Toby wrote:looks also sweet, thx!
Also found a battery pack for the pump.
Is a 12V gel cell lighter as the other batteries? But you also need to carry a charger?
Here is a link that gives a good comparison of the 12V lead (gel cell) battery versus the Nickel Metal Hydride (Nimh) battery, comparing cost, weight, etc.
The lead gel cell battery is about 3 times as heavy, and cannot be recharged as many times... but I would get the lead battery, still, for the sake of simplicity, recycling, and other reasons.
If weight really matters a lot to you, then you could buy a Lithium Ion battery pack... but you would be in for more complexity and expense. Probably, the only kiters who would consider using the Lithium Ion battery are those who already are familiar with the use of such batteries, through the use of some other hobby, like radio-controled devices (airplanes, boats, etc).
For the average "Joe Kiter", who does not know a lot about electronics, does not even own a multimeter, doesn't know what 'polarity', amp hours, or reverse polarity, means, and does not want to know about techy stuff, the sealed lead battery (gel) would be the best choice.