HJ60 sudden overcharging (1 Viewer)

[Keyu]

Hello,
I am new to ih8mud and what an amazing place to share our love for cruisers.
I own an HJ60, which I am now 'fixing/upgrading' and live in Africa.

First of all I would like to thank all the people that participate and help one another. I've been reading many of the threads as I recently started working on my truck but never posted anything and found them very helpful and also a great atmosphere.

Today I've encountered a sort of road block and hopefully someone can help.
I have searched the threads but couldn't find the info I'm looking for.

Basically this is my situation:

I've recently added a 12V (original is all 24V) circuit to my cruiser to power various accessories (dash cam, tyre pressure monitor, stereo, and others). Did this via an additional fuse box and main line from the 2nd battery -ve post. Grounded the fuse box to the body via a bolt in the cabin. For some devices I used a relay as I want them to power on as ACC.
All works well apparently.

I also went trough the original harness in the engine bay and cleaned it up a bit but didn't make any changes. I have howeverd moved around the harness, tied it up with tape where needed etc.

Yesterday I went for a test drive and noticed charge light was coming on when revving up the engine, even just above 2,000 rpm.
Then noticed the voltage meter in the instrument panel going over the limit (32V).

As this clearly means overcharging went straight back home. Checked the regulator which seems to be ok (followed the tests indicated in the workshop manual).
I did find the regulator ground wire to be burnt out and interrupted. Looks like it shorted but seems from an old event. Probably when I cleaned up the harness it broke alltogether.

I repaired this wire hoping it would fix it but I imagined it wouldn't, since the regulator is also grounded via the body anyways.

I did a test with the regulator cap open and engine running. By naked eye it seems the regulator relay remains in one position, and I assume this is telling the alternator to continously charge.

I haven't checked the fuses as everything works but I will do tomorrow. If main engine or charge fuse were blowin I assume the cruiser wouldn't even start.

To cut it short, can anyone help me understand what's happening?

I haven't tried adjusting the regulator and was thinking of doing that next, but perhaps someone has seen this before?
My brother has an HJ62 which occasionally behaves the same way but in his case it's random and seems like regulator relay gets stuck but then starts working again. Mine has been working flawlessly for years and this has suddenly popped up and it's doing it constantly.

Any help is greatly appreciated.

 

[Seth S]

Had to read your post again.

it sounds like your two batteries are combining voltage as if wires in series which would give you 32 volts or so. More when charging

 

[Keyu]

Hi, thanks for your very quick reply

The batteries are in series yes. This is factory, as the whole system is 24V unlike the FJ which is 12V, unless I misunderstood what you were trying to say.
At idle voltage meter will show around 24V which is fine. As soon as engine is revved up quickly goes to 30 or so and revving even more make it go over the limit of 32V. Aroun 30V charge light comes on.

 

[Seth S]

Hi, thanks for your very quick reply

The batteries are in series yes. This is factory, as the whole system is 24V unlike the FJ which is 12V, unless I misunderstood what you were trying to say.
At idle voltage meter will show around 24V which is fine. As soon as engine is revved up quickly goes to 30 or so and revving even more make it go over the limit of 32V. Aroun 30V charge light comes on.

Is it (2) 12v batteries in series or a 24v battery and you added a 12v battery?

in a 12v system normal charging voltage is around 13 to 14.4 volts. I’d guess a 24v alternator would be 26-29v as normal? But I’d want to check the Toyota manual for sure.

 

[Keyu]

Is it (2) 12v batteries in series or a 24v battery and you added a 12v battery?

in a 12v system normal charging voltage is around 13 to 14.4 volts. I’d guess a 24v alternator would be 26-29v as normal? But I’d want to check the Toyota manual for sure.

It's the factory (2) 12V batteries in series.

 

[joshuageoffrey]

Have a similar 'issue' mate, not because of what you're describing but the symptoms are the same...

Basically, by adding additional accessories you are putting more load on the system, drawing more current and therefore the relatively 'simple' (yet effective) charging system in these old cruisers recognises that the batteries have lost voltage and therefore attempts to remedy this as quickly as possible. Once the regulator identifies that the batteries have been topped up, the voltage level with decrease to a 'normal' operating level on your cluster gauge.

I chased this, what I thought was an 'issue' for weeks on end, replacing the external regulator and alternator, chasing wires in the loom trying to find what the cause could be but the answer is that you have an old truck, which already had a certain amount of voltage drop across an old wiring circuit and by adding your additional 12 volt system you have increased the load on the system, thus seeing the higher voltage readings as the system tries to keep up.

 

[georgebj60]

I would double-check your 12V setup to make sure you haven't created an imbalance in the system. It sounds like you're taking 12V off of one battery, and nothing from the other. Given my very limited experience about 24V systems, this sounds like a recipe for disaster where you will be burning up batteries at an alarming rate.
Have you verified the actual charge voltage with a meter? The dash gauges are not very accurate...

EDIT: I would also check the state of each battery, making sure they are both good health and have similar states of charge.

 

[Keyu]

Have a similar 'issue' mate, not because of what you're describing but the symptoms are the same...

Basically, by adding additional accessories you are putting more load on the system, drawing more current and therefore the relatively 'simple' (yet effective) charging system in these old cruisers recognises that the batteries have lost voltage and therefore attempts to remedy this as quickly as possible. Once the regulator identifies that the batteries have been topped up, the voltage level with decrease to a 'normal' operating level on your cluster gauge.

I chased this, what I thought was an 'issue' for weeks on end, replacing the external regulator and alternator, chasing wires in the loom trying to find what the cause could be but the answer is that you have an old truck, which already had a certain amount of voltage drop across an old wiring circuit and by adding your additional 12 volt system you have increased the load on the system, thus seeing the higher voltage readings as the system tries to keep up.

Thanks for the info.

I don't understand however why the system would overcharge. Voltage regulator should keep it within "adjusted" range shouldn't it? As I haven't touched it and it worked fine until 3 days ago, it should be max 29V approx.

The additional accessories don't consume much. If everything is ON I don't go over 15A.
In any case I disconnected the 12V system alltogether to see what would happen and problem persists.

Voltage meter in the dashboard stays at 24V as soon as engine is started, then suddenly goes up. Revving the engine just a bit makes it go up to 32V. I know it's not accurate but 1) battery light comes and 2) even if not accurate it still should shoot up to 32V or above. This is not normal.

 

[rustybucket]

Hello,
I am new to ih8mud and what an amazing place to share our love for cruisers.
I own an HJ60, which I am now 'fixing/upgrading' and live in Africa.

First of all I would like to thank all the people that participate and help one another. I've been reading many of the threads as I recently started working on my truck but never posted anything and found them very helpful and also a great atmosphere.

Today I've encountered a sort of road block and hopefully someone can help.
I have searched the threads but couldn't find the info I'm looking for.

Basically this is my situation:

I've recently added a 12V (original is all 24V) circuit to my cruiser to power various accessories (dash cam, tyre pressure monitor, stereo, and others). Did this via an additional fuse box and main line from the 2nd battery -ve post. Grounded the fuse box to the body via a bolt in the cabin. For some devices I used a relay as I want them to power on as ACC.
All works well apparently.

I also went trough the original harness in the engine bay and cleaned it up a bit but didn't make any changes. I have howeverd moved around the harness, tied it up with tape where needed etc.

Yesterday I went for a test drive and noticed charge light was coming on when revving up the engine, even just above 2,000 rpm.
Then noticed the voltage meter in the instrument panel going over the limit (32V).

As this clearly means overcharging went straight back home. Checked the regulator which seems to be ok (followed the tests indicated in the workshop manual).
I did find the regulator ground wire to be burnt out and interrupted. Looks like it shorted but seems from an old event. Probably when I cleaned up the harness it broke alltogether.

I repaired this wire hoping it would fix it but I imagined it wouldn't, since the regulator is also grounded via the body anyways.

I did a test with the regulator cap open and engine running. By naked eye it seems the regulator relay remains in one position, and I assume this is telling the alternator to continously charge.

I haven't checked the fuses as everything works but I will do tomorrow. If main engine or charge fuse were blowin I assume the cruiser wouldn't even start.

To cut it short, can anyone help me understand what's happening?

I haven't tried adjusting the regulator and was thinking of doing that next, but perhaps someone has seen this before?
My brother has an HJ62 which occasionally behaves the same way but in his case it's random and seems like regulator relay gets stuck but then starts working again. Mine has been working flawlessly for years and this has suddenly popped up and it's doing it constantly.

Any help is greatly appreciated.

Boy I wish I had an answer and I troubleshooted a lot of Automotive electrical systems in my time. Usually when a generator puts out a higher voltage it's usually because the wire gauge was smaller and it had more windings on the stator. I would also say the regulator was shot. Try to reconfirm where you Source out the alternator. I've never seen anything like this before

 

[DiehSt]

To have two batteries in serie and to take 12 volt of one of the two batteries is not a good idea.
When you want 12 volt out of a 24 volt (2x12volt batteries) system, use a 24-12 volt converter.

 

[OSS]

Regardless of what battery configuration is used (single, double series) if the charge voltage exceeds the recommended maximum, there's a problem with the voltage regulator or how it's hooked up.

 

[Keyu]

I would double-check your 12V setup to make sure you haven't created an imbalance in the system. It sounds like you're taking 12V off of one battery, and nothing from the other. Given my very limited experience about 24V systems, this sounds like a recipe for disaster where you will be burning up batteries at an alarming rate.
Have you verified the actual charge voltage with a meter? The dash gauges are not very accurate...

EDIT: I would also check the state of each battery, making sure they are both good health and have similar states of charge.

You are correct... did some research and indeed there's an imbalance now and I need to install a battery equalizer. But this doesn't explain the problem I'm having.
Today I adjusted the regulator as per the manual and now everything seems fine. Measured the voltage at the alternator B terminal and it won't go above 29V.

I cannot explain the sudden change in behaviour of the regulator though...

 

[Keyu]

To have two batteries in serie and to take 12 volt of one of the two batteries is not a good idea.
When you want 12 volt out of a 24 volt (2x12volt batteries) system, use a 24-12 volt converter.

Yes I was not aware of this and after some research you're indeed correct.

The options are an equalizer or a DC-DC (24-12) converter as you mentioned. With low loads on the 12V circuit a converter should be enough but I need to do some calculations.

 

[Keyu]

For everyone reading this, I was not able to identify what caused this sudden overcharge, perhaps the fixing of bad wiring connections done by others, not sure.

In any case I adjusted the regulator as per the manual and everything seems to work ok now. Still need to drive it but at idle and also when revving the engine voltage will not go past 29V which is according to Toyota specs (27-29 V between idle and 2,000 rpm).

Was pretty simple, just hooked up a voltmeter to the alternator and bent the voltage regulator arm, per the manual, until I got the desired voltage. I did wait for the engine to warm up before adjusting as I saw the voltage reading changed somewhat between cold engine and warmed up.

 

[Keyu]

Regardless of what battery configuration is used (single, double series) if the charge voltage exceeds the recommended maximum, there's a problem with the voltage regulator or how it's hooked up.

I thought so too. Battery config or additional loads shouldn't suddently make the whole system stop working as it's supposed to.
As I mentioned in my post above, I re-adjusted the regulator and now things are working as expected. Will drive it for a few days and see.

 

[Keyu]

Boy I wish I had an answer and I troubleshooted a lot of Automotive electrical systems in my time. Usually when a generator puts out a higher voltage it's usually because the wire gauge was smaller and it had more windings on the stator. I would also say the regulator was shot. Try to reconfirm where you Source out the alternator. I've never seen anything like this before

Thanks for the feedback.
My cruiser has all stock components and I've had it for 20+ years so unless something went wrong I would say the alternator design is fine.
Shot regulator yes, could very well be and I thought so too. I tested it according to the manual though and everything is within specs so I was a bit baffled.

 

[hj 60]

In my Hj the ground was also burned,

I overcharge a bit as the alternator is sometimes a 25 amp model or 40, so it barely keeps up when all blingbling is on:

the fsm is nice to do a check up:

like mentioned it is better to use a converter, possibly switch it on with key to prevent battery drain.

 

[Keyu]

In my Hj the ground was also burned,

I overcharge a bit as the alternator is sometimes a 25 amp model or 40, so it barely keeps up when all blingbling is on:

the fsm is nice to do a check up:

like mentioned it is better to use a converter, possibly switch it on with key to prevent battery drain.

Thanks for the great info and found a lot more your signature links
Will definitely look into using a converter or equalizer ASAP. Any recommendations?

 

[Keyu]

Many thanks to everyone. Very helpful. Wish you happy cruisin'

 

[joshuageoffrey]

Thanks for the info.

I don't understand however why the system would overcharge. Voltage regulator should keep it within "adjusted" range shouldn't it? As I haven't touched it and it worked fine until 3 days ago, it should be max 29V approx.

The additional accessories don't consume much. If everything is ON I don't go over 15A.
In any case I disconnected the 12V system alltogether to see what would happen and problem persists.

Voltage meter in the dashboard stays at 24V as soon as engine is started, then suddenly goes up. Revving the engine just a bit makes it go up to 32V. I know it's not accurate but 1) battery light comes and 2) even if not accurate it still should shoot up to 32V or above. This is not normal.

Mate, you and me both... as far as I'm concerned (according to multiple auto electricians also), there is no 'issue' - I battled with this concept too. I will just add that this is assuming that the 12v system you have wired in, is wired in correctly...