Solar Panel Charger

So I have been looking for different solutions for charging a battery without a power supply in the garage. I tried the small Oxford solarizer panel but it was useless. Saw this and thought I'd give it a go. It's a proper solar panel and had good reviews.

I wasn't expecting amazing results as it is winter and most days it's overcast. However reviews and their own literature suggested I would still get a good charge despite it being overcast.

I've used it four days initially, 3 were overcast but still bright and one had clear skies and strong sunlight.

My battery started on 3.90v and after day four that had risen to 3.94v.

I was fairly disappointed. As the battery was so low I stuck it on a mains charger thinking maybe that was a reason it wasn't getting an increase in charge. I wanted the clip in panel as removing the battery is a ball ache as I have a few bits wired in and to get to the battery I have to get under the tank. I charged the battery overnight and put it back first thing. Voltage was 10.2v. I left it for another 3 days. 2 days were overcast and bright but a few showers and then one day clear skies. My voltage was exactly the same, 10.2v at the end of the three days.

I'm sure in summer you'd see much much better results, but in summer I use the bike in the day when it would be best charged. Also I don't loose charge then, it's winter time when the voltage drops so defeats the purpose of my buying it.

Long post but thought I'd share my experience!