Most LED lights require a driver or 'light engine' to operate and that driver has an input range. The LED's I'm using myself will accept anything from 9V to 50VDC which makes a 3S1P (11.1V) ideal. The initial voltage will drive them effeciently and when the voltage drops below the minimum 9V required, everything shuts down. Which has the secondary effect of protecting the Lipo cells from over discharging.

I went to Lipos because lead acid, besides being heavy, doesn't like heavy drains or deep discharges. The rated capacity falls off rapidly and they are only good for a few hundred cycles. Some people might be happy with that - I use batteries for multiple applications, some of which draw a lot of amps, and I want to get as long a useful life as possible - hopefully hundreds of charges at close to full capacity. So far, moving into the second year - everything still looks good.