21700 Mini UPS Enclosure for a Router

Building a router UPS from 21700 cells? We print a PETG enclosure for it: cradles for the cells, room for a BMS and a 12 V converter, cut-outs for DC jacks, a switch and a voltmeter, and vents above the boards. You buy and assemble the electronics — the enclosure arrives ready for assembly.

Order the “Compact” enclosure All models

Models

A printed PETG enclosure and lid — we’ll reply to your request with the price. You buy the cells, BMS, converter, jacks, switch, voltmeter and self-tapping screws yourself — the list is below. We print from 1 day and ship by Nova Poshta across Ukraine.

Compact for 3 × 21700
The cells lie side by side in cradles, the boards next to them. At the end — two DC jacks (12 V in and out) and a switch; on the lid — a voltmeter window and vents above the converter.

Size
147 × 77 × 34 mm
Cells
3 pcs, 3S1P

Get a price
Router stand for 6 × 21700
A flat block for 6 cells with the router standing on eight ribs on top — air flows under it. At the front — a switch and a voltmeter, at the back — DC jacks.

Size
155 × 147 × 37 mm
Cells
6 pcs, 3S2P

Get a price
Wall-mounted, 3 × 21700
A slim wall enclosure: the cells at the top, the boards at the bottom, the jacks and switch underneath so the cables hang down. Two keyhole slots for screws at the back.

Size
79 × 34 × 153 mm
Cells
3 pcs, 3S1P

Get a price
Didn’t find your version?
Tell us what you need — we’ll pick one of ours or make one just for you.
- A different size or colour
- Your text, name or logo
- A completely different shape — we’ll model it ourselves
Message us
We reply within an hour during working hours. Modelling is charged separately.

What to buy

We send only the printed enclosure and lid. You buy the rest at an electronics shop; the sizes below are the ones the enclosure is designed for.

Cells: 3 or 6 identical 21700 cells from one batch, up to Ø21.7 × 70.8 mm
Protection board: a 3S BMS rated 10–20 A with balancing, up to 60 × 46 mm
Router power: a 12 V 2–3 A converter up to 50 × 30 mm, plus a 3S charging board or charger
On the panel: 2 panel-mount 5.5 × 2.1 DC jacks (Ø8.2 hole), a KCD1 rocker switch (19 × 13 mm cut-out), a 0.28″ voltmeter
Fasteners: 4 self-tapping screws 3 × 10 for the lid; for the wall version — 2 screws with plugs; 4 rubber feet

An enclosure for a DIY UPS

People build router mini UPS units from 21700 cells themselves because it is cheaper and gives more capacity than ready-made ones — but the boards and cells need a home. We print an enclosure with a place for everything: the cells sit in cradles and don’t move, the boards are behind a divider, and the cut-outs for jacks, a switch and a voltmeter fit common sizes. Assembly and electronics are yours: we sell only the enclosure.

How long the router will run

Roughly: a 10 W router runs for about 4 hours on three 4.8 Ah cells (3S1P, ≈ 53 Wh) and 8–9 hours on six (3S2P, ≈ 107 Wh). The exact time depends on the cells, the converter and what else the UPS powers: an optical terminal adds another 3–5 W.

Safety

Never build it without a BMS: it protects the cells from overcharge, deep discharge and short circuits.
Use identical cells from one batch, at the same voltage before assembly.
PETG holds its shape up to about 70 °C: keep the enclosure off radiators, out of the sun and out of closed niches without airflow.
The enclosure protects against knocks, dust and touch, but it does not replace a BMS and a fuse.

Fits your boards

The enclosure is a parametric model: if your BMS or converter is larger, or you need a different number of cells, send us the dimensions — we’ll adjust the enclosure and quote it by weight. A ready-made mini UPS goes on the wall with our mini UPS and router holder, cells are stored in the 18650 and 21700 battery box, and an enclosure from your own model is on the power bank, UPS and battery enclosures page.

Close-up

The router stand at work: the router sits on the ribs with air flowing underneath.

Images are renders of the 3D model — this is how the product will look once printed.

FAQ

Do you sell a ready-made UPS?

No, only the printed enclosure and lid. The cells, BMS, converter, jacks and assembly are yours. A ready-made mini UPS goes on the wall with our mini UPS and router holder.

Which cells fit?

Any 21700 cells up to Ø21.7 × 70.8 mm — for example Samsung 50E, Molicel P42A or LG M50LT. Use identical cells from one batch, and only with a BMS.

Will my boards fit?

There is room for a BMS up to 60 × 46 mm and a converter up to 50 × 30 mm. Different sizes? Send us the board dimensions — we’ll adjust the enclosure and quote it by weight.

How long will the router run?

Roughly, a 10 W router runs for about 4 hours on three 4.8 Ah cells and 8–9 hours on six. The exact time depends on the cells and the converter.

Won’t the enclosure overheat?

PETG holds its shape up to about 70 °C, and there are vents above the boards. Keep the enclosure away from radiators, out of the sun and out of closed niches.

Can I get another colour?

Yes, we print PETG in different colours — tell us which one you need.

Other products

All ready-made products (40)All 3D printing services

Your own size or a different number of cells?

Send us the board dimensions and the number of cells — we’ll adjust the enclosure and quote it by weight.

Telegram WhatsApp Fill in the form