Wonky battery or wonky BT keyboard?

[iamsen47]

I have the Apple BT keyboard, been using it for about half a year. I put in a fresh set of batteries about 3 months ago. It remained at 100% the whole time but in the past couple of weeks, it's drained exceedingly quick.

I usually turn it off when I'm not using it. When I turn it back on, it's somewhere around 40~50%. Along the course of the day, it slowly drains till ~15%. Sometimes it cuts off.

Is this typical behaviour?
I know batteries restore their charge when left unused, but 20% -> 50% is quite a huge variation.

 

[GGJstudios]

I know it's very basic, but have you made sure the batteries are installed facing the right direction?

 

[iamsen47]

Yes I have.

Batteries were 43% when I made that post. It's 18% now.

 

[Giuly]

If you are using eneloops or Apple rechargeable batteries, that's normal. Low self-discharge NiMH batteries (read 'eneloops') keep their charge around 1.3V for the most time, but then drop rapidly. Regular AA alkalines have a different discharge curve.

And as Apple's charge sensing mechanism seems to be adjusted to alkalines, the meter drops to 50% relatively quickly, but stays there for the most time, and then drops rather quickly towards 0%. Usually, consumer electronics shut off at 1.1V.

 

[iamsen47]

Guess that makes sense. Thanks.