DC-DC PSU that is NOT opus/inverter question

jusatry · 12-26-2003, 01:24 PM

hi everyone.

i have a C134 w/M9000 motherboard, slimline DVD, 2.5" HD and a 7" Lilliput screen from HK i got on ebay. i am currently fabricating a setup to fit it in my double DIN dash.

my question is about power. i bought a 300 Watt inverter from radioshack ($99), thinking i should better be safe than sorry in terms of having enough power. I thought i didnt want an Opus because i dont need a shutdown controller (my on/off button is in my dash) and becuase the case is already assembled with whatever PSU is in there and an AC adaptor that came with it.

here is the actual question: 1. will the inverter, if hardwired, drain my battery if the computer is off? 2. where can i get a DC-DC power supply that isnt fancy, and therefore isnt pricy. I just need to get around the inverter - shutdown controller and startup on ignition are options i dont need. I also do not want to wait 4-6 weeks to get it.

Any help is much appreciated.

wizardPC · 12-26-2003, 02:28 PM

1. If the inverter (which, by the way, you paid WAY too much for) is on, it will draw power
2. there isnt really a good answer for this. you could get a pw-70 and the ITPS, or one of these, but that combo is not going to be "cheap", but it is cheaper than an opus

jusatry · 12-26-2003, 02:51 PM

Quote: Originally Posted by wizardPC

1. If the inverter (which, by the way, you paid WAY too much for) is on, it will draw power
2. there isnt really a good answer for this. you could get a pw-70 and the ITPS, or one of these, but that combo is not going to be "cheap", but it is cheaper than an opus

did i pay too much because i got a 300 watt one and i lonly need a smaller model, or because radio shack sucks? I just tested it on the car, and it doesnt put out a dirty audio line, so i am happy about that - it also has 2 plugs, which is convinient.

any ideas on an easy on/off w/the ignition for the inverter, so i dont have to switch it each time i get in and out of the car? Also, how much should i pay/what brand should i get? i know i am supposed to wire it from the battery (to avoid blowing a fuse) and i also know i am supposed to put an inline fuse so as to avoid starting a fire.

Any other suggestions are much appreciated. I hear that my C-134 case has no room for a DC-DC PSU in the case - is that one you linked to going to give me good power/not drain my battery? (my cig-lighter is always on).

Thanks for the help.

wizardPC · 12-26-2003, 03:16 PM

you paid to much because radio shack sucks--see here

I would (did) hook up a relay on the power line of the inverter to the accessory power of you car. that way, the inverter will get power only when the car is on, so if you leave the inverter power switch on the inverter will come on when the car does.

then, depending on BIOS options, you can set the computer to "power on after AC loss" so the computer comes on when the inverter is turned on.

you will still have to shutdown the computer manually with this method

jusatry · 12-26-2003, 05:07 PM

how/where do i get one of these relays? are they easy to hook up? i am not electronically gifted but i can figure most things out. One question about the walmart/target brand inverter......why the price discrepancy? is it at all a quality issue? (will i be more likley to get a noisy output from the wal-mart brand than the shack brand?). Thanks so much for all the help.

danon · 12-26-2003, 05:53 PM

the thing is as long as you introduce AC out of a DC setup (e.g. inveter) you'll always going to have a humming/noise issue...

jusatry · 12-26-2003, 05:59 PM

Quote: Originally Posted by danon

the thing is as long as you introduce AC out of a DC setup (e.g. inveter) you'll always going to have a humming/noise issue...

really? i tried mine out and didnt notice anything too bad.....but i was running the audio through the tape adaptor in (for my connvineince) so i expected a certain amount of hiss. Unfortunatly it apprears a DC-DC is out of the question with my C134 casetronic case packed to the brim.....any thoughts on minimizing the noise? i kinda see the inverter as a necessary evil. any brands that are better than others?

thanks for the input

MikeH · 12-26-2003, 06:29 PM

Jusatry,

I have the C134 also. I bought the cheap WalMart inverter and had very bad nosie on my audio (I believe the cheap version does not filter the output of the inverter like many of the more expensive versions do).

You CAN keep using the inverter, but the more elegant solution would be to get a 12V "pre-regulator" (the internal C134 power supply does NOT provide additional regulation to the incoming 12V from the car so you need SOME sort of 12V regulator) to feed directly into your C134 internal power supply. I bought the Radio Shack laptop adapter and the ITPS Shutdown Controller (bypassing it's on-board regulator) to provide turn-on & shut-down control over the carputer ( your will need to bring the PWRON control signal out to the ITPS). This setup does most of what the Opus solution does and allows you to keep your C134 chassis intact, and use the internal power supply. It works pretty well. The Opus would require you to run an ATX-like power cable into your chassis....(ugly).

Anyway, the C134 chassis presents some interesting challenges. It's packed so full, you don't have many options.

jusatry · 12-27-2003, 02:56 AM

Quote: Originally Posted by MikeH

Jusatry,

I have the C134 also. I bought the cheap WalMart inverter and had very bad nosie on my audio (I believe the cheap version does not filter the output of the inverter like many of the more expensive versions do).

You CAN keep using the inverter, but the more elegant solution would be to get a 12V "pre-regulator" (the internal C134 power supply does NOT provide additional regulation to the incoming 12V from the car so you need SOME sort of 12V regulator) to feed directly into your C134 internal power supply. I bought the Radio Shack laptop adapter and the ITPS Shutdown Controller (bypassing it's on-board regulator) to provide turn-on & shut-down control over the carputer ( your will need to bring the PWRON control signal out to the ITPS). This setup does most of what the Opus solution does and allows you to keep your C134 chassis intact, and use the internal power supply. It works pretty well. The Opus would require you to run an ATX-like power cable into your chassis....(ugly).

Anyway, the C134 chassis presents some interesting challenges. It's packed so full, you don't have many options.

If i dont care about a shutdown controller (the puter is gonna be in the dash and i have it set to shutdown when i push the power button), do i need the ITPS? in other words, does the laptop power thing regulate the 12v? if so can i just plug that straight into the C134 from the cig lighter?

Another option i was considering was car adaptor from idot: http://www.idotpc.com/TheStore/Deskt...t.status=green . But people on other threads have been saying it only puts out 50-60 watts, which i think could be cutting it close with our case.

Thanks for the help, its much appreciated. I am hesitant to open that case up for fear that i will not be able to get it closed again

so any solution that does not involve any extra installations within the computer would be ideal.

thanks in advance.

Confused · 12-27-2003, 07:40 AM

You're using an Epia, and not using any desktop drives, so IIRC, you're not using the 12v line anyway.

I am using that power supply in my car, wired directly up to the battery, and I'm running a desktop hard drive (which uses 12V) and i've been using it for about 4 months without any problems.

Garry

jusatry · 12-27-2003, 12:39 PM

Quote: Originally Posted by Confused

You're using an Epia, and not using any desktop drives, so IIRC, you're not using the 12v line anyway.

I am using that power supply in my car, wired directly up to the battery, and I'm running a desktop hard drive (which uses 12V) and i've been using it for about 4 months without any problems.

Garry

Garry:

Are you saying that the amount of wattage the iDot PS puts out will be enough, or that i need a different, non-12V supply? sorry if that is a stupid question. i am still figuring out this whole PSU issue. Thanks for the help.

MikeH · 12-27-2003, 03:45 PM

Jusatry,

I have measured the current consumption of my C134 with slim (laptop) HDD and slim (laptop) CD/DVD. The total input current varies from 2.7 to 3.4 amps under all conditions (cold startup, spin up, etc). My math says that a power consumption of (12x3.4=) 40.8 watts max. I would say that you could easily get by with a 60W external regulator if your configuration is similar.

I looked at the iDot regulator. If you look at the back of the unit (on their web site) you will see that it is an EDAC Power Car Adapter. The specs on this unit says it's the model 1060 with a 19V output. I looked on EDAC's web site for more detailed specs, but could not find this unit. This makes me nervous. The also don't offer a 12V version on their web site. I'm not sure how iDot is getting a 12V supply from EDAC.

Another thing to consider, as you use your carputer more, you will find that pushing a button to shut down your computer is very inconvenient at times. You'll find yourself having to wait for the computer to shut down as all you friends pile out of your car and run into the movies.....while you're sitting there waiting for the stupid thing to gracefully shut down. I've found that the ITPS is very convenient for starting and stopping the carputer.

However, ITPS is NOT a good solution for an external regulator. It has a linear regulator that requires 1.3V drop from input to output to maintain a constant 12v output. This means, any time your car battery/alternator drops below (12+1.3=) 13.3v your output 12v will drop also. My battery is a little old and sits around 12.5v when the engine is not running. In the C134, this 12v feeds directly to the motherboard.

Now, what I'm NOT sure of, and what I'd love to hear from others is.....what does the motherboard use +12v for? If it truely is NOT used on the motherboard itself, you may get away with a looser spec on the 12v. All I know is, Casetronics states on their FAQ that the 12v input needs to have a tolerance of +/-5% (ie 11.4v to 12.6v).

Just some random thoughts..... hope it helps.

jusatry · 12-27-2003, 06:10 PM

Quote: Originally Posted by MikeH

Jusatry,

I have measured the current consumption of my C134 with slim (laptop) HDD and slim (laptop) CD/DVD. The total input current varies from 2.7 to 3.4 amps under all conditions (cold startup, spin up, etc). My math says that a power consumption of (12x3.4=) 40.8 watts max. I would say that you could easily get by with a 60W external regulator if your configuration is similar.

I looked at the iDot regulator. If you look at the back of the unit (on their web site) you will see that it is an EDAC Power Car Adapter. The specs on this unit says it's the model 1060 with a 19V output. I looked on EDAC's web site for more detailed specs, but could not find this unit. This makes me nervous. The also don't offer a 12V version on their web site. I'm not sure how iDot is getting a 12V supply from EDAC.

Another thing to consider, as you use your carputer more, you will find that pushing a button to shut down your computer is very inconvenient at times. You'll find yourself having to wait for the computer to shut down as all you friends pile out of your car and run into the movies.....while you're sitting there waiting for the stupid thing to gracefully shut down. I've found that the ITPS is very convenient for starting and stopping the carputer.

However, ITPS is NOT a good solution for an external regulator. It has a linear regulator that requires 1.3V drop from input to output to maintain a constant 12v output. This means, any time your car battery/alternator drops below (12+1.3=) 13.3v your output 12v will drop also. My battery is a little old and sits around 12.5v when the engine is not running. In the C134, this 12v feeds directly to the motherboard.

Now, what I'm NOT sure of, and what I'd love to hear from others is.....what does the motherboard use +12v for? If it truely is NOT used on the motherboard itself, you may get away with a looser spec on the 12v. All I know is, Casetronics states on their FAQ that the 12v input needs to have a tolerance of +/-5% (ie 11.4v to 12.6v).

Just some random thoughts..... hope it helps.

Mike:
Thanks so much!

I bought the radio shack item Garry suggested and am planning on (hopefully tommorow) cutting the cig lighter end, adding an inline fuse and wiring it to the battery (actually a dist block under the dash in my car).

I can imagine the inconvinience of waiting for shutdown, and i have 2 questions, one for Garry, one for everybody. 1. Garry said in an earlier post that he uses the external regulator (the shack) and an ITPS card. how did he do this, since in the most recent post it appears you are saying this does not work? 2. can you shut the car down while the 'puter is going through her fancy shutdown rituals, if the power is routed directly from the battery?

Thanks for the help, i appreciate it.

By the way, you can call me shamir.

MikeH · 12-28-2003, 08:44 AM

Shamir,

Quote:

Garry said in an earlier post that he uses the external regulator (the shack) and an ITPS card

I don't see where Garry said this, but I (Mike) did...

I connect the input of the RS regulator to my battery thru a 20A fuse. I connect the output to the ITPS. The ITPS has two functions: 1)another 12v regulator (which I have disabled in my setup since the I have the RS in front of it. This is what I said is NOT a good 12v regulator solution), and 2) turn-on/turn-off controller. When you first turn on your car the ITPS will delay 3 seconds and then pass the regulated 12v thru to your carputer. When you turn off your key, it waits 5 seconds and then send a turn-off pulse to the carpc thru the PWRON line (it's still passing regulated 12v at this point). This SHOULD begin the graceful shutdown of the carpc. In case the carpc is "stuck" and won't shut down on it's own, the ITPC disconnects the 12v line after 45seconds, to prevent battery drain. This is a "non graceful" shutdown. If the carpc is already shut down, no problem. If it is stuck, when you turn it on the next time, it will go thru the "scandisk" routine. Undesirable, but better than a dead battery.

You can read all the details of how this works on THIS document. There a bunch of good info on power supplies in it.

I hope this helps..

Confused · 12-28-2003, 08:55 AM

I am not using any external regulator, ITPS or anything.

Only the DC-DC PSU that comes in the C134 case. Hooked directly to the battery. No regulator. No shutdown controller.

Garry