Can I use this power supply in my car?

**G@briel** · 01-19-2012, 05:32 AM

Hi, I'm new to this stuff and I have a question. I have a little budget project here so I'm trying to use parts I have laying around :-)

I've got a "NEXTerminal" with a DC-DC power supply. The input voltage is said to be 12v, but I do not know how tolerant it is to lower or higher voltages.

I have figured out a way to keep the voltage from dropping to low - I'll connect a small motorcycle battery to my main one with a diode, and run the PSU from the smaller one. that way it will keep the CarPC power from dropping too low during cranking, and the small battery won't be able to power the accessories in my car. However, during normal alternator operation the voltage in my car gets as high as 14.5 volts, can I let my psu run off this without any adverse effects?

Also, perhaps someone has a good way to convert a signal from an analog push switch to a keyboard command without an expensive emulator?

Cheers :-)

**soundman98** · 01-19-2012, 08:22 PM

do you have the original power adapter for it? what are the specs of the adapter?

usually, pc devices like that are only expecting 12.0 v and don't fare too well when the voltage fluctuates more then 0.2-0.3v..

also, i have seen that plug before--on a couple of external hdd's i have, and the ones i have, the power adapter actually outputs both 12v and 5v. so you'll also want to try to confirm that the power adapter is 12v only.

**OldSpark** · 01-20-2012, 01:25 AM

(soundman98) If you mean the LHS 4-pin plug, it looks the same as the microphone connector used on CB radios etc.

(G@briel) As for keyboard on, any output pin that you can dedicate to go hi or lo (on/off) can drive a transistor to energise a relay.

And a car generally varies from ~10V (cranking) to 15V or more (short-term charging) whereas a "12V supply" probably expects ~11.5V to 12.5V or maybe a grater range, but rarely as high as the ~13.8 to 14.4V that a 12V vehicle typically sees.
For vehicle use, an automotive type PSU is required to cope with the voltage range etc. Although there are ways of limiting peak/high voltages, IMO it isn't worth it (unless low power - eg: a few Watts) besides which auto PSUs usually have a low minimum voltage (6V, 8V, etc) to ride thru cranking and other system voltage dips (eg, flashers, headlight switching, big audio).