DC-DC Car Power for Mac Mini - Page 3

NiN^_^NiN · 02-08-2005, 04:53 PM

MikeH: Bad news my friend it seems that everyone i've spoken to hasn't seen that type of adapter and can't find it from any of their contacts either

It looks like there is a possibility that apple had it cutom made altho i think thats pushing it it's probably a korean or chinese design which isn't sold to many places.

Quote:

Dear Matt,

Thank you for your inquiry to Mouser Electronics. We are unable to
supply or locate recommend on a replacement connector for the one you
are requesting.

They even asked all their contacts for me but still no luck

I'm fresh out of ideas of where to get it from

Sorry MikeH

Lake · 02-08-2005, 06:42 PM

That's a pretty good idea actually. I'll go play with the iMac later (I hate to sleep/reboot this machine) making an AppleScript to 'wake in 10 minutes + shutdown'.

~Lake

Lake · 02-08-2005, 07:27 PM

I didn't immediately see how to script setting a specific startup time, but I did come across something that looks handy in general. http://www.ibeezz.com/en/

~Lake

MikeH · 02-08-2005, 09:15 PM

Quote:

Bad news my friend it seems that everyone i've spoken to hasn't seen that type of adapter and can't find it from any of their contacts either

That's OK. I think we're going with the recommendation to cut the power cable as the initial approach. I'll post pictures on the way to do this later next week. I think we're not going to find a source for this power connector.

Thanks for checking.

NiN^_^NiN · 02-08-2005, 09:19 PM

Quote: Originally Posted by MikeH

THat's OK. I think we're going with the recommendation to cut the power cable as the initial approach. I'll post pictures on the way to do this later next week. I thing we're not going to find a source for this power connector.

Thanks for checking.

Well maybe you could get people to send in there Mac PSU and what you can do is cut the cord then add a ps2 connector on to both ends so you can plugin the DC DC Adapter and also they can bring it inside and plug in the orignal mac psu

Thats if you want to be getting mac psu's from people tho.

But it's a good solution for setting it up inside and outside if needed

Bugbyte · 02-08-2005, 10:25 PM

Quote: Originally Posted by Lake

I didn't immediately see how to script setting a specific startup time, but I did come across something that looks handy in general. http://www.ibeezz.com/en/

~Lake

That works! Good find!

agentofchange · 02-09-2005, 10:16 AM

A cheap UPS can provide this kind of functionality. When you hook up a UPS to a PC/Mac you get to make a few decisions like what happens in the event of a power failure.

You can set the UPS up to turn the machine off x minutes after power failure. I would think 10 min would do nicely (so if you stop at 7/11 to pick up a drink it won't shutdown).

As far as startup goes, you could hook up a relay to one of these USB power on buttons which are $15 (or hack the one on your mac):

http://www.welovemacs.com/usb-key-bt.html

The on button acts just like the ones on the older keyboards that shipped with G4 450's and the iMacs of the time)

Of course some of the downsides to this setup is you need to:
1. Mount a UPS in your car (some are quite small though)
2. Get a power inverter.

TxMazda3 · 02-09-2005, 12:15 PM

Quote: Originally Posted by MikeH

THat's OK. I think we're going with the recommendation to cut the power cable as the initial approach. I'll post pictures on the way to do this later next week. I thing we're not going to find a source for this power connector.

Thanks for checking.

Does this mean .... we're close to a launch? Our struggle for power might soon be taken care of?? That the day of the Mac mini driven carputer has come? does this mean that we can eat popcorn again? oh sweet pop tarts from the toaster- this is good news ... or i could be reading into this too much .... if so then I'll blame this on forgeting the meds again ....

peace
Michael

kandyman676 · 02-09-2005, 04:43 PM

Quote: Originally Posted by agentofchange

A cheap UPS can provide this kind of functionality. When you hook up a UPS to a PC/Mac you get to make a few decisions like what happens in the event of a power failure.

I agree, but when you have a UPS, unless you have a DC one that is cheap (i've never seen one as such for a computer to control, so point in the right direction), then you will also need an invertor...which most of the time produces static over your sound.

This is why (again) I am leaning toward a Powerbook in the car, like i did with a Dell laptop. The other reason for the Powerbook is so i can have free mobile internet (from my work footing the bill...) with celluar broadband access:-)

TxMazda3 · 02-09-2005, 04:50 PM

Quote: Originally Posted by kandyman676

I agree, but when you have a UPS, unless you have a DC one that is cheap (i've never seen one as such for a computer to control, so point in the right direction), then you will also need an invertor...which most of the time produces static over your sound.

I was in best buy yesterday and saw a Monster power inverter that claimed to help fight the static noise and came with all hardware needed to hardwire it to your battery .... Monster is a pretty good brand (as far as their audio cables go I believe)

Peace

Michael

thecapitalizt · 02-09-2005, 07:13 PM

the usb button wont work on modern macs, they stopped supporting that awhile ago, with the crt imacs. Anyone here have electronics skillz and is attempting the DIY UPS?

agentofchange · 02-09-2005, 11:11 PM

You dont actually need the ups. If you use a DC-DC power supply all you really want is something to plug in the usb that makes the computer think it has a UPS connected.

Then you can make use of the features - consider this:

You turn the car off and the message of "power off" is sent to the computer. Your machine is still on and powered by the DC-DC converter but will shut down in 10 minutes if the car isnt started and the "power on" message is sent to the computer.

A simple program could be written to mange this.

Edit: would also require a small amount of electronics.

turbocad6 · 02-10-2005, 01:12 AM

Hey mike, I want to buy one of these 19v power supplys from you even without the plugs, do you have any ready to sell? I'm actually looking to power a laptop install that I am about to do, &the 19v along with the 5v for usb sounds ideal.....was you planning on integrating a start up/ shut down curcuit in this power supply or would that be handled seperately?

vinthewrench · 02-13-2005, 07:40 PM

Hi all; great forum..

so I want to repost some info (from a private forum) about the mac Mini and the power supply, lets start with the fact that I am getting a lot of this info from the horses mouth.. and some of it is just emperical data, I will try and talk to the horse soon enough.

lets start off with the Apple specs:
Electrical and environmental requirements
Meets ENERGY STAR requirements
Line voltage: 100-240V AC
Frequency: 50Hz to 60Hz, single phase
Maximum continuous power: 85W
Operating temperature: 50° to 95° F (10° to 35° C)
Storage temperature: -40° to 116° F (-40° to 47° C)
Relative humidity: 5% to 95% noncondensing
Maximum altitude: 10,000 feet

The power supply claims 18.5V @ 4.6A. This give a max power rating of 85W as noted above in the web specs. Now, given there is some margin in this supply, the likely max power you could pull would be somewhere in the 65W to 70W range. This would be from a 1.4GHz mini, with a 1GB power sucking DIMM, optical drive going full power (maybe burning?) and the HDD R/W'ing its brains out, in a hot room so the fan is going full bore, along with full power (up to their fuse break point) being sucked on both USB ports & Firewire port.

OKay - now that we have that reality in our pocket, lets get on with the business of running this puppy from automotive power.

One of the first things you will notice is the non-standard power connector - RadioShack and Fry's will not have this in their connector parts inventory. However, if you happen to have one of the newer Apple flat panels, you will notice it uses the same connector on the display's cable octopus - you could always snip this power connector off and repurpose it. Or not. My first order of business was to cut the mini power cord in half (well, maybe 1/3 & 2/3) and attach a set of Anderson PowerPole connectors on both ends. Now I have the ability to move the connector side to other power supplies as I see the need.

Unfortunately, it got complicated - a key, sort of like the PowerBook power supply key, protects the power to the Mac mini. Without it, the unit will not power on. Here is the breakdown of the connector (as seen from the power supply):

The connector is symmetric:
Ground on the outer pins
Power (18v) on the inner pins
Middle pin is the signal line

On my power supply, the signal line is attached to ground through a tiny little 6651? resistor. I have tried this signal resistor as a 6.8k?, a more reasonably available value, and the mini still powers on - so I guess the value need not be exact.

As I stated above, I chose to wire up the power cable via a set of PowerPole connectors (SinglePole Connector Series): Red/Black on the mini side and Red/Black on the supply side. Easy. I chose to wire up & hide the signal line (6.8k?) in the Mac mini side of the power cable. This avoids the need to run an extra wire/connector from the power supply solely for this power signal key.

Now for the automotive fun. (horse went to) PowerStream for their DC-DC power converters where I found the ED1010-18. This is an 18v 6.6A (120W advertised) supply that takes in 11 to 16 volts and outputs a clean 18v. The quick specs are: 300mV max ripple/noise, +/-0.5% line regulation, +/-5% load regulation, 88% efficient, 0-40 degree C operating temp. At a cost of only 1/5th that of the mini, this was a bargain! OKay, a tad sarcastic, but I wanted a decent automotive supply for this experiment.

With the ED1010-18 in hand, a hot soldering iron, and a package of PowerPole connectors, it was time to get to work and put all of this crap together. I started by placing the PowerPole connectors on both ends of the ED1010-18 supply. I had previously added these connectors to the mini power cable, so I was now able to attach the mini to the ED1010-18 supply. To drive the supply from the battery, I built up a Marinco 12VPG cigarette lighter plug with PowerPole connectors. The Marinco part is a high quality plug that locks into place when inserted in the Marinco receptacle (which I have mounted in my truck - replacing the cheesy OEM receptacle).

I did not add the cigarette lighter plug to the ED1010-18 because:
1) I wanted to run some tests with the mini running off the 12v battery supply directly, just to see what happens.

2) If I end up wiring this thing in permanently, it will not go through a lighter plug - it will be hardwired, so the PowerPole connectors are perfect for this eventuality.

The system:
Mac mini 1.42GHz, 1GB RAM, 80GB HDD, Superdrive
Wired Apple Extended Pro keyboard (the older white USB version)
Wired Apple mouse attached to the keyboard
Xenarc 700TS 7" VGA display with touch screen USB cable attached to the mini. The display was powered via 120V inverter so was not part of the power draw data.

Now for the tests: I wanted to know power off current, max current, and max fan RPM. To do this, I ran:
iTunes playing music from a CD
iTunes visualizer running in a window
The HDD attempting to zip an archive of the /Apps & /Lib folders (about 6.5GB)
(and some other private tool ..that forced the fan on)

Here is the data: Tests run from both the ED1010-18 power converter as well as from the 12V battery (with engine off)

12V System -
Power off/plugged in: 0.018A draw
3.1A max current draw (with above noted test parameters)

18V System - 18.2V ED1010-18 Power Converter
Power off/plugged in: 0.017A (taken from the 18V output side of the supply)
Unplugged from the mini: 0.088A (taken from the 12V input side of the supply)
Power off/plugged in: 0.119A (taken from the 12V input side of the supply)
2.1A max current draw (taken from the 18V output side of the supply)
3.6A max current draw (2.1A on the 18V side of the supply, not quite 88% efficient based on my gross, non-lab clean, cheap DMM, data gathering).

There you have it. Hope this is helpful. The most interesting data: 3.1A draw from the 12V supply & mini, and 3.6A draw from the ED1010-18 & mini. Takes 1/2A to run the DC-DC power converter. Well, not quite true since the fan was running faster in the ED1010-18 test so the system was drawing more current.

you should perhaps note that the fan did not seem to spin as fast/loudly when run from only 12v in extreme usage conditions

someone making a power supply should be aware of the resistor value and that it can run at a lower voltage, but with possible fan issues..

btw I would be interested in a beta PS even without the connectors..

MikeH · 02-13-2005, 10:18 PM

Sorry for the late response. I've been out of town all week. Hopefully I can answer some of the questions/issues that have been raised.

turbocad6, we expect to be able to give an eta for production units by the end of this week. And yes, the unit will have a startup/shutdown controller (SSC) like the existing P1280. In fact, most of the features will be identical except that the P1900 secondary output can be either +5V or +12V. The challenge will be connecting the SSC to the mini. We have yet to find the name of the manufacturer of the "ACPI"-like jumper on the mini motherboard (see other posts with pictures).

vinthewrench, your findings are in line with what we have found (including the sense resistor). However, I would be a bit worried about running the mini on +12V. It's input DC-DC converter was clearly designed to take a higher voltage, and hence less current. You could well be stressing the power components beyond their spec limits (ie capacitor ripple current). This could cause premature failure. Even tho it "works" it is operating outside of its design range. I would recommend caution here....

Since we cannot find the source of the power connectors used by the mini, our initial recommendation will be similar to your "power pole" connectization. This gives the greatest flexibility for inside the house, and inside the car operation. It does cause a bit of angst when you actually have to cut the power cable, but most of the hard core hobbyists will be willing to do it. The best solution would be a reliable manufacturing source of the original power connector, but so far we have not been able to find the source.

I'll try to keep you posted on availability later in the week.

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