Solderless 21700 Battery holder

2026-08-05 07:42
Status :
Tags: #mesh #design #personal

Solderless 21700 Battery Holder

Designed with low cost and 3d printing in mind.
Designed for very low power draw applications such as LoRa nodes, weather stations etc.
Will hold one 21700 cell.
Additional holders can be added using printed in connectors. Pass through slots will allow one piece of nickel strip to pass through multiple holders.
Parallel only
Will hold nickel strip in place through the use of slots and channels printed into the holder.
Pressure will be provided by machine screws that wedge part of the holder against the nickel strip and battery.
Nickel strip can be locked in using slots placed at one end of the holder.
16 holders can easily be arranged on a 256x256 build plate.
Around 16 grams per holder.
Print time of around 67 minutes per holder.

Solderless 21700 Battery holder-2026-08-07.png

Final Notes

After the third iteration I am mostly satisfied. The fitment of the batteries remains very tight even though I've made adjustments to this in both iterations. Extending the holder length again should alleviate this in my final iteration. The final prints will be in ASA to see if that causes any issues.

Cost

Qty.	Material	Cost	Per	Extended Cost
16	ASA Filament	$0.025	Gram	$0.40
2	M2 Screws	$0.02	ea	$0.04
6	Nickel Strip	$0.0102	cm	$0.061
	Total Cost			$0.50

3D Prints

Print	Date	Notes
1	2026-08-05	First prototype print. Almost there. Needs the nickel strip pathway adjusted on one end? Or check the slicer for issues. (Issue appears to be in the slicer. Arachne was not selected when slicing the first prototype.)
1		Increase the pathway size for the nickel strip slightly. Do not increase the locking slot. (Complete 2026-08-05)
1		Increase the screw hole size slightly. the fitment is very tight. Much tighter than a typical battery holder with spring contacts. (complete 2026-08-05)
1		Make the mating pins larger, and tighter. (complete 2026-08-05)
1		Add depth to bottom of the base and increase the screwhead clearance. (Complete 2026-08-05)
2	2026-08-05	Larger alignment pins are causing thin wall issues. Will move them inboard to accomodate (Complete 2026-08-06)
2		Adjusting alignment holes to increase snugness (Complete 2026-08-06)
2		Fitment still very tight. Considering adding length to the holder. (Added .1mm 2026-08-06)
2		Need to chamfer screw holes at the top. (Complete 2026-08-06)
2		Increased height of nickel strip slots by .2mm (Complete 2026-08-06)
Extras		Replace the two rear mounting screws with four located outboard of the current screw hole location. two screw holes would be clearance holes, and two would be sized for an m2 screw to thread in. Arranged so two holders can be screwed together back to back. (Added this feature 2026-08-06)
3		Battery fitment still too tight and the pins are still not snug. Plan to add more length to the holder and decrease the clearance setback from the pinholes.