**How Temp Hit Me Badly**
I have been using Sandisk Ultra 128 Micro SD with USB reader from Costco. Sandisk never advertises its write speed on its package but my software told me it is around 20M/s. In theory it is much faster than 4M/s. Have been using it since September. No issue untill last week, got the the 4M error message a couple of times. A replug resolve the issue almost immediately.
After a couple of incidence, I notice the pattern:
1. The error message was always triggered by the sentry mode, not the dash cam, and it is always when the car is parked outside.
2. If I got a couple of incidences from sentry mode, the car stops recording after about 30 minutes.
3. The temperature was around freezing point (welcome to Canada).
I thought I was going to get Sandisk Extreme to fix the issue, until I met this very knowledge guy at Canada Computers. He told me Sandisk Extreme won't help because all consumer grade micro sd and usb sticks slow down significantly when temp drops. When it reads "temp proof" on the package, it only means the data won't loss when it gets cold. It does not guarantee read/write speed at low temp.
He suggested to get the professional grade sd for outdoor photography. Unfortunately, Canada Computers does not carry one. Did some researches, Kingston does have a few that specifically guarantees read/write speed in cold temp.
As an alternative, I used styrofoam and foil paper to build a case for the micro sd card + usb read. If it works, I will let you know and post the pic.
In summary, if you live somewhere that gets cold and you like to keep you sentry mode running all the time, you will need a micro sd that guarantees performance at low temp.
