Jayco Precept 2018, Owner'S Manual

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Section 6: Electrical System
House Batteries
Your motor home 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:
When the power cord is plugged into 120-volt shore power, or when the generator (if
so equipped) is operational, the inverter/charger functions as a battery charger and will
automatically charge the house batteries when required. A bi-directional charge relay
incorporated into the electrical system allows the inverter/charger to charge the chassis
batteries once the house batteries are sufficiently charged.
The chassis alternator charging system supplies power to the house auxiliary batteries
when the engine is running and the chassis batteries are sufficiently charged
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 auxiliary
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
Battery inspection & care
Check the level of electrolyte in each battery cell once a year.
Add distilled water as needed to reach the split-level marker on each battery. Keep batteries
and battery terminals clean and tight.
Check the external condition of the batteries periodically. Look for cracks in the cover and
case. Make sure battery vent caps are tight and replace them if they are cracked or broken.
Battery storage instructions
To prevent house auxiliary battery discharge when your motor home will not be connected
to shore power for extended periods of time, it is recommended you turn “off” the 12-volt
battery disconnect switch, or “main power switch,” and disconnect each battery bank at the
negative battery cable running to the chassis frame.
During storage, it is important to check battery voltage at least every two weeks and to
recharge them as needed. If you remove the batteries from your motor home protect them
from accidental shorting and keep them in a cool, dry, well ventilated area.
Battery replacement
If house auxiliary batteries need to be replaced, only deep cycle batteries of the same
size and type should be installed.
Do not reverse the positive and negative battery cables. Doing so will blow the reverse
polarity fuses that protect the power converter.
For more information
Contact the battery manufacturer for more information on the house auxiliary batteries.
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