Solar Charging/Pulsing Circuit and Variants

[shubhamforme]

charging my aa 1.2v nimh batteries with cap pulsing

hi,, i am trying to pulse charge my aa batteries 1.2v with a joule thief circuit which puts out 135 v,,,i want the cap dump at 15 volts every time. so i am using a 15 volt zener with a in4007 diode..
i have few question for you,,,
1.is it necessary to use a In5408 diode always...can we use others like 1n4148 or in4007

2.can we use any volt zener diode ,,,as in 15 v,36v,90v?? if my cap is charging up to 135 volts then can i use any zener diode below 100v??

3.also is there any way of attaching an led to the scr so that it blinks every time it discharges the capacitor???

4, can i use an triac also ???

5.are there any type of calculations for which i need to put the zener diode in the scr?? as in if the capacitor reaches a vlotage reading upto 130volts then only a zener diode upto 30volts will work or maybe a larger value zener will also work???

6.is there some power loss when we pulse charge the batteries with an scr????

link for the circuit--

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.. i am using this circuit ...but i dont think its working properly...


waiting for your expert comments...

thanks
shubham

[shubhamforme]

hi,, i am trying to pulse charge my aa batteries 1.2v with a joule thief circuit which puts out 135 v,,,i want the cap dump at 15 volts every time... i am using this circuit ...but i dont think its working properly....any suggestions

[Farmhand]

.

I mean the effect happen not because of solar behaviour but because of capacitor behaviour. It is possible that we can get same results even with other power source too.


You want to stop charging after it hit spesific voltage? The problem is some battery will hike its voltage for the first minutes and then going down later. Just like slow spike.

Don't be surprised with 19V. I hit 25V a couple of times . Just let it cook for an hour and see if its come down to 12V. If it goes higher, then consider it unrecoverable.

Yeah I think it should be testable with a regulated suplly like through one of your 1n3055 regulators, I been playing with them they are pretty neat, I made a 1n2955 PNP one too. It can regulate right down to a few milliamprere's.

The problem with the bike is it doesn't stop charging, it will boil the battery at 21 volts all day long if I let it, I'm trying to fix the wiring now, the original stuff. It's a two phase AC setup, it pumps out 22 volts or so from two AC outputs from the alternator.

I'm going to scope it and see if it was wired wrong, maybe get a new regulator.


Cheers

Yay fixed it finally. Quadbike is now charging to 14.4 volts with it's original hardware no need for any bodgy relays. I just dissasembled some 4 pin connectors and scoped the AC outputs then put it back together and Hey Presto fixed.

[kcarring]

Side note: Sorry

I need more batteries more than anything.

Have you checked into edsworkshop? I have an evolving experiment with DIY Nife, and mine are getting better now. Not spectacular but i will say for what is worth they are indestructable.

[sucahyo]

.

Sucahyo, the caps are all good one's.

I mean the effect happen not because of solar behaviour but because of capacitor behaviour. It is possible that we can get same results even with other power source too.

Sucahyo, I have to put together a charge controller for the " Farm " Quadbike it's charging the battery up to 19 volts. Very quickly. It's dried out a 12 aH gell cell, which I rehydrated and desufated back to very good condition, when I connected it back into the bike I measured the voltage of the battery to make sure the bike was charging it up, and wow, 19v I have no hope of actually fixing the bikes original componants, so I was thinking I could just make a relay charge controller that works like my battery swapper.

You want to stop charging after it hit spesific voltage? The problem is some battery will hike its voltage for the first minutes and then going down later. Just like slow spike.

Don't be surprised with 19V. I hit 25V a couple of times . Just let it cook for an hour and see if its come down to 12V. If it goes higher, then consider it unrecoverable.

[Farmhand]

Hi guys, No luck with the Mosfet. I can get it to turn on but not properly and it wont turn off. Looks like the SCR is still the best way.

Sucahyo, the caps are all good one's. And you are right of course haha at the moment I have more power than storage seems like, I don't use much power thats why I like batteries, and battery chargers. I'm getting an average of 1 out of four junk batteries are very good 1 is not good but usable and 2 are no good. I need more batteries more than anything.

Sucahyo, I have to put together a charge controller for the " Farm " Quadbike it's charging the battery up to 19 volts. Very quickly. It's dried out a 12 aH gell cell, which I rehydrated and desufated back to very good condition, when I connected it back into the bike I measured the voltage of the battery to make sure the bike was charging it up, and wow, 19v I have no hope of actually fixing the bikes original componants, so I was thinking I could just make a relay charge controller that works like my battery swapper.

What do you think ? Would that be the best way ? I can't think of a better way but there might be one, funny that i should be needing to use a relay like this right now. Last year I wouldn't have known how to do it.

With any luck i'll have a win and it will work, it's about time something works for me.

Cheers

[sucahyo]

It's difficult to know what is the right thing to do, the capacitors charge very quickly for the first few volts but as the voltage of the caps gets closer to the open circuit voltage of the panels it seems to slow down, current is reduced in all ways i tried but to differing degree's.

The capacitor faults?

I measured 11Ma initial currrent to the paralelled caps 10Ma to the series connected caps. Not much difference but the paralelled caps got to a higher voltage aswell, the more caps in paralell the less resistance or impedance allows the panels to achieve a higher voltage in low light. How I measured it in low light the difference was only .2 of a volt or something but with more panels and caps in low light and good light the difference will be there still.

As the panel gets hotter its internal resistance gets higher and availiable current gets less. I've measured my panels at over 70 degree's celcius, the ouput and the open circuit voltage go's down when they get that hot.

I see. thanks .

I'm starting to think there is no real need to switch the caps from paralell to series anyway. With enough capacitance I should be able to dump enough joules from 5 or 6 volts above the battery to cause good charging.

Lol, I guess your current state now is too much sun to make the effort worth it .

[FRC]

Thanks Farmhand

Thanks for the effort Farmhand, no hurry.

FRC

[Farmhand]

Hi all, after all the stressing out I did last night I realised I did a silly mistake and had the diode's in the wrong place. I'll give it another shot tonight.

[Farmhand]

Farmhand when you use a zener diode as a voltage limiter, what, generally speaking, happens to the current. Do you always have to add a resistor in series with the diode? Thanks

Well that depends on some things but in this case the current charges the cap and mosfet gate capacitance and then gets drained by the resistor to ground 0v, but in the SCR setup i'm using all the time the current go's through the SCR gate some is disapated as heat, I should do something about it. Like put an LED or resistor in there. Good thinking.

With a mosfet the gate has a very high resistance and so the current will prefer to go through even a high value resistor to ground rather than the gate it can be like that because it is the field effect that triggers it not actually current like a regular transistor or SCR needs I think.

Video is almost uploaded, 3rd time lucky. Link soon.

Cheers

Here's a vid YouTube - Solar pulser 25.wmv

Well i've set up a 24 volt supply limited to 30 Ma and the mosfet isn't working.
So i'm going to try some things with an SCR see what happens.

[kcarring]

Farmhand when you use a zener diode as a voltage limiter, what, generally speaking, happens to the current. Do you always have to add a resistor in series with the diode? Thanks

[Farmhand]

Umm I can't fit a 1N5408 into my solderless board without damaging it so I will use a 1n4007 instead 0.56 volts drop across mine. I found some 5.1 volt zeners so i'll try one of those too and some other values also, and if it works i'll try it with a normal mosfet just to see what happens, for sure. I've found a range of little caps aswell. My intuition tells me I should be able to at least make the mosfet switch on. Everything after that is a bonus.

Yes I see about that drawing you linked, I want to try the LED on the gate of the SCR thing I might even solder one into my board on the one I use for a tryout.

Cheers

[FRC]

Koggs circuit

Its a charging circuit. But it involves charging to caps then dumping to battery.
Part of what we want.

FRC

[Farmhand]

I can only half understand what the drawing of kogs does, looks alright though.

I'll post a new drawing in few minutes, i'll edit it here in this post.

Here it is, The 6A10 diode has been moved to between the panel and the capacitors. And I changed some things around to how I will try it.

I'll use 5.6 volt zener a 1N5408 diode and an IRL3705N is the mosfets I have.

I'll use a 5k pot a 0.01uf cap is all have I think, maybe I can find a 0.1 one if I look hard enough and a 100 ohm fixed resistor between the zener and fet gate.

It might work, i'll find out.

Cheers

[FRC]

Thanks Farmhand

FRC i'll try my darndest to get that mosfet dump setup together tonight on a solderless board so I can try it tommorow.

Great, would be much simpler than the one I just posted from BFW thread.

FRC