BroMikey's Capacitor Dump Circuit

[Farmhand]

OK with about 250 mH inductance in the coil and if I reduce the output caps to 15000 uF then I should get resonance at about 2.5 Hz.

So then I think I can switch at double that frequency to still almost double the voltage in the dump cap after switching.

And with the diode the voltage stays and no reversal so anything between 2 Hz and 5 or 6 Hz should work well with the charging circuit.

If so the 15,000 uF cap will end up with almost 50 volts on it. I'll try it out while I'm going, mosfets are only rated to 55 volts so I might lose it.

Ahh the joy. 
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[Farmhand]

I only got a little tiny voltage rise. I backed off the input to take care, with more input voltage and more current caused the coil will work more because it will get more current.
Yellow is the dump cap voltage and blue the supply caps.

[Farmhand]

I hear youse all, MileHigh, I already had one such setup dealing with solar input to a system that is often under what most charge controllers deal well with, it sensed the input voltage, the output cap dump voltage and the battery voltage when the mosfet was conducting with the same voltage divider that sensed the output dump cap voltage. It used a boost converter to boost the low input from the panels to 22 volts so as to apply some rejuvenating to the battery, and when the battery was charged it would go into float mode then kick back in when the batt voltage dropped. It is no use if the battery is badly sulfated though because it automatically goes into float mode if the voltage rises above 14.4 volts. I made it so it would float at 13.6 volts.

I'm only doing this for fun and to help BroMikey cast out the fallacies he hes been fed by "the crew" over there. One of the big problems is that the battery is drawing from the supply through his resistor, using a MOT primary I can dump 15 K uF in 40 mS and 350 mS between pulses to recharge the cap and get down to almost zero current flow, longer and the MOT primary starts to pass current directly from the supply to the battery, this is to be avoided.

The other way is to disconnect the  + rail of the supply from the dump section before dumping and I've already done that too.

Using a big low resistance coil and the right on time is simpler and less parts.

My coding is very basic self taught, I can only do so much without wasting too much time.

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Now if it was me I would be inclined to go down to a 4000 uF dump capacitor and increase the frequency.

[Farmhand]

SeaMonkey, Talking of driver capacitors, this board I made mainly for controlling relays and small motors ect. and for LF experiments for ease of power control. So I ran out of space for another capacitor on each driver chip so I might just use a 100 uF cap across all of them and I can fit a 10 uF cap across the two with PWM outputs. They all have a 100 nF across them. I've seen several combinations used but usually they all contain at least one ceramic cap. Why is that ?

I've got four mosfet switch outputs on the "B" output side of the 14M2 picaxe chip (two have pwm ability), on B.5 pin I use the analogue to digital converter to sense the variable voltage provided by a voltage divider which is a big 5 K pot, I use the pot to set the program into different "stages" manually which I can make to do whatever. On the input "C" side of the chip I have them set up to take inputs or be outputs to other boards.

I think I can have the board play a music tune when the battery is charged.  I wonder what funky tunes are available.
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[TinselKoala]

SeaMonkey, Talking of driver capacitors, this board I made mainly for controlling relays and small motors ect. and for LF experiments for ease of power control. So I ran out of space for another capacitor on each driver chip so I might just use a 100 uF cap across all of them and I can fit a 10 uF cap across the two with PWM outputs. They all have a 100 nF across them. I've seen several combinations used but usually they all contain at least one ceramic cap. Why is that ?

The small ceramic cap right at the chip is "AC bypass" that keeps the chip from responding to noise on the supply feed and helps to prevent false triggering. This is just about universal, especially if supply leads are long. Put the bypass cap as close as possible to the chip itself.

I've got four mosfet switch outputs on the "B" output side of the 14M2 picaxe chip (two have pwm ability), on B.5 pin I use the analogue to digital converter to sense the variable voltage provided by a voltage divider which is a big 5 K pot, I use the pot to set the program into different "stages" manually which I can make to do whatever. On the input "C" side of the chip I have them set up to take inputs or be outputs to other boards.

That is the same technique I use to control which subroutine is running in my NeoPixelRing demonstrator. I have eleven different independent program segments, each selectable by the 50 k 10-turn pot with turn-counting dial on the front panel. Select something between 100 and 200 on the knob for example and you get program segment 2, and while "2" is running I can even control a function by varying the pot within that range (one full turn of the 10-turn pot). Since the picaxe (or in my case Arduino Pro Mini) ADC input is sensing voltage and is a high impedance input, you can make the voltage divider pot just about any value, even 1 megohm. Making this voltage divider pot large will cut down on the overall current consumption. I use 50K because that's what I've got on hand.

I think I can have the board play a music tune when the battery is charged.  I wonder what funky tunes are available.

There are billions of bits of 8bit music out there. It takes a bit of fiddling to get accurate note values but sure, you can do that if you have the memory available once the "meat" of the program is in the chip. I don't know what is available for picaxe but for Arduino there are many many aftermarket "shields" that simply stack onto the main board, no soldering or wiring required, that will do all kinds of things. Music shields that incorporate microSD card slots are available that will play high-resolution music or any audio file you can put on an SD card.