

As he says, it is rated at 9w and is amazingly bright. At 9W, it would consume 1Ah in 1 hour 20minutes. So a 3.2Ah battery would last over 4 hours between recharges. However, you will not see THAT sort of life out of the one on the MB site, as I doubt if that is rated as 0.5Ah (and it has really cheap terminals on the end of the wires).
If you want to check out batteries, visit the Yuasa website. The download files gives you all the info you should ever need.
http://www.lucasbatteryshop.co.uk/data- ... ds-4-w.asp
I have my own plans for this spotlight, on a full DC system.
