[tj2]

12 volts with 1.5 watts equals approximately 0.13 amps
even if the solar panel reaches 14 volts it will still only be a trickle charge current of around the same amperage
Basic charge rate on an optimate is around 0.6 amps or so.
I would presume that a good battery would be kept "topped up" in good sunshine conditions.................


Helps?


Cheers Terry