Ok guys I have a new curve ball to throw to you ;-)
After much testing and changing things around I have a little improvement too the setup.
I have been exploring this idea of triggering more dipole events on the cap, same idea as before but I have figured something out.
What I have done is make a new cap dump board with only one mosfet and I upgrade the diode to a fast switching 8 amp diode. I wanted cleaner switching and I figured the four mosfets on the other board were probably not triggering at the same time, same issue we have with matching transistors. I am getting a little heat now because it is only one mosfet but it is still not bad, about 20 degrees over the rest of the circuit components. That is not the thing I want to share but it is worth mentioning for anyone keeping track of how this system is setup.
What I want to share is that I have figured out how to get these dipole events to appear on the cap with repetition and they are producing 400v spikes. This is what I was trying for all along and now I can actually see it happening on my meter.
The key to what I am doing is first off I have to dump on at least 40v in the cap or the large spikes do not appear. The challenge with my system is that it is not strong enough to keep that large cap (60,000uf) in there and still dump with enough frequency to move the battery very well. I can hold it back for 6 seconds and get enough charge but dumping once per 6 seconds does not move the battery very well. As usual it is all a matter of tuning. I had to swap out to a smaller cap arrangement.
I have a 1000uf on it currently which charges up to about 45v in 250ms, then I dump for 250ms, then some “dance pulses” 55,65,35 and then it repeats. Because I am now working with such a small capacitance I had to decrease the amount of dance pulses. I can take this idea farther when I get my stronger machine built. This shows up on the Amp meter as about a 1A dump to the battery, not very much but it is happening nearly twice a second.
What I have observed for good cap dumping in general is that the dumps must happen with a certain speed or the battery will not move very well. It can change depending on the target battery but generally quicker seems better. You want to size your cap to be able to charge to whatever voltage you like BUT it must be able to do it fast enough. When I have a stronger machine I can double or triple the cap size and still keep the short charge time for the cap but for now I have to downsize to accommodate this method I am trying.
The key to what I am presenting in this update is that to get the really nice 400V spikes you need to dump on at least 40v. I tried dialing back the frequency with various caps and on every configuration I did not see these large spikes until I was going over 40v. I tried it with the 60k cap, could do it but only if I let the charge build for 6 seconds. I tried it with a 15k, again had to let it build for about 2.5 seconds. I see the best charging if I keep the dump cycle at one second or less so the only way to do it was to downsize the cap until I could achieve that cycle rate ( with this machine).
I had hopes of charging large batteries with this machine but I just don’t think it can accommodate. I can charge garden tractor batteries and small AGM’s no problem but my 75AH and 100AH are not going to do it on this machine. I mean I can get it to charge them but it takes way too long for my liking. I am fine with it though. I have a ton of small batteries and this machine is fine for them. It has been a great experimenting platform and now I want to scale up with what I am learning from it.
Here you see a chart of the cap voltage. It is dumping at 46v or so but the dipoles are contributing 400v, over and over! I need to do much more testing but this is what I have been looking for. I am pretty happy with this performance. Remember the chart only samples once per second so there are things happening that it does not always catch.
Again this is charting directly off the CAP to watch the dump cycle.
(The forum pictures hosting is not working so I am hosting these on my web storage. If you click the "download" button you will get a much better resolution than the preview on the link, same for video.)
https://files.secureserver.net/0swaxIKnzM6zZW
And here is the charge curve for the same period. The target battery is the same garden tractor one I used in the beginning of this post. It was not dead to start but not charged either. It was resting at about 12.52v The primary draw is just over 1A, maybe 1.10 – 1.18, again there is a little bouncing on the meter.
https://files.secureserver.net/0sn6GrW3lCW2pz
Here is another video so you can see it in action.
https://files.secureserver.net/0sq3iS0e5LrwVt
It is too early to say really if this is of great benefit but I am happy that I am able to produce the effect at will. I think what I may do is compare some runs like this and then lower my cap dump down to about 35V, just under where the spikes appear to see what effect it has on charging, and the primary. I have to believe that inducing these 400v spikes contributes to the gains but more testing to come.
SO many ways to tune these circuits! ------Bob
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