Recharging Batteries using only voltage spikes. A Results Log Thread

[jeanna]

I added a new battery to my charger today.
While I was watching the results of last night's charge on the Nicd, I put a very old and very depleted duracell into the charging seat. This was a battery that I have used UP and it was on the floor waiting to go to the dump.
that was before I started this project.
Today I gave the old duracell its first spike recharge. It took a while like 6 hours to get above 0.96v, but then after only a couple more hours it was at 1.76v. I tried it in the test light.
It is very bright.
I have a box of these duracells. mmm nice.

I was making a video to demo the reedswitch motor I made from a kit, when I noticed the light was still really bright so I filmed it too.

here is the video:
http://www.youtube.com/watch?v=bt15wCEW6Hs


jeanna

(I don't like the lisp but my other camera won't turn on any more.)

[jeanna]

The Nicd which has been getting only spikes for recharging has reached a new level.
Twice this week, I left it on running a light overnight, and in the morning it was flashing then recovering then flashing again.
This is remarkable.
In the past this battery has slowly diminished until the light went out, and that was it.
Recovering by itself is another level of recovery to my mind.
I had to take the measurements fast, but what I saw was 0.203v which quickly recovered to 1.18v.
There are a couple of remarkable things about that.


The duracell is also doing really well. It goes for a long time too.
Basically, it is taking longer to run down these batteries than to charge them.

Here is how I know that.
I recharge one on the charging jt circuit while I discharge the other on the discharge jtc circuit.
The one is not finished discharging before the other is charged.

I have an idea on how to test this.
It is easy but it will take scheduling that might make it more difficult.
If I recharge one of the batteries for 6 hours, and switch, I should have a build-up of charge in the 2 batteries, since those same 6 hours will not at all drain it out.
Maybe I can do this.

Does anybody else want to try this?
It is better with the duracell than the nicad. It was immediately working with that duracell, and that puppy was gonzo.

Next, I need to get a 2 battery holder and see what happens with 2 in series.

jeanna.

[crowclaw]

Hi Jeanna,

just an update on my findings. I have been experimenting  with various charging techniques and am currently using a 555 timer. My joule thief circuit does work OK with varring results regarding charge times, however a 555 timer offers the advantage of a wider frequency spectrum and marks/space output. A PP3 nicad that I have on charge is currently charging from under 1 volt to over 10 volts within approx 30 mins. But I must emphasize after many hours of trials I have found that (A)  frequency is dead critical, (B) The mark/space ratio and rise time must be spot on. Now the only problem is, results vary widely with cell types. The frequency I'm using is 1.7kHz-2kHz for my set up. A 15 turn pott is used to " fine tune" to find the sweet spot giving the fastest charge rate, but when you can find it the charge moves rapidly. If you imagine a JT circuit without a feedback winding where the base is driven from a 555 timer and the output taken via a diode from the collector to battery + with negative of battery to positive of source... this is where I'm at. My battery is now at 10.06 volts. Will post more info when I get chance OK 

[jeanna]

Hi crowclaw,
That IS interesting.
1.2-1.5Khz is much slower than what I have been using.

So, I am saying this back to be sure I get what you are doing.
You are using a 555 timer in the place of the base resistor of a 'normal' jtc.
You are using the transistor C-E junction with a single diode at the collector connected to the positive of the battery you are charging... then the neg of that same battery gets connected to the positive of the source battery.

So, it means the battery you are charging does not go from the C to E of the transistor??
Is that right?

And where is the fine tuning pot?
Is it after the 555 at the base?

thank you,

jeanna

[crowclaw]

Hi crowclaw,
That IS interesting.
1.2-1.5Khz is much slower than what I have been using.

So, I am saying this back to be sure I get what you are doing.
You are using a 555 timer in the place of the base resistor of a 'normal' jtc.
You are using the transistor C-E junction with a single diode at the collector connected to the positive of the battery you are charging... then the neg of that same battery gets connected to the positive of the source battery.

So, it means the battery you are charging does not go from the C to E of the transistor??
Is that right?

And where is the fine tuning pot?
Is it after the 555 at the base?

thank you,

jeanna

Hi Jeanna,
Yes the battery being charged is effectively connected across the primary coil winding which is C to positive line of circuit... via a diode. The 555 timer circuit has two Potts, one to adjust the frequency range and the other to adjust the mark to space ratio of the output signal. The capacitor/resistor values (C/R) chosen set the frequency of the 555 timer (astable mode), using a pott allows the R element to adjust the frequency of course. If you set up a similar test circuit you may find a different frequency could work for you!! but it is as I mentioned very very critical to the charging time period. My PP3 9 volt Nicad cell ( normally 8.4 volts for Nicad's) was terminated at 10.07 volts. I have left a very low resistance across it to completely discharge it again so I can repeat this experiment. I am also going to charge 12 volt gel cell again using same set up, so I am interested to see if the results compare at the same frequency or perhaps some other value? we will see. BTW the source voltage = 8.4volts but I don't think this is critical as long as the spikes are being produced. The coil was reclaimed from scrap and has a laminated core and is quite substantial, I will repeat the experiment with my JT coil using only the primary winding. Just keeping notes for now but if the results look generally encouraging I will post circuit details etc later, but there's more I want to do yet... time permitting. Kind regards