AAA Battery in IHD3 - rechargeable or not?

ok cool, that’s what I thought. Thanks for confirming!

Just curious, what’s the purpose for the back up batteries? When there is no electricity – there is nothing to display, the meter itself wont be able to send any data. Am I wrong?

I guess it is so you can walk around the house with it to test what appliances are using etc.

The primary purpose is to keep the IHD functioning for Prepayment customers in the event they Self-Disconnect as a result of their credit running out - the backup battery allows the customer to still use the PPMID (Prepayment Meter Interface Device) functionality of the IHD to punch in UTRN Codes and restore supply without having to do so on the meter itself. This is something they rely on pretty heavily so it has to be a viable option.

But yes, a secondary function can be to make the IHD a bit more portable for short-term walking around the house.

It's a Friday afternoon and a short, amusing (well to me) story to round off the battery back up thread. A few years back when the energy prices went crazy I went round the entire house looking for vampire drains (fogotten devices plugged in / connected to the mains) to identify all of them and how much they took. The IHD was on the lower ring final (main) circuit and I had found and switched off all the power draining equipment except, annoyingly, the IHD was still saying 1W. All circuits in the consumer unit were off except the lower ring final. I double checked each socket again. Nothing was plugged in /wired in but still it said 1W. And suddenly went to zero when the backlight on the IHD went out!

Doh!