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Battery-Powered Apple IIc, Part 2

DC-to-IIc

This funny-looking device is a DC barrel plug to Apple IIc DIN-7 adapter, inspired by last week’s musings on constructing a battery-powered IIc. The adapter makes it possible to power an Apple IIc with a standard DC supply between 9V and 20V, or a suitable battery pack with a DC plug. The supply or battery should be capable of delivering at least 20 watts, or about 1.67 amps at 12V.

For my experiments, I used a Belkin BU3DC001-12V, which is essentially a fancy 12V 7.2Ah battery with built-in charging circuitry, output regulation circuitry, and fuse. It’s intended to be a backup battery for VOIP systems, but can easily be repurposed for any 12V DC application. Best of all, it’s only about $20 used, which is hardly more than the cost of the battery itself.

The current draw estimates from my earlier post proved to be about right. When running from the 12V battery, the IIc pulls about 1.5 amps for a few seconds while the floppy drive spins. Once the drive stops, the current drops down to about 700 mA. Given the 7.2 amp-hour capacity of the Belkin unit, that ought to be enough for several hours of battery-operated IIc fun.

Building your own DC to IIc adapter is simple, and only requires some wire and a few dollars in parts.

Female DC Jack to Screw Terminal Connector – $1.99
DIN 7 Pin Plug Set – $6.21

 
Video

If you’re wondering why there’s no funny video here of a IIc running in the woods, it’s because I’ve only solved half the problem. A battery-powered IIc is pretty useless without a battery-powered monitor to use with it. Fortunately, 12V DC powered LCDs with a composite video input aren’t difficult to find. Many portable DVD players and car entertainment systems can do that job. To power it, I could build another custom cable to run the monitor and the Apple IIc off the Belkin battery, but I’m going to be lazy and simply buy this splitter:

12V Splitter Cable – $6.59

It remains to be seen how much current the monitor will draw from the battery, but hopefully not much. I’ll report again when I have solid numbers.

While I already have a portable DVD player that will work here, its 5 inch diagonal is a little bit underwhelming. I also have a much nicer 14 inch LCD monitor that runs from 12V DC, but it only has a VGA input and no composite input. I’ll keep my eyes peeled for an LCD that’s 9 inches or larger, running from 12V DC, with a composite video input, to create the ultimate battery-powered Apple IIc system. Then I can… um… OK, I admit there’s no real point to this project. 🙂

Read 3 comments and join the conversation 

3 Comments so far

  1. Charles Mangin June 14th, 2016 9:06 pm

    You can cut down on the current significantly by swapping the floppy drive out with a floppy emulator (where would you find one of those, hmm?)

    I actually use the A2Heaven SDFloppyII on my portable IIc, since it drops right in as a Disk II to the internal port.

  2. Steve June 15th, 2016 6:37 am

    I had assumed the floppy drive didn’t draw much current when it wasn’t spinning– am I wrong? I’ll have to try actually removing it.

  3. Chris Hanson September 15th, 2016 1:53 pm

    You could always use a //c to VGA adapter to run the 14in LCD from the //c video expansion port.

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