Low Voltage DC Battery Relay to 120V AC Contactor

[BlueMarblePA]

I need the wisdom of the group.

I have a 24V 100Ah battery Battleborn LiFePo4 charged by solar 1.1kW. In the summer, I want to run an electric pool vacuum cleaner 180watts. I want to create a low voltage DC disconnect.

I am new to this, and I have no electrical background.

I am thinking I need a low voltage disconnect relay that sends a signal in low amps

https://www.amazon.com/Digital-Battery-Low-Voltage-Protection/dp/B07929Y5SZ/ref=sr_1_14?crid=IKVVMPGCA6RB&keywords=low+voltage+disconnect+24v&qid=1669998888&sprefix=low+voltage+disconnect+24v%2Caps%2C50&sr=8-14

OR this one

https://www.amazon.com/Acogedor-Monitoring-Over-Voltage-Under-Voltage-Protection/dp/B07RBX718L/ref=sr_1_2?crid=2BG8GROC1KSYX&keywords=low+voltage+disconnect+svr1000+single+phase+overvoltage+under+voltage&qid=1669999163&sprefix=low+voltage+disconnect+svr1000+single+phase+overvoltage+under+voltage%2Caps%2C36&sr=8-2

Then the signal needs to connect to the 120V high amperage AC line black/neutral through this contactor

https://www.amazon.com/Contactor-Replacement-Compatible-Conditioner-Refrigeration/dp/B095KKYL6B/ref=sr_1_4?crid=L9QW13EEAL16&keywords=120v%2Bcontactor%2Bcoil&qid=1669998382&s=industrial&sprefix=120v%2Bcontactor%2Bcoil%2Cindustrial%2C47&sr=1-4&th=1

I am confused, though. One is sending DC current, and the other is expecting AC current. I just want to sense low battery DC voltage and then shut off AC current and stop my vacuum cleaner which will be on a timer.

 

[Bob B]

Is something like this what you are looking for? https://www.mobile-solarpower.com/automatic-transfer-switches.html

 

[TacomaJoe]

Your inverter should have low voltage disconnect. Are you looking to build something that has a different voltage cut out?

 

[BlueMarblePA]

Is something like this what you are looking for? https://www.mobile-solarpower.com/automatic-transfer-switches.html

My solar system is currently not connected to the grid and so I don't think the transfer switch would work, unless I can just use it as a programmable disconnect?

 

[BlueMarblePA]

Your inverter should have low voltage disconnect. Are you looking to build something that has a different voltage cut out?

I was thinking of just letting the battery bms do its thing disconnecting at low voltage, but it seems that the restart procedure requires connecting it to a high amperage car battery to wake it up.

Hence I want to disconnect before I reach that low of a voltage

 

[TacomaJoe]

Hence I want to disconnect before I reach that low of a voltage

Do you know what voltage your inverter shuts down at. My inverter stops before my battery BMS cuts out. No wake up needed.

 

[BlueMarblePA]

Do you know what voltage your inverter shuts down at. My inverter stops before my battery BMS cuts out. No wake up needed.

I looked this up. Unfortunately my inverter low voltage cut off is too low. I think it would work for lead acid battery? But not for lifepo4?

 

[Bud Martin]

Does your inverter have remote ON/OFF terminal? spec of the inverter?

 

[BlueMarblePA]

Does your inverter have remote ON/OFF terminal? spec of the inverter?

It does have a remote. Cotek sk-1500 24v model.

I tried to figure out the wiring to turn it on and off with the telephone wire cable? I couldn't find it, but this would be another option