Just a quick update on the latest on the TopSpeed unit.

Out of about 200 sold items we had about 12 users that reported issues. Interestingly some of these had multiple units go out on the same bike, while others (including my own bike) have over 10k miles on them without any issue.

I believe I finally found the issue and will be testing the fix shortly.

The circuit has been designed to operate at the 12 V supply of the bike. It is common knowledge that the voltage can reach about 13.8V and slightly more depending on battery, charging level and modifications like the removal of bulbs (e.g. running lights) and replace them with low power LEDs.

I recently removed the front running lights and am now seeing up to 14.6V on my bike. On another VMax with issues we have seen the voltage exceed 15V - the rated maximum voltage of the chip used. While the chip will take a slightly higher voltage initially, it will make it fail eventually.

The fix is very simple: drop the voltage on the circuit by 2V to move it further into the save zone.

95% of users will never experience the issue, but it seems some VMaxes are running a bit 'hot' in charging voltage.

I will provide a very simple fix that requires only a single extra resistor inline with the power supply.

The next version of boards will come with that.

I will keep you posted.

I don't have running lights anymore, so it may very well be that's a possible explanation. Most charging systems operate at the range of 12+ to 14.8 volts. The amperage varies also depending on the battery size or altenator output, with the motorcycles charging ability being a very light duty application.

I'll go and measure my voltage output at the battery during operation at all rpm's and see what it is. I'll PM you the results later this morning.

I do believe you are right on the money on this one. As you can see I have NO turn signals @ ALL. Would love to have one for testing Oliver! I was going on my 4th speedfix and had to give up on this because it was getting frustrating having it keep going out on me..Good find!

13.34 volts at idle, and as high as 13.75 reving up the engine. I'm sure it could be a lot higher on the road at WFO in the upper RPM ranges.

What needs to happen is a current limiting resistor in the power circuit so not to damage components down line...

Just a thought~~~~

sfcrick wrote:


I found that most bike will start out in the 13.x V range at idle after firing up the engine (battery partially discharged from starting. Several minutes later the voltage will slowly start climbing. I saw it climb to 14.6 at idle, with higher rpms even more.

It does not happen all the time. That's why only a few of you and only after some riding had any issues.

Various bike modifications will change that charge voltage.

This problem can append also with Exup eliminator, Oliver?

Iceman29 wrote:


No - the EXUP does not have that issue at all. It is specific to the chip used in the TopSpeed unit.

If the light still comes on when the bike is running is the topspeed module still working?

If it is not working the speedo will show 0 all the time. As I said only very few had that issue.