Problem seemed to be defective leisure battery but it is not.
Symptom:- Plug in 12v television and voltage drops to 11, 10, and then 9 volts on Sargent display. TV fails to work properly, loses picture or breaks up etc. Also running water pump causes similar voltage drop to less than 12v on the Sargent display and flickering of lights, if on.
A digital meter directly on the battery terminals while running these devices however, shows the voltage to drop only slightly from 12.8 to 12.4 or 12.5 approx, for example and then quickly recover to 12.8 when turning device off..
I have metered the voltage at a 12v socket which reads 12.8v but then running the pump caused it to drop to 11.9 at the socket.
It seems to me that there may be a problem with the 12v output from the Sargent control unit.
It is not easy to gain access to the wiring connections so before ripping things apart do any of you have any opinions or ideas on how to proceed with diagnosis.
You have a dirty or corroded connection somewhere on your leisure battery circuit.
Start by isolating this fault to positive or negative side by repeating your test but first connect the meters black lead to a chassis point and NOT the leisure battery. If the reading still holds good then the fault is in the live. If the voltage drops you have a poor earth, otherwise likely a poor connection in the positive feed to the Sargent panel. Check voltage at every point you can access working from the battery towards the panel and when the voltage falls you have found your faulty wire/connection.
Check the connections onto and near the battery and the in-line fuse in the positive lead.
Posted: 16 September 2015 10:10 AM Subject: RE: Electrical problem, seeking help.
Gets involved
Posts: 274 Location: Hampshire
Thanks Keith,
I have a 'wiring schematic' although not 'point to point'. It does show an earth from the leisure battery ( and engine bat of course ) but no others. All negatives appear to go back directly to the neg. battery terminal; but it is only a schematic.
I will do as you suggest and I will report back. It may be a while but will report the 'fix' or progress as it goes.
Well, that was simple. The test showed a bad earth as you suggested. There is a multiway connector adjacent to the leisure battery and there lay the problem. Reseating fixed it and then contact cleaning to be sure.
If it happens again I will know where to look first.
