Sunday, Mar 07, 2004 at 21:36
Hi Eric,
I have read and re-read your posts and my posts, because I'm very worried that I have missed something here, and may be spreading furphys.
I thought I'd check out my Prado with a DMM to find the "resistor between the common point and the battery" that you refer to. I put the headlights on for a little while, then started the vehicle. I then measured voltage drop between the common point and the
battery + immediately after starting the vehicle, as I wanted the alternator to be putting current into the
battery. Voltage drop was 0.06 volts. Starting
battery was 14.30V, common point (located in the fuse box on the Prado) was 14.36V. This voltage drop is negligible, and consistent with the wiring, connectors, and the current flow at the time.
I then thought I'd measure the voltage drop between the two
battery pos terminals to measure the voltage drop after the isolator allowed current flow to the aux
battery - current drop over about 5ft of 8Ga cable was 0.07volts - again negligible.
I then hooked up my 30amp, variable voltage power supply to the starting
battery, and checked the current output into the
battery at both 14.30 and 14.36 volts - there was very little difference - not easily discernible with the resolution of a 30amp ammeter.
I would appreciate you doing your own measurements on your own vehicle. I don't discount at all what you say - I just know that on my vehicle, that is not the case.
I also checked my workshop manuals for my current vehicle as well as previous model Landcruisers, as I have manuals for back to '75. The Prado has a different setup with the alternator wires in that it has an extra wire leading back somewhere to the "common point". Its an extra voltage sensing wire.
I don't think I'm being difficult. I enjoy a
technical discussion, but my measurements on my current vehicle don't fit with your description of the way a charging system works.
Sincerely,
Phil G
FollowupID:
311281