Queston conerning stinger 200 amp relay

vash · 05-25-2004, 12:50 AM

http://www.darvex.com/miva/merchant....roduct_Count=1

First question incase nobody feals like readin this whole post. How much currect in amps would a computer with the following specs draw. I am wondering this so I know if a 200 amp relay will even do the trick

Via Epia M-10000 w/256 megs ram
Opus 150 watt DC-DC
7" liliput screen
IBM 40 gig laptop hard drive
Panasonic slim slot loading CD/DVD drive
USB wireless ethernet
USB IR device

Ok I have done searches on tank circuits for a while and noticed a few things.

1. Diodes produce a voltage drop
2. Diodes restrict the speed that voltage from one source moves to another source so that you dont damage the battery or whatever the other source is I assume, and the drop in voltage is probably due to heat disipation, im not sure

3. Relays do not produce a voltage drop, so you are able to get the battery fully charged which is what the computer and components will need to operate correctly.

I see that relays usually are shown in amps, I have seen 80 amp and 200 amp relays

If I am not mistaken though a relay is something that opens up and then current begins to transfer as quickly as the resistance in the wire and components will let it.

So if I wanted to run my computer off a backup battery that got its charge through a relay that would work ok if the backup battery never got dead assume, now if the backup battery where to go dead from the computer because it didnt shut off or something, then i went to start my car, the relay would open and try to charge my near dead battery right, which could cause fires and who know what else(a little exageration here but its not good to throw that much juice that quickly into a dead battery). So what im wondering is what in the world you could safely use a relay like this one for:

http://www.darvex.com/miva/merchant....roduct_Count=1

What would I have to do so that the second Battery gets fully charged without having to use a dangerous relay. Also using the relay between my main battery and the backup battery would be no different than using a jumper cable right?

Superduck · 05-25-2004, 01:18 AM

Two things.
One, that rating is the maximum amperage that can flow through the relay. It's not saying that it automatically flows 200 amps through whatever is connected to it.

Two, no electrical (aside from the actual starter) will draw anything close to 200 amps. That's huge. You could run ~2800 watts of amplifiers before you'd hit the 200 amp mark. My alternator only puts out 100 amps max. I don't think anyone even makes a 200 amp alternator from the factory. Some car audio specialists (Stinger, of course) produce high amp alternators, ranging from 135 to 270.

I don't think you need to worry about blowing that relay. I think it might be a bit of overkill for just your computer. An Opus 150W should draw a little over 10 amps. Even using a 400 Watt AC/DC inverter, it'll only draw about 30 amps.

Cheers,

Kris

wizardPC · 05-25-2004, 10:15 AM

I am using that exact relay to charge my second battery in my trunk. I have had it for almost 6 months with no problems, and I have totally drained the second battery twice.

I had professionals install it and the second battery, since I had a bit of bad luck trying to do this to my truck a few years ago.