Volt drop: 2005 FZS1000

[b1k3rdude]

Got a volt drop on the bike, mainly from the sub-loom that connects to the clocks, headlight, horn etc.

Whats the best place to start looking, and for that matter how many earth points does the FZS1000 have and where are they located...?

[AdieR]

How much of a voltage drop are we talking? Bear in mind you'll naturally have a certain amount of voltage drop anyhow (due to wire lengths).

[Falcon 269]

http://www.yamahafz1oa.com/eskortsbatter...efix.shtml

[b1k3rdude]

How much of a voltage drop are we talking? Bear in mind you'll naturally have a certain amount of voltage drop anyhow (due to wire lengths).

With the engine off I'm seeing 10volts at certain points within the clocks

http://www.yamahafz1oa.com/eskortsbatter...efix.shtml

Thanks for that Falcon, I will add this to the other electrical upgrade - http://foc-u.co.uk/index.php?topic=4820.0

[AdieR]

If your battery voltage is good (12.8V) (how old is your battery?), I wouldn't worry too much about it (unless it's causing a problem?). You say 10v "at certain points" and "within the clocks" - I'm guessing you're testing for voltages on the printed circuit board? PCB's tend to contain semi-conductors (inc internal voltage regulators), and can give readings that seem out of kilter with battery voltages (engine management units for example can use 5v and even 3.3v internally).

External factors like temperature and humidity can have an effect (some circuits are more sensitive than others in this regard) (bear in mind your battery will taking a hammering with the current cold weather, so may be lower than normal to start with), if there's any AC circuitry / signals in there (haven't seen the clocks up close, so not totally familiar with them off-hand) that can cause spurious readings (bearing in mind the battery voltage is DC so most people will naturally test for that), and even the very use of test gear can alter the behaviour of some systems.

That's a few ideas for low voltages (though diagnosing at a distance is always tricky).

[b1k3rdude]

If your battery voltage is good (12.8V) (how old is your battery?), I wouldn't worry too much about it (unless it's causing a problem?). You say 10v "at certain points" and "within the clocks" - I'm guessing you're testing for voltages on the printed circuit board? PCB's tend to contain semi-conductors (inc internal voltage regulators), and can give readings that seem out of kilter with battery voltages (engine management units for example can use 5v and even 3.3v internally).

The battery is fine and in good cond.

To summarise, the first I noticed when I bought the bike (this is my 4th FZS1000) was that all the instruments lights, headlight and the indicators were all dimmer than I'm used to. I then popped the panels off and started measuring

• the battery
  
• sub-loom connector (left side of the f-fairing)
  
• headlights (connected and disconnected for comparison)
  
• instrument connector on sub-loom
  
• then each of the illumination bulbs in the clocks. (it was some of these that were showing 10v)
  

As I moved away from the battery I saw a volt drop which is normal, but a 2v+ drop is not, the biggest drop is in the sub-loom that connects the clocks & instruments etc.

One option is to buy a spare and swap it out first to see if the volt drop improves otherwise do a strip, clean & upgrade (of the 12v line/s) and see if the Vdrop improves before going down the route of creating a upgraded +12v by-pass circuit.
But before I do anything, I am to get a pro to tell me where he thinks the Vdrop/s are occurring and I will work from there.

[AdieR]

Cheers for the info, I understand your issue now.

As an quick experiment (and before spending dosh swapping parts) I'd try running a wire from your clock negative straight to the battery negative and see if it makes any difference.

[b1k3rdude]

I finally got around to looking at (on this fazer, as the previous one got smashed) the low voltage issue to the bulbs in the clocks by fitting LEDS, doing so has reduced the max load from 6-12w down to 1-2w

But thats only one half of the problem, there is a still a massive volt drop at the headlight bulbs when they are on. What is considered a normal voltage at the bulbs with them on? as I am seeing 9.5-10v with the engine running. I didnt think to check the voltage from the headlight relay> the fuse box so will do that tomoz.

In the mean time I am considering two way to fix the vdrop.

• upgrading the hi/lo wires from the relay, but VDI (voltage drop index) says the wire is thick enough already (5amps x 5feet / 12v x 5% loss = 0.5 / 16 guage (1mm wire) . I can't see the copper in the wires to from the relay to the headlight being under 1mm.
  
• Or create a relay_switched feed straight from the battery by cutting into and using the feed going to the headlight relay. I could at a later date use the same 'hot' live to do eskorts fix for the clocks at a later date should I need to.
  

Thoughts...

[b1k3rdude]

Did some more measuring and it seems there are lots of little volt drops from the battery, through the fuse box, then each connector, then the relays and then the bulbs.

So I am going to make a relay-switched by-pass for both the lights and the clocks to take power direct from the battery.