Understanding Electrical Systems

[Ralph L. Fullenwider]

Hello Brian:

Certainly some skills with a multimeter and amp meter are a definite plus
when it come to working on Birds or even home systems and an understanding
of schematics and the theory of electrical circuits are a good place to
start. You don't need ohms law to read a meter but it helps and a darn good
understanding of series/parallel circuits is a must read. Example of that
is; a Coach has 6 12 vdc deep cycle batteries wired series parallel gives
you three banks of 12 vdc output. If you replace those batteries with 12
vdc batteries and wire them series parallel you will get 24 vdc out put to
everything in the Coach and most 12 volt dc systems will pop it's buttons.
So an understanding of that system I would say is required reading. There
are several good manuals on the market that gives a good understanding of
DC electrical 101. Then of course knowing how relay logic works is a must.
All this can be done with a good read.

Ok, freedom inverter and the Link 2000; If you simply switch off the switch
on the inverter, the link 2K should go out, if not then I would seriously
take a look at the on and off switch on the inverter.

Alt fault light; As stated, you may not have a problem with your alts and
the fault could simply be indicated due to a bad Bosh relay. Those relays
should be located behind the curb side grill in the upper portion above the
Primus boilers ( if you have Primus). On the back fire wall, in that same
area you will see a series of circuit breakers and to the left of those
will or should be 3 shunts. Attached to the center shunt should be 2 large
cables with red taped ends and those ends are the feeds from the
alternators. This info is for locational value alone.

One question I always ask a new owner;"Have you read your manual?" This is
in no way trying to be offensive but to drive home that there is a
multitude of important information there and much will "come to light" with
a little study.

Even though the master switches are off and the master electronic switch is
off, there are some systems that stay energized by design so a few days of
dis charge is more or less a normal thing. Battery maint is primary in
these Coaches.

Ok, the polarity indicaters: Doug Hampton of PMMI is a member if this
forum, contact Doug ( a darn nice guy by the way) and set up how to ship
your units to PMMI for repair. And if you do this, be sure that the GFI mod
is added to the unit.

Winter storage is a Coach by Coach thing. It depends on where the Coach is
stored what part of the Country it is stored in and so forth. If you plug
into the house 20 amp circuit with your 50 amp cord and an adapter, your
chargers will work and you can run one electric heater in the Coach. Open
the doors to the kitchen sink and the bathroom sink, turn on the bath
electric heater and it will keep the interior of your Coach at an even 52
degrees F through out. You can even leave the refer and ice maker on with a
20 amp circuit.

Lets talk relay logic a moment. Usually a switch will not handle the
amperage needed for most circuits, so how is this amperage controlled. It
is done with relays that have 20/30 or 30/40 amp contacts that will handle
the amperage. So in effect the switch on the dash energizes the "coil" of a
relay and allows the amperage to flow across contacts that were open until
the relay "pulled" in.

Enough 101, sorry if this is a little too long.

Safe travels,

Ralph and Charolette Fullenwider
Ralph's RV Solutions, Duncan, Oklahoma
http://home.swbell.net/rlf47/index.htm

At 01:07 PM 1/29/2006 -0800, you wrote:
>I am debating how "educated" I need to become before troubleshooting
>and/or repairing some electrical issues I am having.
>
>The coach is new to me and has been in the shop for the past month
>getting many things repaired.
>
>One of the items repaired was the Freedom 25 inverter. It was found
>that the inverter received an electrical spike of some sort and several
>critical parts were damaged. I was told this could occur either by bad
>shore power or by a lightning strike.
>
>Right now there are several things that I don't understand and need to
>figure out if there is trouble somewhere that needs to be repaired.
>
>1. Alternator Fault - When the engine is running ALT1 fault light is on.
>
>2. Shore Power Polarity - The polarity light does not indicate good or
>bad polarity when plugged into shore power.
>
>3. Xantrex Link 2000 - When everything is shut off (master electrical
>switch and AT switch) the Link 2000 is still on.
>
>4. LoBat - Within a few days, it appears that the batteries are already
>low (I do not have the coach plugged into shore power).
>
>I have read through the Link 2000 manual and it appears that there are
>many settings in being sure the batteries are used and charged
>correctly.
>
>The first thing was to determine the type of batteries being used. It
>took me several hours just to figure out the kind of batteries they are
>and I am still not 100% certain.
>
>They are Deka 8G4D and I believe they are Gelled and not Sealed
>Absorbed. There are 4 batteries with 6 cells each and 2.35 V per cell
>at 68 degrees.
>
>There are many questions I have in addition to the items above
>(obviously I am not electrically inclined):
>
>1. Should I just hire an "expert" and have them check the entire system
>and train me on managing power? Any "BB experts" that can be
>recommended?
>
>2. Or, do I just take my time and learn everything myself risking damage
>to systems and delaying the time that we can use the coach?
>
>3. Are the batteries being damaged right now?
>
>4. On our first trip I would like to believe that the electrical system
>is functioning correctly (we don't have an immediate trip planned, but I
>will plan a trip only when I know the problems are resolved).
>
>5. Are the settings of Link 2000 interface correct? What are the
>correct settings?
>
>6. Are the batteries bad? Or, is there something out of the ordinary
>draining the batteries?
>
>7. Is the alternator bad? How do the 2 alternators work? My engine
>mechanic did not indicate that there were any problems with the
>alternators. He was pretty thorough in checking everything.
>
>8. What is the best way to store the coach in cold weather? Can I plug
>it into a 20 amp house circuit just to keep the batteries up? Do I need
>to install a 30 or 50 amp circuit ASAP in order to store the coach
>properly?
>
>9. Are there good "RV Electrical Systems for Dummies" resources out
>there?
>
>10. Are BBs so complicated and/or specialized that basic RV electrical
>information would not be helpful?
>
>Brian Gatley
>93 WLWB PT40
>Bend, OR
>