THOR Jayco Precept 2021, Owner'S Manual

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Section 6: Electrical System
Batteries
House Batteries
Your motorhome is equipped with Group 27 deep cycle batteries.
Unless a battery has been fully discharged, house auxiliary batteries are normally charged
in one of two ways:
 The chassis alternator charging system supplies power to the house auxiliary bat-
teries when the engine is running and the chassis batteries are sufficiently charged.
 When the power cord is plugged into 120-volt shore power, or when the generator
(if equipped) is operational, the inverter/charger functions as a battery charger and
will automatically charge the house batteries when required.
A fully charged battery will read 12.65 volts DC with a specific gravity of 1.265 at 80°F
(32°C). A battery is considered discharged at 11.89 DC volts or when it has a specific gravity
of 1.120 or less. When voltage drops to 11.89 volts, irreversible battery damage can occur.
Dry Camping
House auxiliary and chassis batteries should be fully charged prior to dry camping. When
disconnected from 120-volt shore or generator power (i.e., while dry camping or tailgating)
all electrically operated appliances and accessories must be used sparingly. Typically, a deep
cycle battery has an amp-hour rating of 75-100 amps.
During this period these appliances and accessories are being powered by the house auxil-
iary batteries directly, and/or indirectly through the inverter/charger. If excessive amounts
of power are drawn from the house auxiliary batteries, they will become deeply discharged.
Permanent battery damage will occur after repeated deep discharge cycles.
 Do not store anything inside the battery compartment(s) or near the
batteries that could touch the battery or battery cable terminals. Contact
with the battery or battery cable terminals could cause an electrical short
circuit, discharge the batteries, or start an electrical fire.
 Keep sparks, cigarettes and flames away from the batteries as the
hydrogen gas they create may explode. Do not connect a booster bat-
tery or other power source that outputs more than 14.2-volts DC to the
motorhome batteries. Use adequate ventilation when charging or using
batteries in an enclosed space.
 Remove metal jewelry and always wear eye protection when working
around batteries.
 D o not allow battery electrolyte (acid) to come into contact with skin,
eyes, fabric or painted surfaces . Electrolyte is a sulfuric acid solution
that could cause serious personal injury or property damage. If your
hands, eyes, clothes or the painted surface of your motorhome are ex-
posed to electrolyte, flush the exposed area thoroughly with water. If
electrolyte gets in your eyes, immediately flush them thoroughly with
water and get prompt medical attention.

Make sure the inverter/charger is turned “off” before disconnecting
the negative battery cable from the battery bank.
Keep the batteries
out of the reach of children.
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