Outer Limits 4x4 Board

I've got an 86 LN65 hilux which has just started to flicker the timing belt, charge and filter lights. The brightness of the lights increase as the revs drop below 2000rpm.

I recently welded sliders to the chassis without removing battery terminals.

Currently getting 12.6V across the battery and 12.6V between alternator and battery when running at speed. So to me it seems it's not charging.

Could this be related to the welding?

Or the voltage regulator? Or fried alternator?

Cheers

I Though Disconecting the Batterys was to stop them Going flat
If your Getting 13.6v from the Alt its ok
Prolly you Stuffed your Battery maybe

beinthemud wrote:If your Getting 12.6v from the Alt its ok

Really? I was under the impression that the alternator supplies between 13.8-14.8V when charging?

beinthemud wrote:Prolly you Stuffed your Battery maybe

Bahaha.. You sound very certain there sir!

beinthemud wrote: If your Getting 12.6v from the Alt its ok

If you don't known what you are talking about you shouldn't pretend you do.

Should be between 13.5v and 14.5v

As for welding with the battery connected, i never disconnect the battery and have never had any ill effects. Maybe im just lucky.

That why I put Maybe

http://cf.linnbenton.edu/hhs/pe/gibbsr/ ... ?pgID=2086

This is a good guide to fault find your charging system

You should disconnect the battery before welding to the vehicle or you risk damage to the diodes in the alternator. I am pretty sure this is standard recommended practice.

Also, the 12.8V you are measuring may be just voltage from your battery, depending on how long it was since the charge system stopped working. If you measure the voltage off the back of the alternator it is probably feeding straight down from the charge wire to the battery. I had this happen on my alternator, and it was then in for a new regulator - approx $40 if you fit it yourself.

PBBIZ2 wrote: Also, the 12.8V you are measuring may be just voltage from your battery, depending on how long it was since the charge system stopped working. If you measure the voltage off the back of the alternator it is probably feeding straight down from the charge wire to the battery. I had this happen on my alternator, and it was then in for a new regulator - approx $40 if you fit it yourself.

This is what I was thinking as well. Voltage reg not letting the alternator charge the battery..
Bursons gave me a price on one - $40.

Only shit thing is the PO has cut the plug on the current reg and put a 6 pin one on. Should be fun matching them up..

Would there be voltage at the alternator if the brushes were on the way out? I don't have a big enough ammeter to check the output.

Not really sure if you can have 'brushes on the way out' - they are either in contact and transferring voltage or they are worn out and not contacting, so no output. If no volts, no amps.

I would whip it out, take to an auto elec and have them bench test it. If its the reg, either get them to put it in on the spot and recheck, then its done. If they diagnose it as something else, then you have not wasted the trip. I know this might not be convenient, but could save you time and money in the long run. Either way you walk out with a guaranteed solution.

If its more than the reg, and you just replace it alone, then find its something else, you might get a bit angry - perhaps!

quick test is to loosen + terminal bolt, turn motor on , turn high beam on. Put meter on to see voltage. Lift terminal off bat +with meter lead attached. If lights stay on then alternatercan put out current, if voltage stays the same then regulator is working.This was shown to me by auto sparky , the important bit is that the alt is seeinga load which protects the reg etc. I added last comment because you do get a lot peoplenot understanding the process

Thanks for the suggestions guys.

I'll try that scratcher, always heard never to disconnect battery when alternator is running though. But this is ok because of the load from the high beam?

dillza_69 wrote:

beinthemud wrote: If your Getting 12.6v from the Alt its ok

If you don't known what you are talking about you shouldn't pretend you do.

Should be between 13.5v and 14.5v

As for welding with the battery connected, i never disconnect the battery and have never had any ill effects. Maybe im just lucky.

I have never disconnected my battery, noone i know disconnects it when welding, but yes i have heard you should never leave it connected, i guess thats what puts the Backyard in Boondall Backyard Performance haha

scratcher wrote:quick test is to loosen + terminal bolt, turn motor on , turn high beam on. Put meter on to see voltage. Lift terminal off bat +with meter lead attached. If lights stay on then alternatercan put out current, if voltage stays the same then regulator is working.This was shown to me by auto sparky , the important bit is that the alt is seeinga load which protects the reg etc. I added last comment because you do get a lot peoplenot understanding the process

Tried this, headlights stopped. Ordered in some alternator brushes. Will see if thats the issue..

So I replaced the brushes, old ones were worn but within specs. No change. Replaced the voltage regulator, and the dash lights went from flickering to staying on all the time.

I checked the voltage at the battery, still remains at about 12.8V. However seems to be charging - I ran the battery down to about 12.3V and then started it and watched the voltage creep back up to 12.8V and stay there after the engine was off. So its charging, but not at the proper ~14V?

Anything else I could try? Going to double check the wiring..

Most often you can damage the diodes in the alternator.
The alternator creates an ac current, the diodes convert it to DC

Thats my suggestion.

Take it apart, test with a multimeter, rekon you have a fried diode or 2.

ALWAYS disconect the battery when welding in any car.

Trains

trains wrote:Most often you can damage the diodes in the alternator.
The alternator creates an ac current, the diodes convert it to DC

Thats my suggestion.

Take it apart, test with a multimeter, rekon you have a fried diode or 2.

ALWAYS disconect the battery when welding in any car.

Trains

Thanks mate, I'll give it a shot.

So if say one side of the rectifier is fried, only half the amount of AC would make it to the battery? Because at the moment, its charging, just slowly and not at 14V.

Also make sure there is +12 or more volts at the back of the alt.. as if you have changed the brushes ect there might be a short between the alt case and the positive points created during the rebuild... Just somthing to cheak as i have fucked this up berfore and im a electronic tech

yamaha__308 wrote:

trains wrote:Most often you can damage the diodes in the alternator.
The alternator creates an ac current, the diodes convert it to DC

Thats my suggestion.

Take it apart, test with a multimeter, rekon you have a fried diode or 2.

ALWAYS disconect the battery when welding in any car.

Trains

Thanks mate, I'll give it a shot.

So if say one side of the rectifier is fried, only half the amount of AC would make it to the battery? Because at the moment, its charging, just slowly and not at 14V.

So how many diodes were fried??

If you have not checked yet, let us know when you do.

Trains

S.CoXy wrote:Also make sure there is +12 or more volts at the back of the alt.. as if you have changed the brushes ect there might be a short between the alt case and the positive points created during the rebuild... Just somthing to cheak as i have . this up berfore and im a electronic tech

Cheers. There's voltage at the alternator.

trains wrote:So how many diodes were fried??

If you have not checked yet, let us know when you do.

Trains

Haven't pulled it back down yet, need the lux to get a few parts yet, but I'll report back when I do.

ITS CHARGING!!!

Stripped the alternator down, found one diode that had died and come away from the frame. I replaced it with another one, just soldered it to the frame and then to the stator lead. Its a big diode so it should last without a heat sink.

Put it all back together to find it still didn't work, but after a few checks found a loose plug that I didnt do properly.

I chucked the old regulator back on and it played up again, so it was a combination of one dead diode and one dead regulator.

Thanks for letting us know.

So from now on, no more welding with the battery connected eh hehe.

T