I'd like the monitor the current consumed by my 12v backup sump pump. I'll use this to determine if the pump is working. I will already be monitoring the float switch, so I'll know if it should be on. Comparing this to the current sensor should tell me if it's working correctly (if pump relay is on, but current consumption is not near the expected amount, then something is wrong). FYI the pump consumes around 13A when pumping.
I see two ways to get this data into my ADS1115 and then into the raspberry pi.
One would be a ACS712 current sensor. Unfortunately this is a 5v device so I'd have to add some complexity (a voltage divider?) to get the voltage into the range of the ADS1115 (which is a max of 3.6v since it's running on 3.3v to communicate with the raspberry pi). FYI a 20A version of a ASC712 circuit board outputs a base of 2.5v + 100mv for each amp.
Another idea I had was to measure the voltage drop between the battery and somewhere else in the circuit. I just used my voltmeter now and was able to see a .45v difference when the pump is running. Unfortunately when the pump is off I read the full battery voltage. I think this is because the relay switches the positive wire to turn on the pump, rather than switching the ground wire. So I'd have to figure out how to not to send the full 12v from the battery into the ADS1115 when the pump is off, or rewire my system so the ground is switched instead of the positive.
Thoughts? Thanks.
I see two ways to get this data into my ADS1115 and then into the raspberry pi.
One would be a ACS712 current sensor. Unfortunately this is a 5v device so I'd have to add some complexity (a voltage divider?) to get the voltage into the range of the ADS1115 (which is a max of 3.6v since it's running on 3.3v to communicate with the raspberry pi). FYI a 20A version of a ASC712 circuit board outputs a base of 2.5v + 100mv for each amp.
Another idea I had was to measure the voltage drop between the battery and somewhere else in the circuit. I just used my voltmeter now and was able to see a .45v difference when the pump is running. Unfortunately when the pump is off I read the full battery voltage. I think this is because the relay switches the positive wire to turn on the pump, rather than switching the ground wire. So I'd have to figure out how to not to send the full 12v from the battery into the ADS1115 when the pump is off, or rewire my system so the ground is switched instead of the positive.
Thoughts? Thanks.