Achieving high voltage spikes and high voltage battery charging

[Rob_Esq]

Hi all. I recently bought my first scope, and can now see the spikes that my SSG is producing. First I used it to test a bifiliar coil, built to spec with just over 850 winds. This wave was more 'n' shaped than 'h' shaped, with no discernible spike, and maxing at about 35 volts. I've since given up on this, because I was getting poor results, with charging tapering of at about 13.75V.

I'm now playing with an 8 filer that I built: 7x power plus 1 x trigger @ about 50m each. The waves are definitely 'h' shaped now, and at about 65V, with 12V input from the power battery. Charging is better but seems to taper off at about 14.4V.

I've been reading about other people's builds with spikes of 300V +, and am wondering what are the factors required to achieve these. (Excluding increasing the input voltage to 24V, 36V etc, as I already understand this factor.)

I'm also wondering what are the benefits of high voltage spikes? Is there a correlation between the size of the spike, and the maximum voltage the battery will be charged up to, as I've yet to achieve charging much above 14.5V.

Cheers .. Rob

[James Milner]

Adding to your question Rob,
When I built my first SSG I tested the spikes without the neon bulb protection between the collector and emitter, and without the secondary battery (charge battery) connected and was getting spikes of about 420v plus. With a load, the charge battery( secondary) in place it dropped to about 30ish volts. Is this the spike we out to be "using" for our HV pulse observation OR with both the neon and the charge battery connected?

[blackchisel97]

Hello. Neon bulb is an indicator of HV and not much of a protection for transistor rated at 200V, not mentioning 2N3055 which is rated at 60V only. You should always have the output or secondary battery hooked up. HV spikes can penetrate non conductive layer deposited on the battery plates and gradually remove them. During this process battery impedance will be decreased back to mOhm level. You may notice battery voltage climbing up at first due to the sulfation (higher impedance) and dropping down to 12 ish. After awhile battery will start to rise again. Sometimes it takes a few cycles of charging-resting-discharging-resting to see battery rising higher. Also, charging time will be shorter due to the battery being conditioned.

I hope this was helpful.
Regards
Vtech

[Woody]

One thing I have noticed is that the spikes seem to increase in voltage when additional batteries are added on the charging end. I also noticed an increase in voltage when an ammeter was added to the secondary to read input amps. My builds have always given me at least 90v and usually higher. Don't crank the trigger resistance up too high. J.B. says the draw on primary should be no more than 120ma for the vanilla bike wheel. I would start there and see what kind of spikes you get. Also, minimum 12ga. wire to the batteries, solder your connections, no clip leads and short wires. It all makes a difference. Keep at it!

-Woody

[Rob_Esq]

@ James, I've noticed something similar. When I first got the scope, and was getting 30V 'n' shaped waves, I was curious to know why when I disconnected the battery the neon was lighting. So I used the scope with the battery disconnected, and saw 60V spikes. (I only did this very briefly, with an initial spin because I didn't want to damage anything.) I never did get to the bottom of why this is, and nobody else has helped clear it up as yet ...

@ Woody, I have 2 batteries on the charging end lined up as one of my next tests anyway, so I'll look out for that. I saw a post yesterday in another thread, saying keep the primary draw low to increase the spike. I noticed with zero ohms the draw was v.high (off my meter), and the wave was a 30V 'n'. With a little bit of resistance, the draw came down under 500mA, and the wave resumed its normal 55V 'h' pattern. Further reduction in primary draw, down to 200mA, did not seem to significantly effect the spike. I've strayed away from the vanilla SSG and am now using an 8 filer coil, and a wheel made from styrofoam. I read your reply in your 'COP 1' thread last night, and have retuned my machine to a two-pulse sweet spot, with 200mA draw, and am going to run a COP test today. In terms of draw, this is a big improvement on my previous run, which had a draw of 320mA, which was the best I could do with a single pulse. I'll see how the test goes today, and what effect it has on the battery COP and system COP. The wheel is turning a lot slower than in the previous run, so my guess is that the battery COP will decrease, and the system COP will increase, but the SSG never, ever does what I expect it to do, so we'll see.

@Vtech, I've been playing around with this battery now for a year or so, and it's pretty much conditioned I'm sure. When I was running the bifiler coil, it was levelling out at 13.75V. Now with the 8 filer, it goes rapidly up to 14.4V, then charging slows down. I've not pushed it much past that, as I've been concentrating on shorter runs, to do COP testing, but I was kind of hoping to see the voltage increase steadily beyond 14.4V, all the way up to 16+ V. I'm wondering if there is a relationship between the maximum charging on the battery, and the size of the spikes ...

[forelle]

Hi to all,
i measure the voltage spikes with a cap.I take + and- from the chargebattery and hook them up to a cap for 10 seconds and after i measure with a voltage meter.With a coil with 8 wires 1mm each and about 50m i get 450v.
Is this the wrong method?