Voltage Boosting Diode

[rob_macca67 Avid PP Poster! Find all posts View Profile Close rob_macca67]

I stand corrected then. Thanks Rob, do you have any close up picks by any chance? The cheapies ive seen havent been fused but sounds like youve got something better. If the fuse blows can you replace just the fuse or does the whole thing get binned?

the Whole thing gets binned.....

I'll try and get some pics if I can get the misus out of the car

[rob_macca67 Avid PP Poster! Find all posts View Profile Close rob_macca67]

I have no doubt these work. I have been considering it for a while.
I mentioned it to a friend who is a electrical engineer or similar.
He was quick to say that it's not good for the alternator.
I don't understand it, but basically my understanding is, well it's kind of like a chip for your engine, yep 15k, 60k, 200k, who knows how long it will go with no problems, but it does put additional loads.....

Also I did blow the fuse in a water crossing. I'd want to be sure it will do what it was designed to do and pop fast.

I don't think it's got anything to do with load.... It's increasing the voltage, that's all. Your ALT output will always be limited by its rating. Increasing the voltage does help more current to flow (if req'd) but it is still only to the limit of the ALT...... but I could be wrong.

[AJ120 Out of control poster! Find all posts View Profile Close AJ120]

I have no doubt these work. I have been considering it for a while.
I mentioned it to a friend who is a electrical engineer or similar.
He was quick to say that it's not good for the alternator.
I don't understand it, but basically my understanding is, well it's kind of like a chip for your engine, yep 15k, 60k, 200k, who knows how long it will go with no problems, but it does put additional loads.....

Also I did blow the fuse in a water crossing. I'd want to be sure it will do what it was designed to do and pop fast.

Don't you have a V6? These are only needed in the D4D which has low voltage.

Cheers Andrew

[craigm Addicted PP Member Find all posts View Profile Close craigm]

These are only needed in the D4D which has low voltage.

Mmmmm... Once again the V6 reigns supreme eh Andrew?

Diesels, underpowered all round!!!
GO THE V6!!!!





Sent from my iPhone using Tapatalk

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

I don't think it's got anything to do with load.... It's increasing the voltage, that's all. Your ALT output will always be limited by its rating. Increasing the voltage does help more current to flow (if req'd) but it is still only to the limit of the ALT...... but I could be wrong.

Like an engine also, limited by its cubic displacement......More voltage has to come from somewhere.....
I'm not the expert, but I understand it may be working to its limit more.......burn out diodes........?

Hi Andrew, I don't mind the v6 at all, but for 4x4 and touring, diesel manual for me! 1kz at te moment, yes it puts out 14v easy, like after 1 minute at idle. But I always look at any improvements possible, it's hard to do better than Toyota and keep the feeling.

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

I have done a fair bit of research and as I understand it pretty much all the modern common rail diesels charging systems are controlled by the ECU. The idea is to reduce engine load and therefore emissions. The ECU monitors the main battery state and the load on the battery and then changes the alternator’s charge to suit. The ECU also works to the extent that the battery is charged ‘enough’ as opposed to absolutely full. In some cases the alternator output is also changed depending on under bonnet temperatures. So in effect the diode is tricking the ECU into thinking the state of battery charge is lower than it really is so that the alternator provides higher voltage and thus the auxiliary system works correctly.

As to whether this will affect the life of the alternator or not I would have to say yes because the alternator is working harder than it otherwise would. Whether it is a measureable effect or not is another thing. That all depends on whether Toyota have sized the alternator for the expected lower duty cycle. Possible but I think unlikely. Maybe in the future that will be the case so I would think you will not notice any life shortening using a diode. Certainly there haven't been reports of dead alternators on here and the diodes have been around for a while now.

I know there are plenty of posts about DC DC chargers and I don’t want to start another debate but again from the research I have done I lean that way. Because I am running AGMs (inside the car this time coming) I want to ensure that I give the battery the best possible charge from either the altenator via the main battery or the solar panel.

Finally if I recall correctly from Leigh’s initial post there is still a fuse incorporated in his system so the protection is the same as OEM.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

The increase voltage will have little effect if any on the life of the alternator.

For example, an the alternator rated at a 100A will develop its maximum output
current at quite a low voltage ie 12.5V. At this loading the voltage regulator will be
driving the rotor coils at 100% with or without the diode fitted, ie the diode will have no
affect on the maximum current output.

Ignoring battery charging for the moment, and looking at the additional loading on the
alternator at higher voltages. At a 50A load, a increase from 13.8V (690W) to 14.2V (710W)
equates to 20W increase in load on the alternator, the equivalent of a couple of interior light
globes, turning on the headlights is an increase of 120W.

The higher voltage will cause a slight increase on engine load but then so will adding
any accessory.

Regarding the affect on the alternator from a battery charging perspective, yes the increased
voltage will cause more charge into the battery therefore more load on the alternator but then
that is why we are fitting the diode.

By comparison, for the same equivalent charge current into a battery a dcdc charger will
consume around 10% - 30% more power from the alternator than just having the battery
connected straight off the alternator.

Conclusion:

Fitting a booster diode will have little or no effect on the longevity of the alternator, having
an overtightened drive belt, dirt & mud would be of more of a concern.

Cheers
Leigh

[gumboot Avid PP Poster! Find all posts View Profile Close gumboot]

Don't you have a V6? These are only needed in the D4D which has low voltage.

Cheers Andrew

So everyone says, but my testing proved otherwise....
At a recent get together, I had a multimeter and testing the voltage of some of the diesels ( 120 and 150's) and a petrol 150 that were still hot and running, with ancillarys off. Most of the diesels d4d's (4) were in the range 13.3-13.6 volts. The 150 petrol read 13.45 volts. Mr Fluke doesnt lie...
I would have to test more petrols to check the sample size, that there was not an issue with this though.

Cheers

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Both the petrol and diesel variants can suffer from low charge
voltage. With the petrol engines it depends on model and date of
manufacture and can even can within productions runs, it just depends
on what alternator was installed.

Cheers
Leigh

[AK7 Senior Member Find all posts View Profile Close AK7]

Hey Leigh, sent this in a PM to you a few months ago but no response. Figured you were busy at the time. Could you please provide a response now? Thanks.


I have a 150 series D4D and am about to install a Redarc SBI12. I'd like to purchase one of your alternator booster diodes but wanted to make sure I was looking at exactly the right product for my needs. Could you please point me in the right direction?

[maxjj Senior Member Find all posts View Profile Close maxjj]

So everyone says, but my testing proved otherwise....
At a recent get together, I had a multimeter and testing the voltage of some of the diesels ( 120 and 150's) and a petrol 150 that were still hot and running, with ancillarys off. Most of the diesels d4d's (4) were in the range 13.3-13.6 volts. The 150 petrol read 13.45 volts. Mr Fluke doesnt lie...
I would have to test more petrols to check the sample size, that there was not an issue with this though.

Cheers

what revs where the engines doing when you were doing the tests?
the idle revs would affect output voltage, the V6 may idle slower than the d4d.


I have a booster diode and it works a treat, but I don`t use it for normal running around only when I am running the car fridge. Typically its only on a trip. Its a 10s job to fit.

at a guess, I would think , the only negative is that the main battery and the aux battery may get a bit hot during long running at high ambient temperatures, which could affect their long term life. Basically that is why I don`t leave it in, certainly not at the moment with the summer we are having

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

"I have a booster diode and it works a treat, but I don`t use it for normal running around only when I am running the car fridge. Typically its only on a trip. Its a 10s job to fit.

at a guess, I would think , the only negative is that the main battery and the aux battery may get a bit hot during long running at high ambient temperatures, which could affect their long term life. Basically that is why I don`t leave it in, certainly not at the moment with the summer we are having"

Maxjj,

There is no need to remove the booster if not using the fridge, once the batteries are fully
charged the difference in current flowing into the battery with the higher voltage will be very
little, less than an amp, ie less than 12W being dissipated in a battery that has a large surface
area and weighs over 16kg will be undetectable in heat terms.

Leaving the booster in is more benificial as it will ensure the cranking battery is properly charged
and you'll have brighter head lights.

Cheers
Leigh

[maxjj Senior Member Find all posts View Profile Close maxjj]

I hear you, but I am not worried about current flow.

To max life of a battery the charging voltage at high temps needs to be reduced. ie at zero you can charge at higher volts than at higher temps. ie there is a formula cannot remember exactly what it is.( at work at the moment)
I got a link at home on pc on batteries that is a real good read.

from memory at 0c the recommended float charge is 14.1V and at 40C is 13.2v.
that doesn`t mean batteries cannot cope with more for the charging phase, but for a float charge high voltage and high temp will reduce battery life.

[Anth120playdo Banned Find all posts View Profile Close Anth120playdo]

I hear you, but I am not worried about current flow.

To max life of a battery the charging voltage at high temps needs to be reduced. ie at zero you can charge at higher volts than at higher temps. ie there is a formula cannot remember exactly what it is.( at work at the moment)
I got a link at home on pc on batteries that is a real good read.

from memory at 0c the recommended float charge is 14.1V and at 40C is 13.2v.
that doesn`t mean batteries cannot cope with more for the charging phase, but for a float charge high voltage and high temp will reduce battery life.

Correct......... Heat is a battery killer

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

Temperature compensation is still active in the alternator and under high ambient
temperatures it will reduce the charge voltage.

In reality unless your talking about standby battery banks sitting on float charge
24/7, as long as the float voltage is not excessive high it is going to have little if
any effect on a battery in an automotive environment.

On the other hand your cranking battery is more likely to die a premature death
from the constant low charge without the booster installed, warranty claims for
cranking batteries has risen significantly since the lower charge rates were introduced.

Also a lot of those tables refer to conventional battery technology, and increase in electrolyte
loss due to excessive gassing. Modern batteries have very low gas rates due to the use of calcium
and ultra pure lead, you would need a very high charge voltage to produce any significant gassing in
modern batteries.

Cheers
Leigh