OpenWrt UPS SNMP

Sets up NUT (Network UPS Tools) on a MikroTik 951Ui-2HnD running OpenWrt (20.0.0.26) to monitor a Tripp Lite SMART1500 UPS connected via USB.

View UPS status in the LuCI web interface (Services → UPS)
SNMP exposure so the UPS data is queryable from the network like the RouterOS device at 10.223.135.242

SNMP community: fsr

How it works

NUT usbhid-ups driver talks to the Tripp Lite over USB
upsd serves UPS data locally on 127.0.0.1:3493
luci-app-nut adds a UPS status page to the LuCI web UI
net-snmp extend entries call upsc to expose each UPS metric as an SNMP OID

This mirrors what RouterOS does natively for its connected UPS.

Deploy

./deploy.sh root@20.0.0.26

Or manually:

scp -r openwrt/etc/nut  root@20.0.0.26:/etc/
scp -r openwrt/etc/snmp root@20.0.0.26:/etc/
scp openwrt/install.sh  root@20.0.0.26:/tmp/ups-install.sh
ssh root@20.0.0.26 "sh /tmp/ups-install.sh"

Viewing UPS status

UPS status web page (nut-web-cgi):

http://20.0.0.26/cgi-bin/nut/upsstats.cgi

LuCI — NUT configuration only (not live status): http://20.0.0.26 → Services → NUT Server / NUT Monitor

CLI on the router:

upsc tripplite@localhost

SNMP from the network:

snmpwalk -v2c -c fsr 20.0.0.26 .1.3.6.1.4.1.8072.1.3.2

SNMP OIDs

UPS data is exposed under the NET-SNMP extend tree. Query with snmpwalk above or use individual OIDs for polling tools (Zabbix, LibreNMS, PRTG, etc.).

Extend name	UPS metric	Notes
`battery_charge`	battery.charge	%
`battery_runtime`	battery.runtime	seconds
`ups_load`	ups.load	%
`input_voltage`	input.voltage	V
`output_voltage`	output.voltage	V
`ups_status`	ups.status	`OL`=online `OB`=on battery `LB`=low battery
`battery_temp`	battery.temperature	°C (may not be reported by all units)
`battery_voltage`	battery.voltage	V

Each OID follows the pattern: .1.3.6.1.4.1.8072.1.3.2.3.1.2.<name-length>.<ascii-bytes-of-name>

Packages installed

Package	Purpose
`nut`	Core NUT tools (`upsc`, `upsmon`)
`nut-server`	`upsd` daemon
`nut-driver-usbhid-ups`	USB HID driver for Tripp Lite
`luci-app-nut`	UPS status page in LuCI
`net-snmp`	Full snmpd with extend support

Troubleshooting

UPS not found:

lsusb | grep -i tripp   # Tripp Lite vendor ID is 09AE
dmesg | grep -i hid

upsc returns "connection failure":

upsdrvctl stop && upsdrvctl start && upsd

SNMP returns "No Such Object" for extend OIDs:

Make sure net-snmp is installed, not mini-snmpd
Confirm /etc/snmp/snmpd.conf has the extend lines
Test the extend command directly: upsc tripplite@localhost battery.charge

SNMP not responding at all:

Check firewall allows UDP 161 inbound on OpenWrt
Network → Firewall → Traffic Rules → add rule for SNMP

3.0 KiB Raw Blame History