power supply for a hydrogen fuel cell basically

hp1729

Joined Nov 23, 2015
2,304
That's sort of true but mostly for low voltage power supplies where a less than half a volt ripple at 120 Hz accounts for more than 5 - 10% of the working voltage.

At 160 volts that same .5 volt ripple would be tiny and the 100,000 uF 200 volt capacitor bank to make it so a rather spendy unit to build thus going by percentage of ripple to system nominal working voltage allows for a much lower capacitance to be used.

By my estimates a 10,000 uF bank would be more than sufficient for an unregulated 100 amp capable electrolysis system like the OP wants to build.
Sounds better than my thumb rule. 10,000 uF, even if it is more than one capacitor.
40,000 to 60,000 has also been suggested, so there is his range; 10,000 to 60,000, whatever he can find.
 

tcmtech

Joined Nov 4, 2013
2,867
If it was to be for supplying a fairly low ripple and stable DC power for a power supply that could jump from near 0 to near 100 amps and back in very short bursts or such while also feeding electronic loads that need the voltage to stay stable then I would push for the 40 - 60K uF but for an electrolysis only ripple is not much of an issue.
 

Thread Starter

chaz0144

Joined Mar 18, 2016
8
Okay I will play. I love these vague I don't know what I am doing or talking about but I need high power to do it threads anyways. :D

120 VAC rectified and ran through a capacitor will give you around 160 VDC after losses and ripple are factored in.
Now given your 100 amp capacity rectifier I would assume it has a pretty high peak current rating so rectifying 120 VAC @ 100 amps RMS likely won't kill it due to excessively high peaks.

Anyway for a 100 amps @ 160 VDC I would recommend a 40,000 - 60,000 uF capacitor bank but being electrolysis is not that fussy about ripple you could cut that down to 10K or less.

As for voltage and current control either you will have to go to a solid-state phase angle controlled regulator system or a huge assed variac transformer or more practically an old fashioned magnetic amplifier regulator system like what was used in arc welder power supply before modern solid state control came into being or run a large bank of motor run type AC capacitors in series with your live line to limit the current by simple capacitive impedance. That would be the simplest and cheapest method to go with.

That ought to keep you busy reading about wht I have underlined online for a while.



He probably has the same style I have (grey tank on a nearby pole or big green box in the yard) that isolates him from his main utilities 7200 volt system.


Despite how some will squeal there is nothing illegal about running a high current load off of one leg of your homes 120/240 power system if it was built to work as a true 200 amp system.

The general rule of thumb for system loading would be not to go much over 80% of your system capacity for continuous duty application which in your case would give you 160 amps on a single 120 volt leg provided you used properly sized fuses or circuit breakers.

Personally, if I was you I would be looking at finding a big old constant voltage ( MIG/wire feed type) type welding power supply.
Okay I will play. I love these vague I don't know what I am doing or talking about but I need high power to do it threads anyways. :D

120 VAC rectified and ran through a capacitor will give you around 160 VDC after losses and ripple are factored in.
Now given your 100 amp capacity rectifier I would assume it has a pretty high peak current rating so rectifying 120 VAC @ 100 amps RMS likely won't kill it due to excessively high peaks.

Anyway for a 100 amps @ 160 VDC I would recommend a 40,000 - 60,000 uF capacitor bank but being electrolysis is not that fussy about ripple you could cut that down to 10K or less.

As for voltage and current control either you will have to go to a solid-state phase angle controlled regulator system or a huge assed variac transformer or more practically an old fashioned magnetic amplifier regulator system like what was used in arc welder power supply before modern solid state control came into being or run a large bank of motor run type AC capacitors in series with your live line to limit the current by simple capacitive impedance. That would be the simplest and cheapest method to go with.

That ought to keep you busy reading about wht I have underlined online for a while.



He probably has the same style I have (grey tank on a nearby pole or big green box in the yard) that isolates him from his main utilities 7200 volt system.


Despite how some will squeal there is nothing illegal about running a high current load off of one leg of your homes 120/240 power system if it was built to work as a true 200 amp system.

The general rule of thumb for system loading would be not to go much over 80% of your system capacity for continuous duty application which in your case would give you 160 amps on a single 120 volt leg provided you used properly sized fuses or circuit breakers.

Personally, if I was you I would be looking at finding a big old constant voltage ( MIG/wire feed type) type welding power supply.
Okay I will play. I love these vague I don't know what I am doing or talking about but I need high power to do it threads anyways. :D

120 VAC rectified and ran through a capacitor will give you around 160 VDC after losses and ripple are factored in.
Now given your 100 amp capacity rectifier I would assume it has a pretty high peak current rating so rectifying 120 VAC @ 100 amps RMS likely won't kill it due to excessively high peaks.

Anyway for a 100 amps @ 160 VDC I would recommend a 40,000 - 60,000 uF capacitor bank but being electrolysis is not that fussy about ripple you could cut that down to 10K or less.

As for voltage and current control either you will have to go to a solid-state phase angle controlled regulator system or a huge assed variac transformer or more practically an old fashioned magnetic amplifier regulator system like what was used in arc welder power supply before modern solid state control came into being or run a large bank of motor run type AC capacitors in series with your live line to limit the current by simple capacitive impedance. That would be the simplest and cheapest method to go with.

That ought to keep you busy reading about wht I have underlined online for a while.



He probably has the same style I have (grey tank on a nearby pole or big green box in the yard) that isolates him from his main utilities 7200 volt system.


Despite how some will squeal there is nothing illegal about running a high current load off of one leg of your homes 120/240 power system if it was built to work as a true 200 amp system.

The general rule of thumb for system loading would be not to go much over 80% of your system capacity for continuous duty application which in your case would give you 160 amps on a single 120 volt leg provided you used properly sized fuses or circuit breakers.

Personally, if I was you I would be looking at finding a big old constant voltage ( MIG/wire feed type) type welding power supply.
Yea I thought about this but for a continuous duty mig is either expensive or hard to find a cheep one but once I can run my test on scaled up version I'll know my amperage that I will need to stay constant but thanks for the help your tag will be helpful
 

tcmtech

Joined Nov 4, 2013
2,867
Yea I thought about this but for a continuous duty mig is either expensive or hard to find a cheep one but once I can run my test on scaled up version I'll know my amperage that I will need to stay constant but thanks for the help your tag will be helpful
I guess it depends on what you consider cheap or expensive and where you are looking. I picked up a pair of Miller 600 amp continuous duty rated welding power supplies years ago for about $100 each figuring I would scrap them for the copper being they were the old design that had a single huge three phase transformer and a magnetic amplifier type voltage regulation system.

Joke was on me being although they looked like they were all copper wound transformers and inductors everything in them was copper clad aluminum which as far as scrap value goes is worse than dirt so to this day they are sitting up in the bushes behind my shop. :(:mad:

My point is if you do some looking around at scrap yards and industrial equipment auctions you can still pick up these old high powered monsters for cheap.
 

tcmtech

Joined Nov 4, 2013
2,867
Where is the 160 Kw coming from? o_O

My math says 120 VAC rectified and filtered at 100 amps would be about 16 KW.

And yes for me 16+ Kw @ any number of voltages, line level or otherwise, is a common thing for me to play/work/experiment with. :cool:

As for highly flammable gases liquid and solids. Heck that's a day in and day out thing around here.

Isn't it for everyone? o_O
 

tcmtech

Joined Nov 4, 2013
2,867
Well you have to factor in that for many of the people on electronics sites they are primarily dealing with the low voltage and power end of electronics and not the high power end that people like myself have worked with in industrial applications.

For many of them a 24 VDC circuit or one that uses a good 10 amps is high power electronics to them and utility AC power is off the charts.

For me a Junkyard magnet crane power and control system that works at 250 - 300 VDC and 50 - 100 amps and is all solid state circuit control is just getting to the level of being interesting DC power to work with. As for home 120/240 VAC 200 amp service work to me that's about the equivalent for them as working with a dual rail 12 volt power supply! :p
 

ronv

Joined Nov 12, 2008
3,770
Well you have to factor in that for many of the people on electronics sites they are primarily dealing with the low voltage and power end of electronics and not the high power end that people like myself have worked with in industrial applications.

For many of them a 24 VDC circuit or one that uses a good 10 amps is high power electronics to them and utility AC power is off the charts.

For me a Junkyard magnet crane power and control system that works at 250 - 300 VDC and 50 - 100 amps and is all solid state circuit control is just getting to the level of being interesting DC power to work with. As for home 120/240 VAC 200 amp service work to me that's about the equivalent for them as working with a dual rail 12 volt power supply! :p
Maybe you should give him a link for his capacitor so we can see what you have in mind.
 
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Kermit2

Joined Feb 5, 2010
4,162
Well I'm gonna capture lightning in a bottle.

Anyone know someone selling a Leyden jar about the size of Guam?

I'll be selling the electricity at shockingly low prices.
 
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