Battery Charging

[Cassidy]

Does anyone have much experience of using solar mats for recharging drill batteries and/or re-chargables for hi-output led divelights, maybe even scooter batteries.

I'm thinking of more remote areas - maybe lots of sun areas - were mains charging is not an option and batteries are specialised and not taken in great quantities.

What wattage output would be required for a solar mat? Cost? Availability? Availability to buy in the UK or Europe as well would be useful.

[TobinGeorge]

Does anyone have much experience of using solar mats for recharging drill batteries and/or re-chargables for hi-output led divelights, maybe even scooter batteries.

I'm thinking of more remote areas - maybe lots of sun areas - were mains charging is not an option and batteries are specialised and not taken in great quantities.

What wattage output would be required for a solar mat? Cost? Availability? Availability to buy in the UK or Europe as well would be useful.

Nickle based batteries require about 150-160% of capacity to be returned. In other words if you discharged a 100 watthour battery (~9 amphour @ 12 volts) you would need to return 150 watthours to recharge it.

For solar apps you should plan on only about 6 hours per day of good sun orientation.

150 / 6 = 25 watts of power required.

The charge efficiency of Li-Ion is much better, approaching 95%. That means to recharge a 100 watthour battery you only need a bit more than 100 watthours.

100 / 6 = ~ 17 watts.

For large scooter batteries the size of the solar panel gets huge fast.

Tobin

[deepairmike]

Most lights need 1-2 amps for 3-6 hours this would take a mat about 9 sqft. The same mat would take 3-4 days to charge a scooter. Could be done but $$$$ a small generator would be more cost effective.