Solid State Bedini

[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

Michel

Perhaps a better method than just limiting the current and one I use to effect is to bond a 60 or 70 degree C thermal fuse to the TVS diode with super glue and connect the thermal fuse in series with the master transistor base trigger circuit . When the thermal fuse open circuits the charger will shut down to prevent the transistors from getting damaged by an open circuit output.

Hoppy

[theremart]

RE: Resistor setup.

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.

Ok, tonight I finished my 10 transistor setup with Jetijs design. With a 200 ohm base resistance it is pulling 2 amps with a 12V as primary. Everything is cool to touch, the waveform is 70V h wave spikes on all transistors attached to the battery. The charge is much deeper, as I am seeing a higher resting voltage than I have seen before in my batteries. I am excited about this setup!

BTW Jetijs, there is a new version of the West Mountain Battery software, version 2.0 that has some new features, that I was told about. Looks well worth the download. FYI

[Jetijs]

Hi all
I noticed that if I leave the battery on the charger for longer time, the battery increases the capacity much more. The battery does warm up, but nevertheless I had the most increase in capacity after long charging times. Maybe that cold/hot boiling takes care of the sulfate better. See for yourself:



I let the battery on the charger over night, that is about 12 hours of charging. The battery was warm and you could hear it boiling. I let it rest for a hour and then started the discharge.
Thanks

[selamatg]

@ Jetijs,

Thanks for your sharing the circuit... I will replicate very soon but I'm still not quite sure how to determine the base resistor value (as your experiment)?

Also, I ever hear that someone talking discharge load the battery using Resistor, if anyone know how to do that please advice and how to calculate the resistor value to the Amp draw as we need?

thanks in advance,
Selamatg

[dambit]

Hi,

As far as I know there is no real calculation, just a guestimation. I now think the base resistor is simply there to make sure that there is some resistance to the base, because I can get the circuits working fine without base resistors. I'm probably wrong but that's what I think.

Cheers

[Jetijs]

Selamatg,
I would take one 500 or so Ohm 2w resistor as a base resistor at first and see what the amp draw is. If it is too low, then take another resistor of the same value and connect it in parallel with the first one. This will lower the resistance twice, but increase the heat handling properties. Make the amp draw lower and lower till you get about 0.5-0.7 A durrent draw per transistor. That means that if you have 3 transistors in the circuit, the optimum amp draw would be 1.5-2A.
Hope this helps.
Thanks,
Jetijs

[Shamus]

@selamatg: For a resistor discharge you want to take the C20 rate of the battery and multiply by 0.8 (80% of the discharge rate). Then divide that number by 20 to get the amount of amps the battery can safely discharge at that rate. Then, use Ohm's law to determine the value of the resistor you need: R = V/I where R is the resistance in ohms, V is typically 12 volts, and I is the amps you calculated above.

So, the formula would be R = V / ((Ah * 0.8) / 20) or R = 25 * V / Ah where Ah is the amp hour rating of the battery. I've heard that for CCA and MCA ratings that you have to divide those by 20 to get the amp hour rating, but I'm not sure where that 20 comes from.

Also: Make sure that watt rating of your resistor can handle the discharge! 1/4 watt resistors won't cut it.

[selamatg]

@selamatg: For a resistor discharge you want to take the C20 rate of the battery and multiply by 0.8 (80% of the discharge rate). Then divide that number by 20 to get the amount of amps the battery can safely discharge at that rate. Then, use Ohm's law to determine the value of the resistor you need: R = V/I where R is the resistance in ohms, V is typically 12 volts, and I is the amps you calculated above.

So, the formula would be R = V / ((Ah * 0.8) / 20) or R = 25 * V / Ah where Ah is the amp hour rating of the battery. I've heard that for CCA and MCA ratings that you have to divide those by 20 to get the amp hour rating, but I'm not sure where that 20 comes from.

Also: Make sure that watt rating of your resistor can handle the discharge! 1/4 watt resistors won't cut it.

@Shamus..

Thanks you....
So if I have 60AH battery should use 5 Ohm Resistor and 2.5 Ohm for 120 AH battery?

Thanks in advance

Selamatg

[selamatg]

Selamatg,
I would take one 500 or so Ohm 2w resistor as a base resistor at first and see what the amp draw is. If it is too low, then take another resistor of the same value and connect it in parallel with the first one. This will lower the resistance twice, but increase the heat handling properties. Make the amp draw lower and lower till you get about 0.5-0.7 A durrent draw per transistor. That means that if you have 3 transistors in the circuit, the optimum amp draw would be 1.5-2A.
Hope this helps.
Thanks,
Jetijs

Thank you Jetijs...

I will try later soon and see what I can get.....


Selamatg

[Shamus]

@Selamatg: If those are 12V batteries, then that is correct. Just make sure those are high watt resistors!

[Jetijs]

Battery is up to 14Ah now and keeps improving.
Interesting, if I put an iron bar in one of the coils, it gets hot rather fast. After a minute it is already so hot, that I can't hold it in my hands
The power of induction

[theremart]

More testing with jetijs circuit.

Today I tried the circuit at 5 amps. The transistors got very too warm for me after 10 hours so I switched back to 20V at 2 1/2 amps that is running great all is cool and the golf cart batteries are going up in charge.

I measured the amps going to the charge battery when I had the 5 amps going in at 12V it was over 2 amps going to the charging batteries. The golf carts did not even get warm. They are tough batteries

I will attempt to do a charge comparison of previous charges with the multi coil Bedini verses this, but from what I can see this one has the other beat hands down.

Yet, to be fair, I did remove bad places in the coils I had, and this circuit is in much betters shape.

[dambit]

Hi All,

I feel so stupid. I found out why my circuit wasn't working....... my power supply was shot. I didn't even think to check it. Oh well.

I recieved my new coils today and have set one of them up with my existing coil. They are drawing 3.4A @ 15V. The coils are only slightly warm, the charge rate is very good and I am now able to charge some of my larger batteries that I couldn't before. I can't wait to add the third coil (and circuits) to the mix.

The scope was set at 5V per devision and .5ms time intervals.

[dambit]

Hi Guys,

Sorry to double post, but I took an interesting photo of the wave on the scope. I have essentially zoomed in on the spike of the wave. I set the time interval to 0.5 Us and kept the volts the same. In one of the pictures I have superimposed the two so you can see they match.

It's amazing what you see when you zoom in on things.

Cheers,

Steve.

[theremart]

Video of my replication of Jetijs circuit

I am very happy to see both of my golf cart batteries now up to 13.90 V ! with the Solid State setup. I have not ever seen this high of voltage with my 4 multi coiler setup with the same amount of voltage.

http://www.youtube.com/watch?v=XixT5KCM27Y

Things are looking very good with 20 V 2 1/2 amp input.