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Correcting Voltage Drop
Author: BigRabbitMan (Show all albums)

My refrigerator was not working correctly and it was determined that there was too much voltage drop between the domestic batteries and the refrigerator. This album follows the process of correcting the problem.
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Here you see a grounding block attached to the inside of the kitchen cabinet between two doors. Very accessible. The bottom wire is the 12 guage lead from the new grounding post. The others are the individual grounding lines from each unit that is attached to the fuse block. This system results in a direct, unshared positive and negative lead for each electrical unit. Individual, fused circuits for each electrical unit ensure proper performance and easy trouble shooting if needed. ... and the refrigerator is working great!


Now the grounding side. Grounds that deteriorate over time are a challenge for all okder vehicles and ours are no exception. To ensure a good ground so that full voltage will be seen by the various electical units, a new ground post was added by drilling into the top of the frame, tapping it and then screwing in a stud (it will be welded to the frame later). I then attached another 12 guage line to the stud and ran that lead inside the coach to an accessible location.


Going inside the coach, we see the other end of of the yellow 12 guage wire where it terminates on a 6 position fuse block. The fuse block was positioned out of the way just to the rear of the heater and just inside a cabinet door so that it is both out of the way and yet accessible. The leads attached are for the refrigerator, the Fantastic fan, and a new 12V recepticle that I installed just to the left of where the oven used to be. The remaining connections will be for the heater, the air horn and, possibly, a bathroom switch for the water pump.


An earlier photo shows the original tape wrapped positive wire. This photo shows the replacement wire with the new inline fuse holder. It has a 30 amp automotive spade fuse in it. The new fuse holder's pigtails attach to the battery and, at the right rear of the picture, the yellow 12 guage wire leading back into the coach. The fuse holder was tucked away to the right of the battery after the picture was taken.


(1 Comments)
A major reason for the new ground location was that under the front of the coach a number of additional ground wires were spliced to the ground wire that orignated at the refrigerator. All of these additional ground wires added to the resistance and load on the one ground wire that eventually made it to the frame ground post next to the battery (which you can see in an earlier picture). These addittional ground wires will remain connected to the oringinal ground post.


Because all of these pairs of wires went down into the hole, then to the right through a hole in some sheet metal and then forward through a PVC pipe and out under the front, pulling the new wire was a real chanllege. We ended up pullin all of the old wires out together while using them to pull the new wire in. We also decided to only pull the hot wires through and to create a new frame ground in a visible locatin by the heater and ground all of the the domestic things in this area to the new ground.


Here is the yellow 10 guage wire we are going to run from the battery to a fuse block and then on to the refrigerator to minimize voltage drop. By this time we had determined that not just the refrigertor was powered from this line. The line had been spliced into to also power the Fantasic ceiling fan and the air horn. Each of these splices added resistance to both the hot wire and the ground wire.


There were also a pair of "mystery wires" that come out of the hole, but are not connected to anything and show no evidence of ever being connected to anything.


The pair of wires we are interested in are joined by other wires going to the heater and water pump and disappear down into a hole in the wood floor along with the engine hot water lines that heat the hot water heater while traveling (a feature on the later coaches).


However, going to the inside of the coach reveals that it is more complicated than thought.


(3 Comments)
A couple more steps to the left and you can see where the wires are attached to the battery and to a ground post just as the schematic says it is.


One step to the left and the wires turn and go towards the interior of the coach. Hidden to the right was the splice that took the hot wire up to the air horn solenoid.
Show Newest Photos First | Show Oldest Photos First14 Photos - Page : [1] [2]

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