ITPS problems

numberone · 12-08-2003, 03:34 PM

I wired the whole bunch of cables yesterday and finally pluged the ITPS unit to my morex cubid 3688 case. Well, I thought I can finally run my carputer and relax. No way, the ****ty thing seems to have problems with my car voltage cause it keeps reseting the computer every 30sec or so. Below you can find some info about the voltage:

Ignition off, motor not running:
Un-Switched voltage(input) = 12,45v
Switched voltage(input) = 0v
ITPS output voltage = 0v

Ignition on, motor not running:
Un-Switched voltage(input) = 12,45v
Switched voltage(input) = 12,45v
ITPS output voltage = 11,5v

Ignition on, motor running:
Un-Switched voltage(input) = 14,5v
Switched voltage(input) = 14,5v
ITPS output voltage = 11,98v

Does anybody know what can be wrong with it? As I said the ITPS can start my computer without a problem. It runs a couple of seconds and reset the whole system. It looks like a voltage dropdown or something like this

Ricky327 · 12-08-2003, 03:40 PM

Was your engine running when the PC reset itself? or was it a shutdown?

11.98V into your PC look fine to me.

Also check if this 11.98V is more or less consistent during the pc draining the most current. It may have dropped down when your CDROM spin up together with some other high current stuff.

numberone · 12-08-2003, 04:06 PM

the engine was running because I cant start my pc otherwise with 11,5v provided by itps.

Ricky327 · 12-08-2003, 04:44 PM

Did you have a diode connected as in tanks circuit?

If not, I suspect you are draining more than the ITPS can provide.

Its seems your voltage drop is too much, try reducing your hardware to minimum and see the effect. If it does work than you know what the problem is.

numberone · 12-10-2003, 01:33 PM

Well, I've just added a tank circuit(sla+diode) to my setup and it seems to work pretty good. I get 12,5v in each situation I'd described above.

Ricky327 · 12-10-2003, 03:46 PM

Well, I've just added a tank circuit(sla+diode) to my setup and it seems to work pretty good. I get 12,5v in each situation I'd described above.

Thats strange...adding a diode actually made your ITPS output from 11.5V to 12.5V? Ill say thats not possible as you seems to have the oppsite effect, most poeple here have done it and it will sure drop your voltage into the PC by 0.6V or so.

KapMan · 10-29-2004, 03:12 AM

numberone: I have a morex case like yours and am looking to mount the itps inside. Is that what you did??? Where did u put it?? Also, did u use a fuse between the itps +12V line and the car batt?? Does anyone know if this is essential? Would a 5A fuse be enough?

Any help would greatly be appreciated.

Thanx.

ptk · 10-29-2004, 04:06 AM

Numberone
i guess you figure out the issues.
just in case

ITPS prevents over voltage. it doesn't not have the capability to prevent undervoltage. in addition, it does this at a price (voltage drop). it's common quoted at 0.6V drop, but in your case, seemed to be closer to 0.8V drop.

effectly, when your motor is not running, the input voltage will be that of the car batter... round about 12. so the output voltage will be below 12V.

your molex case most like comes with power supplys that doesn't regulate 12V, so your carputer won't be able to start when your 12V line is under voltage. even if they start, most likely will hang when load applies.

your tank circuit make sure your input never drops below 12V, hence allow the carputer to boot up. however, it still doesn't solve the issue of running the carputer when engine's off, coz you are basically running off your tank circuit which won't last you too long, depending on setup.

kao

ptk · 10-29-2004, 04:07 AM

Quote: Originally Posted by KapMan

numberone: I have a morex case like yours and am looking to mount the itps inside. Is that what you did??? Where did u put it?? Also, did u use a fuse between the itps +12V line and the car batt?? Does anyone know if this is essential? Would a 5A fuse be enough?

Any help would greatly be appreciated.

Thanx.

your ITPS is rated at 60W, 5A is minimun.