Would This Setup Survice Crank?

**pr3d** · 03-06-2005, 05:38 PM

Hi, i'm kinda new to this, and searched around, got most of my power flow mapped out using other topics and thread, but just had last couple questions and doubts, i made a map of the power source and supply, its pretty simple to comprehend, the diode between the 2 batteries is still just an idea, most likely i'll break the circuit wired to the ignition so it'll break that circuit when i crank, the battery i've acquired from a APC battery backup UPS, its 12v, and thought it would fit this setup. I just would like to know if this setup would work, and also
-what dc to dc supply do i need and does mp3car.com carry it?i'm sure i wouldnt need the opus since i already have a backup battery keeping the carpc alive.

-Thanks, this forum has really been a lot of help already, just need a final touch to complete this setup on paper and join the rest happy with pc's in their car!

**Bugbyte** · 03-06-2005, 05:44 PM

I think this one will work. Depends on your power draw.

http://www.mp3car.com/store/product_...products_id=67

I'm not a tank circuit expert, so I'll leave it to them, although this looks similar to other circuits I've seen on the boards. I think you need a "Schotkey" diode, which can handle a lot of power. If you haven't already, search on terms like "tank circuit diagram" and so forth.

**pr3d** · 03-06-2005, 06:10 PM

yea i forgot to mention the power draws, heres what i want running so far off the powersupply, and the motherboard:

-One (1) Maxtor 80GB 7200RPM Hard Drive
-4 USB Connections
-GPS
-Touch Screen (liliput 7")
-Wireless 802.11 G USB reciever
-Removable Thumb Drive
-3 Small Fans for cooling the CPU(1 of which for HD)

-MAYBE a cd reader-writer, but i want this to work first, and the optical drive isnt a priority.

**WebDog** · 03-06-2005, 06:12 PM

i have the M1-ATX runing with out a tank and it always survives crank. (sorry about spelling killer headache)

**pr3d** · 03-06-2005, 06:34 PM

ok the M1-ATX does seem like it fits this setup, but adding that backup battery, would that help? like would the backup battery allow me to put more load on the M1-ATX, obviously the battery will be set to match the higher watts being consumed by the power draws, also does the M1-ATX have like a safety, like even if its got a lot power supply, like this tank circuit, would the M1-ATX ONLY give 90 watts, or is it capable of giving out more, if supplied with more..? thanks.!

and also does someone have a detailed pic of the M1-ATX, i jus wanna see what the terminals looks like on the supplied power source on the M1-ATX, thanks.

**Bugbyte** · 03-06-2005, 06:54 PM

In simple terms, 90 watts means 90 watts. Power supplies can often supply a peak that is higher but only for a very short time.

I think you're misunderstanding the concept of power draw vs. supply. Your shiny new M1-ATX will supply what your computer requests it to supply up to the 90 watt limit (okay you EE's, I'm just illustrating the concept as simply as I can). The components in the power supply are designed to do this and probably have some type of safety "cutoff" that will prevent them from supply more than your setup will ask.

The fact that your battery can supply WAY more than 90 watts doesn't affect the power supply. The way you phrased it, if this were true, when you plugged your vacuum cleaner into the wall outlet it would explode because of the amount of power that COULD be supplied.

Now, you do want a regulator in the circuit because your car's electrical supply can and does vary depending on whether the car is running and what's happening to it at the moment. Sometimes that can result in voltage spikes that exceed the capacity of the power supply. You don't want those passed on to your power supply. The regulator will keep that from happening.

I don't know if the M1-ATX includes power regulation in it or not. Others can tell you.

I can tell you -and DON'T TRY THIS YOURSELF, that I have run my PC power supply and setup directly off of my battery with no regulation at all and it survived just fine. But I don't now and am not going to do so in the future.

**WebDog** · 03-06-2005, 07:10 PM

the M1 does regulate, it can go down to 5.7 volts for cranking, and the max power input is 30 Volts. so it has regulation built in.

**pr3d** · 03-06-2005, 07:19 PM

ok i get the idea, only 90 watts are supplied and only 90 at peak, ok on the regulation of power supply, using what i have above, adding a small battery, wouldnt that be a regulated power supply? once again i'm new at this, but would adding that backup battery help? atleast the supply a standard 12v?

**Bugbyte** · 03-06-2005, 09:55 PM

It helps keep the power dropping BELOW 12 volts. But you can still get spikes above. But that ought not be a problem with the regulation in the M1-ATX. Go for it!

**pr3d** · 03-07-2005, 02:37 PM

Originally Posted by Bugbyte

It helps keep the power dropping BELOW 12 volts. But you can still get spikes above. But that ought not be a problem with the regulation in the M1-ATX. Go for it!

ok, def. going with the m1-ATX, one last question, i already have this battery, the one mentioned above from the UPS, are there any benefits, or anything good if used it? i jus had this battery, dint want it to go to waste.