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Dry camping drains the camper battery overnight with very limited
use of the 12-volt lights. The battery recharges okay while on
landline. A sixty-mile trip did not recharge the battery via
an alternator charge. Where and how should I continue to troubleshoot?
First be sure the battery is "fully" charged. Monitor
the specific gravity of the electrolyte while charging and record
the readings every two to three hours. A battery is considered
fully charged when the specific gravity peaks and does not increase
over a two-hour period. A fully charged battery will have a specific
gravity of about 1.265. This may take awhile, so be patient. Do
not charge rapidly. Stay below the gassing voltage of 14.3 volts
during the complete charging cycle.
Once you are sure the battery is fully charged, look for drains
on the system by using a volt-Ohmmeter with a minimum ten-amp scale.
Here’s how; turn all 12-volt devices off. Disconnect the negative
cable from that battery and insert the meter in-line with that
cable. Any current draw over 600-800 milli-amps indicates an excessive
drain on the system. At the fuse block, remove each fuse, one fuse
at a time. The circuit with the drain will be revealed when the
current drain disappears as that fuse is pulled. The final step
is to simply identify the components in that circuit to find the
culprit.
If no drains are found, inspect the positive and negative terminals
at the truck/camper connection. Be sure the positive and ground
wires are the same gauge. Oftentimes technicians install a large
positive wire, (as they should), but neglect to have a like-sized
or larger wire on the ground side. Remember, in a DC circuit the
negative side of the circuit is just as important as the positive
or "hot" side. Look also for frayed wires in the charge
line to the camper or the ground connection on both vehicles. Rusted
fuse holders, incorrect butt splices, loose terminals, etc., can
all contribute to poor charging. Check each inch if necessary.
As a final check, have the alternator tested for proper charge
output. Batteries should indeed last longer than overnight
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What does the power inverter do?
The RV power inverter is the electrical opposite
of the power converter. While the converter takes 120 volts
AC power and converts it to 12 volts DC to operate RV lights,
pumps and fans, the inverter uses the DC power from the auxiliary
battery system and inverts it to 120 volts AC output for use
with typical household-type appliances like a toaster, computers,
televisions, hair dryers, microwave ovens, etc.
Electronically processed, this inversion is totally silent. There
are no moving parts aside from an occasional cooling fan application.
The sophisticated models today even have battery charging capabilities
so whenever you plug into shore power at a campground, for instance,
the inverter senses another form of 120-volt AC, switches modes,
and becomes a high output, three step battery charger.
Best installed near the batteries to minimize voltage drop, many
inverters can be mounted horizontally or vertically making aftermarket
installations a relatively easy task.
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What should I know if I'm thinking of adding
an inverter to my present RV?
If you are considering adding an inverter to your present RV,
realize that certain upgrades are prerequisite to adding the inverter.
For optimum results, it is recommended that the following items
be employed with inverter systems.
* High quality, properly sized 12-volt battery bank
* High output automotive alternator, (motorhomes)
* Accurate battery monitor (voltmeter and ammeter)
* Solar panels to aid in charging
* Advanced AC to DC converter
Inverters designed for RV applications are available in two basic
output waveform technologies; quasi-sine wave, (sometimes referred
to as modified sine wave), produced by low frequency transformers,
and pure sine wave as produced by microprocessor-controlled,
high frequency circuits and components.
Though low frequency inverters are less expensive and considered
efficient devices, they are, however, prone to voltage fluctuations
which can cause disturbances in some DC circuits in the RV. Pure
sine wave inverters, on the other hand, are extremely sophisticated
and can produce AC power at or above the quality levels of shoreline
power grids. Comparisons can be made by looking at the total harmonic
distortion, (THD), produced by each type. The harmonic difference
between the low frequency RV inverter wave form and true sinusoidal
wave shape is a percentage figure that affects the operation of
induction type loads such as motors, compressors, or other capacitor-started
devices. The higher the percentage, the higher the heat factor.
The higher the heat factor, the more damaging to the device.
Additionally, voltage stability is crucial in many RV applications
such as microwave ovens, battery chargers and some televisions.
Unpredictable cooking times, buzzing in stereo equipment and video
distortion on TVs and computer monitors can be virtually eliminated
by installing a high frequency inverter. If you are one of the
many RVers with computer equipment on-board, a high frequency inverter
is a must for laser printers.
By and large, inverters are worthwhile if you RV often or are
considering full-timing.
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What is AC polarity, and how can I determine
when it's correct at the campground pedestal?
Understanding the nuances of electricity can be most confusing
and daunting. The biggest problem is our propensity to confuse
what we know about the RV's DC battery systems with the AC system.
Each system has it's own set of rules and most are not interchangeable.
While DC current flows in one direction only, in North America
the AC system operates at a frequency of 60 cycles per second or
Hertz and it alternates directions. Direct Current has a polarity
of positive and negative which remain constant; positive is always
positive and negative is always negative. Alternating Current,
on the other hand, switches polarity between the hot and neutral
wires sixty times per second.
Picture “time” as a straight line drawn across a piece
of paper. Above the line is considered positive voltage, below
the line it's a negative voltage. Therefore the polarity is positive
half the time and negative half the time. They are said to have
a polarity of alternating values. Obviously too fast to measure
with a typical volt meter. An oscilloscope, however, will clearly
show the alternations in the form of a measurable Sine wave.
Wiring is accomplished via a "hot" (black) and a "neutral" (white)
along with a third, uninsulated grounded wire. In theory, many
AC devices would still operate okay with reverse polarity, (Remember
seeing lamp plugs that could be plugged in either way?), but polarity
is most important for people and pets around the RV. AC polarity
is easily checked with a device called a polarity tester. It simply
plugs into one of the receptacles inside the RV and a series of
LED's indicates if the polarity is correct or if the hot and neutral
incoming wires are reversed, or if any of the wires in the circuit
are "open" (not connected). Consider it extremely value-priced
(cheap) insurance that could save your life in some situations.
No RVer should be without one.
We recommend checking the voltage and the polarity at the campground
pedestal before even connecting the shoreline cord. If the voltage
is between 105-volts and 130-volts AC and the polarity is correct,
you know it is safe to plug in. Also consider the addition of a
surge protector for your rig. Both high and low AC voltages can
be damaging to sensitive equipment on the RV.
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What should I do with my battery before I store it for the winter?
Batteries
in storage:
* Store batteries in fully charged condition. (12.6
volts 100% charge).
* Batteries will loose about 0.1 volt per
month even when disconnected. (0.1 volt X 6 months = .6 volts.
12.6
volts - .6 volts = 12.0 volts,
state of charge is less than 25% with no draw just setting).
*
Charge your batteries every 30 days when disconnected in storage.
*
Coach Battery NOT disconnected will use from 0.1 amp to 0.5 amp
or more. (A 105 ah battery will be dead in less than
200 hours
with a .5 amp draw). Remove the battery cables from the
battery if you do not have a battery disconnect, and recharge
every
30 days.
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What type of maintenance should
I do for my 12-volt battery?
Battery Maintenance:
1. Keep the batteries clean.
2. Check the water levels and fill as needed. (distilled only)
3. Recharge batteries every 30 days even when not in use.
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