Hi there,
I'm interested in modifying an off the shelf, automotive low battery voltage alarm. The devices inputs are Battery Voltage and Ground, and there is a single pot to modify the voltage at which the alarm triggers. I imagine that in essence it's little more than a comparator.
The issue is that once below the threshold voltage (say 10v for a normal automotive battery), the buzzer buzzes continously. That creates three issues. First, it drains a low battery even faster if you don't notice, possibly damaging it. Second it's a bit ridiculous, as well as annoying, to have it beeping continuously even after you've already connected the vehicle to a charger. And third, some chargers will not charge your car battery if they detect the continous drain which is a beeper buzzing, since it detects it as the battery not charging properly and shuts down.
Oddly enough, I haven't found any commercial low battery alarm that does this. At least not cheap and compact. The low battery alarm is less than 5 dollars.
All I want is something to put at the output of the device, before the buzzer, which would make the buzzer beep for a fraction of a second, stop for 10-30 seconds, beep for a fraction of a second, and so on. I'd like to use a 555 timer should it be suitable, but I've only seen how to easily make it "beep" symmetrically, as in 10 seconds on, 10 seconds off, and so on. That wouldn't be worth the effort for me.
The voltages would be less than 15v, and low currents. also don't know if the output voltage is constant until the battery drains, or if it decreases proportionally. I can look up both if needed, but don't know a priori.
I would be using either one of the following two circuits (I already have both).
First option:
Second option:
Is there any easy solution for this? Or better still if someone can point me to some post from someone who had the same issue? I didn't quite find it.
I'm interested in modifying an off the shelf, automotive low battery voltage alarm. The devices inputs are Battery Voltage and Ground, and there is a single pot to modify the voltage at which the alarm triggers. I imagine that in essence it's little more than a comparator.
The issue is that once below the threshold voltage (say 10v for a normal automotive battery), the buzzer buzzes continously. That creates three issues. First, it drains a low battery even faster if you don't notice, possibly damaging it. Second it's a bit ridiculous, as well as annoying, to have it beeping continuously even after you've already connected the vehicle to a charger. And third, some chargers will not charge your car battery if they detect the continous drain which is a beeper buzzing, since it detects it as the battery not charging properly and shuts down.
Oddly enough, I haven't found any commercial low battery alarm that does this. At least not cheap and compact. The low battery alarm is less than 5 dollars.
All I want is something to put at the output of the device, before the buzzer, which would make the buzzer beep for a fraction of a second, stop for 10-30 seconds, beep for a fraction of a second, and so on. I'd like to use a 555 timer should it be suitable, but I've only seen how to easily make it "beep" symmetrically, as in 10 seconds on, 10 seconds off, and so on. That wouldn't be worth the effort for me.
The voltages would be less than 15v, and low currents. also don't know if the output voltage is constant until the battery drains, or if it decreases proportionally. I can look up both if needed, but don't know a priori.
I would be using either one of the following two circuits (I already have both).
First option:
Second option:
Is there any easy solution for this? Or better still if someone can point me to some post from someone who had the same issue? I didn't quite find it.