Hi Guy's,
I'm pulling my car apart again to fix the little creatures that hide in your wiring.
My charge light has never turned off. I am mostly positive that I had it connected properly. But for some reason the alternator was only putting out 6.4v on the charge line.
It was charging my battery at nearly 14v. Is there any way to tell if it is stuffed?
Is there a suitable replacement alternator that I could use from the wreckers?

I'm planning on tidying up the wiring on my car and adding more relays and fuses and doing away with the 40+ year old wiring loom as best I can.

Any help is much appreciated.

Cheers

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18

Hey Ross,

After just going through this process. Highly recommend taking to an autoelect for:

1. Test (some will do for free)
2. rebuild (Will be about $200)

Don't waste your time like I did with my one

Cheers,

Trent

_________________
1600 Build: http://ozdat.com/forum/viewtopic.php?f=59&t=22694

see, for $200 and its still charging I'll just disconnect the light and use the gauge. unless there is a direct replacement I can just jam into it!

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18

Typical Charging circuit for an SR20: -

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

Thanks Graeme. Now that the car is in bits it might be a bit easier to trouble shoot the issue.
Those Doco's are certainly helpful.
What other wiring diagrams have you got for 1600's and SR20's? I'm after one in particular for the Digital Climate control for an S13 SR. There are a few redundant wires I need to have a look at, all the other ones were in Japanese!
I have a 1600 diagram, i'm planning on rewiring the dash wiring and getting rid of the old fuse box. So i might have to see what I can do about getting a different 1600 wiring diagram to rewire that to make sure that all appropriate parts have power when necessary!
Doesn't seem too hard of a job though.

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18

I have the wiring schematics for all P510 models.
https://www.mediafire.com/folder/t0932s ... g_Diagrams
I also have the FSMs for the S13, 14 and 15 models all digital.
https://www.mediafire.com/folder/52sxrychy59lz/

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net

Hey guy's, i'm digging this up again.
I need to know if anyone know's how to wire up a LED alternator light in lieu of the incandescent bulb. I feel after some internet reading that this is causing my issue.
Everything is hooked up as per spec, but for some reason I can't seem to drop the wattage of the charge light down low enough for the alternator to cut off the power.
Does anyone know how to do this and can provide a wiring diagram?
Its a generic 10mm red LED.
Thanks

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18

Looking at one of the diagrams Nissanman posted prior - the charge warning lamp is also in parallel with a resistor. Work out the wattage of your LED and also work out how much resistance you will need to make roughly about 2W in total for it function like an incandescent would.

Personally I don't think that its the type of lamp causing the issue, alternator circuits are quite simple with internally regulated alternators now. Providing your battery sense is correct, your circuit to your ignition switch is correct and the charge can go straight to the positive terminal (or similar) it should all function sweet.

Alternatively (excuse the pun), you could try and eliminate wiring or component by trying another alternator.

Best of luck.

yeah, I was hoping someone could just tell me the values of the resisters needed.

I know they have a resister, that's also for circuit protection for the alternator incase the bulb blows.
Here's the thing... LED's are a lower wattage globe than incandescent globes.
Mine is a red Narva chrome pilot light. 14.2mm bezel, 12v.
according to the specs, it has a current draw of 0.02amps at 12 volts, which means (v=ir) the wattage is 0.24 watts. The resistance is 600ohms. That's quite a bit less than the original. Maybe I need to bump up the resistance further.

Hence why I want someone with more circuit skill to see if that's my issue.

Thanks!

Probably want something around the 80 ohm mark.

_________________
910 S3 Bluebird - FJ20ET, E85, IRS, 5 Speed, 4.4 LSD
910 S3 TRX - RB25DET, Coilovers, S13 Front end, Power Steering
RA23 Celica - 18RG, Twin 40mm Webers, Coilovers, rolling on SSR mesh 15x7 0s.

Hey Ross,

Dont bother with the LED unless you want some bling, there is another issue going on there. I'd take it down to your local autoelec for a quick test. Takes 5 mins and you will know how it's working. Sounds like it might be a regulator issue.

Cheers,

Trent

_________________
1600 Build: http://ozdat.com/forum/viewtopic.php?f=59&t=22694

You can not use an LED for the charge light on an alternator won't work ever.
Needs a resistance to work.

There is a light wire and a sence wire on all SR20 alternators ive delt with,

The sense wire is to go direct to a constant power source, Or ignition source,.

The light wire is to run to a bulb. 5W at least, The other side of the bulb run to a power source,

Then your done. If that does not work take your alternator to a auto sparky as its broken.

_________________
Past:
A10 160J Coupe
R30 Turbo Manual
Present:
KP710 160JSSS Coupe (My Standard Car)
KP710 160JSSS Coupe (My SR20DET 6Spd Car)
KP710 140J Delux (New Road Car)
KP710 Parts POS

I have used this circuit with good results.
The alternator sense needs to be switched from an ign on source.
Failure to do this will result in a flat battery. If the vehicle is not used regularly.
A 100ohm 1/4 watt resistor across the warning lamp is required.

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT

Led can be done, I've seen it. just have to get the voltages right.
I'll have a play with resistances soon, I have all values.
My sense wire is hooked up to ign circuit from a relay. Ido get a very slow battery drain that I haven't been able to source yet!
thanks for that schematic Baz, didn't know you were using two diodes. I had originally wired it up with the resistor in parallel, I can't remember what happened, I'll have another play and tweak the values and see if I can get it to work.

just to clarify, is the normal incandescent bulb wired in parallel with a resistor also?

Ross the green diode is the LED.
Yes always use a 100 ohm resistor parallel with incandescent, 1/4 watt is ok.
This covers if the globe fails. can result in alternator failure.

_________________
A little knowledge is a dangerous thing.
www.datsport.com

"R.I.P. Baz. 29 April 2022. Thank you for all your contributions to the Datsun community over the years. You will be missed." - OZDAT