Ducati.ms - The Ultimate Ducati Forum banner
  • Hey Everyone! Enter your bike HERE to be a part of this months Bike of the Month Challenge!

1 - 2 of 2 Posts

·
Registered
Joined
·
99 Posts
Discussion Starter #1
In the process of my build, I've noticed that there are several red/hot wires, in addition to the heavy gauge wire which connects to the positive terminal of the battery and the starter solenoid. In addition, there is the main ground strap (connected to the case) as well as several other smaller gauge ground wires that connect directly to the negative battery terminal. My question is, do these 5-6 smaller black ground wires HAVE to connect to the negative terminal, or can they not just be grounded properly to the frame itself? I do realize the main ground strap from the battery to the engine block needs to be in place to complete the main circuit... it just seems silly that 5-6 14-18 ga wires all need to connect to the negative (ground) terminal... Never seen this many ground wires being connected directly to the negative terminal on any of the many other bikes i've worked on...

I might be missing something here...?
 

·
Excel Addict
2001 900SSie
Joined
·
5,345 Posts
In the process of my build, I've noticed that there are several red/hot wires, in addition to the heavy gauge wire which connects to the positive terminal of the battery and the starter solenoid. In addition, there is the main ground strap (connected to the case) as well as several other smaller gauge ground wires that connect directly to the negative battery terminal. My question is, do these 5-6 smaller black ground wires HAVE to connect to the negative terminal, or can they not just be grounded properly to the frame itself? I do realize the main ground strap from the battery to the engine block needs to be in place to complete the main circuit... it just seems silly that 5-6 14-18 ga wires all need to connect to the negative (ground) terminal... Never seen this many ground wires being connected directly to the negative terminal on any of the many other bikes i've worked on...

I might be missing something here...?
I expect that the extra negative connections direct to battery negative are to ensure that there is no offset voltage due to current flowing between a "remote" battery negative and the ground.

All the sensors, such as TPS, air temp etc. are referenced to battery negative. For example on the 900SSie, the TPS voltage "closed" is 150mV.
If that was remotely grounded via a cable carrying possibly significant current, then the TPS voltage would not be correct.

I have been in the solar PV industry for 40 years and when I was involved in designing PV charge regulators/controllers we always used separate voltage sensing wires rather than measuring the voltage at the controller as voltage drops in the power cables will provide incorrect battery voltage readings for the controller.
 
1 - 2 of 2 Posts
Top