Home › Builds › Wi-Fi router mini UPS: TP5000 charger, 1S BMS, four 18650s and a TPS61088 boost set to 12 V

Wi-Fi router mini UPS: TP5000 charger, 1S BMS, four 18650s and a TPS61088 boost set to 12 V

Bench build · Module builds · Beginner · about 35 minutes

Keeps a 12 V router online through a brownout, with no changeover gap. The router always runs from the battery through a TPS61088 boost module set to 12 V (it starts from 2.7 V, so it works down to an almost empty cell; an XL6009 needs 5 V in and would not run from one cell); the 5 V adapter keeps the battery charged through a 2 A charger board. When the power goes out nothing switches, so the router never even blinks. Four 18650s in parallel (10 Ah at 3.7 V, about 37 Wh) run a typical 3–4 W router for 8 hours or more, a busy 7 W one for about 5. Check the boost board’s output is 12.0 V with nothing connected before plugging in the router.

Wi-Fi router mini UPS: TP5000 charger, 1S BMS, four 18650s and a TPS61088 boost set to 12 V: the finished build running on the simulator's bench

Build it in the labGuided build, test sheet and fault finding, free in your browser.

zencircuitlab.com/l/wi-fi-router-mini

Parts list

Test procedure

Each test has an expected value and a pass range, like a factory test sheet:

  1. Mains on: router voltage
  2. Mains on: battery charging
  3. Brownout: router still at 12 V
  4. Brownout: router power, and current from the cells

How it works

What it does: Keeps a 12 V router online through a brownout, with no changeover gap.

Build it (guided or ready-made), then run its test procedure below. Every test has an expected value and a pass range, just like a factory test sheet.

Background

The “mini DC UPS” boxes sold for routers are this inside, often with fewer cells than the label says.

More builds: module builds