RomRaider

So I was advised by my tuner not to flash my car via car PC as he has seen too many car pc's lock when under 12 volts. Is there anything I can do to make it a bit safer to flash via my car pc? It's kind of the entire reason i bought the damn thing, so I can log and flash without messing with my laptop from work all the time. It already uses the special car pc power supply, but would there be any way to integrate some sort of additional battery or something that would ensure the power stayed at a usable level to prevent lockups?

Any help would be greatly appreciated. I would much rather avoid bricking my ECU.

Simple answer, Yes

Do you have any electronics knowledge?
If so why not just build in a back up battery using an old laptop or some thing thats 12~14 volts. Or you could just add in a switch on the power feed to the carPC. One side of the switch would go to car power & the other would go to a different power source. Just make shore that you switch both the +12 and the -12 (the ground) on the power input to the carPC & that you don't have any other grounds powering the carPC that are still pulling -12 from the cars ground.

I would use a three position switch set up like this

position 1 = power from cars 12 volt system
position 2 = OFF
position 3 = Backup Power source

Maybe a cheep battery to use would be a 14.4 volt pack from a power tool?

Let us know what you end up doing

I ended up talking to a few people that have car pcs, and 2 of them have watched movies in their cars with the cars off, and had the battery get so low it wouldnt even crank the car over, but the PCs both still ran flawlessly. Noone i have talked to that owns a carpc has had any problems with it locking up due to voltage. I have played with mine extensively and haven't ran into any problems at all. My system doesnt need much power anyways, It stays up through cranking the engine without a blip, and my voltage gauge shows like 10.2 volts while cranking the car over. I have sat in the car for over 3 hours configuring it without it on, running my amp listening to music and never had it drop below 11.5 volts.

I'm not worried about it.

because of the smps that is used in the pc, wide variations in input voltage will still net the desired output rail voltage.

can you elaborate on that. What output rail? are you talking about a voltage on the OBD2 port?

I'm pretty sure he's talking about the power supply used in car pc's.

no, i am talking about the +/- 5 and 12 volt rails in a computer's SMPS.

Ahhh yes yes i see. But one can make a power supply that will keep a fixed & clean output, With a varying input

I can be done

Hello,
I know this is an old post but I have successfully used my Carputer to flash my ECU numerous times with no I'll effects. I built and installed my carputer using a mini itx board with a gig of ram and windows XP, it runs off a power inverter and could run for 2+ hours on battery power alone, more than enough time to flash your ECU the amp draw is less than 2 amps on the car battery. Not only do I flash but I also can log with RomRaider I have a 7" touch screen mounted in the double DIN radio location and it works great.

same here. I've flashed my ECU via car pc MANY MANY times now with no ill effects. My voltage never drops below 12.2 or so. I usually just crank the car up for a minute or two to get the voltage up, then shut it off and flash. Havn't had any issues yet...knock on wood...

One solution if you don't planning on flashing on the road is hook a battery charger during flashing operations; preferably one with a voltmeter attached.