Wiring Loom - Alternator

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01 Mar 2013 10:42 #1 by Rick Whitworth
Rick Whitworth created the topic: Wiring Loom - Alternator
On XT 149 I have a disconnected white wire that comes out of the loom which runs along the drivers side chassis rail beside the clutch and handbrake cables.
The wire goes into the loom at the same place as the alternator wires. It runs rearward through the loom plug and ends at the Charge Relay on the dedicated starting plate setup behing the drivers seat.

Can anyone tell me what it is supposed to be connected to?
see dashed line and question mark as attached
Rick
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01 Mar 2013 12:30 #2 by dandjcr
dandjcr replied the topic: Wiring Loom - Alternator
Rick, this area of Oka wiring is a mystery to everyone I think.

With the changes to the wiring for second and dedicate battery systems, I think the white wire became redundant, the charge relay doesn't need it. The charge relay is fired up by the W (Tacho) signal when the alternator gets up some steam.

Also the blue wire from your B+ to the (unnamed) D+ terminal doesn't and shouldn't exist. If it did, it would be shorting out these terminals (and to the battery +ve). The service manual wiring diagram also shows this wire which shouldn't be there. D+ should only have a connection to the Alternator Warning Light otherwise it can't control the alternator field winding.

David and Janet Ribbans - Oka 148
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01 Mar 2013 14:31 - 01 Mar 2013 14:33 #3 by Rick Whitworth
Rick Whitworth replied the topic: Wiring Loom - Alternator
thanks David,
...thought white wire might be redundant.
...There is also an extension of 6mm purple earth wire bound into the loom along with the 2 x 6mm red wires that connect the B+ terminal to charge relay. I didn't show it on the diag because it has also been dead ended inside the loom. All looks original, so maybe this was mod done to existing looms when OKA made change after build 136 to connect fusible links directly to alternator rather than battery.

re your comment on the blue wire in my diag that appears to go from the D+ terminal to B+.
My diag was badly drawn.
On Bosch 0120 484 038 they are separate wires that enter through one single rubber boot.
The blue wire connects to the "S" battery sense terminal
The light brown wire connects to the "L" warning lamp terminal.
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01 Mar 2013 20:33 - 01 Mar 2013 20:36 #4 by dandjcr
dandjcr replied the topic: Wiring Loom - Alternator
Rick, looking at the circuit in the manual, it shows a resemblance to your diagram so maybe what I thought was a single D+ terminal is also 2 separate wires as you describe.

My Bosch alternator has only one D+ terminal but if it had a battery sence input, it would be correctly wired to the battery +ve.


David and Janet Ribbans - Oka 148
Oka148 profile here.
Visit our technical and travel blogs: here.
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02 Mar 2013 06:47 - 02 Mar 2013 07:05 #5 by Rick Whitworth
Rick Whitworth replied the topic: Wiring Loom - Alternator
David,
Intention in service manual was probably to indicate the separate "S" and "L" (D+) terminals

...Bosch Alternator 0 120 484 038 14V/85A and BXU1285A are equivalents and both have the S terminal
www.bosch.com.au/content/language1/downl...ID_Alternators_B.pdf


I was initially wondering if OKA intended that the white wire should connect to the "S" terminal (effectively the same as connecting S to B+, just the other end of the wire!)

All this has come about in my search to find and eliminate unattended current draw.
So far I have kept my solar system completely independant of the OKA truck dedicated/auxillary battery circuits and the solar batteries should "kept alive" by solar panels when truck is unattended. Looking for ways to extend this to truck batteries but trying to eliminate any power loss from items like clock, radio etc.

Although minute current, alternator sense is reputed to drain 0.12 milliamps
holdenpaedia.oldholden.com/Alternator
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Last Edit: 02 Mar 2013 07:05 by Rick Whitworth.

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02 Mar 2013 09:49 #6 by Tony Lee
Tony Lee replied the topic: Wiring Loom - Alternator

Although minute current, alternator sense is reputed to drain 0.12 milliamps


which would take 8000 hours to drain one amp-hour and that is way way less than the self-discharge even of AGM batteries.

Tony

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02 Mar 2013 11:53 - 02 Mar 2013 11:54 #7 by Rick Whitworth
Rick Whitworth replied the topic: Wiring Loom - Alternator

Tony Lee wrote:

Although minute current, alternator sense is reputed to drain 0.12 milliamps


which would take 8000 hours to drain one amp-hour and that is way way less than the self-discharge even of AGM batteries.


yep, amongst other losses too small to measure
Last Edit: 02 Mar 2013 11:54 by Rick Whitworth.

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02 Mar 2013 15:10 - 02 Mar 2013 15:26 #8 by dandjcr
dandjcr replied the topic: Wiring Loom - Alternator

eliminate any power loss from items like clock, radio etc.


Rick, on another thread I listed the sorts of things that can draw power when everything is apparently off:

Radios on standby, solar regulators (when there's no solar energy), remote door/window controls, clocks, inverters on standby, alarm systems or even good old leakage through the wiring. To those I would add battery protection components (wired across batteries to limit voltage spikes), winch controller, faulty alternator diodes, lights/relays that don't turn off, and there are many other potential faulty devices.

In my experience radio/hifi systems and inverters are the main culprits but all of the above contribute to power drain.

You can check the amount of current drawn quite easily. First, disconnect or disable your solar system and other battery chargers. That's important so they can't attempt to charge while batteries are disconnected and damage electronic equipment. Disconnect all batteries (doing this on individual batteries won't necessarily work if they are in parallel) and measure the current from the battery cable to the battery terminal post. Disconnecting the earth straps on all batteries is usually the easiest.

If there is a significant current draw (more than 10-20 mA), replace the battery terminals and remove fuses one by one. Measure the current by connecting your multimeter across the fuse socket. That should enable you to track down the area of the current drain but not all devices will be fed from the Oka fuse panel, some will have their own fuse connected direct to a battery supply (eg our HF radio and inverter).

There are plenty of internet resources on this subject but they all say pretty much the same thing.

David and Janet Ribbans - Oka 148
Oka148 profile here.
Visit our technical and travel blogs: here.
Last Edit: 02 Mar 2013 15:26 by dandjcr.

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