gltrimble
2017 170 4x4
LITHIUM BATTERY HEATING SYSTEM
Earlier in 2020 I installed four Lion Energy 105 ah lithium batteries, replacing my existing AGM batteries. The new lithium batteries were slightly smaller in size compared to the AGM batteries which provided enough space to wrap each pair of batteries with an 80 watt battery heater and 3/4” of mini-cell foam for insulation. I also installed two Victron Battery Sense Bluetooth temperature monitors. Now that snow season is approaching I needed to finish up the control system for my battery heaters. Each heating pad is rated for 80 watts but my test showed they consumed about 60 watts. They are 120 volt heaters. I chose a pair of Inkbird 12 volt temperature controllers to activate the battery heaters. I had also installed the Inkbird temperature sensors in the middle of each pair of batteries.
I used a 4”square plastic electrical box from Home Depot to house the external components and connections of the heating system. The electrical box contained a dual DC-AC relay, one 120 volt lead/plug for each pair of batteries, one lead/plug for the 120 volt power supply, and two wires from each temperature controller.
I installed the electrical box in the center of the van underside directly on a crossmember. A combination of VHB tape and a couple of sheet metal screws secured the box. The 120 volt power source was already present via my heat tracing I had previously installed to heat the external water lines. A simple $2 male/female 120 volt splitter from Home Depot allowed me to intercept the existing 120 volt plug. All of these 120 volt connections were conveniently tied to my “freeze protection” circuit.
I ran a total of eight 16 gage conductors from the underside of the van into the van through two new penetrations for the Inkbird controllers. Four wires for the pair of temperature sensors and four wires to activate the AC heating relay. I located the two Inkbird temperature controllers in a new aluminum panel I fabricated to replace a wood panel that accessed my inverter. The controllers would be at floor level but once they were programmed I would only need to access them during cold weather trips if at all. In cold weather, I typically turn my freeze protection circuit on which activates the battery heating, heat tracing of the external plumbing, and the water heater low temperature controller (also an Inkbird).
initial testing of the system was achieved by setting the controller to 65F, above the battery temperature of 60F. With the amount of battery mass and the low wattage the battery heaters are slow to effect a change in the battery temperatures. It took 20 minutes or more before the batteries slowly warmed up. For now I programmed the controllers to activate at 40F with a 3 degree window before shutting off. I will do a real world test next month in the local mountains where it is already snowing periodically.
As mentioned earlier I also installed a pair of Victron Battery Sense temperature monitors. These sensors work using Bluetooth and are powered by the battery terminals. I can read the battery temperatures using the same Victron app for my battery monitor and my solar controller. The Battery Sense also communicates with the solar controller allowing it to shut down when the temperature falls below 41F.
Earlier in 2020 I installed four Lion Energy 105 ah lithium batteries, replacing my existing AGM batteries. The new lithium batteries were slightly smaller in size compared to the AGM batteries which provided enough space to wrap each pair of batteries with an 80 watt battery heater and 3/4” of mini-cell foam for insulation. I also installed two Victron Battery Sense Bluetooth temperature monitors. Now that snow season is approaching I needed to finish up the control system for my battery heaters. Each heating pad is rated for 80 watts but my test showed they consumed about 60 watts. They are 120 volt heaters. I chose a pair of Inkbird 12 volt temperature controllers to activate the battery heaters. I had also installed the Inkbird temperature sensors in the middle of each pair of batteries.
I used a 4”square plastic electrical box from Home Depot to house the external components and connections of the heating system. The electrical box contained a dual DC-AC relay, one 120 volt lead/plug for each pair of batteries, one lead/plug for the 120 volt power supply, and two wires from each temperature controller.
I installed the electrical box in the center of the van underside directly on a crossmember. A combination of VHB tape and a couple of sheet metal screws secured the box. The 120 volt power source was already present via my heat tracing I had previously installed to heat the external water lines. A simple $2 male/female 120 volt splitter from Home Depot allowed me to intercept the existing 120 volt plug. All of these 120 volt connections were conveniently tied to my “freeze protection” circuit.
I ran a total of eight 16 gage conductors from the underside of the van into the van through two new penetrations for the Inkbird controllers. Four wires for the pair of temperature sensors and four wires to activate the AC heating relay. I located the two Inkbird temperature controllers in a new aluminum panel I fabricated to replace a wood panel that accessed my inverter. The controllers would be at floor level but once they were programmed I would only need to access them during cold weather trips if at all. In cold weather, I typically turn my freeze protection circuit on which activates the battery heating, heat tracing of the external plumbing, and the water heater low temperature controller (also an Inkbird).
initial testing of the system was achieved by setting the controller to 65F, above the battery temperature of 60F. With the amount of battery mass and the low wattage the battery heaters are slow to effect a change in the battery temperatures. It took 20 minutes or more before the batteries slowly warmed up. For now I programmed the controllers to activate at 40F with a 3 degree window before shutting off. I will do a real world test next month in the local mountains where it is already snowing periodically.
As mentioned earlier I also installed a pair of Victron Battery Sense temperature monitors. These sensors work using Bluetooth and are powered by the battery terminals. I can read the battery temperatures using the same Victron app for my battery monitor and my solar controller. The Battery Sense also communicates with the solar controller allowing it to shut down when the temperature falls below 41F.
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