Battery Indicator

I get notifications about low battery for TRVs that show green / full battery status (from rooms & devices section). I've only ever seen full/ green, or empty / red. Is this the granularity if the battery indicator - basically completely empty or not completely empty?

Related to this I've had low battery notifications where the TRV carried on working for about 6 weeks (and was in use) - are there any known issues with the battery reporting/ measurements?

Comments

  • What battery chemistry are you using?

    You could measure the voltage when inserted with that when it's declared to be low and note the difference.

    NiMH (rechargeable) are 1.2V when fresh, Alkaline are 1.5V. I'm using the supplied Alkaline but got the low battery warning after only two months.

  • I don't believe that measuring voltage with a multimeter is reliable as there is no load.

    I believe an old battery can still deliver 1.5V (or close) but when a load is put on it, the voltage drops. I think the drop is what tado is measuring when the motor opens/closes the valve.

    Think about the example of a torch. When the battery is going low, the light dims but if you turn it off for a few seconds and back on, the light is bright then dims again as the load quickly drains the battery

  • That is true, but 'better' meters provide a load for testing 1.5V batteries.

    Probably not much of a guide if using Lithium (as I plan to do) because I don't think their voltage drops much, until the very end.

  • wateroakley
    wateroakley ✭✭✭
    edited March 2023

    We treat repeated email battery notifications with a big pinch of salt. Now using the recommended Panasonic eneloop 1900 mAh batteries that start at 1.45V. A) The loo TRV reports ‘low battery’ email warnings most days. Still working weeks later at 2.4V (1.2V + 1.2V). B) One bedroom TRV eats batteries. No warning till it goes off-line after a couple of weeks. I swapped the TRV for a spare and now keep the battery eater on the kitchen table to measure when it goes off-line. Latest off-line voltage was at 1.0V (0.8V + 0.2V).