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![](https://fry.gs/pictrs/image/c6832070-8625-4688-b9e5-5d519541e092.png)
Careful using the word efficiency there, as it has a different meaning when talking about solar panels - it indicates how much energy the panel can extract from the light hitting it. The best modern panels you can buy are below 25% efficient, and since these are from the 90s they were probably about half that when new.
RaspberryBye.