When I first got my plugin in February this year, I was seeing a pretty consistent charge of up to 3 KWH each time I plugged in. Now, the max charge I'm seeing is around 2.7 KWH. In fact, the drop off started becoming noticeable in June, just 5 months after purchase. Anyone else seeing this? It's a pretty linear degradation.
to tell you the truth, i don't measure it, but what is recorded on the hsi, has always been the same for me. that's energy spent, not incoming.
Of course it depends on how far the battery was discharged. Here are my results where I calculate total battery capacity based on an assumed charging efficiency. You can can see the variation based on starting state of charge. You can also see some possible total battery capacity reduction with time.
Yeh - My charge degradation is similar. You can see the peak charges dropping pretty linearly over the last few months. I wonder how low it will go.
I have a 2012 PIP with just under 9 K miles. I only track my charge when I do a full charge from empty at a chargepoint station which happens about twice a month. On Jan 30 of this year Chargepiont reported that I used 2.691 KWh. This morning my charge took 2.739 KWhrs. Over this year the charge has varied from a low of 2.611 KWHrs to a high of 2.797 KWhrs. My start-up range has shown anywhere from 10.1 miles to 10.8 miles with the most common being 10.3. This estimate is pretty close to my actual miles per charge (City driving with lots of lights and stop signs). IIRC I have only seen values above 3 KWhrs once since I started tracking this and that was around the middle of 2013.