Hi Brody, I remember you from Tribe.
The trick to getting the most out of your solar powered batteries is to simply [b]upgrade the batteries[/b] that come with your solar light to better solar batteries.
The batteries in most solar powered lights (path lights, etc.) are only designed to last for 6 hours...because the manufacturer assumes that the lights don't have to work at 3AM (decent folks in the suburbs should be in bed). They figure it's better to conserve the solar battery energy spent between 3:00-6:00am as back-up power for those cloudy days.
However, the solar batteries that come in solar powered dock lights are designed to last all night and into the wee hours. The difference is the batteries.
So, just switch out the solar AA batteries that come in your store bought solar lights for some higher grade AA solar batteries, and they will last all night and into the wee hours of the morning.
Another suggestion I have for night time safety is using cheap, non-powered retro-reflective pinstripe tape (or just stickers) as an outline along the corners of your benches.
The tape won't work for 'darktards', but it will bounce back the lights from any flashlights or headlights (like a traffic sign or license plate does) from about 200 feet away. Never wears out, never runs out of batteries. $8 for a 40' roll.
You can get retro-reflective tape in pretty much any colour and/ or design, so it doesn't have to make your bench look like the side of a truck. The tape itself might even be invisible by day, or have a funky 'secret' night time design or pattern (flames, hearts, words, etc.)
I am also thinking of motion activated 'closet' lights, and using rechargeable batteries that you could recharge yourself in a hand-held solar charger as a back-up. These lights are about $10 each (in Canada), and light up for about 30 seconds whenever someone gets within six feet of them. They switch off after that, so they are pretty conservative of battery power. They have about a 60 degree radius, so it's pretty hard to 'sneak up' on them.
Six feet is not enough distance for the art cars, but their purpose would be mainly for the darkwads that would otherwise bark their shins on your bench, having no flashlights to bounce back the light of the retro-reflective tape. Art cars have headlights, and will see the retro-reflective tape on your bench clearly from 200 feet away. That is, if your solar lights completely fail for whatever reason.
These motion activated lights also makes your bench 'interactive' in a weird, minimalist way.