Charge/discharge efficiency

ZenUser306By01c

Strange: can it be that the loss of energy when storing in the battery is so high?
I charged 34 kWh and could only retrieve 20 kWh (this month, up to today). That's really bad: 14/34 lost, or 40%. Is my battery bad, or is the electronic circuit so bad?
I can't believe it.
Any advice from anyone?

Jochen Zen

Well, there is consumption for wifi etc... maybe 30W as my Hyper reports. So around 2.5 kWh per month. And with my Hyper, I observed an efficiency around 70 percent.
If you want to to measure only efficiency then discharge fully, charge fully and discharge it quite fast so with the 800 watt.