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"Expert in regulator rectifiers" 


8+1 tips for rectifiers

21/10/2023 09:01
8+1 tips for rectifiers

Are you ready to dive into the complex world of motorcycle maintenance? We show some tips how to approach it's electrical system!

Tip 1:

The first and most important thing: If you don't understand it, don't start tinkering! You will only do more damage, and at the end of the day you will pay a lot more for merchanic. This is not a light bulb replacement. If you are not sure how to measure the the voltage at the regulator rectifier or the stator, then do not start by trying to disassemble and reassemble the electrical network of the motorcycle by yourself.


Tip 2:

If anything from the „holy trinity” (battery - regulator rectifier - stator) goes wrong, check all of them! Here is our checklist! If you notice that one of these parts is broken, it is possible that you have not found the actual faulty part, but only the victim of the failure.

For example, a battery failure can be caused by the regulator rectifier overcharge. It is no use replacing the battery, if the bad regulator rectifier will overcharge the battery again.

But it is also possible that the regulator failed because the stator had a ground fault and this caused a terribly large ground fault current to the regulator rectifier. In this case, if you change the regulator rectifier, but didn't repair the stator, then it will kills the new rectifier also in a very short run.

So just because the regulator rectifier is broken, it is not yet certain that it was the cause of the error. So it's pointless to replace it with a new one, if after 20 kilometers the new one will also be destroyed due to the actual defect still existing.

If you notice an error with any of the battery - regulator rectifier - stator, the minimum is to check all of them!

Tip 3:

The regulator rectifier will be good for a long time, if you install a suitable and reliable component. The regulators manufactured by us have been present on the market for more than a decade. Feedback from mechanics and motorcyclists is also positive about the product.

Tip 4:

"My regulator is hot like hell, so it's broken" - many people already buy a new voltage regulator with this reason. However, this is not true. The temperature of the heatsink is still acceptable up to 80-90 °C. A metal surface at 50 °C cannot be touched by bare hand. The surface of the regulator will never be lukewarm. The temperature also largely depends on the ratio of the current taken into the network and returned to the stator (shunted). This is especially true for traditional (older) thyristor rectifiers. Based on the temperature of the rectifiers, it is not possible to clearly judge whether it is working perfectly or is broken.

Tip 5:

"If the charging is not correct, then it is the rectifiers 's fault" - this is not quite true in this form either.

In the case of overcharging (charging above 15V), the voltage regulator is probably the cause of the fault. (Although this cannot be said with 100% certainty, it is also worth checking the multimeter (or do the mesurement with a different multimeter). It may incorrectly indicate overcharging with a discharged battery of multimeter.)

However, in the case of undercharging (charging below 13.7-14V), other factors beyond the regulator rectifier can also result in improper charging. One of the most typical reasons is that there is too much loss in the wiring of the motorcycle, for example, the connectors are loose, softened, melted or the sliding contacts are oxidized or dirty. Oxidation, overheating, and voltage loss also can occur in cable whip (anywhere!). This is also common with the connection at the main fuse. In most cases, the main fuse is located near the starter relay with a 30 amp fuse. In addition, with old motorcycles, it may also happen that the electrical network is so obsolete that it could even be replaced.


+1 tip for slightly undercharging (charging between 13.5-14V)

With special care (and expertise), only as a test, it is possible to try to connect the current (positive and negative) wires of the regulator rectifier directly to the battery (even by inserting an extension wire, if the wiring of the regulator rectifier is short). When connecting, loosen the screws of the battery and place the wire under it, then tighten it back.

If with this procedure the voltage of the network is correct (it should be 14.4 - 14.7V), then the error (voltage loss) is clearly somewhere in the motorcycle's wiring (typically such "weak points" are a bad connection anywhere in the wiring) its maintenance and repair is required

We emphasize the need for professional competence for this test.

The correct polarity must be strictly observed, because a reverse polarity connection will destroy the voltage regulator!! This test connection can only remain for the duration of the measurement, the wiring error must be eliminated!!



Tip 6:

When installing a new regulator, it is very tempting to think that if you see two wires of a similar color shade, they must belong together and connect them. But I say, DON’T DO THAT. I recommend that it is definitely worth measuring and identifying each wire with a multimeter before you plug it in. A reverse polarity connection can destroy your brand new voltage regulator instantly.

This is really a problem, that's why we made a separate blog article about the wiring for Aprilis Pegas 650 and BMW F650 motorcycles, because the colors of the wires are always different for them, which has caused problems several times when connecting.

Of course, you obviously don't do this, because you already listen to us in the 1st tip above, that’s why you should definitely measure the wires intended for connection.

Once somebody called us by telephone saying that the newly purchased regulator rectifier was not working, and after a little dicussion over the phone, it turned out he managed to connect a single-phase voltage regulator to the three-phase stator... after this little „action”, the rectifier really didn't work anymore.

Tip 7:

And if we're talking about the wires: When you're installing the rectifier, do it only in a de-energized state! (with the battery terminal disconnected) When connecting, pay special attention to make sure that the blanked wire ends do not touch each other, because this can also cause a short circuit that can destroy the rectifier.


Tip 8:

Use an on-board voltage meter to check the system charge while driving. In this way, in case of improper charging, you can intervene before the damage is done, or you can save yourself from having to wait for help in the deep countyside at 10:30pm, because your battery is dead.

If you are looking for an on-board voltage meter, you can try ours.

Charging between 14-14.5V is the ideal.

AGM (Absorbent Glass Mat) batteries tolerate a slightly higher charge (14.5-14.9V) better; but in the case of normal batteries in this charging range (14.5-14.9V), frequent refilling with distilled water is necessary due to water decomposition.

Charging above 15V overcharges and destroys the battery in a short period of time, while charging below 13.8-14V leads to the battery's slowness and sulphation (capacity reduction) in the long term.


We hope you found our article useful. If you have a similar tip or experience, share it with us in the comments!





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