Vanner IQ12-2600 Owner's Manual - page 40
VANNER POWER GROUP
VANNER POWER GROUP
IQ SERIES
IQ SERIES
- 40 -
IQ SERIES OWNERS MANUAL
2.
Calculate the watt-hours required for each appliance by multiplying the power requirement by the
operating time of that appliance.
3.
Calculate the total watt-hours needed by adding together the watt-hours of each appliance.
4.
Find the amp-hours consumed by dividing the total watt-hours found in step 3 by 10 for 12 volt DC
systems or by 20 for 24 volt DC systems.
5.
Multiply the amp-hours consumed by 2 (for 50% depth of discharge) to get the battery amp-hour capacity
desired.
DC Charging Systems
The DC charging system is a very important part of your inverter installation. The system consists of the primary
charger (engine alternator or photovoltaic array), a secondary charger, if used, the battery, and other equipment
which may be used such as battery isolator diodes. The complexity of the system depends on the way the
inverter is used. In some cases, such as utility or service vehicles, the system may be as simple as the engine
alternator and the cranking battery which also powers the inverter. In most cases, additional equipment is needed
to provide additional DC power and/or protection. These systems can be grouped into two categories, the single
battery and the dual battery systems.
In the single battery system, there is one battery which is shared for starting the engine and operating the inverter.
This is a common practice in a service vehicle where the engine runs all the time and allows the alternator to
provide continuous charging for the battery. In this case, the inverter’s auxilliary batteries can be connected
directly to the engine cranking battery. Great care should be used when operating this type of system. If the
engine were to be shut off and the inverter operated, it would not take a very long time for the inverter to
discharge the cranking battery and disable the vehicle! The most important detail of this system is the alternator
output rating. The continuous output of the alternator needs to be at least as much as the total DC current draw
on the system. The total DC current draw must include the inverter, warning lights, radios, engine controls, and
any other device connected to the DC system.
The dual battery system uses two separate batteries, one for starting the engine and operating the vehicle's
systems, and one for operating the inverter. The two batteries are usually referred to as the "cranking battery"
and the "house battery" respectively. The two separate batteries are usually charged from the same source, the
engine alternator, but are separated by a device called a battery isolator. The battery isolator allows DC current
to flow from the alternator into each battery, but blocks current from flowing from one battery to the other. This is
a must to protect the cranking battery in recreation vehicles, boats and other vehicles where the inverter needs to
be operated when the engine (therefore the alternator) is not running.
Up to this point we have spoken of the battery as if it were a single battery. In some cases this may be true, but in
general, the battery may be made up of several individual batteries electrically connected together to form a
"Bank" of batteries. Batteries can be connected in series, parallel, or a combination of series and parallel as long
as all of the batteries in the bank are of equal ratings, are from the same manufacturer, and are the same age.
Old and new batteries should never be mixed in the same battery bank. A series connection is where two or
more batteries are connected positive (+) to negative (-) and the total voltage of the battery bank is the sum of the
voltage of each battery in the bank. For example, most large custom coaches require a 24 volt battery to crank
the large diesel engine. The 24 volts is usually provided by connecting two 12 volt batteries in series, and
sometimes by connecting four 6 volt batteries in series. The ratings of the series connected battery bank remain
the same as the individual battery's rating. If the battery bank is made up of two 8D size batteries in series, each
with a CCA of 1050 amps, 425 minutes RC, and amp-hour capacity of 200 A-H, then these individual battery
ratings are also the ratings of the entire 24 volt battery bank. This unis is considered a 200 A-H battery system,
but runnig at 24 volts.