Zen Dog
VIP Member
Hi all, I know it's a bit of an old chestnut. My leisure batteries finally expired. No problem with that, they were at least 10 years old. However, while I was in there I checked the resistance from the negative lead which goes from the rear battery to the shunt and a known good earth on the body, getting a reading of about 500 ohms. As the earth shunt resistance is 0.2 ohms it confirmed in my eyes that the shunt to body earth has failed. No surprise, it's a known and well documented fault.
On removing the front battery I noticed an earth lead from the negative terminal to a bolt on the seat base. It was very professionally done, so much so that I took it to be an original part of the wiring.
But then I got to thinking; an unusual occurrence. Surely a second earth in the system would effectively short out the earth shunt? So my questions are:
Am I correct in thinking that the earth to the front seat is a workaround done by a previous owner after the earth shunt failed, or does everyone have one?
Second question, does the earth shunt reading just affect the display on the camping unit or does it also affect the charging rate from either the charger unit or the engine?
If it helps anyone, I found it easy to remove the front battery by undoing the star bolts at the back of the seat runners and slackening off the nuts at the front of the runners. The seat can then be pivoted forwards to give plenty of clearance.
In a similar vein, to access the earth shunt I cut an access panel from the battery bay. There is about 6 inches clearance on the fridge side for the hacksaw/jigsaw blade. I then drilled an earth point behind the battery and ran the new earth to that, which will let me check it easily in future.
Plan A was to replace the hatch, but I was disturbed by the lack of cooling to the fridge heat exchanger and charger unit, so I will leave the hatch open and maybe drill a couple of vent holes up to the wardrobe. This might even give the wardrobe some mildly heated air.
On removing the front battery I noticed an earth lead from the negative terminal to a bolt on the seat base. It was very professionally done, so much so that I took it to be an original part of the wiring.
But then I got to thinking; an unusual occurrence. Surely a second earth in the system would effectively short out the earth shunt? So my questions are:
Am I correct in thinking that the earth to the front seat is a workaround done by a previous owner after the earth shunt failed, or does everyone have one?
Second question, does the earth shunt reading just affect the display on the camping unit or does it also affect the charging rate from either the charger unit or the engine?
If it helps anyone, I found it easy to remove the front battery by undoing the star bolts at the back of the seat runners and slackening off the nuts at the front of the runners. The seat can then be pivoted forwards to give plenty of clearance.
In a similar vein, to access the earth shunt I cut an access panel from the battery bay. There is about 6 inches clearance on the fridge side for the hacksaw/jigsaw blade. I then drilled an earth point behind the battery and ran the new earth to that, which will let me check it easily in future.
Plan A was to replace the hatch, but I was disturbed by the lack of cooling to the fridge heat exchanger and charger unit, so I will leave the hatch open and maybe drill a couple of vent holes up to the wardrobe. This might even give the wardrobe some mildly heated air.
