http--www.liberatedmanuals.com-TM-10-4520-262-12-and-P.pdf Schematic Pg. 53 of 435-----Batt. Conn side (Battery#1 [Green Pin #1 White Pin #3]) (Battery#2 [Black Pin #2 Red Pin #4]) Check Polarity Batteries, both can be charged at same time with pack removed and positive to positive connect to Charger Pos. Terminal and Negatives Connected to Charger Neg. Terminal. Make sure you wire batteries in parallel for 12 VDC and NOT IN Series for 24 VDC Unless You have a 24 VDC Charger. When Fabricating your batt pak remember the originals have a temp SENSOR AND a HEATING PAD INSTALLED, not sure if that will effect function if removed, per following Quote from Manual,
The battery pack assembly consists of a 12-volt lead-acid gel cell battery
(3) with an electrical heating
element. The battery pack assembly location is clearly marked and is located in a recess
(4) below the
lower housing assembly. Two fuse holders
(5) carrying 20 amp fuses are incorporated into the side of the
battery pack. Two spare fuses
(6) are located at the breathable air inlet end of the heater.
The battery is used for burner ignition, and to power the control system until the thermoelectric generator
(TEG) generates power. The battery is recharged during heater operation by the TEG(Thermal Electric Generator). Depending on
battery condition and temperature, the battery has a approximate 30-minute recharge time.
If battery temperatures are below 40°F (4.4°C), it is electrically heated by the heating element. When the
battery reaches 60°F (15.6°C), the heating element is shut off by the controller. When battery heat is
called for, only excess power is used for heating the tent.
Considering Using 12VDC from TEG to Power LED String Lights.