The 1040 battery life is immense. Very impressive. Solar even more so.
However, be warned if you do finally run out of battery there’s no warning - just dies. Further, you aren’t able to connect it to a portable backup power source and immediately power it back on again - instead it seems to need to charge up a small amount first (10-15 minutes) this being similar with other modern electronic devices.
On the plus side, when it does power up, your unsaved data is there waiting for you.
Bug logged.