Alexkor Air Core Coil Radiant Charger

[SkyWatcher]

Hi sean, thanks for reply.
You'd have to experiment with what thicker gauge would still oscillate, though do not think just one coil and transistor would do it for those large batteries.
A multistrand, multitransistor, meaning one transistor per strand, will probably be needed.
Don't know if air coil will still work in that setup, though with the capacitor to get it into oscillation, it probably will work.
A ferrite core should work well also.
I've tried rejuvenating a car battery once, though did not have a good multistrand, mulitransistor setup at the time, with good thickness copper (18-20awg.) to have much effect on it.
Hope that helps for now.
peace love light
tyson

[Tvrepair]

Capacitor

What is the purpose of the cap under the battery. What value is it ?
Thanks

[SeanK]

Cap under battery ?

Hi, please clarify if you're referring to the screen shot above.
If so, which cap, there is a lot of junk in the photo as I am trying lots of things.

sean

[Tvrepair]

Capacitor

Hi. The schematic shows a cap under the battery. I understand the rest of the schematic. Sorry if that is dense. Thanks

[SkyWatcher]

Hi folks, hi tvrepair, the only capacitor in the circuit, is the one in parallel with the transistor base resistor, mine is 100nf capacitor.
Under the battery is a switch.
peace love light
tyson

[Tvrepair]

Nice charger

Have replicated circuit and it works per your discription. Transistor gets hotter than I like but was using garden variety audio amp trans T0 2 case, used 100n cap at base for best results. Will get higher freq trans and a better heat sink The diode was Schottky barrier diode works well NTE 579. 9 volt alkaline charged from 7.2 to 9.2 over night no over heating or damage. Have not worked with charged battery yet. I like the circuit.

Thanks

[SeanK]

Well done Tvrepair. I am now charging 9 volt alkaline batteries which don't seem to get hot. However, I notice that one of them is bulging at the base, so probably I over charged it.
The NiMh batteries I charge (AA size) start to get warm as they fill up, I think they can safely go to around 40c.

sean

[Tvrepair]

New transistor

Changed trans to 2SC5387 not as fast as the one recommended by Kelly. I have gone as high as 800 K and does not heat as much .

[Tvrepair]

2sc3552

Received 2sc3552 today charger runs much cooler. The voltage is about 150 volts on a 12 volt battery being charged. Circuit powered by 12 v power supply. I am very impressed . Great little circuit

[SkyWatcher]

Hi folks, hi tvman, glad to hear it's working so well for you.
How are the charged batteries doing under load.
Still using my air coil charger almost everyday, best, cheapest charger i know of and recovers the batteries at the same time.
peace love light
tyson

[Tvrepair]

Charged batteries

The batteries seem to be as strong as new 9 volt alkaline . One ran a 60's circa radio for 6 hours no problem.

[SeanK]

Hi tyson, Tvrepair,
Great to see this working. It got me back to the circuit again.
Here's a recent observation:
the current draw (and heating up ) is related to teh charge battery and the cap being used.
So by changing caps you can get the circuit to run cool.
But if You use a different set of batteries, you have to retune.

I found with one configuration, I was pulling > 1 amp from the source and by changing the cap, got that down to 100ma. Ofcourse the output spike changes.

[Tvrepair]

Batteries

Yes I agree it seems to some how adjust to the voltage of the battery. The wave shape and frequency are effected by cap and resistor value. A 12 volt car battery has a 150 volt spike at about 125k hertz. I can post some scope shots if you like and I can figure out how.

[SeanK]

Hi Tvrepair,
would love to see your scope shots so I could compare.
I tried to charge 4 AA Alkaline batteries this morning, they got warm in about 20mins. Had to time to see what the SOC was.
The shape of the pulse would be nice to see and also the time between pulses on the scope.
Cheers
Sean

[otten]

Hi =)
I'm new in this very interesting forum.
Please help, and sorry for my english
Only this thread about "Alexkor" system here?
I have a some questions. In the PJK book, in chapter 7, we can see original scheme with one module (4 diodes). But there are another modified scheme see, where tree modules which contains 12 diodes summary, and one big capacitor C1 100uF 400v. If I put there 20 modules in parallel instead of 3, so what capacitor C1 must be there? 20 modules must give more power I think. Another moment with thyristor and neon tube. They will not die with 20 modules?
Thanks!