low temperature cutoff switch

[geoloz]

hello and thanls in advance for help. I have an rv solar system that uses 2 agm batteries, 2 90 watt panels, go power ul 30 controller. I want to convert to lithium batteries.

I want to buy the ckin older battery w/o low temp cutoff and add an external lo temp disconnect switch.

Question:

what switch do I buy and how do (where) instal it?

thanks
geoloz

 

[time2roll]

Temperature controlled relay

Connect the relay to a DC contactor. In storage the battery could just be disconnected. If in use a silicone battery heater might serve you better.

 

[12vDC]

There are many temp relay controllers on the net, eBay, and Amazon.

I have used a couple from Amazon with success. Manuals are written in Chinglesh or are hard to find.

There is an interesting mix of naked PCB's like in the post above, and also a bunch which are enclosed.

Currently using this one: Temp Relay because it fit the form factor of my install.
I took mine apart and siliconed the frame and interface and then put it in an Amazon plastic jbox since it is installed underneath my van exposed.

 

[mikefitz]

PWM controllers are not ideal for Lithium, usable but not the best option, and the Gopower ul30 is very overpriced.
The problem with a relay or module. is that it will consume power. A better option is a mechanical thermostat switch,

KSD301 Temperature Switch Control Sensor Thermal Thermostat 5°F-86°F/-15°C-30°C | eBay

KSD301 Thermostat Temperature Thermal Switch Normally Open/Closed NO/NC. Automatic reset. Application for household electric appliances, PC, microwave ovens, Irons, refrigerators, electronic oven, heating unit, coffeepot, water heater, and many more.

www.ebay.com

Although not rated for DC should be OK in the panel positive lead with a 90 watt panel.

An alternative would be a battery with low temperature cut off or a controller that could be configured to stop charging at low temperature