Low voltage shutoff protection

[Model97]

I have a fridge that does not have low voltage protection built in. What’s the cheapest way of protecting my house battery in a failsafe way? I don’t want to have to be physically monitoring it.

 

[IdaSHO]

Cheapest? or suggested?

Loads of these cheap units available.
They seem to work well out of the box....

Amazon.com : CZH-LABS Electronics-Salon Low Voltage Disconnect Module LVD, 12V 10A, Protect/Prolong Battery Life. : Patio, Lawn & Garden

Amazon.com : CZH-LABS Electronics-Salon Low Voltage Disconnect Module LVD, 12V 10A, Protect/Prolong Battery Life. : Patio, Lawn & Garden

www.amazon.com

What I would suggest is something along the lines of this...

Amazon.com: Victron BatteryProtect BP-65-65AMP - 6-35 VDC [BPR000065400]: Electronics

Buy Victron BatteryProtect BP-65-65AMP - 6-35 VDC [BPR000065400]: Power Inverters - Amazon.com ✓ FREE DELIVERY possible on eligible purchases

www.amazon.com

 

[VanWaLife]

I just installed the Bluesea m-LVD in my rig. Good balance between cost, features, and reliability IMO.

m-LVD Low Voltage Disconnect - Blue Sea Systems

Senses low battery voltage and disconnects non-critical loads to save power for engine starting.

www.bluesea.com

 

[john61ct]

The generic term to google is "Battery Protector"

Being able to adjust the setpoint is IMO important.

 

[hour]

You could get the Victron BatteryProtect 65a "smart" version for $60 and set a custom shutoff point. And also have a way to view your battery voltage whether the fridge is running or not on your phone via bluetooth.

(er yea like IdaSHO said)

 

[Model97]

Thanks for all the help. I'm conversant in valence electrons but helpless with I^2*R electrons.

 

[Rando]

The relay based Low Voltage Disconnects (such as the BlueSea mLVD) have a pretty major flaw in that they require 100mA or so to keep the relay energized. If you don't have solar or drive the vehicle for a week or two, this pretty much guarantees you will need the LVD, as the LVD itself burns through about 17Ah a week.

The MOSFET based ones (eg the Victron Battery Protect) don't have this issue as they only draw 1mA or so whether on or off. You do have to be careful how you wire them thought to make sure the current only flows one way.

 

[verdesard0g]

Thanks for all the help. I'm conversant in valence electrons but helpless with I^2*R electrons.

chemestry over electronics huh?
For DC circuits all you need to know is I=E/R and all the varations of that one equation.
And by the way current does not take the path of least resistance, it takes ALL paths.

 

[john61ct]

A master switch at the House bank is essential for when the rig is not in use.

And for routine maintenance

and especially for in emergencies.

But yes, very low parasitic draws are better than big ones, whatever the device type.