Alternating capacitor discharge circuit

[Farmhand]

Being a complete electronics noob, I drew this very rough diagram and intend try this to see if it works, I figured I may as well post it and ask if it will work.

It is designed on a single cap pulser that I know works, which was posted by
a person on this forum I can't remember how to spell his name I think Inquorate (found it) i've been looking to find a post so I could get it right.
Anyway if it's already been done I haven't seen it.

So will this work ? Hope the pics are viewable network scanner is down.

The idea is to allow the solar panel to work in it's peak power range, without interuption to it's output, and pulse charge a battery.

Any help appreciated. Even if to tell me i'm wasting my time.

Andrew.

[sucahyo]

I don't get it. Have you build it yet?

can you tell by what means relay 1,2 and 3 will be powered and thus activated?

[Farmhand]

No I haven't built it, but I will soon. The operating principal is outlined in the second attachment, well that is how I would hope it to work weather or not it does is another matter.

The power from the solar panel would go through the relay coil to the discharge cap opening the contact to prevent flow to the battery and when the cap is charged the flow of energy slows and the relay contacts close to disharge the cap. While one is discharging the other charging. Relay one coil is in the path to C2 so while C2 is charging the path to C3 is broken. Relay one contact and normally closed pin complete the path to C3, which should be a path of lesser resistance.

I think I see a flaw that as C3 is charging the resistance would be rising I imagine.

The solar panel i'm looking at says max power voltage 18 volts, doesen't that mean it can deliver it's maximum power at that voltage.

So i'm looking for a way to keep the output voltage as close to 18 volts as possible without too much interruption to it's output.

I actually have another question.

Is goal worth the effort ?

I'm not very good at drawing or explaining but I try. And I will persist until I am satisfied one way or the other .

Maybe someone can think of a better way to achieve what I want to do but I wont know if I don't ask.

Cheers sucahyo

[SeaMonkey]

Is goal worth the effort ?

I'm not very good at drawing or explaining but I try. And I will persist until I am satisfied one way or the other .

Maybe someone can think of a better way to achieve what I want to do but I wont know if I don't ask.

Cheers sucahyo

Yes, effort expended towards realizing a goal
is nearly always worthwhile.

Would it be possible to better "define" what
the goal is:

You are wanting to take the output from a Solar
Panel (18 Volts) to capacitors which are alternately
charged from the panel, then discharged into the
battery?

Do you plan to increase the panel voltage by doubling
it before discharging the capacitors into the battery?

Would you prefer to do the above with semiconductors
rather than mechanical relays?

[Farmhand]

Hello SeaMonkey,

To answer your last questions first yes ,yes to charge two in parallel then switch to series for discharge maybe and yes.

Basically what you asked here is what I want to achieve yes.-

You are wanting to take the output from a Solar
Panel (18 Volts) to capacitors which are alternately
charged from the panel, then discharged into the
battery?

Is that an achievable goal worth the effort do you think. As in do you think it could work with good effect with Mosfets or some such thing?

Thanks and cheers.

[Farmhand]

Do mosfets pop like this IGBT did to me.

http://public.bay.livefilestore.com/...GBT.JPG?psid=1

It was part of a cap discharger. I think I pushed it too hard it was rated to 1200v . GP30B120kd-e I think was written on the piece that went flying.

I have a couple of IRF PG50's amongst other goodies.

I know it would be a lot of trouble to go to but I was going to try making the relays maybe using auto ignition points for contacts with large coils with thick wire I don't even know if it would work but I could always use them for something else fun.

[sucahyo]

No I haven't built it, but I will soon. The operating principal is outlined in the second attachment, well that is how I would hope it to work weather or not it does is another matter.

When there is power on the solar panel, would relay 1 will turned on right away? I don't see power difference high enough to turn on relay 1, 2 or 3?

[SeaMonkey]

Do mosfets pop like this IGBT did to me.

http://public.bay.livefilestore.com/...GBT.JPG?psid=1

It was part of a cap discharger. I think I pushed it too hard it was rated to 1200v . GP30B120kd-e I think was written on the piece that went flying.

I have a couple of IRF PG50's amongst other goodies.

I know it would be a lot of trouble to go to but I was going to try making the relays maybe using auto ignition points for contacts with large coils with thick wire I don't even know if it would work but I could always use them for something else fun.

The IGBT was developed for high voltage/high
current applications where its increased conductivity
makes it superior to the MosFet. It is difficult to make
a MosFet for high voltage use that has a low "ON"
resistance; but that is an easy task for the IGBT.

For low voltage/very high current the MosFet reigns
supreme; it would be the best choice for this project.

As a matter of fact, this very project has already been
developed by several forum members already. Perhaps
they'll join the discussion once they become aware of the
topic.

It is possible to implement a capacitive discharge circuit
using relays; but it is very difficult to obtain reliable
operation and long life when using mechanical contacts.

Your best option by far is with MosFets.

Whenever an IGBT or a MosFet "self-destruct"
explosively it is nearly always due to very heavy current
flow with insufficient Gate Drive to put it into its fully
"ON" or saturated state. Unless those devices are driven
fully "ON" they'll run very hot and have short lives.

[EgmQC]

The IGBT was developed for high voltage/high
current applications where its increased conductivity
makes it superior to the MosFet. It is difficult to make
a MosFet for high voltage use that has a low "ON"
resistance; but that is an easy task for the IGBT.

For low voltage/very high current the MosFet reigns
supreme; it would be the best choice for this project.

As a matter of fact, this very project has already been
developed by several forum members already. Perhaps
they'll join the discussion once they become aware of the
topic.

It is possible to implement a capacitive discharge circuit
using relays; but it is very difficult to obtain reliable
operation and long life when using mechanical contacts.

Your best option by far is with MosFets.

Whenever an IGBT or a MosFet "self-destruct"
explosively it is nearly always due to very heavy current
flow with insufficient Gate Drive to put it into its fully
"ON" or saturated state. Unless those devices are driven
fully "ON" they'll run very hot and have short lives.

Usually people destroy mosfet really fast not because of a over current but because the gate get too much voltage, there a maximum gate voltage, mosfet unlike transistor are voltage controlled and a great care should be taken to the gate voltage and good isolation to avoid static when you touch it. Always read the datasheet for the maximum value at the gate and you will rarely blow one , they are relatively tough about intermittent over current .

Best Regards,
EgmQC

[Farmhand]

Hi SeaMonkey

As a matter of fact, this very project has already been
developed by several forum members already. Perhaps
they'll join the discussion once they become aware of the
topic.

OH, can't say i'm surprised, there is so much to read and with all the technical jargon I can hardly tell what is being said. It must be more complicated than I think. Is there a drawing I can use to make one for myself ?

Can you direct me to the thread ? I don't really need series switching or anything fancy. Though the more efficient the better. If there is nothing simple in the thread I am probably better off without it.

sucahyo

When there is power on the solar panel, would relay 1 will turned on right away? I don't see power difference high enough to turn on relay 1, 2 or 3?

It would depend on a few factors I guess if it did I would have to solve that problem. You don't need to connect positive and negative to a relay coil to make it work. The coil can be in series with a load. I think is how to explain it.

EgmQC Thanks, I did touch it to feel for heat.

Cheers all

[Farmhand]

SeaMonkey, is there any particular document or information source you would personally recommend for me to begin to educate myself about Mosfets ?

I think now is as good a time as any to start.

Ta.

[SeaMonkey]

SeaMonkey, is there any particular document or information source you would personally recommend for me to begin to educate myself about Mosfets ?

I think now is as good a time as any to start.

Ta.

HERE is a link to a short tutorial.

The page contains additional links for more data.

There are others which can be found by using your favorite
search engine: "mosfet tutorial"

Some of the links will be to .pdf documents by the various
semiconductor manufacturers which are especially good.

[Farmhand]

Thank you very much for that SeaMonkey. Thats good info, I already have several new idea's after reading that one page. I read datasheets all the time, I was looking at the IRFPG50 datasheet when I noticed something familiar, the Unclamped Inductive Waveform.

IRFPG50 datasheet pdf datenblatt - International Rectifier - Power MOSFET(Vdss=1000V, Rds(on)=2.0ohm, Id=6.1A) ::: ALLDATASHEET :::

Seems similar to this-

http://public.bay.livefilestore.com/...a-2.JPG?psid=1

[sucahyo]

You don't need to connect positive and negative to a relay coil to make it work. The coil can be in series with a load. I think is how to explain it.

You use 6V (18V-12V) relay then?

[Farmhand]

Hi sucahyo, Thanks for your interest. I have actually taken a slightly different approach for now relays is still an option maybe, and I did some crude testing with an SCR and some caps today, in the rain. Results were promising. I am uploading a video very shortly.

I will post a link when done.