DC-DC step-up converter

sasha · 26th February 2004, 02:22 AM

Hi all,
I am planing to make DC-DC step-up converter. 12V-15V input and
20V-24V output. Current needs to be regulated up to 20A on output.
It will be used for hydrogen generator.
If You have useful schematic or suggestions please post it here.
Thanks!

Sch3mat1c · 26th February 2004, 03:19 AM

If it's doing it by electrolysis, why not just use approx. half as many cells, using wider plates (to carry more current)?

Tim

sasha · 26th February 2004, 04:49 AM

The cell resistance is greatly dependent on electrolyte temperature, and to have constant flow of hydrogen the current need to be constant and voltage variable. That is why higher voltage is a must. The power source is 12V car battery.
Regards.

haldor · 26th February 2004, 12:58 PM

In that case it would be alot cheaper and simpler to just use two car batteries.

sasha · 26th February 2004, 02:37 PM

Unfortunately two battery trick can't help because of changing resistance of the cell. Voltage needed for operating cell is ranging from
7V to 18V depending of electrolyte temp. and to have constant flow of hydrogen current needs to be constant.
Regards.

Sch3mat1c · 26th February 2004, 04:20 PM

Why constant?

haldor · 28th February 2004, 03:39 AM

Quote:

Originally posted by sasha
Unfortunately two battery trick can't help because of changing resistance of the cell. Voltage needed for operating cell is ranging from
7V to 18V depending of electrolyte temp. and to have constant flow of hydrogen current needs to be constant.
Regards.

How much current do you need?

Use two batteries and make a constant current source out of a power transistor, a diode and a couple of resistors.

Here is a set of links to get you started.
http://www.discovercircuits.com/C/constant.htm

Phil

sasha · 28th February 2004, 05:20 AM

Hi guys,
Thanks for link, Haldor. I think I will find something useful on the site.
Have my eye on buck convertor and with some mods should be able to output 20A. Regarding suggestion for linear power supply,
two problems: 1. input voltage is limited to 12V (hydrogen gen. is installed on the truck) and 2. power dissipation is huge (24V in, 7V out
@ 20A = 340W

)
Regards.

li_gangyi · 28th February 2004, 07:43 AM

woah wada u want a truck hydrogen gen for?? Could be dangerous u know...20A for a boost converter is also not gonna be easy...super thick cables...super explosive shorts...might wanna go slow here...

sasha · 29th February 2004, 03:16 AM

Dangerous, Yes but I am building only power supply. Somebody else have truck with HG. And I think they now what they doing

.

26th February 2004, 02:22 AM	#1
sasha diyAudio Member Join Date: Aug 2002 Location: Canada	DC-DC step-up converter Hi all, I am planing to make DC-DC step-up converter. 12V-15V input and 20V-24V output. Current needs to be regulated up to 20A on output. It will be used for hydrogen generator. If You have useful schematic or suggestions please post it here. Thanks!

26th February 2004, 03:19 AM	#2
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	If it's doing it by electrolysis, why not just use approx. half as many cells, using wider plates (to carry more current)? Tim __________________ See my Electronics webpage -- the home of Vacuum Tube Drag Racing. The key to being a successful Audiophile: "I reject your reality and substitute my own!"

26th February 2004, 04:20 PM	#6
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	Why constant? __________________ See my Electronics webpage -- the home of Vacuum Tube Drag Racing. The key to being a successful Audiophile: "I reject your reality and substitute my own!"

28th February 2004, 07:43 AM	#9
li_gangyi diyAudio Member Join Date: Jun 2003 Location: Woodlands Circle	woah wada u want a truck hydrogen gen for?? Could be dangerous u know...20A for a boost converter is also not gonna be easy...super thick cables...super explosive shorts...might wanna go slow here... __________________ Kids in the back seat cause accidents...Accidents in the back seat cause kids...

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26th February 2004, 04:49 AM	#3
sasha diyAudio Member Join Date: Aug 2002 Location: Canada	The cell resistance is greatly dependent on electrolyte temperature, and to have constant flow of hydrogen the current need to be constant and voltage variable. That is why higher voltage is a must. The power source is 12V car battery. Regards.

26th February 2004, 12:58 PM	#4
haldor diyAudio Member Join Date: Aug 2001 Location: Columbus, Ohio	In that case it would be alot cheaper and simpler to just use two car batteries.

26th February 2004, 02:37 PM	#5
sasha diyAudio Member Join Date: Aug 2002 Location: Canada	Unfortunately two battery trick can't help because of changing resistance of the cell. Voltage needed for operating cell is ranging from 7V to 18V depending of electrolyte temp. and to have constant flow of hydrogen current needs to be constant. Regards.

28th February 2004, 05:20 AM	#8
sasha diyAudio Member Join Date: Aug 2002 Location: Canada	Hi guys, Thanks for link, Haldor. I think I will find something useful on the site. Have my eye on buck convertor and with some mods should be able to output 20A. Regarding suggestion for linear power supply, two problems: 1. input voltage is limited to 12V (hydrogen gen. is installed on the truck) and 2. power dissipation is huge (24V in, 7V out @ 20A = 340W ) Regards.

29th February 2004, 03:16 AM	#10
sasha diyAudio Member Join Date: Aug 2002 Location: Canada	Dangerous, Yes but I am building only power supply. Somebody else have truck with HG. And I think they now what they doing .

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