So "parking mode" is basically where it records 24/7 with the optional fuse box power supply? And it automatically shuts off when it senses the car battery is getting low?
Is it okay to always be recording 24/7, or will that run a higher risk of the memory card failing sooner due to writing/deleting non-stop?
This is a bit more complex than it might seem.
Low-bitrate parking mode is always recording, as does
time-lapse recording; the main difference is that it's slower and transferring less data so the images will be fewer, lesser quality, or both. Not all cams do this.
Buffered (pre-buffered) parking mode is always running the cam but not sending data to the card until an event is detected; then it will record what is happening now as well as what has already happened before the event and afterwards too.
Other parking modes will begin recording only when motion or an impact has been sensed; the camera is on standby and not recording anything until then. With this type of parking mode, there is a slight delay before the cam can 'wake up' and start recording which varies by cam from maybe 1 1/2 seconds to several seconds after an event has been detected. While almost all cams claim this feature,
it is dependent on the motion-detect or impact-sensing functions working properly which in many cams they do not do.
Along with this is how the cam enters it's parking mode. Most cams need a hardwire kit (HWK) to switch between modes automatically for you. Other cams do this when GPS or a motion sensing function determines that your car isn't moving anymore, thus is probably parked. This type of function does not require a HWK but again the time needed to do this varies by cam. Any cam which has any kind of parking mode can have that activated via a button push or menu selection.
The motion detection and impact sensing functions of many dashcams either do not work at all, or have such a small range of adjustability as to make them either not record minor events or to record tiny inputs you want them to overlook. Darn few cams get this right, and that can vary a bit between individual cams of the exact same kind. Research and questions to owners of the cam you have in mind are crucial to you getting a parking mode that works as it should. There are now a few cams which use
radar detection for activating parking mode recording. It's a somewhat new technology with some 'teething pains' but I think that once the glitches are worked out it will become the premiere parking mode detection scheme. Research well if you want to try this method.
On
recording continuously yes it is possible. I have at least one cam running in normal recording mode 24/7 because this is my preferred way of achieving parking protection. To do this requires a very good quality cam, a large SD card, and a large car battery (or external power such as a powerbank).
It will void the warranty of any cam, it will shorten the service life of your car battery, the cam, it's card, and if there's an event while you're absent you might have to view many hours of cam footage before you find the culprit and the event. Unless you use a HWK with low-voltage cutoff or external power to do this, you may discover a dead battery when you get back to your car. But other than with low-bitrate recording, this is the only method which will absolutely capture an event every time without fail for as long as the cam is working properly. I may have more experience doing this than anyone else on DCT as I've been doing it for 4+ years now with a few different cams and I can tell you that it's not for everyone but it works for me because I drive my vehicle every day and it has a huge battery compared to most cars. I've had only one time where I wanted to find recorded footage and that way a PITA to do. The odds of getting damaged while parked are usually very small but again that varies hugely from user to user and where we park, so it's your decision to try this or not. If anything goes wrong in the process it's on you.
I mentioned HWK's with
low-voltage cutoff. What these do is stop power to the can when the car battery reaches a minimum voltage that will prevent it from excessive wear or leave you with a no-start situation when you return to your car. Best to use a HWK which allows you to select the cut-off voltage- there are some which do not. It's generally advised to set that voltage level at 12.4 to 12.2 volts to best protect the car, but that can lead to you only getting a few hours of parking protection before the cam is shut down. With a newer car battery and easy starting conditions you may get away with a 12.0 volt setting but you will then get a markedly shorter service life from your battery, perhaps a 50% loss. Some non-adjustabkle HWK's are set as low as 11.6 volts; almost guaranteed to bring much failure. The easiest work-around to this problem is to use a powerbank when you're parked, but you have to remember to keep it charged and switch the cam power cable manually every time you drive and park which is too much for most folks to deal with. There are some hard-wired powerbanks made especially for dashcam user such as the Cellink and B24 devices. These switch from car to powerbank for you automatically and charge while you drive automatically too. Not cheap, but lots of folks use them. Their downside is that they do need adequate and regular driving time to charge, so they don't work well for occasionally driven cars or ones which only see very short trips. And their capacity is somewhat limited but usually enough.
Sorry for the "tldr" but all this is pertinent information which you will need to know to make the best selection of cam and how you want to gain parking protection from it. And you now see why I initially said it's more complex than it might seem
Phil