Dash voltage reading vs. at the battery...

[uncle]

Just curious...

My '07 Griso G11 has always read much lower voltage on the dash than my meter does at the battery directly.  For instance my battery reading 12.8 at the battery shows 12.2 on the dash.  I was under the impression that this was normal until talking with someone with a newer Griso 8v - (guzziownr) - and he had something like 12.7 at the battery and 12.7 on the dash- 

I am wondering what others were experiencing - 

[ITSec]

My 08 Norge reads 12.2-12.4 at the dash, 12.8-13.3 at the battery. Always has. I always figured if they can't calculate the mileage accurately, it's not surprising the power level reads funny.

Oddly enough, the speedo is among the most accurate I've ever had on a motorcycle - only 3-4 mph off the GPS reading at 65 mph!

[Mackers]

My '06 Breva 1100 reads 12.8 at the battery and 11.7 on the gauge.  I've never seen it above 12v on the gauge.  At least the fuel gauge is accurate!

[Bulldog9]

Are you measuring at the battery with they key on or off? That would make a difference. Also remember that the 'voltage meter' in the display is likely not taken direct from battery and is likely pulled from the ECU which is energized along with the ignition, lights, coils, and other systems through 1-2 fuse buses that are powered by the 'on' key position. All that would create some parasitic draw and cause the voltage to read lower the farther you go from the battery along the line.  If it helps, think of voltage as water temperature, and amperage as volume or flow.  Test your water temp at the heater, it will be hotter than it is at the tap. .6 V is not a big deal anyhow, so nothing to worry about.

[Waterbottle]

Uncle : From new my 09 Griso always measured no better than 13.2 V on the dash , engine running and .2 V higher at the battery. During a recent refurb I had the  entire harness out ( had the frame powder coated black ) and on reassembly payed attention to all the earth points, clean and tight.
Now reads 13.8 on the dash.  I always thought the alternator was a bit lazy 

[Sasquatch Jim]

 One of your meters is lying to you.
 The most accurate speedo I have ever had was on my 250cc Morphus.
 It was never more than one tenth of a MPH away from what My GPS read.
 It was electronic and probably capable of being adjusted for accuracy.

[Kiwi_Roy]

The dash meter is probably quite accurate, it can only read what it sees.
Out of curiosity measure at the dash with your multimeter, I think you will find it quite close to the dash reading.
Then just for a giggle measure from the battery Positive to the dash this will be the Voltage drop in the wiring.

[rbm]

If your multimeter is reasonably accurate, it would probably be more reliable of a reading than with the dash voltmeter.  To do a proper comparison, you should be measuring the voltage with the multimeter at the same same point as is being taken by the dash voltmeter (practically impossible BTW).

However, assuming that the dash voltmeter is reasonably accurate, the reading it takes is more indicative of the voltages being supplied to the various circuits of the bike, by taking into account the voltage drops that will occur over the wiring.  It therefore is more "indicative" of the health of the bike than would be a voltage reading taken at the battery terminals.  For example, a low reading could indicate excessive voltage drop across poor electrical contacts, something not able to be detected by a voltmeter measuring battery terminal potential.

[tris]

My B11 dash is 0.5v down on the battery

I just add 0.5 on 

[sign216]

My B11 dash is 0.5v down on the battery

I just add 0.5 on 

My aftermarket "edgewise" meter on the V7 also read 0.5 v less than true value.  Vender simply said that's within the margin of error.  I learned to live with it.

[charlie b]

When I was having alternator problems I did some measuring on mine.

Stock wiring harness I had almost 1V drop between battery and dash voltmeter.  This was just kind of a pain until I went to wire in the new alternator that needed an accurate battery voltage reading.  So, after completely rewiring the main harness I am now at 0.2V difference. 

What made all the change was a larger 'power' feed to the dash and nice, new, clean connectors with fresh crimps.  I also have newer swtichgear on the bike.  I did keep the old fuse box, but, the connectors on it were cleaned as well.

[PJPR01]

I had a similar issue on my Norge...Chuck pointed that out to me.

The Dash reads at 12.5 while running while actually it's pumping out 13.3 (measured at the battery with bike running)...very consistently...test ed with 2 different voltage meters.

[Kiwi_Roy]

Adding a relay to bypass the ignition switch would do a lot to improve the Voltage to the dash, the trick is to drop the current as this also reduces the Voltage drop.
Suppose for example there's 10 Amps going through the ignition switch and its wiring of 0.1 Ohms = 1 Volt
but if only 1 amp is going to the dash from the battery thru the relay of 0.1 Ohms = 0.1 Volts drop
Since the other 9 amps is going through the switch the Voltage drop it gives is out of the picture.
I think I'm going to have to draw a sketch to explain that 
Some of the modern bikes with digital Voltmeters also have heated grips fed from the dash, that must make quite an impact on the reading when they are on.

I think the first thing you do should be clean the ignition switch.