I'm working on an outdoor LED lighting project. It just basically works as a motion detection light (turns on when movement is picked up through a PIR sensor). The amount of LEDs I want to use brings the power consumption to 7.2W (12V, 600mA), but the LEDs will only stay on for 20 seconds per trigger from a motion detected (~40mA consumed?, can also limit it through the connected STM32 uC if battery levels are too low) It also incorporates a solar panel and battery charging devices (LTC4056).
I wanted to use multiple 18650 batteries (3-4) in parallel and charge them with the LTC4056, however, I read it's not safe to charge lithium batteries this way. It is best to charge them individually. The problem is I want to be able to use the capacity of multiple batteries to power the LEDs. It's possible that the LEDs will drain a single battery faster than the solar panel can fully charge it.
I came up with using multiple batteries, but multiplexed so that if the first battery drops below a reference voltage (3.7V), the circuitry will select a different battery to use. Also since each battery is connected to its individual LTC4056 it would be safely charged?
Is this design feasible? Or maybe there's a better solution/design to my problem?
I wanted to use multiple 18650 batteries (3-4) in parallel and charge them with the LTC4056, however, I read it's not safe to charge lithium batteries this way. It is best to charge them individually. The problem is I want to be able to use the capacity of multiple batteries to power the LEDs. It's possible that the LEDs will drain a single battery faster than the solar panel can fully charge it.
I came up with using multiple batteries, but multiplexed so that if the first battery drops below a reference voltage (3.7V), the circuitry will select a different battery to use. Also since each battery is connected to its individual LTC4056 it would be safely charged?
Is this design feasible? Or maybe there's a better solution/design to my problem?