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sparkey

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Joined: 15/06/2011
Location: Australia
Posts: 819

Posted: 03:13pm 11 Jul 2011

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so i got out my 800 coppermine eb p3 and loaded a pci modem and a sata raid card
windows xp service pack three lg dvd ripper 40 gig sata 7200 spinner 256 meg of ram
running only a 100 watt powersupply that i found in the junk box ...but i am going to be running a 486 dx4 or amd 133 soon with my own power supply comming from my battery bank ..it only requires 12v/5v pos and the same in neg ative rails so along with thast i have my maxi tapped at 12volts with a 9volt zenner hooked up to a 2n3055 and a 200mafuse in line with a 12 volt zenner if the voltage reaches to high ...any way got to keep ones self busy ..no rest for the wicked...laters for now.....

technicians do it with least resistance

RossW
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Joined: 25/02/2006
Location: Australia
Posts: 495

Posted: 08:45pm 11 Jul 2011

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sparkey said so i got out my 800 coppermine eb p3 and loaded a pci modem and a sata raid card
windows xp service pack three lg dvd ripper 40 gig sata 7200 spinner 256 meg of ram
running only a 100 watt powersupply that i found in the junk box ...but i am going to be running a 486 dx4 or amd 133 soon with my own power supply comming from my battery bank ..it only requires 12v/5v pos and the same in neg ative rails so along with thast i have my maxi tapped at 12volts with a 9volt zenner hooked up to a 2n3055 and a 200mafuse in line with a 12 volt zenner if the voltage reaches to high ...any way got to keep ones self busy ..no rest for the wicked...laters for now.....

Wow, thats a heck of a lot of work for such a small return.
I'm not certain that such a "simple" series regulator will be very efficient - the bulk of the current is on the 5A rail, so you'll be throwing away something like 70% of your input power as heat.

Did you consider something like this: http://tinyurl.com/6l68aly
For $25, delivered, a proper switchmode ATX supply *designed* to run in a car?Edited by RossW 2011-07-13

sparkey

Senior Member

Joined: 15/06/2011
Location: Australia
Posts: 819

Posted: 09:33pm 11 Jul 2011

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i have 6 times 225 ah trogens so its easy to just take tappings ..i run a 36 volt system regards sparkey

technicians do it with least resistance

RossW
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Joined: 25/02/2006
Location: Australia
Posts: 495

Posted: 10:01pm 11 Jul 2011

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sparkey said i have 6 times 225 ah trogens so its easy to just take tappings ..i run a 36 volt system regards sparkey

Err... not a great idea either!

I run 48V, made with 72, 2V cells (3 strings), so taps would be really easy. Problem is, you end up working some cells harder and your string gets out of balance, then it's all downhill.

Even if your board only takes 50W (and it likely takes more) off the 5V rail, thats 10A. Sure, you could tap at one 6V cell, but thats 10A more *THAT* cell has to supply compared to any other. If you only discharge to 10%, you can run your computer for about 2 hours, as long as *NOTHING ELSE* is running off your batteries at the same time. You see where I'm going with this?

Conversely, with a SMPS, (and some of them will happily run up to 30V, so you could run off the 24V tap, others will run off 10-60V, so would happily run off your whole 36V bank) - that same 50W is only 1.4 amps - and is spread evenly across all your cells. (1.4A would run for over 15 hours to a 10% DoD)

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