Battery voltage never increases

Should I be concerned that my battery voltage is always decreasing and never seems to get a significant charge?

The unit is situated in an unshaded area, but even on bright days the voltage doesn’t seem to recover.

Is this likely to be fault with the hardware or do I have to accept that this will eventually die during the winter and only really work during the summer?

Thanks for any advice

4 posts were merged into an existing topic: Tempest Battery Not Charging; Need Power Booster