Fredxx wrote:
On 20/02/2021 14:28, Theo wrote:
That may be true for some battery chemistries but not most. For example,
lead acid last longer if they don't undergo a deep discharge.

Solar lights will typically flatten its battery during the winter. I
would suggest the choice of battery chemistry is critical.

When people say 'solar lights' they usually mean the plastic sticks with a
small solar panel and a few NiMH cells. I've not seen those use lead acid.

Having said that, our lights do last a lot less time in winter, so the
amount of daylight is also an issue. I'd have thought that modern solar
cells would be able to produce usable power even on an overcast winter's
day.

The cells probably work less well in the cold.

I would have thought the opposite, diodes have a sharper IV curve at
lower temperatures and reverse current leakage would also be lower.

I meant the battery cells. The panel itself is happy in the cold (ask every
satellite).

Theo