Solid State Bedini

[theremart]

RE: your circuit

Mart, no problems Glad to hear that it works good for you. My aircored coils also do not start by themselves at 12v, I have to put a ferrite rod in the coil and then tap this rod with a magnet to get it started. Now I am conditioning a dead sulfated battery that has its plates in tact, so far it works very well and each discharge cycle gets more and more amp hours out of the battery. But I noticed, that if I leave this charger on a battery for too long, after it is already full, the battery does get warm, but I have not noticed any ill effects from this heat. After that overcharge, I still got more out of the battery than in previous discharge.
Thanks,
Jetijs

Hmm I just tested it now it works at 12V... oh well... Does it work better for you with empty cores? I just switched to 2 100 meg in parallel and it is now drawing 800 ma. very nice charging, I hooked up a scope and I am getting over 100V spikes of 'h' waves with the battery connected. I did VERY VERY well, I got each of these transistors for $2.00 and they are doing great!.

I am wondering it seems we are wasting a lot of energy on the resistor I wonder if we could something else with that ... hmmm

[Jetijs]

Mart, I used the air cored coils just because the welding rod cores would heat up to 60 degree celsius over time, I think that this is because of the eddycurrents. Anyway, air cored coils operate at higher frequency and the amp draw is greater, but so is also the charging rate. I can get the amp draw less if I insert a core material in the coil, but that makes the frequency smaller and the core material starts to heat up.

[theremart]

RE: core..

Mart, I used the air cored coils just because the welding rod cores would heat up to 60 degree celsius over time, I think that this is because of the eddycurrents. Anyway, air cored coils operate at higher frequency and the amp draw is greater, but so is also the charging rate. I can get the amp draw less if I insert a core material in the coil, but that makes the frequency smaller and the core material starts to heat up.

None of my cores are hot nor are my coils, but I am up to 200 ohms on my resistor. I just emptied one of my coils of the ferrite beads the amps shot up from 300 milla amp to 600 milla amps, however the charge shot right up too. I can change the charge rate by the number of circular ferrious beads I put in. Very sweet. everything is cool to the touch now drawing 600 milla amps. Perfect for my 13 amp hour batteries.

[Jetijs]

I think that your cores are not heating up, because your amp draw is so low. You can't heat anything with that. My coils together are consuming 5.5A and that is enough to heat the core due to the eddy currents. Its like a induction heater. The greater the amps flowing through the windings, the more heat you get.

[dambit]

5.5 A. Wow, how many transisters are you running? Mine draws 1.7 with five transisters.
This setup does work very well, but I am still unable to get mine to start again, so I will build a second one to see if it is the transisters that have gone. Very odd as I did nothing to burn them out. Working perfect one minute, I unplug it, plug it pack up and now it doesn't work.

Cheers.

Steve

[theremart]

RE: cores....

Yes you are right, big difference of amperage. I am starting off small with the low amp hour batteries, then hope to work up in amperage as you have.

As I look at your setup, you have 2 sets of 5 transistors so you have two trigger coils?

I am thinking of taking one of my full spools of bifilar 20 gauge wire and cutting it in half so I can fire more transistors. Looking at your setup, that should work just fine for me.

[theremart]

RE: problems.

5.5 A. Wow, how many transisters are you running? Mine draws 1.7 with five transisters.
This setup does work very well, but I am still unable to get mine to start again, so I will build a second one to see if it is the transisters that have gone. Very odd as I did nothing to burn them out. Working perfect one minute, I unplug it, plug it pack up and now it doesn't work.

Cheers.

Steve

I had a short in my coil that did that to me. I have seen that with marginally bad transistors... I have also seen this that you have to unhook either positive or negative from primary then hook it up alone, if I plug it in it does not work, I am guessing.... that the transistor is going into solid state mode and it does not function unless the coil is away from the magnet when you start... just an idea...

Those cold soldered connections also can do you in... sigh...

[Jetijs]

I use two coils. One coil has five strands and one of those strands is used as a trigger wire. With one coil I could get the circuit to consume about 3.5A, but for my 200Ah batteries I needed more power, so I just made another circuit from another coil and just made them work in parallel. That means that both coils are powered from the same power source, but all the output diode cathodes are connected together and then go to the Charging battery positive wire. Now I am using 7 transistors, but the second coil still has two unused strands, so I can go bigger. If I use those remaining strands I could get the circuit to consume about 7A
That would be great for conditioning several big batteries at once.

5.5 A. Wow, how many transisters are you running? Mine draws 1.7 with five transisters.

Steve, you can get the circuit to consume more amps by decreasing the base resistor value, but this will also make the resistor heat up more so be sure to use a high wattage resistor. I chose the resistor value so that they are getting hot, but not too hot to touch. This makes each of the transistors to let about 0.7A through, so if you have 7 transistors in parallel, that gives you a current draw of about 5A

BTW, there are no neon protection bulbs in my circuit, you might add those across each transistor collector and emitter, just to be safe
Hope this helps.

[Jetijs]

Hi all.
I found a dead battery with all the plates in tact. This is a 60Ah Panasonic lead acid car battery from my toyota yaris. It was dead last year and was sitting all the winter outside. Here is a discharge cycle chart:



It keeps getting better and better

[dambit]

Hi Jetijs,

Is the bottom scale the time scale, as in how long it was discharging for? Just asking cos it's labled amphrs.

Cheers,

P.S. Still not sure whats going on with my circuit, so I'm just going to build a new one as I can still find nothing wrong. Too hard basket.

[dambit]

This makes each of the transistors to let about 0.7A through, so if you have 7 transistors in parallel, that gives you a current draw of about 5A

Hi again,

Are you still getting a good spike when you have this much conventional current on the output. I chose to set mine to draw 1.7A because I still got a good spike at that level of draw (and I can't draw any more without changing the base resistors to less than 100ohms.) Now that I am rebuilding it, I will use much lower values for the base resistors so that I can draw more and see what happens.

Cheers,

Steve.

[theremart]

Not quite understanding..

I use two coils. One coil has five strands and one of those strands is used as a trigger wire. With one coil I could get the circuit to consume about 3.5A, but for my 200Ah batteries I needed more power, so I just made another circuit from another coil and just made them work in parallel. That means that both coils are powered from the same power source, but all the output diode cathodes are connected together and then go to the Charging battery positive wire. Now I am using 7 transistors, but the second coil still has two unused strands, so I can go bigger. If I use those remaining strands I could get the circuit to consume about 7A
That would be great for conditioning several big batteries at once.

Do you have all of the base resistors tied together? I noted in earlier pictures that you have 2 sets of resistors.... Not sure on the latest one where you are using 25W how you are setting up the base resistors.

thanks

[dambit]

Hi All,

Well, I think the problem is my coil. Even though none of the strands have shorted it is the only remaining part I have not replaced. I built an entirely new five transistor circuit identical to the specs of my last one, soldered the coil wires to it and still nothing. I find it unlikely that all ten of these transitors are buggered. Especially the new ones. Not to worry, I have three new coils arriving within the week so I will soon find out.

Cheers,

Steve.

[Jetijs]

Hi Jetijs,

Is the bottom scale the time scale, as in how long it was discharging for? Just asking cos it's labled amphrs.

Are you still getting a good spike when you have this much conventional current on the output. I chose to set mine to draw 1.7A because I still got a good spike at that level of draw (and I can't draw any more without changing the base resistors to less than 100ohms.) Now that I am rebuilding it, I will use much lower values for the base resistors so that I can draw more and see what happens.

Cheers,

The bottom scale show amp hours and is also showing how long the test went. The longer, the better.

The spikes seem just as any spikes from Bedini circuits, so no problems there.

Do you have all of the base resistors tied together? I noted in earlier pictures that you have 2 sets of resistors.... Not sure on the latest one where you are using 25W how you are setting up the base resistors.

Mart, I have two coil circuits in parallel. There are two tesistor sets, one for one coil and other for the second coil. All the base resistors are tied together to get the needed resistance and to reduce the heating.

[Druide]

Hi Michel

The emitters should all be connected to ground and preferably through the very low value resistors to share current more evenly.

The output stage is correct and conforms to the basic Bedini SG configuration, that is output to charging battery positive. The TVS diode if correctly rated to have a 'strike' voltage above the highest possible charging battery voltage plus drive voltage will not short the supply battery or PSU. For example if the nominal voltage of the secondary (charge) battery is 24V, it should not go any higher than 31V (2 x 15.5V) when fully charged. If the supply (primary) battery is 12V, it should not rise above 15,5V. The total voltage of the batteries in series is therefore 46.5V. The TVS diode should be a few volts above this and I would give a good margin and go for a diode between 60V and 80V.

Remember that this diode is fitted to switch very fast in the event of the output becoming open circuit and preventing a damaging high voltage across the transistors. A low value power resistor can be placed in series with TVS diode to limit the fault current and resultant heat build up in the TVS diode.

Hoppy

Hi Clive

Thank you for these precisions. Wich resistance and wattage values would you suggest for the fault current limiting resistor ? Should this resistor be inserted between the drive negative and TVS or between charge positive and TVS ?

Thanks !

Michel