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Old 10-06-2021, 08:18 PM   #3
91cavgt
Ten Point
 
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Join Date: Jun 2013
Location: San Antonio
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On this video I go over some progress. Got the weather stripping replaced on the back doors, except for the bottom. Later I will be putting weather stripping at the bottom of the doors to help keep out creepy crawlys.

I found a solar panel that fits the roof PERFECTLY!!! It is about 4’ wide and 7’ long and less than 1/4” thick. It is also flexible with no glass on it so no worries about hail damaging it. Found this panel on eBay as a NOS model. It is a VERY high voltage but low amperage model. It puts out a little over 74 volts and a hair over 3 amps. This makes it around a 230 watt model. After going through the MPPT charge controller, it will end up putting around 15 amps of current into the battery.


The battery, this is a part that’s taking a while. I’m building a lithium battery bank. It is made of 76 lithium pouch cells that are rated at 8 amp/hr each at a nominal voltage of 3.6 volts each. There will be 19 of these cells wired in parallel to make a “brick”. There will be 4 bricks that will then be wired in series to build the battery. It will end up being a 152 amp/hr battery that will have a maximum voltage set to 14.8-14.9 volts and a minimum voltage of 10.0 volts. If the battery is discharged down to 10 volts, then charged to 14.8-14.9 volts, that is 1 cycle. These cells are rated for 2,000 cycles! If I don’t let the battery run all the way down then these cells can go for at least 4,000 cycles! To control the battery bank, there is a 200 amp Daly BMS(battery management system). This BMS will prevent the battery voltage from going too low or too high. The MPPT charge controller also has a temp sensor that will be set to stop charging if the battery bank temperature drops below freezing. Charging a frozen lithium battery can destroy it.

Even though these cells are rated for being able to supply a LOT of current(200 amps per cell continuous and 400 amps for a 3 second burst), the entire battery will be fused with a 150 amp fuse to help prevent a meltdown!


The last thing that I got done on this update was to install the foam board insulation in the ceiling. Between the solar panel being on the roof and the foam board insulation, interior temps have dropped tremendously! I’m confident once the insulation on the walls goes up and the cedar planks get installed, it is going to stay pretty comfortable inside.


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