Solid State Bedini

[dambit]

Hi Jetijs thanks for the report and sharing man, if those batteries hold charge you have done it, some time they don't and they appear to be charged and the spikes ruins them, but i think you already know this . Just keep this in mind when using these experimental chargers, our spikes ruined nearly ruined our battery once.

Are you going to run any load tests at the c20 charge rate on them?
Ow and yup would love to know what your doing, i can compare to ours to see if it will do any damage

Hi Ash,

Could you please elaborate a bit more on how the spikes nearly killed your battery?

Cheers,

Steve.

P.S. Jetijs, great pic and setup.

[Jetijs]

Are you going to run any load tests at the c20 charge rate on them?

Hi Ash,
yes I am going to use my computer controlled battery tester to load the battery with a constant current. But after the first charge I will disassemble the coil and remove the welding rod core to get rid of the heat problem. Then I will continue the load tests.

Hi Jetijs
Wich wire gauge have you used ? It seems that there's three paralleled diodes at the collectors, is it for higher currents handling ?
Michel

Hi Michael
I used AWG21 wire for the strands of this coil, but for more current I guess you would need thicker wires.

Nice build Jetijs. I'm also curious to know if you've done any load testing to see if you get more bang for your buck with this configuration.

I'm sure you've noticed that the oscillations are faster without iron in your coil. I've done load testing with both core configurations and it seems there is very little difference in charging between the two. I think even the amp draw was similar--right around 400 mA. My SS is the cap dump version with 555 timer, trifilar coil 22 ga with each strand 100 ft.

Hi Shamus,
No load tests so far, I started charging up the 200Ah battery just yesterday evening. Now the battery has gone up from 7.50V to 12.30V and still keeps climbing. I guess I will let it climb to about 13.5-14V to cold-boil some sulfate away, then let the battery settle and only then do the loading.
Higher frequency at the same current consumption would be great, it is an additional motive for me to switch to air core.
I noticed that now that the battery has gained some voltage, the current draw has increased a little bit - from 2.3A at start to 2.8A now. The transistors are still cool, but the coil core is hot.
Thanks

[theremart]

Hi Ash,
yes I am going to use my computer controlled battery tester to load the battery with a constant current. But after the first charge I will disassemble the coil and remove the welding rod core to get rid of the heat problem. Then I will continue the load tests.

I have been testing my coil empty and I found it does not charge as well as with something in the core with my setup. Jetijs, you might consider removing the tape on the outside of the coil, this would allow the coil to release its heat better. you may also consider just using a few welding rods instead of filling it. I am finding that one can about tune the frequency of the charge by changing the core.

Just some thoughts, I hope your design works, because this is just what I am looking for my golf cart batteries.

[Jetijs]

I have been testing my coil empty and I found it does not charge as well as with something in the core with my setup. Jetijs, you might consider removing the tape on the outside of the coil, this would allow the coil to release its heat better. you may also consider just using a few welding rods instead of filling it. I am finding that one can about tune the frequency of the charge by changing the core.

Just some thoughts, I hope your design works, because this is just what I am looking for my golf cart batteries.

Hi Mart
I already removed the tape from the coil. I also attached another fan to cool the coil better. Hope it will survive the first charge. Then I will change the core to a plastic tube. This will allow me to experiment with different core materials.
Thanks.

[ashtweth]

Hi Ash,

Could you please elaborate a bit more on how the spikes nearly killed your battery?

Cheers,

Steve.

P.S. Jetijs, great pic and setup.

Hi dambit, it was our fault, We were using a 7aH battery and experimenting with a solid state charger that Clive built a while ago, he wanted us that he didn't think it was suitable for a 7Ah battery , i think from memory he was using a 35 ah one. The battery now wont get any higher then 12.8V for a charge. Still get some run time out of it but the point is if you don't know what wave form to get from these , and battery you could do some damage.

Ash

[Hoppy]

Hi dambit, it was our fault, We were using a 7aH battery and experimenting with a solid state charger that Clive built a while ago, he wanted us that he didn't think it was suitable for a 7Ah battery , i think from memory he was using a 35 ah one. The battery now wont get any higher then 12.8V for a charge. Still get some run time out of it but the point is if you don't know what wave form to get from these , and battery you could do some damage.

Ash

Hi Ash

John Bedini has always stressed that its important not to over current charge with high voltage spikes as this will 'smash' the battery in time. A 7A/Hr gel battery is fine on a small wheel charger like the ones specified for learning but not on a powerful rotor or SS energiser.

If the final battery voltage can be monitored so that the charger cuts-off when the terminal voltage reaches say 15V then even small batteries should be OK on big chargers if they are well conditioned to start with. Otherwise, if they are not conditioned, pumping high current into them will just push up the terminal voltage fast and cut-off the charger. Battery conditioning needs to be a staged process starting gently until the internal resistance drops to allow an increasing charge current. A variable voltage supply to the energiser helps to regulate the charging current with solid state chargers.

I have learnt not to allow my batteries (once conditioned) to be regularly charged to a high terminal voltage when using Bedini charging methods. This is only needed occasionally to equalise the cell voltages. My normal fully charged float voltage is within the battery manufacturers specification at around 13.8V. The final terminal voltage for my golf cart type batteries is limited to 15.3V.

Clive

[theremart]

Re: shutoff voltage.

Hi Ash

John Bedini has always stressed that its important not to over current charge with high voltage spikes as this will 'smash' the battery in time. A 7A/Hr gel battery is fine on a small wheel charger like the ones specified for learning but not on a powerful rotor or SS energiser.

I have learnt not to allow my batteries (once conditioned) to be regularly charged to a high terminal voltage when using Bedini charging methods. This is only needed occasionally to equalise the cell voltages. My normal fully charged float voltage is within the battery manufacturers specification at around 13.8V. The final terminal voltage for my golf cart type batteries is limited to 15.3V.

Clive

Interesting Clive, my manufactured cut off voltage is

"Following discharge, constant current charge the CR-225 battery at 25 amperes until the battery voltage measures 2.42
volts per cell (7.26 volts open circuit voltage)."

So for 2 batteries it would be 14.52. Interesting your cut off voltages is 15.3, I have found that for me to get the most out of my 12 amp hour batteries I have to raise the cut off voltage to 16V.

It is so nice to be able to talk with someone else who have Golf cart batteries Thanks for sharing Clive.

[theremart]

Double take on Jetijs setup.

Hi,




Thanks,
Jetijs

I have looked hard at your circuit agian, and I noticed

1. You are using multiple resistors..... I have not seen this done before.

2. Multiple diodes, which I have seen.

3. No solder connections but using the screw connectors, inovative.

5. Looks like you are using brass solder right on the diode comming out of the transistor to charging battery?

Looking forward to your load test.

[Jetijs]

Hi Mart
1. I use multiple resistors because one resistor (2w) at the needed resistance gets very hot. Multiple higher resistance resistors in parallel gives me the same low resistance, but they can handle the heat with ease. The overall resistance of this resistor array is about 50 Ohms.
2. I could use also just one diode per transistor, this should work just fine since there is almost no current in the inductuve spike, but just to be sure I am using three 1n4007 diodes in parallel.
3. It is hard to solder a connection to a 2n3055 transistor collector (case), because to do so you need to heat up almost the whole transistor and this can damage it, that is why I am using small bolts to attach the connections to the case. Also in an event of transistor death, it is now much more easy to change the bad transistor out.
4. Yes, those are brass press-on connectors that I am using to connect the diodes with the transistor case, for better holding the diodes are also soldered together with the brass connector.

Today the voltage has climbed up to 12.55V (from 12.25v yesterday evening). I have noticed that lead acid batteries are charging up fast from anywhere below 10v to about 12v, then the charhing gets slower till the voltage reaches about 12.6-12.7V, after that the voltage starts to go up faster

Today I will make an air core coil and replace the current one. Also I have another 4 strand coil form a SSG that I will also use on this charger connecting the outputs of both coils together. This should increase the amp draw to about 4.5-5A and the big 200Ah battery should charge up faster

[Hoppy]

Interesting Clive, my manufactured cut off voltage is

"Following discharge, constant current charge the CR-225 battery at 25 amperes until the battery voltage measures 2.42
volts per cell (7.26 volts open circuit voltage)."

So for 2 batteries it would be 14.52. Interesting your cut off voltages is 15.3, I have found that for me to get the most out of my 12 amp hour batteries I have to raise the cut off voltage to 16V.

It is so nice to be able to talk with someone else who have Golf cart batteries Thanks for sharing Clive.

Mart

My fully charged cell voltage is 2.58V.

More capacity can be got from a battery by taking the charge voltage higher than the manufacturers specification which is a 'safe' limit. This should not be necessary using the Bedini charging method because long term conditioning should automatically increase the battery capacity over conventional DC charging methods by lowering internal resistance. My understanding is that John Bedini takes his golf cart type batteries up to 15.3V. I have found that pushing a battery to a higher final charge voltage increases the surface charge, so that a little more capacity can be gained even with a unconditioned battery. I would say that once a battery rests at 13V or above about 4hrs after disconnection from the energiser on a regular basis, it can be considered to be reasonably well conditioned. I have found that the better conditioned a battery is, the higher the resting voltage will be.

Clive

[dambit]

Hi Jetijs,

I have modified my circuit to be solid state similar to yours and it works very well. My coil is a little bigger and I have five transistors, but that is the only difference. I have attached a pic of the circuit. All I had to do was remove the diode between the emitter and base. My trigger resitance had to be increased to about 600 ohms for the circuit to be at it's most efficient, but it still passes the one ohm test.

I am using this to charge two 135 Ah batteries in a 24V bank. Seems to be working quite well.

Cheers,

Steve.

P.S. The neons are well used!!

[Jetijs]

Hi Steve,
A nice setup you got there. I am glad that it works well for you. Thank you for sharing.
What is your coil specs? And how much current does all the circuit draw?

Here is the circuit I am using:

[mrbreau]

Transistor Socket

Hi Mart
(snip)
3. It is hard to solder a connection to a 2n3055 transistor collector (case), because to do so you need to heat up almost the whole transistor and this can damage it, that is why I am using small bolts to attach the connections to the case. Also in an event of transistor death, it is now much more easy to change the bad transistor out.
(snip)

Hello Jetijs? Are you aware that there is a socket for TO-3 transistors? For very little money it is a lot easier, for me, to change out a transistor if it fails since there is NO soldering TO the transistor.

Here are a couple pictures of one setup I use for the Bedini. I think, repeat think, that I got these for less than a dollar each. I'd like to note how much EASIER it is to connect the transistor to whatever combination of components you want. BTW, I have since added a pot to this circuit. These are easily replaceable modules I've come up with for multiple coils. It is so much easier and quicker for me to makeup and redo the systems I'm building.

You can fine the part # (4667) here; http://www.keyelco.com/pdfs/M55p103.pdf
AND, they are $1.77 per.

I hope this helps you some.

Warren
..

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"When a man's knowledge is not in order; the more of it he has, and the greater will be his confusion." Herbert Spencer

[dambit]

Hi Steve,
A nice setup you got there. I am glad that it works well for you. Thank you for sharing.
What is your coil specs? And how much current does all the circuit draw?

Here is the circuit I am using:

Hi Jetijs,

My coil is spool is just over 4" long with a 3 1/2" flange. The core is 3/4" in diameter. Not sure how many turns as I just told my coil guy to fill it, but it has five power winds (23 SWG) and a trigger (25 SWG). It is one of four coils for this enegizer.

I have tuned the circuit to draw 1.15 amps. This seems to be the best area to be in for charging larger batteries. So far. As I know of no exact proceedure for tuning a circuit I have got it to within a ballpark and then set it to what "feels" ok. Sounds odd, but that's how I've done it.

My scematic is the same as yours except I am running off 24V and have 100 ohm resistors on each base along with the 600 ohm main resistor. (which at the moment is a 1K 5W pot)

Cheers,

Steve.

[dambit]

Hi Guys,

Just posting some pics of my new solid state charger I built today. It's designed to charge dry cell batteries. You know, AA, AAA, C, 9V, etc. The input is a 12V power adapter I had spare and the coil is a single bifilar with approximately 350 turns.

I have yet to do some propper testing with it, but I put a 9V battery in it tonight which was down to 8V and in ten minutes it was charged. Three hours later it is still sitting at 9V. Early signs are good. I think it will simply be a matter of working out how long each type of battery takes, or just monitoring them as they go.

Jaycar had run out of AA cradles and panel volt meters, so I will add them when I can. I think I will also add a small amp meter for the input so that I can tell its running. I would add a light but sometimes the coil does not self oscillate when I switch it on, so that would be no good. Thats the problem with the solid state machines, there is no visual cues that it's on, and the frequency of this is so high that I have trouble hearing the coil.

Cheers,

Steve.