I bought this one just now just to give it a shot

http://www.ebay.com/itm/New-Mini-Dig...item3377c297ad

It's got a flush mount so it looks clean if you have a flat surface to put it in.

Is there any way to tell if it's accurate or not?

Any ones designed specifically for HHR's?

What would be the best place to put it?

I was thinking the terminals on the sub amp and then getting 2-3 more. one for battery, one for the terminals under the hood and another for the highs amp i have under the seat.

any feedback appreciated

 

Idk. It's only four bucks. Doubt it will last long but hey ya never know.

Me personally I'm running an obd2 sensor and the torque app on my tablet. Ever thought of doing that? You can get all sorts of information. Voltage, intake temp, mpg, oil temp, etc etc...

 

Why would you want 3 or more of these??....just get one for the entire charging system. Everything else shouldn't matter unless you aren't getting juice from the main source.

 

I figured I would put one on everything almost but it sounds like I can just put one on the cigarette lighter leads and it will be fine?

 

Yup..or any power source thats powered off the key.....