Outer Limits 4x4 Board

I have been having trouble with my alternator dying on a HZJ80. First time was most likely due to mud and age. Second time (a month or so later) died, not certain why. Repaired again no cost to me.

Third time died (12 mths later) after winching, motor running, nothing major just pulling a Zook back onto its wheels. Repair at no cost.

Fourth time died (2 weeks after last repair), no 4wdriving, winch used to move body while refitting panard bar, car not running, ignition off.

I have hi-mount winch with in cab controls and the car is now back at the auto electrican who has fixed it the past three times. The winch runs of a the second battery which has some sort of isolation and charging system (fitted by previous owner).

Does anybody and any ideas what could be the problem?

Frustrated
Stinger
Locked, lifted, hair dryer and armour plated 94 HZJ80

change auto electricians, or he is supplying dodgy alt bits, or the amps is not high enough on the alt.

stinger wrote: Fourth time died (2 weeks after last repair), no 4wdriving, winch used to move body while refitting panard bar, car not running, ignition off.

if the car is not running, how could it be effecting the alternator if its just draining off the batteries

With the car running I though may be a spike or something, but then the last time it was off???

Could a winch still operate if wired back to front (positive to negitive and and negitive to positive). This might cause some issues with alternator.

stinger wrote:With the car running I though may be a spike or something, but then the last time it was off???

Could a winch still operate if wired back to front (positive to negitive and and negitive to positive). This might cause some issues with alternator.

It would really help to know what's failing each time. Regulator? Diodes? Winding burnt out?

If something in your winch was wired back to front you winch would either run in the wrong direction, or (worst case) you'd short out your battery.

I don't think that's the issue.

Since it happened with the engine not running, I'd guess it's a spike issue killing regulator/diodes. But I'm only guessing, and more information would be really useful.

Make sure winch positive and negative is run STRAIGHT to the battery, DO NOT earth the negative through the chassis or body as this will bring the alternator into the circuit and the winch is way to high current for the alt to handle.

RoldIT wrote:Make sure winch positive and negative is run STRAIGHT to the battery, DO NOT earth the negative through the chassis or body as this will bring the alternator into the circuit and the winch is way to high current for the alt to handle.

Can you draw me a diagram of that?

i have been told it is the regulator that is failing???

The winch has both bositive and negitive cables wired directly to the second battery...

-Scott- wrote:

RoldIT wrote:Make sure winch positive and negative is run STRAIGHT to the battery, DO NOT earth the negative through the chassis or body as this will bring the alternator into the circuit and the winch is way to high current for the alt to handle.

Can you draw me a diagram of that?

Nope. I'm just speaking from experience and what I was told by a auto elec. I was told, in that configuration, the alternator tries to supply the winch directly, instead of charging the battery, then the winch using the battery charge.

Friend of mine had his earthed through the engine block and had a brand new alternator burn out twice, straight after (within hours) of two seperate winching operations.

If you have another explination, I'm open to ideas.

Winch wont affect alt in that config.

Ensure all your batt terminal, earth points, fuse box, alt connections are tight, clean and no corrosion.

Bazzle

It would have something to do with the Voltage drop accross the earth strap between the battery and the engine/chassis/body but you should not see much voltage drop accross the earthing strapp if it is a good size cable. (But standard is about 16mm2 which is rated at about 100amps continous)

As the altinator should be 13.8-14.4 volts the winch will try to take the power from the source with the higher voltage which would be the altinator, When it does this it will max out the altinator. eg drain 70amps from the altinator and then the remainder from the battery.

This is only my theory, plase let me know your ideas.

PS. When winching under load (draining more than the altinator can produce) and weater or not the winch is connected directly to the battery or earthed to the chassis/engine block it will always max out the altinator.

Simon.

If there's really been a dual battery isolator fitted by the previous owner, and it's been fitted properly, then there is no way the winch could kill the alternator while the alternator's not running.

So I think the winch is really a red herring here and you should forget about it. If it always and only died after winching, that would be a different story.

It reeally could be anything, are these new alternators or second hand jobs? And what does the auto elec say is the problem?

Well the verdict is back from the auto leccy.

Say no issues with winch. He removed alternator again (they must be good at it by now). Regualtory catcus again. Rest tested fine, but send it to a rewinding mob and they pulled it apart and while it tested fine the found some burnt parts (not certain what) but these were apparently causing a fault. SO they fixed them replaced the regulator and reinstalled it. Working fine for now and they did not charge me for it which is the best news.

So yes the winch was coincidental and the red herring.......

Thanks for all your help and thoughts..

Cheers,
Stinger

chimpboy wrote:If there's really been a dual battery isolator fitted by the previous owner, and it's been fitted properly, then there is no way the winch could kill the alternator while the alternator's not running.

Jason - you should appreciate that there are few absolutes in life.

Since I am currently inclined I shall explain.

Some dual battery controllers, such as the Jaycar kit, use MOSFETs as the switching device. While these prevent the auxiliary battery from draining the starting battery, they won't prevent the starting battery from draining the auxiliary.

MOSFETs have three terminals - Drain, Source and Gate. Normally, a voltage is applied to the Gate terminal to allow current to flow from Drain to Source. Starting battery is connected to Drain, auxiliary battery to Source. (Yes, the names seem to be screwed around - they are named for electron flow, not conventional current flow.)

If the Source terminal has a higher voltage than the Drain terminal, the MOSFET can behave like a forward-biased diode - and conduct bulk current with a small voltage drop. I know this, because I've blown my FETs! Twice.

So, if the winch switching is creating large voltage spikes on the aux battery circuit these spikes could forward bias the FETs and transmit the spikes to the starting battery side.

One would expect the starting battery to act like a large capacitor, and absorb the energy of these spikes, but any dodgy connections in the circuit could interfere with this - and theoretically such spikes could affect the regulator and/or alternator diodes.

This is all theoretical, and only applies to isolators using FETs (or diode isolators, but that's another story.)