topic Re: If my Nest Learning Thermostat shows 40mA LIN, does that mean its charging the battery? in Nest Thermostats

If my Nest Learning Thermostat shows 40mA LIN, does that mean its charging the battery?

Royalboater — Sun, 03 May 2026 13:20:29 GMT

How do I know if the battery is getting charged?

I am seeing 40mA on the LIN.

I dont have a C-Wire but have a connection on RC.

Re: If my Nest Learning Thermostat shows 40mA LIN, does that mean its charging the battery?

Patrick_Caezza — Mon, 04 May 2026 03:57:09 GMT

@Royalboater

Check the power information menu by following this link.

Nest thermostat information menu - Power

Re: If my Nest Learning Thermostat shows 40mA LIN, does that mean its charging the battery?

Royalboater — Mon, 04 May 2026 11:13:10 GMT

@Patrick_Caezza, thank you.

I dont have a C wire, is the battery getting charged via one of the other wire(s)?

Re: If my Nest Learning Thermostat shows 40mA LIN, does that mean its charging the battery?

kelvinjack7 — Wed, 06 May 2026 19:48:46 GMT

40mA on LIN usually indicates low-level power/data communication, not necessarily active battery charging—Nest often trickle-charges through system wiring when available, but without a C-wire it may rely on power stealing so behavior can vary; if you’re troubleshooting device behavior like this.

Re: If my Nest Learning Thermostat shows 40mA LIN, does that mean its charging the battery?

Patrick_Caezza — Wed, 06 May 2026 01:21:16 GMT

@Royalboater

Kinda, The Nest has the ability to steal power from the W or Y wires from the system, but it doesn't always work

BY looking at the numbers on the Power information screen you can tell if it is keeping itself charged or not.

Post some pictures of those screen and I'll take a look.

Re: If my Nest Learning Thermostat shows 40mA LIN, does that mean its charging the battery?

Royalboater — Wed, 06 May 2026 11:21:55 GMT

@Patrick_Caezza see picture.