Got my Keypower 250 watt ATX PS.

LESLIEx317537 · 01-30-2002, 01:28 PM

It arrived, my carputers done.

I'll have pics soon. Made a custom suspension mount (Plexicase).

How do I hook it up? There are 3 inputs.
(G)(-)(+)
Isn't the Ground and (-) the same thing? Can I just hook + to the car batt and - to a nice solid ground screw in my trunk?

Thanks.

gizmomkr · 02-04-2002, 04:53 PM

Yeah, you can short the - and the G together and run the + to your battery

LESLIEx317537 · 02-04-2002, 05:58 PM

Thanks!

My friend said that ground and (-) are two different things, I didn't believe him.

PatO · 02-04-2002, 08:24 PM

They might be the same....
When the thing is running, I put a multimeter on the ground and the (+) and measured 12v...

Either way, without ground connected, there was ABSOLUTELY NO ENGINE NOISE in the signal! It was a cleaner signal than my home stereo! Quite impressed, to say the least.

PaulzY · 02-05-2002, 12:27 AM

Quote:

Originally posted by gizmomkr:
<STRONG>Yeah, you can short the - and the G together and run the + to your battery</STRONG>

so what you dont need to ground dc-dc power supply's ?

or do you ground one and short it with the other aswell

gizmomkr · 02-05-2002, 05:16 PM

You technically dont need to hook the ground terminal to anything.

you need to hook the + terminal of the PSU to the + terminal of the car batt, and the - terminal of the PSU to the - side of the car Batt or the ground of the car.

I *recomend* hooking the ground of the PSU to the body of the car, but its not reauired.

lifeboat · 02-09-2002, 05:56 PM

WHY are there seperate - and G connections? I have + and - connected to battery, not using the G at the moment and it seems ok so far.

lifeboat · 02-10-2002, 03:13 PM

[ 02-10-2002: Message edited by: Lifeboat ]

gizmomkr · 02-11-2002, 10:08 PM

The manufacturer built the supply that way.

I put a meter on it when I first bought one, and I seem to recall the G block on the keypower supply connects to the case ground of the PSU, but this is NOT the same as the black wire coming out of the PSU (DC out to Mother board / Hard drive)

I guess they designed it that way incase you had a true need for a ground....

SuperAJ · 02-12-2002, 10:42 AM

Okily Dokily, I setup my Keypower DC-DC PSU and figured out the connectors... My car electrician expert guy helped a bunch too.

You need to run a wire from your battery's (+) positive and (-) negative. That's what you'll attatch to the (+) and (-) on the PSU.

Then you'll need to attatch the (G) ground connector to the frame of your car... meaning a screw, nut or other bolts most attached to the metal fram likely found under the cars carpet. (These things are all over the place so it shouldn't be too hard finding one)

I assumed the (G) and (-) were the same, but from what I understood the psu needs a direct run to the (-) negative of the battery, AND a ground to avoid any surges (and or explosions

) When I tried it the first time assuming that, the PSU sparked and sent tiny fireworks into my trunk.

It's been working for me this way ever since i got the unit. Plus I don't think anyone with a $170 dc-dc psu would want to risk blowing the unit, or even worse damaging the computer components.

Hope it helpes,
SuperAJ

LESLIEx317537 · 02-12-2002, 10:58 AM

So now I gotta go out and buy some 8 awg black wire to run next to my (+) wire to my batt.?

Do I need to fuse the (-) run from the batt?

Are you sure this isn't redundant? You're saying my PS can catch on fire or blow up if I just ground the (-) in the trunk?

CALIBOY · 02-12-2002, 11:20 AM

LW...it sounds redundant to me.

The battery is grounded to the Chassis of the car and if you connect (g) and (-) to the chassis of the car you are essentially grounding these wires. I see no need to run a wire to the battery for ground. And no you wouldn't need to fuse the ground wire from the battery to the PSU (if you decided to wire it this way...which as I said before doesn't make much sense.)

jboy · 02-12-2002, 03:25 PM

These are industrial power supplies's originally made for use in equipment that has +dc or/and -dc as well as a chassi/AC ground with +24vdc and +48vdc being much more common than +12vdc in automation and telecom systems. The ground (G) would be tied to "earth" ground for AC protection, and may help reduce the hum from a car electrical system

AC: ~HOT ~NEUTRAL ~GROUND (neutral & ground may be the same)

DC: Vpos Vneg "Grounding" is not always to negative, some old cars have a positive ground

LESLIEx317537 · 02-12-2002, 04:19 PM

Before I buy all this cable.
Im going outside to my trunk and seeing if the chassis in connected to my (-) terminal on my batt.
I'll use my handy multimeter.
I want to hook it up without the (-) cable. Like a stereo amp.

jboy · 02-12-2002, 07:23 PM

Quote:

I want to hook it up without the (-) cable. Like a stereo amp.

You don't need to run a neg wire from the battery to the trunk, but you may want to run a heavy wire from the neg batt to a good part the body of the car, Most cars have a heavy wire from the batt- to the engine block and a thin wire from the batt- to the body, the block and body may not have a good connection . ( the metal around the strut/shock towers is usually good, thick metal w/ lots of welds to the rest of the body , but watch where you drill and be sure to clean down to bare metal under the terminal, use some dielectric grease or that red goop you can get at an auto parts store to stop battery terminal corrosion to protect the bare metal) do the same in the trunk for your neg amp/PS connections and run your pos wire as planed. you may want to run another heavy wire from the alternator pos output/charge ( if you can get to or find it) to the pos batt terminal to get the most out of your alternator.