Back to the Morris. I have an ammeter, 30-0-30, and the dynamo is rated
13.5v, 22 amps. Still +ve earth. What I don't have is suitable brown
cable, and there seems to be a lot of conflicting advice.

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Any idea of 'standard' car Lucar connector size? Options seem to be
6.3mm, 8mm etc. I'm guessing 6.3, being equivalent to the old 1/4 inch?

Thanks!
--
Graeme

On Tuesday, 17 April 2018 10:55:42 UTC+1, Graeme wrote:

Back to the Morris. I have an ammeter, 30-0-30, and the dynamo is rated
13.5v, 22 amps. Still +ve earth. What I don't have is suitable brown
cable, and there seems to be a lot of conflicting advice.

was the original brown?

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Voltage drop is likely to be the no 1 consideration. 1mm2 pair drops 44mV per amp per metre, so 22A 3mm2 drops 0.323 volts per metre. 1m of that is going to seriously hamper your battery charging.

Any idea of 'standard' car Lucar connector size? Options seem to be
6.3mm, 8mm etc. I'm guessing 6.3, being equivalent to the old 1/4 inch?

Thanks!

you're the one with the measurand!


NT

On 17/04/2018 10:55, Graeme wrote:

Back to the Morris.Â* I have an ammeter, 30-0-30, and the dynamo is rated
13.5v, 22 amps.Â* Still +ve earth.Â* What I don't have is suitable brown
cable, and there seems to be a lot of conflicting advice.

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Any idea of 'standard' car Lucar connector size?Â* Options seem to be
6.3mm, 8mm etc.Â* I'm guessing 6.3, being equivalent to the old 1/4 inch?

Thanks!

Someone better informed will be along in a minute, but bear in mind that
you don't want to introduce too much voltage drop in the cable and
connectors on those ancient Lucas systems. My recollection (which may
well be flawed) is that the original cables in those days were more like
modern 6 mm^2 than 4 mm^2.

In message ,
writes
On Tuesday, 17 April 2018 10:55:42 UTC+1, Graeme wrote:

Back to the Morris. I have an ammeter, 30-0-30, and the dynamo is rated
13.5v, 22 amps. Still +ve earth. What I don't have is suitable brown
cable, and there seems to be a lot of conflicting advice.

was the original brown?

There isn't an original as such, but yes, the cable being extended is
brown, so I would like to follow the same scheme.

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Voltage drop is likely to be the no 1 consideration. 1mm2 pair drops
44mV per amp per metre, so 22A 3mm2 drops 0.323 volts per metre. 1m of
that is going to seriously hamper your battery charging.

OK, good point. I will go for the larger size. It is certainly a
common addition to a Minor, even (or particularly) those still using a
dynamo.

Any idea of 'standard' car Lucar connector size? Options seem to be
6.3mm, 8mm etc. I'm guessing 6.3, being equivalent to the old 1/4 inch?

you're the one with the measurand!

grin Well, yes, but measuring to a fraction of a mm with a steel rule
is not easy, particularly when the connection is buried under the
bonnet. I'm sure 1/4 inch was the 'standard' automotive size back in
the day, and 6.3mm is close enough to 1/4 inch.
--
Graeme

On 17/04/2018 10:55, Graeme wrote:

Back to the Morris.Â* I have an ammeter, 30-0-30, and the dynamo is rated
13.5v, 22 amps.Â* Still +ve earth.Â* What I don't have is suitable brown
cable, and there seems to be a lot of conflicting advice.

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Any idea of 'standard' car Lucar connector size?Â* Options seem to be
6.3mm, 8mm etc.Â* I'm guessing 6.3, being equivalent to the old 1/4 inch?

Thanks!

The terminals on a Lucas ammeter I have here are 3/8". I suggest you use
6mm cable as a minimum.
Have you considered fitting a digital ammeter? The shunt resistor can be
fitted in a plastic box somewhere where the battery lead doesn't need to
be extended. Then you simply take two (thin) wires to the actual meter,
or to the dividing circuit if the meter needs one. If it does, build the
dividing circuit into a sealed box because otherwise damp affects it
(very high value resistors are involved) and alters the reading. The
meter also needs a supply and a ground. You can take the supply from the
ignition circuit. If you get an illuminated one it's best to select one
rated at 15V, otherwise the little LEDs will burn out prematurely.

Bill

On Tuesday, 17 April 2018 12:05:45 UTC+1, Graeme wrote:
In message ,
tabbypurr writes
On Tuesday, 17 April 2018 10:55:42 UTC+1, Graeme wrote:


Back to the Morris. I have an ammeter, 30-0-30, and the dynamo is rated
13.5v, 22 amps. Still +ve earth. What I don't have is suitable brown
cable, and there seems to be a lot of conflicting advice.

was the original brown?

There isn't an original as such, but yes, the cable being extended is
brown, so I would like to follow the same scheme.

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Voltage drop is likely to be the no 1 consideration. 1mm2 pair drops
44mV per amp per metre, so 22A 3mm2 drops 0.323 volts per metre. 1m of
that is going to seriously hamper your battery charging.

OK, good point. I will go for the larger size. It is certainly a
common addition to a Minor, even (or particularly) those still using a
dynamo.

Any idea of 'standard' car Lucar connector size? Options seem to be
6.3mm, 8mm etc. I'm guessing 6.3, being equivalent to the old 1/4 inch?

you're the one with the measurand!

grin Well, yes, but measuring to a fraction of a mm with a steel rule
is not easy, particularly when the connection is buried under the
bonnet. I'm sure 1/4 inch was the 'standard' automotive size back in
the day, and 6.3mm is close enough to 1/4 inch.

4.5mm2 will get you 0.215v drop at full current, not as bad but still hampers charging on an already low voltage output.

A battery voltmeter is a way to avoid the issue, preferably expanded scale from 10v to 15v, or in your case 14v.


NT

On Tue, 17 Apr 2018 10:55:31 +0100, Graeme
wrote:


Back to the Morris. I have an ammeter, 30-0-30, and the dynamo is rated
13.5v, 22 amps. Still +ve earth. What I don't have is suitable brown
cable, and there seems to be a lot of conflicting advice.

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Any idea of 'standard' car Lucar connector size? Options seem to be
6.3mm, 8mm etc. I'm guessing 6.3, being equivalent to the old 1/4 inch?


Many years ago I decided to add an ammeter to my Mini. No idea what
cable I used but I sited the ammeter on the little shelf to the right
of the steering wheel.

One day going to work I smelled burning and realised it was the
ammeter and in a flash I grabbed the cable with my hand and pulled it
with sufficient force to break the connections but not after the
burning hot plastic and wire had seared my hand.

Of course nowadays I would ask on here before making such an
installation. Drove the rest of the way with my right hand out of the
sliding window in an attempt to keep it cool.



--
AnthonyL

On Tue, 17 Apr 2018 10:55:31 +0100, Graeme wrote:

Back to the Morris. I have an ammeter, 30-0-30, and the dynamo is rated
13.5v, 22 amps. Still +ve earth. What I don't have is suitable brown
cable, and there seems to be a lot of conflicting advice.

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Any idea of 'standard' car Lucar connector size? Options seem to be
6.3mm, 8mm etc. I'm guessing 6.3, being equivalent to the old 1/4 inch?

It's very easy to 'oversize' the cable to try and reduce losses but it could
inadvertently mechanically overstress the connections either at the regulator,
or at the ammeter

The 3mm^2 especially being multistranded looks similar to what would have been
fitted new on cars thus equipped.

At these current levels sizing the cable to the connectors you will be using and
getting a quality interface, preferably crimped, between the wire and the
connector is IMHO slightly more important than the actual wire size itself.

The Lucar connectors came in iirc about 5 sizes, 1/4" being most common but also
3/8" 3/16" , 110 thou which is just below 1/8" plus half inch.

The dynamo regulator connections will almost certainly be a mix of 1/4" and 3/8"
and possibly 3/16" or on earlier models bare wires into screw terminal blocks.

Every wire will be brown, either plain or with a tracer. The correct colour
codings are online.

http://www.expeditionlandrover.info/Lucaswirecode.htm

https://www.autoelectricsupplies.co....ew_order_2.pdf

--

On 17/04/18 10:55, Graeme wrote:

Back to the Morris.Â* I have an ammeter, 30-0-30, and the dynamo is rated
13.5v, 22 amps.Â* Still +ve earth.Â* What I don't have is suitable brown
cable, and there seems to be a lot of conflicting advice.

Go for some kind non-invasive DC hall effect sensor, and log the
readings digitally?

--
Adrian C

In article ,
Graeme wrote:

Back to the Morris. I have an ammeter, 30-0-30, and the dynamo is rated
13.5v, 22 amps. Still +ve earth. What I don't have is suitable brown
cable, and there seems to be a lot of conflicting advice.

http://www.vehicle-wiring-products.e...dard-pvc-cable

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Use what Lucas did?

Any idea of 'standard' car Lucar connector size? Options seem to be
6.3mm, 8mm etc. I'm guessing 6.3, being equivalent to the old 1/4 inch?

The metric sizes are simply modern measurements of the old. They are
interchangeable.

Thanks!

--
*A bartender is just a pharmacist with a limited inventory *

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
Bill Wright wrote:
Have you considered fitting a digital ammeter? The shunt resistor can be
fitted in a plastic box somewhere where the battery lead doesn't need to
be extended. Then you simply take two (thin) wires to the actual meter,
or to the dividing circuit if the meter needs one.

You can actually just measure the voltage drop across the ground lead from
battery to chassis. No need for a shunt resistor as such.

I made one for the ol' Rover which doesn't have an ammeter. But arranged
it to drive a tri-colour LED. Red for discharge, amber for balanced, green
for charging. A lot easier to fit on the dash than a meter.

--
*Don't squat with your spurs on *

Dave Plowman London SW
To e-mail, change noise into sound.

Is this one of those plus and minus gauges?
I used to have a Morgan on in my shed and it really was an ammeter, may of
the ones you see these days have a shunt and a millivoltmeter sender and a
normal meter or lcd.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Graeme" wrote in message
...

Back to the Morris. I have an ammeter, 30-0-30, and the dynamo is rated
13.5v, 22 amps. Still +ve earth. What I don't have is suitable brown
cable, and there seems to be a lot of conflicting advice.

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Any idea of 'standard' car Lucar connector size? Options seem to be
6.3mm, 8mm etc. I'm guessing 6.3, being equivalent to the old 1/4 inch?

Thanks!
--
Graeme

In message , "Dave Plowman (News)"
writes
In article ,
Graeme wrote:

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Use what Lucas did?

I fitted several ammeters to cars many years ago, but each came as a
kit, with cable. Trouble is, I now don't know what Lucas supplied, back
then. I find it very difficult to visualise what cable looks like. Easy
to read the description, but without seeing drums of the stuff, I'm not
confident I would choose the correct size from description alone.
--
Graeme

In article ,
Graeme wrote:
In message , "Dave Plowman (News)"
writes
In article ,
Graeme wrote:

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Use what Lucas did?

I fitted several ammeters to cars many years ago, but each came as a
kit, with cable. Trouble is, I now don't know what Lucas supplied, back
then. I find it very difficult to visualise what cable looks like. Easy
to read the description, but without seeing drums of the stuff, I'm not
confident I would choose the correct size from description alone.

Snag is modern cable can look very different from older stuff at a glance.
From the pretty old woven fabric to the later PVC and later still thin
wall PVC. But you can measure the diameter of the conductor and calculate
the metric cross sectional area, which modern cables are specified in.

It also depends on what is wired via your ammeter. It will obviously show
charge, but not everything on the car might be wired through it to show
discharge.

However, as with all such cables, you won't do any harm using a larger one
- provided it can fit the terminals.

--
*60-year-old, one owner - needs parts, make offer

Dave Plowman London SW
To e-mail, change noise into sound.

In message , "Dave Plowman (News)"
writes

It also depends on what is wired via your ammeter. It will obviously show
charge, but not everything on the car might be wired through it to show
discharge.

The main connection from the battery goes to the starter switch. From
there (same side of the switch), a brown wire goes to the A terminal of
the Control Box. The idea is to break that brown wire for the ammeter,
so the ammeter reads everything except the starter motor.

The existing brown wire is probably 6 inches long, but mounted on the
bulkhead, so extending to an ammeter would require an additional 18
inches or so, in both directions.
--
Graeme

In message , The Other Mike
writes

http://www.expeditionlandrover.info/Lucaswirecode.htm

https://www.autoelectricsupplies.co....de_for_vehicle
_wiring_-_new_order_2.pdf

Very helpful comments and great links Mike. Thank you.
--
Graeme

In article ,
Graeme wrote:
In message , "Dave Plowman (News)"
writes

It also depends on what is wired via your ammeter. It will obviously
show charge, but not everything on the car might be wired through it to
show discharge.

The main connection from the battery goes to the starter switch. From
there (same side of the switch), a brown wire goes to the A terminal of
the Control Box. The idea is to break that brown wire for the ammeter,
so the ammeter reads everything except the starter motor.

Dunno. Remember on my '55 MG Magnette, not everything was wired via the
ammeter. The factory spotlights for one. All too easy to exceed 30 amps.

The existing brown wire is probably 6 inches long, but mounted on the
bulkhead, so extending to an ammeter would require an additional 18
inches or so, in both directions.

Must admit I'd be more inclined to fit an alternator so you don't have to
worry about how many amps you're using. ;-)

And if you want to know battery state, a voltmeter is more useful.

--
*Work is for people who don't know how to fish.

Dave Plowman London SW
To e-mail, change noise into sound.

Graeme Wrote in message:

Back to the Morris. I have an ammeter, 30-0-30, and the dynamo is rated
13.5v, 22 amps. Still +ve earth. What I don't have is suitable brown
cable, and there seems to be a lot of conflicting advice.

Found cable described as 3.0mm² 44/0.30 27.5 Amp, which seems OK, or
should I go for 4.5mm² 65/0.30 35 Amp to be on the safe side?

Any idea of 'standard' car Lucar connector size? Options seem to be
6.3mm, 8mm etc. I'm guessing 6.3, being equivalent to the old 1/4 inch?

Thanks!
--
Graeme


Apart from olde worlde charm, if you're planning on keeping it for
many more years wouldn't an alternator upgrade make more sense
than an ammeter?

Tim
--

On 17/04/2018 15:42, Dave Plowman (News) wrote:

However, as with all such cables, you won't do any harm using a larger one
- provided it can fit the terminals.


Fit a 3" length of the biggest possible cable the connector will take
into the connector. Connect this to a fatter cable by means of a
soldered joint wrapped with self-amalg.

Bill

On 17/04/2018 17:00, Dave Plowman (News) wrote:

Dunno. Remember on my '55 MG Magnette, not everything was wired via the
ammeter. The factory spotlights for one.

That makes the ammeter pointless.

Bill

In message , Tim+
writes

Apart from olde worlde charm, if you're planning on keeping it for
many more years wouldn't an alternator upgrade make more sense
than an ammeter?

Well, possibly, but I have owned the car since 1996, and the dynamo has
always been fine. I don't feel I need an ammeter as such, I just found
it in a box of stuff in the shed. No idea where I got it. Found a +ve
earth radio too, so may have a go at that.
--
Graeme

On Tue, 17 Apr 2018 13:14:42 +0100
Adrian Caspersz wrote:

On 17/04/18 10:55, Graeme wrote:

Back to the Morris.Â* I have an ammeter, 30-0-30, and the dynamo is
rated 13.5v, 22 amps.Â* Still +ve earth.Â* What I don't have is
suitable brown cable, and there seems to be a lot of conflicting
advice.

Go for some kind non-invasive DC hall effect sensor, and log the
readings digitally?

That was my first thought, but he wants to use the period meter so
you'd have to modify that so you could drive it with e.g. an Arduino.

On Tue, 17 Apr 2018 11:58:09 +0100
Graeme wrote:

Well, yes, but measuring to a fraction of a mm with a steel rule
is not easy, particularly when the connection is buried under the
bonnet.

That's why you take the measurement with a small caliper, and transfer
it to a measuring scale or vernier caliper once you have it somewhere
more accessible. Calipers are cheap and very useful.

I'm sure 1/4 inch was the 'standard' automotive size back in
the day, and 6.3mm is close enough to 1/4 inch.

6.35mm is exactly a quarter inch, by definition - I expect they just
dropped the 0.05 for convenience rather than rounding it up. The
connectors are probably made something like 6.30mm male and 6.40mm
female for an easy fit (and they're probably not specified to 0.01mm
anyway).

In article 20180418172431.4f76c30a@Mars,
Rob Morley wrote:
On Tue, 17 Apr 2018 11:58:09 +0100
Graeme wrote:

Well, yes, but measuring to a fraction of a mm with a steel rule
is not easy, particularly when the connection is buried under the
bonnet.

That's why you take the measurement with a small caliper, and transfer
it to a measuring scale or vernier caliper once you have it somewhere
more accessible. Calipers are cheap and very useful.

I'm sure 1/4 inch was the 'standard' automotive size back in
the day, and 6.3mm is close enough to 1/4 inch.

6.35mm is exactly a quarter inch, by definition - I expect they just
dropped the 0.05 for convenience rather than rounding it up. The
connectors are probably made something like 6.30mm male and 6.40mm
female for an easy fit (and they're probably not specified to 0.01mm
anyway).

Modern ones are perfectly compatible with the old 1/4" versions - same
across all the spade terminal range. Although some modern ones ain't as
well made as originals. Thinner brass.

--
*Why is the word abbreviation so long?

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman wrote

Must admit I'd be more inclined to fit an alternator so you don't have to
worry about how many amps you're using. ;-)


Mate of mine running a moggy traveler had some electrical issues and asked
me to look at it.

Found it had an alternator fitted and that had failed, turned out the car
was an ex Oxford Police vehicle and they had the alternator installed to
cope the with extra load of beacon, radio etc.
Nearest match was one off a Ford Transit.
The original had seen a lot of use,as well as the Police use it had first
belonged to my mates brother who took it down through Francos Spain and
Across into North Africa and back again twice.

GH

In article ,
Marland wrote:
Dave Plowman wrote

Must admit I'd be more inclined to fit an alternator so you don't have to
worry about how many amps you're using. ;-)


Mate of mine running a moggy traveler had some electrical issues and asked
me to look at it.

Found it had an alternator fitted and that had failed, turned out the car
was an ex Oxford Police vehicle and they had the alternator installed to
cope the with extra load of beacon, radio etc.
Nearest match was one off a Ford Transit.
The original had seen a lot of use,as well as the Police use it had first
belonged to my mates brother who took it down through Francos Spain and
Across into North Africa and back again twice.

Lots of later cars still used the A series engine but with an alternator,
so fitting one now would give a wider choice than when the Moggy was
current.

I've fitted a modern 100 amp unit to my SD1. Replacing the 75 amp Lucas
unit. Cost me less than finding the correct one new. Apart from upping the
wiring size, etc.

--
*I couldn't repair your brakes, so I made your horn louder *

Dave Plowman London SW
To e-mail, change noise into sound.