2-Slot 21700 Lithium-Ion Battery Holder (SMD / Surface Mount)

Specifications

• Battery Compatibility: 2x 21700 Cylindrical Cells

• Mounting Style: Surface Mount Device (SMD / SMT)

• Contact Material: Nickel-Plated Steel / Phosphor Bronze

• Housing Material: High-Temperature Resistant Plastic (UL94V-0 Rated)

• Negative Contact: Spring tension with 9-dimple grip pattern

• Positive Contact: Solid plate with circular contact node

• Configuration: Independent slots (Wireable in Series or Parallel via PCB)

• Brand Marking: Beilaimoo

Key Applications and Projects

• Custom Power Banks: Designing a high-capacity, dual-cell emergency phone charger PCB for extended off-grid trips.

• High-Drain Flashlights: Creating a custom driver board for extreme-output LEDs that require massive current delivery and extended runtimes.

• Robotics Power Supplies: Building a neat, swappable 7.4V (2S) battery distribution board for RC vehicles or autonomous rovers.

Unlock New Capabilities (Project Evolution) The Hot-Swappable 2S Drone Base Station: Don't limit your projects to built-in, non-replaceable batteries! Design a custom PCB that utilizes this 2-slot SMD holder wired in a 2S (series) configuration. Because the holder is SMD, the back of your PCB remains perfectly flat, allowing it to be mounted flush against a 3D-printed robotics chassis. Integrate a 2S BMS (Battery Management System) on the same board, and you now have a high-power, hot-swappable power management module where depleted 21700 cells can be popped out and replaced instantly to keep your equipment running continuously!

PACKAGE INCLUDED

• 1 x 2-Slot 21700 Cell Lithium Ion Battery Holder (SMT/SMD)

FREQUENTLY ASKED QUESTIONS (FAQ)

1. What specific battery size does this holder accept? It is engineered exclusively for standard 21700 cylindrical lithium-ion cells.

2. How many batteries does this holder accommodate? This specific model features two independent slots to hold two 21700 batteries side-by-side.

3. What do the numbers "21700" mean? They represent the physical dimensions of the battery: approximately 21mm in diameter and 70mm in length.

4. Can I use an 18650 battery in this holder? No, an 18650 battery (18mm diameter, 65mm length) is too short and too narrow; it will not make electrical contact or be held securely.

5. Are the two battery slots pre-wired in series or parallel? No, the slots are completely electrically independent. You determine whether they are in series or parallel by how you design the copper traces on your PCB.

6. How does this attach to a circuit board? It uses Surface Mount Technology (SMD). You apply solder paste to pads on your PCB and solder the four flat metal tabs that extend from the ends of the holder.

7. Are there any through-hole pins on the bottom? No, the bottom of the contacts are completely flat tabs designed exclusively for surface mounting.

8. Will this hold protected 21700 cells? Generally, no. Protected 21700 cells have an internal protection circuit that adds 3-5mm to their length. This holder is strictly dimensioned for standard, unprotected 70mm cells.

9. Can this holder withstand reflow soldering temperatures? Yes, SMD battery holders are typically molded from high-temperature plastics designed to survive standard reflow oven temperature profiles.

10. Why are there dots on the negative contacts? The negative spring contacts have a grid of dimples to increase physical friction and penetrate any minor oxidation on the battery terminal, ensuring a low-resistance connection.

11. How do I identify the positive ends? The positive ends feature a flat metal plate with a single, pronounced circular protrusion designed to touch the positive cap of the battery.

12. Is there a central divider between the two batteries? Yes, there is a plastic ridge running down the center of the holder to keep the two cells separated and physically secure.

13. Does this holder provide battery protection? No, this is a purely mechanical and electrical pass-through component. Over-charge and over-discharge protection must be handled by an external BMS circuit.

14. What voltage will this holder output? It outputs whatever voltage the inserted batteries provide and depends on your PCB wiring: 3.7V nominal if wired in parallel, or 7.4V nominal if wired in series.

15. What is the maximum current rating? While the exact rating depends on the PCB trace width and solder joint quality, standard SMD 21700 holders typically support 5A to 10A of continuous current per slot.

16. Is it safe for high-vibration applications like RC cars? Surface mount solder joints can be stressed by heavy vibration. For high-impact applications, it is recommended to add a strap or enclosure over the heavy 21700 batteries to take physical stress off the solder tabs.

17. Can I use LiFePO4 21700 cells in this? Yes, physically it will hold any 21700-sized cell perfectly, regardless of the internal chemistry.

18. Do I need to buy batteries separately? Yes, this listing is for the plastic and metal holder only. Batteries are not included.

19. How do I remove a battery from the holder? Simply push the battery against the dimpled negative spring contact to compress it, then lift the positive end out of the open top.

20. What does the text on the side of the holder say? The side molding indicates "SMT/THM FOR 21700 X 2" and features the brand marking "Beilaimoo".