The microSD card stores normal driving video, loop recordings, and supported event recordings for a 70Mai Dash Cam. Card quality, supported capacity, sustained write performance, and correct formatting all affect how reliably footage is stored.
[reference] Title: Card type Text: Use a microSD card that matches the capacity and speed requirements of your specific 70Mai model. Title: Endurance Text: A high-endurance card is better suited to repeated video recording and overwriting than a general-purpose card. Title: Loop recording Text: Older normal clips are overwritten as storage fills, while supported protected or event clips may be handled separately. Title: First setup Text: After inserting a new card, format it in the dash cam when that option is available. [/reference] [note] Supported capacity, menu names, recording segment length, and file-system behavior can vary by 70Mai model. [/note]Choose the Right microSD Card
Dash cams write video continuously and repeatedly reuse storage through loop recording. That workload is more demanding than occasional file storage, especially during long drives and in a hot vehicle.
Capacity
- 32 GB: suitable for lighter or shorter driving when supported.
- 64 GB: a practical general-use size for many drivers.
- 128 GB: useful for longer drives or more frequent recording.
- 256 GB: useful for long routes or professional use only when the specific model supports it.
A larger card generally keeps more normal loop-recording history before older clips are overwritten. Always stay within the maximum capacity supported by the specific dash cam model.
Speed Class
- Class 10 (C10): a common baseline for continuous Full HD recording.
- U1 / U3: U3 provides more write-speed headroom for higher bitrates and higher-resolution recording.
- V30 / V60: video-speed ratings found on cards designed for sustained video writing.
Class 10 / U1 is a basic starting point in this guide, while U3 or V30 provides additional margin for higher-resolution or higher-bitrate models. Sustained write performance matters more than a card's peak advertised speed.
High-Endurance Cards
[compare] Standard microSD | Intended for general storage and occasional writes; repeated dash-cam recording can wear it more quickly. High-endurance microSD | Designed for frequent write-and-overwrite workloads and is the preferred type for regular dash-cam use. [/compare]High-endurance cards are especially useful for daily driving, frequent parking surveillance, or long periods of powered recording.
Card Quality
Low-quality or counterfeit cards may report the expected capacity but become unreliable as they fill, run slowly, or corrupt recordings. Prefer reputable card brands and trusted sellers, and be cautious of unusually low prices.
[tip] If a card begins showing repeated write problems, slow behavior, or unexplained recording gaps, do not rely on it for important footage. [/tip]Capacity by Driving Pattern
Capacity should not be chosen by size alone. Card quality, endurance, supported capacity, and sustained write speed are more important than simply using the largest card available.
How the Dash Cam Uses Storage
- The camera records driving video as a series of short files; the exact segment length can vary by model and settings.
- Normal driving clips are used for loop recording.
- When the normal recording area fills, the oldest normal clips are overwritten automatically.
- Supported emergency, impact, or parking-event clips may be protected from normal loop overwriting or stored separately.
The repeated write-delete-write cycle places ongoing load on the card and its file system. Periodic formatting can help return the card to a clean recording state.
File System and Formatting
FAT32 is commonly associated with smaller cards, while exFAT is commonly used on larger-capacity cards. The exact format used by a 70Mai Dash Cam can vary, so the dash cam's own format function is the preferred setup method when available.
Formatting erases the files on the card. Copy any important clips elsewhere before formatting.
Prepare a New Card
[checklist] * Confirm the card is genuine and physically undamaged. * Confirm the card capacity matches what you purchased. * Check that the capacity is supported by your 70Mai Dash Cam model. * Use a suitable speed class for the recording resolution and bitrate. * Prefer a high-endurance card for frequent recording. * Back up any files already on the card before formatting. [/checklist] [step] 1. Stop recording or power off the dash cam first if your model requires it before card removal or insertion. 2. Insert the microSD card gently until it is seated correctly. 3. Power on the dash cam. 4. Open the storage or memory-card settings; the exact menu name can vary by model. 5. Choose the format option and confirm. 6. Allow formatting to finish without removing the card or interrupting power. 7. Confirm that normal recording resumes after the format is complete. [/step] [warning] Do not remove the microSD card or interrupt power while the card is being formatted. Important recordings should be backed up before formatting. [/warning]When to Format
Formatting is useful at first use, after moving a card between devices, when the dash cam requests formatting, or when storage behavior becomes inconsistent.
- New card: format it in the dash cam before regular use.
- Heavy daily use: a practical maintenance interval is about every 2–4 weeks.
- Lighter use: a 1–2 month interval may be sufficient.
- Repeated storage warnings or missing clips: back up important footage, then reformat the card and monitor recording behavior.
These intervals are general maintenance guidelines rather than fixed requirements. Actual needs can vary with model, recording load, card quality, and usage pattern.
Optional External Formatting
Formatting in the dash cam is normally enough. External formatting can be useful if the card has been used in several devices or has an unusual previous file-system layout.
[step] 1. Remove the card only after recording has stopped and the dash cam is safely powered down if required. 2. Insert the microSD card into a compatible card reader. 3. Use the connected device's storage tools to format the card. 4. If a file-system choice is offered, FAT32 is commonly used for smaller cards and exFAT for larger cards. 5. Safely eject the card. 6. Reinsert it into the 70Mai Dash Cam. 7. Format it again from the dash cam so the camera can prepare the storage layout it expects. [/step] [note] External formatting is optional. The final in-camera format is the important step when the dash cam provides its own format function. [/note]Signs the Card Is Wearing Out
Even high-endurance cards eventually wear with repeated recording. Watch for recurring symptoms rather than a single isolated message.
[troubleshoot] Problem: Repeated SD card or format messages Cause: The card may be worn, incompatible, poorly formatted, or unable to sustain recording writes. Fix: Back up important clips, format the card in the dash cam, and replace it with a suitable high-endurance card if the behavior continues. Problem: Missing files or gaps in recording Cause: The card may be slowing down, corrupted, counterfeit, or near the end of its usable life. Fix: Copy any important footage, reformat the card, then check recording again. Replace the card if gaps continue. Problem: The dash cam freezes, restarts, or stops recording unexpectedly Cause: Storage instability can be one possible cause. Fix: Check the card condition and compatibility, back up important clips, and test with a correctly formatted high-endurance card if needed. Problem: The card cannot be read by another device Cause: The file system may be damaged or the card may be failing. Fix: Prioritize any available backup, then replace the card if it remains unreliable after a safe reformat. [/troubleshoot]Do not continue relying on a card that repeatedly loses recordings or becomes unreadable.
How Capacity Affects Recording History
Because loop recording overwrites older normal footage, larger supported capacities generally keep a longer recording history. Actual duration depends on resolution, bitrate, active cameras, file length, and model behavior.
- 32 GB: may hold only a few hours of driving history.
- 64 GB: may hold several hours to roughly a day, depending on recording settings and driving time.
- 128 GB: may provide up to a couple of days for some usage patterns.
- 256 GB: can be useful for high-mileage or fleet use when supported.