criteria would be that the load only activates at a voltage well above your normal dump voltage and can carry enough current off to keep the cap from popping or your transistors from overloading. With some trial and error this could work but I have not tried it so take it with a grain of salt.

[John_Koorn]

Hi guys,

I think if you are using a Bedini SG to charge the cap you are at more danger of blowing the trannys on the SG if the Arduino fails and the cap can no longer take the charge. From my experience the Arduino would only fail if it lost power and if the SS relay failed that you're using to dump the cap, it would normally fail closed - meaning the cap is effectively bypassed.

Personally I would go with the idea of a NO relay in the trigger of the SG that is closed whenever the Arduino has power. If the Arduino drops power (or fails otherwise) the relay opens and effectively disables the trigger circuit on the SG.

John K.