Dometic Battery-Powered Auxiliary Air Conditioning System - Manual (Page 6)

Dometic’s engine-off air conditioning systems for sleepers are designed
to keep the entire sleeper cooled for a minimum of 10 hours to meet the
HOS requirements.
System capacity depends on a number of factors, such as the size and
shape of the space to be cooled, the amount of insulation, the size and
location of windows, the color of the truck and the ambient temperature
outside. Dometic offers 7,000 and 10,000 BTU/hr systems.
The number of batteries needed will depend on the capacity of the air conditioner and the length of time you
will need to run the air conditioner between recharges. The table below offers general guidelines. Note that the
air conditioner normally will not run continuously, but will cycle on and off as needed to maintain the selected
setpoint. The 60% duty cycle in the table means that the air conditioner runs 60% of the time, and is off 40%
of the time. Typically, sleeper systems are specified with 7 to 8 batteries. Day-cab systems will operate to spec
with 3 batteries.
If you are specifying optional built-in electric heat, use the following table to size the electric heat modules.
Electric heat uses a tremendous amount of power. Each KW of heat requires about 8.2 amps of alternating
current. When using electric heat, Dometic systems will only get approximately 50-60% of the run time
compared to the cooling cycle.
Dometic offers a selection of prewired battery boxes that will save time and money on installation. The box can
be mounted on either side rail, or between the rails behind the sleeper. To calculate your return on investment
for a Dometic engine-off sleeper air conditioning system, refer to the following table:
72" High Rise
Batteries 8 Group 31 AGM
Replace existing 4 lead-acid batteries with AGM batteries and
add 4 more AGM batteries. Check on Dometic’s selection of
prewired battery boxes to save time and money on installation.
Alternator 320 amp high output Replace existing alternator on truck engine.
Inverter
2,000 Watt Modified Sine
Wave (MSW) Specify optional inverter/charger combination for charging
batteries from shorepower.
HVAC System 10,000 BTU/hr
It includes ducts, grills, electric wiring and digital control/
display panel.
48 " – 60" Sleeper
Batteries 7– 8 Group 31 AGM
Replace existing 4 lead-acid batteries with AGM batteries
and add 3–4 more AGM batteries. Check on Dometic’s
selection of prewired battery boxes to save time and
money on installation.
Alternator 320 amp high output Replace existing alternator on truck engine.
Inverter
2,000 Watt Modified Sine
Wave (MSW) Specify optional inverter/charger combination for charging
batteries from shorepower.
HVAC System 7,000 BTU/hr
It includes ducts, grills, electric wiring and digital control/
display panel.
SPECIFYING
A SYSTEM FOR
SLEEPERS
6