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

Specifications

• Battery Compatibility: 4x 21700 Cylindrical Cells

• Mounting Style: Surface Mount Device (SMD / SMT) with auxiliary screw holes

• Contact Material: Metal Alloy (Phosphor Bronze/Nickel-Plated Steel)

• 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)

Key Applications and Projects

• High-Capacity Power Stations: Designing a 4P (parallel) emergency power bank PCB for camping and off-grid electronics charging.

• Heavy-Duty Robotics: Building a neat, swappable 14.8V (4S) battery distribution board for large RC vehicles, rovers, or hexapods.

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

Unlock New Capabilities (Project Evolution) The 14.8V Modular Drone Base Station: Stop relying on expensive, proprietary battery packs! Design a custom PCB that utilizes this 4-slot SMD holder wired in a 4S (series) configuration alongside a 4S Battery Management System (BMS) IC. Because the holder is SMD, the back of your PCB remains perfectly flat, allowing it to be mounted flush inside a 3D-printed chassis. You now have a high-power, hot-swappable 14.8V power management module where depleted 21700 cells can be popped out and replaced individually, keeping your drones or robotics running without waiting for a sealed pack to charge!

PACKAGE INCLUDED

• 1 x 4-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 four independent slots to hold four 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 18650 batteries in this holder? No, 18650 batteries (18mm diameter, 65mm length) are too short and narrow; they will not make electrical contact or be held securely.

5. Are the four 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 flat metal tabs that extend from the ends of the holder.

7. What are the circular holes in the plastic base for? Because four 21700 batteries are heavy, these screw holes allow you to mechanically mount the plastic chassis to your PCB or enclosure, relieving physical stress from the solder joints.

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

9. 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.

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

11. 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.

12. How do I easily identify the positive ends? The plastic housing has a small "+" sign molded into the base near the positive terminals, which feature a single circular protrusion.

13. Is there a central divider between all the batteries? Yes, there are plastic ridges separating each of the four cells to keep them isolated and physically secure.

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

15. What voltage will this 4-slot holder output? It outputs based on your PCB wiring: 3.7V nominal (4P), 7.4V nominal (2S2P), or 14.8V nominal (4S).

16. What is the maximum current rating? Standard SMD 21700 holders typically support 5A to 10A of continuous current per slot, heavily dependent on your PCB trace width and solder joint quality.

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. Can I hand-solder this component? Yes. Because the SMD tabs extend slightly outward from the plastic body, they are accessible with a standard soldering iron tip, making hand-soldering onto PCB pads very straightforward.