Hey there guys,
I just recently joined this forum and saw you had a dash cam section. I've been running a DR650-2ch for about 3yrs. Yes, the SD cards they come with are overpriced junk... so let me give you some other tips.
First, make absolutely sure your battery is in good shape. This camera with a power magic pro draws a little over an amp while running. If you don't have a new battery in your car it'll make short work of it quickly as it discharges it over an over again. The alternator should take care of it, but that's not always the case due to sulfide buildup and etc. I have an optima yellow top deep-cycle in my pickup which not only gives me about 2-3 days capacity to run the camera at a 11.8v low voltage trip, has to spin over a 454 when I need it to. I've had to upgrade my alternator as well just to support the battery so if you park in a garage overnight at home, I would suggest unplugging the camera. Batteries fair much better during warmer weather as well, so don't be surprised come next winter if the engine spins over poorly after its been sitting outside in the cold all day or all night. Those buses should have a dual battery setup for cranking, so they're much less likely to ever notice the battery is weak while starting.
Make sure you have a power magic pro. Not only will this save your battery, it'll save your alternator too. If you allow the battery to get down to 9-10v several times and keep getting jumped off you're putting way too much stress on your alternator each time. Mine is soft-wired into my fuse panel with some mini-fuse circuit splitters to T off of a couple of fuses.
You're going to want to order a few Samsung SD cards. Scandisks do not take heat well and will start to break down. You'll notice in the video player on your PC or phone that the video will be "damaged" or just unable to play... that's typically the SD card biting the dust. I've got 3 64gb samsungs that I rotate through and I pull them every 2-3days to check out the parking mode footage. IIRC kingstons work well, but I think I chose samsungs due to the price.
Don't be surprised this summer after a hot day and the camera has been sitting in the sun that it is "locked up" and not recording anything. I've talked to blackvue about it, they suggest running the latest firmware and all that, but it's the heat. The camera is black, so, it gets pretty hot. I ususally unplug the camera after it has been sitting in the sun, crank up my vehicle, turn on the defrost and let that run for a minute before plugging it back in. It sucks, but its life.