How SD card recordings work?

[polaris]

Hi, it seems like a lot of Hikvision cameras support micro SD cards. My idea is to do continuous recording in NVR and to do motion recording to SD card. Is it possible? I would like to reduce wear on memory card by doing that.

 

[TonyR]

By the time your SD card is "worn out", your other devices will likely be technically outdated or already broken so you don't need to worry about "reducing wear on memory cards".

An excerpt from the FAQs of the SD Card Organization:

"What is the service life of an SD memory card?

This depends on how your product in manufactured. SD standards-based memory cards, like most semiconductor cards, store information in flash memory. The current technology along with normal usage typically gives the card a lifespan of 10 years or more, allowing consumers to upgrade their devices for many years and reduce consumer electronic waste."

 

[john-ipvm]

But running SD cards in cameras is significantly far more demanding than regular consumer use cases. These cards are written far more frequently in video surveillance and the cards are often placed in more environmentally challenging areas.

For example, both Axis and Hikvision re-brand / spec specific SD cards (here is Hikvision's one) because of many problems over the years with people using any SD card they wanted.

 

[polaris]

I've just done my own calculations and it does seem to be doable. My local Hikvision distributor provides 5 year warranty for cameras, so I would prefer a memory card to last the same amount of time.

For example 64GB WD Purple is rated for up to 64 TBW. Assuming a bitrate of 4 megabits/s, the card will store 1.5 days of recordings and will last up to 4 years.

This is far better than I expected and doubling the capacity should also theoretically double the lifespan.

Calculations:
Endurance = 1000 (64GB card is rated for up to 64 TBW, so it could be rewritten up to 1000 times)
Recording time (in seconds) = (CARD_CAPACITY_IN_GIGABYTES * 1000) / (CAMERA_BITRATE_IN_MEGABITS / 8)
Recording time (in days) = Recording time (in seconds) / 60 / 60 / 24
Card endurance (in years) = Recording time (in days) / 365 * Endurance

 

[TonyR]

Ah HA! SD Cards designed for surveillance video: Industrial SD and microSD cards and WD Purple microSD cards

 

[Bink]

For some of my Hikvision cameras, that only do motion recording to SD, I have to replace the flash card every two years or so. The good thing is they have a five-year warranty, so the replacement is free. IMHO, if you have an NVR, I’d do everything there and not bother with the cards.

 

[fenderman]

For some of my Hikvision cameras, that only do motion recording to SD, I have to replace the flash card every two years or so. The good thing is they have a five-year warranty, so the replacement is free. IMHO, if you have an NVR, I’d do everything there and not bother with the cards.

the cards are a backup

 

[Rebs]

the cards are a backup

By basic understanding is that the card is a redundancy in the case someone steals your NVR!

 

[fenderman]

If the NVR is onsite, and the whole house burns down (just a bad example), one would have lost the camera, SD card, and NVR.
A Cloud (oh no! I used the C word here ) backup is the only (?) thing that may help identify what happened.

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If you are going to speculate such insane absurdities, how are you going to upload to the cloud if the internet lines are cut. I know, I know, you have a cellular backup, but this oceans 11 perp is way ahead of you an jammed your signal. The reality is that fires that destroy the NVR are so rare its not worth contempating, more rare is a fire that burns the entire exterior of the home destroying the cameras. Cloud recording is a segment pushed by companies seeing to generate RMR without thinking things though.

 

[Tolting Colt Acres]

I've contemplated doing this but frankly it isn't cost effective given the price of the higher capacity cards.

A NUC is easily concealed; its unlikely the typical "smash and grab" break-in will have criminals who will take the time to find it.

 

[Rebs]

What minimum size is recommended for the standard 2mp starlight fanfare? 64gb? For me that would add about $35 (20 USD) extra per camera. 128 is not affordable in the WD purple Surveillance variety.

 

[fenderman]

Arson in some parts of town is not an insane absurdity. A restaurant and an automobile parts place were recent targets of arson in my neck of the woods. From the News footage, the destruction was complete: I didn't see anything that looked like a camera or an NVR that could be recovered. Streaming to the Cloud could have held some info on what happened, at least until the internet connectivity went out.

Then, we also have forest fires around here. Can't really blame/identify bad people for that kind of fire, but the only thing left standing in such an incident is the brick fireplace and the downstairs porcelain toilet.

Never put all your eggs in one basket. Or even two. Granted we don't usually drop the basket(s) all the time...

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Cutting the phone/internet lines is one of the first things they do. Nothing will be saved. Arsonists wear masks as well making your cameras worthless. You can go on and on with the contingencies but there will always be something. Cloud backup is for suckers. You are much better off with a second redundant recording device.

 

[john-ipvm]

Here is Hikvision making the pitch about why to use their SD cards:

 

[nbstl68]

Local news story a year or so ago caught some bad cops on camera ripping out and destroying a business's cameras and NVR...but they had installed a full 2nd system w tiny hidden cameras. Not as good quality recordings but got the job done in this case.
Just another example for backup.