Greetings, first time posting in a while. Ive been in the works building a big Bluetooth speaker (original right) with the heart being a nice SLA battery i got for free that is in great health, takes and holds a charge great. i need some kind of a low voltage protection circuit. my original idea was to have the main VCC, straight off the battery, go through a relay, and have the low voltage cutoff dis engage the relay when a voltage threshold is hit. for SLA i think its around 11.5V. But because my SLA is fairly small at 4.5Ah i dont want a relay to always be drawing current. EDIT: latching relay? my current idea is use the same low voltage detector and power a 555 LED flasher for a "low battery" type thing, but then i have to manually shut it off to avoid over discharging.
For the circuit i need i THINK i would need a basic comparator and some kind of voltage divider, but i dont know how to do that
Can someone sketch me a circuit that will "turn on" when a voltage is reached? Can i have that output of said comparator power the 555 flasher or should i stay with the preferable relay hard shutoff method? BUT ill need a circuit for that too. i have the amplifiers, charging, fusing and bluetooth taken care of im just stuck on this part.