I have a durametric cable, and there are numerous warnings where it says not to use it with a power inverter because it could cause damage. Any idea why this is/what it would cause?

The reason I ask, on previous cars it was never advised that there could be an issue to use power inverter to hook to laptop to provide extra battery power for logging/street tuning.

Not saying I plan to do it, just new thing to me and curious the reason.

 

Interested in that answer as well. I'm a Mac guy and just happened to have an old windows laptop that I was able to use with my durametric. Only issue is the battery is toast, so have to use house power via an extension cord. The inverter method would be a saving grace to buying a new laptop battery

 

I use my durametric with my laptop on battery all the time.

I think the issue is its just "bad practice" to charge a laptop off the battery of the car you're testing.

Worst case scenario it causes power failure during an ECU flash or something, which could really damage your ECU.

I myself hate having to use an extension cord to flash my ecu... part of the reason I'm continuously considering a COBB access port.

 

Could be some sort of potential ground loop that might draw power through it maybe? Really seems odd to me too...

 

Yep, this is the same issue I've been working to solve. Rather not buy a new battery, but don't trust buying a used laptop either since it may have the same issue.

I'm not really thinking to do a flash or anything at this point, just for logging purposes right now. When it's time for upgrades, I'm also going to go with Cobb

Part of me thinks it's a liability thing, something "could" happen and they want to make sure they warned the consumer not to do it. My hope was to datalog at an upcoming track day, and realized there's no way my laptop would be able to do a full session on battery alone.

I know that much data is probably overkill for a novice track driver, but with a GPS laptimer and video feed, I was hoping to be able to find specific points on track and match it with the time on the log to gather the data I need.

Yeah, I was thinking it must have something to do with feedback or creating a loop of some sort. I used an inverter to tune on my Supra and never had a problem, but maybe aftermarket ECU doesn't get effected by this potential issue.... many years ago I had LS1 F-body and to tune the stock ECU with LS1edit I removed the passenger seat and hooked up an entire desktop and monitor with a power inverter since I didn't have a laptop at the time. I figure if anything would have caused a problem it would be that ridiculous setup through a cigarette lighter in a GM product

 

they're just covering their bases. When doing programming on any vehicle it's a good idea to make sure the car is hooked into a tender than can provide proper "programming voltage" this will ensure any fluctuations in power do not occur while flashing volatile memory. With that said, I dont see any reason you would harm anything on the vehicle since you're just reading values. The durametric has the ability to reprogram though and that's probably where this disclaimer is coming from.

 

I have had the Cobb for a little while now and love it. One of the things they dont advertise is the 'valet mode' which sets the cut off at 4k rpm. Just a nice little measure to ensure you dong get a Ferris Bueller scenario.

 

+1, if you are just logging/reading it should not be an issue. You need to be careful when you are writing/programming though. ymmv