Battery Power for a Powermac G4

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I do a lot of filming on the go. And while I do have acess to laptops and whatnot I would like to have the versatility of my powermac G4 (more ports, PCI expansion and more rugged). I don't always have a place to plug it in though. I was thinking about turning it into more of a mobile station. My main problem is that is power first and formost. Does anyone know of a space efficient way to power a powermac G4 (preferably internally like a laptop battery). Something that might fit in the place of the current power supply.

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gobabushka's picture
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Joined: Apr 26 2004
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I've heard of dc-dc atx power

I've heard of dc-dc atx power supplies for using computers in cars. If i can find the link, ill post it.

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Eudimorphodon's picture
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Re: Battery Power for a Powermac G4

tupenzero wrote:

more rugged

I actually wouldn't assume that your Powermac is more rugged then a laptop. The thing that breaks on laptops is the screen. In most other regards even flimsy laptops are much more suited to being lugged around then non-ruggedized desktop machines. Desktop hard disks are *much* more breakable then laptop HDs, among other things. (There's also motherboard flexing, PCI cards popping out of slots, DIMMs coming loose...)

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Go to minibox.com and mini-itx.com and check out their DC ATX converters. The internal boards are quite small, and there are some fairly high current (watts) ones now.

Then go to xlr8yourmac.com and do a search for "ATX". Check out how easy/difficult it is to convert your model to run from an ATX supply. From memory, the PCI video G4/B&W G3/beige G3s are easy (snip one wire or move one jumper), the later models are a bit more involved. If your model's not been documented on xlr8yourmac, try googling.

Then work out the power consumption of your machine, including all the drives and PCI cards. See if there's a DC supply from the above stores with enough current. Then multiply that by the number of hours of run time you want between charging stops, mutliply that by two (because you shouldn't drain lead acid batteries more than half), and go looking for a -sealed- lead acid battery or set of batteries with that many watt-hours of capacity. You'll also require a regulated charger designed for sealed batteries, not car batteries. The charger should be rated (in watts or amps - amps = watts/[12]volts) for 1/10th of the total watt-hours of the batteries.

When you recover from the shock of how much that will cost you, and how many pounds of lead you'll be carting around, have another think about a laptop. If you'll be working from a vehicle and/or money is no object it could still be feasible

Alternatively, you could pick up an inverter (battery to mains power converter) from an electronics, camping or solar power store, and run that from the required amount of batteries, or you could pick up a cheap second hand UPS with dead batteries and re-wire it to larger, fresh ones.

But if you want to work with just the batteries you can fit in your existing case, expect about ten to twenty minutes of run time. Longer running times on a desktop will require lots of battery capacity or a second power source such as a generator (your car idling with an inverter attached?) or large solar panels. Again, expensive.

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DrBunsen's picture
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Oh yeah, don't forget to include the power consumption of a monitor. An LCD will use much much less than a CRT. But if you don't already own an LCD, again that tips the balance towards a laptop.

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Ex-parrot's picture
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Something worth looking at mi

Something worth looking at might be those 12v inverters sold commonly for use in cars... going from DC -> AC -> DC again through inverter -> PSU -> Computer isn't the most efficient thing in the world, but when lead acid batteries are so cheap and have such a great capacity, it may work out more economical in the end.

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Re: Something worth looking at mi

Ex-parrot wrote:

Something worth looking at might be those 12v inverters sold commonly for use in cars

Yeah that's what I was talking about. They sell them at minibox, and I think at mini-itx

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