Battery under voltage protection

[Larry48]

How do i prevent my batteries from dropping below 50% , for example if i go to sleep and the furnace is running i may wake up with a low battery.
I would like the loads to stop drawing amps when the battery gets to 50%.
Thanks

 

[MikeRuth]

That's a tough call considering the LVD must be able to handle the load on the system. There are devices designed for this but I certainly can't recommend any that I know of.
I have no idea how much current is being pulled by your furnace and you will need to know this.

Here's just one example. https://www.amazon.com/Low-Voltage-Battery-Disconnect-EC-LVD2/dp/B00BEA5NPW

Mike R

 

[Oberneldon]

You can also opt for a 12 volt low voltage alarm that is programable to the voltage you wish to be alerted. Also available on Amazon

 

[tbair]

Here is a similar option that I have no experience with but would try since it is adjustable and cheap
https://www.amazon.com/GEREE-Excess...=1481036968&sr=8-6&keywords=low+battery+alarm
This has a 30A relay vs 40A above but I would only use the alarm portion since load shedding is pretty difficult to automate. For example you may not want to shut everything down if your batteries are just below the threshold and you have a short term high amp draw that you know is going to stop soon, you also might shut off a heater if it is 25 but might decide to put a bit more wear on you batteries if it is -10 and just before daybreak (solar on the way and need to get out of sleeping bag). You could use the above though just for its audio alarm and ignore the relay part.

Just some thoughts

 

[Goshawk]

You can also opt for a 12 volt low voltage alarm that is programable to the voltage you wish to be alerted. Also available on Amazon

Yes just get the alarm that goes off if voltage drops to 12.2 or lower. That means your power has reached its limit. Typically.


Sent from my iPhone using Tapatalk

 

[Larry48]

Here is a similar option that I have no experience with but would try since it is adjustable and cheap
https://www.amazon.com/GEREE-Excess...=1481036968&sr=8-6&keywords=low+battery+alarm
This has a 30A relay vs 40A above but I would only use the alarm portion since load shedding is pretty difficult to automate. For example you may not want to shut everything down if your batteries are just below the threshold and you have a short term high amp draw that you know is going to stop soon, you also might shut off a heater if it is 25 but might decide to put a bit more wear on you batteries if it is -10 and just before daybreak (solar on the way and need to get out of sleeping bag). You could use the above though just for its audio alarm and ignore the relay part.

Just some thoughts

I might buy that , when the alarm goes off i'll start my generator and then start charging ,,, i just remembered that my old Vector invertor had something like this built in except it was'nt adjustable , i accidently spilled sawdust in it and that killed it , anyways i have a new invertor model Shumacher pi 750 but i cant find no specs saying if it has a low voltage alarm , it only says it has low voltage shutdown.
The Shumacher has'nt set off a alarm when my battery got low but i was thinking maybe thats  because its turned off  , maybe i have to turn the invertor on and mayby then i'll have the low voltage alarm feature.

 

[Raven+Squid]

Add more amp hours if you can. If it's nawing at you that the batteries may be running low overnight probably need more capacity.

 

[Trebor English]

My cheap $20 Mohoo solar controler has a low voltage shut off.  It is programmed with how low the voltage can go until it shuts off and how high it has to get before it turns back on. If you use it to power the thermostat then the furnace or fridge is cut off also.  It could be used without any solar panels.  Just hook up the battery and the loads you want to control.

 

[frater secessus]

Here is a similar option that I have no experience with but would try since it is adjustable and cheap
https://www.amazon.com/GEREE-Excess...=1481036968&sr=8-6&keywords=low+battery+alarm

How would one go about adjusting pot to the desired setpoint?

Catch the batteries at 12.2v and turn the pot until it alarms/disconnects?
Connect the device to a variable output power supply """""""""""""""""

Or maybe there some trick with a multimeter that I am overlooking.

 

[tbair]

How would one go about adjusting pot to the desired setpoint?

Catch the batteries at 12.2v and turn the pot until it alarms/disconnects?
Connect the device to a variable output power supply """""""""""""""""

Or maybe there some trick with a multimeter that I am overlooking.

Variable resistor and multimeter would work, I would just run down the battery to 50% and use that if I was feeling lazy though