Charging system questions

[DaveWatts]

The R/R sends current to the battery via the fuse board and it also sends unprotected current to the bike components directly. Wouldn't it be better to wire the +ve red lead of the R/R direct to the battery, then it would better charge the battery (without any fuse box voltage drops) and any over currents produced by the R/R would be protected by the fuse box on the return path to the rest of the bike.

Cheers

Dave

[Steve]

The wiring and charging scheme changed a bit over the years, it would help if we knew which year and model we were discussing.

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[Brendan W]

Maybe
The way I look at it the r/r runs the bike. Charging the battery is a secondary function.
It makes sense to let the r/r see the bike before the battery.
If you were to run the r/r output direct to the battery you then have a unprotected path through the r/r if a diode fails.
If you want good battery charging then it will be better to make sure that the difference between battery and r/r ground is as small as possible.

[DaveWatts]

bike information

The wiring and charging scheme changed a bit over the years, it would help if we knew which year and model we were discussing.
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Mines a 1980 GS1000G European model, I would say German, but the wiring diagram from BRD is completely different to my bike.

[DaveWatts]

I was thinking that the battery runs the bike since it is a stable reservoir of charge, whereas the R/R depends on engine speed. Sometimes a 'bad charging' light glows when the bike ticks over on some bikes. But interesting this comment on "unprotected path through the r/r if a diode fails", from what I see of the wiring diagram the only protected path is from the battery & the starter/solenoid (is that what you mean by diode?) to the R/R. So I guess a starter motor malfunction could produce a large voltage that if the R/R was wired direct to the battery (if without inline fuse) which could damage the R/R.

[Brendan W]

The battery can run the bike but not for long. In addition it will be supplying 12.6 Volts initially which will fall as time goes on. The r/r supplies 14 Volts pretty much all the time giving brighter lights and hotter sparks. The battery has three main functions. Starting current, reservoir at idle and a capacitative filter to smooth the ripples from the r/r output. It has to put out at a higher voltage than the battery otherwise it would take forever to recharge the battery after starting as a battery has internal resistance that must be overcome before any charge flows back in.
The diodes in question are in the r/r. A short there would be unprotected unless you fit an inline fuse between the r/r and battery +ve terminal. Many have done exactly that.
You could say that we are discussing Angels on the head of a pin here. My personal preference is the Single Point Ground story. I just like it
The r/r gets as uninterrupted a view of the bike and battery as possible but the battery is secondary and sits in parallel with the main load.
It's important to bring the returning currents directly to the r/r -ve avoiding voltage drops in the frame for example.

[DaveWatts]

The battery can run the bike but not for long. In addition it will be supplying 12.6 Volts initially which will fall as time goes on. The r/r supplies 14 Volts pretty much all the time giving brighter lights and hotter sparks. The battery has three main functions. Starting current, reservoir at idle and a capacitative filter to smooth the ripples from the r/r output. It has to put out at a higher voltage than the battery otherwise it would take forever to recharge the battery after starting as a battery has internal resistance that must be overcome before any charge flows back in.
The diodes in question are in the r/r. A short there would be unprotected unless you fit an inline fuse between the r/r and battery +ve terminal. Many have done exactly that.
You could say that we are discussing Angels on the head of a pin here. My personal preference is the Single Point Ground story. I just like it
The r/r gets as uninterrupted a view of the bike and battery as possible but the battery is secondary and sits in parallel with the main load.
It's important to bring the returning currents directly to the r/r -ve avoiding voltage drops in the frame for example.

I think what might be a good solution is to wire the R/R upstream of the fuse box at the fuse box's bullet connector with the battery input, that way the R/R current to the components is protected and the bike still gets the current before the battery (which will be good for high load items such as heated grips).

I notice that the fuse box has a second 10 Amp fuse on the positive input but can't understand how this is supposed to function (the positive current is also in parallel going to the frame or to the box itself to charge the fusebox up?! isn't this just going to drop voltage for no good reason?), I don't really understand what the + symbol in a circle is supposed to represent here.

[Steve]

I notice that the fuse box has a second 10 Amp fuse on the positive input but can't understand how this is supposed to function (the positive current is also in parallel going to the frame or to the box itself to charge the fusebox up?! isn't this just going to drop voltage for no good reason?), I don't really understand what the + symbol in a circle is supposed to represent here.

That "extra" fuse is for accessory items. Unless, and until, you connect something to that terminal, NO current flows through there. It is unswitched, so power is available without turning the key ON. It is a convenient place to connect your heated clothing and your battery tender.

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[DaveWatts]

Taking on board the single point ground and the relay for ignition mod, I've come up with the following plan, what do you think?

[Gorminrider]

Look at OEM diagram. Mods aren't required. Regulator direct to red which goes through keyswitch to orange. Orange supplies all 10amp fused circuits. Red also charges battery through 15 amp MAIN fuse. EXTRA Fuses are not required on charge output.

Charge output is greater than the chemical battery can ever supply. Therefore, charge output is running the bike.



13-Charging.jpg

Starter circuit is different. It is momentary, until motor spins stator magnets... "starting" is the only time "+" is supplied by battery...that is, when it "flows out" of battery.

[Gorminrider]

here's a cropped image to highlight how red ( battery+stator output from reg/rec) orange wire from key to fused 10 amp circuits...

[Gorminrider]

It's important to bring the returning currents directly to the r/r -ve avoiding voltage drops in the frame for example.

I take issue with this. There are no "voltage drops" in a steel motorcycle frame.

[Steve]

In <my> opinion (for what that's worth ), the frame could be used as the "single-point ground" as long as you can GUARANTEE that there is a corrosion-free path between any of the devices and the ultimate ground to the battery.

There are some devices that do ground to the frame, but most have their own wire that already gets pretty darn close to the battery. It is actually a simple matter of gathering all those black/white wires that are near the battery, connecting them together ("single-point"), then adding another wire from that point to the battery - terminal. Ideally, there will be a total of just three wires connected to the battery. Two of them will be on the - terminal, one will be the large one that goes to the back of the engine block to ground the starter, the other will be a more-modest size one to ground everything else. The third wire on the battery will be the large one on the + terminal that goes to the starter solenoid. The red wire that goes to the fuse box should come from the solenoid end of that wire to minimize the wires you need to keep track of at the battery.

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[DaveWatts]

Look at OEM diagram. Mods aren't required. Regulator direct to red which goes through keyswitch to orange. Orange supplies all 10amp fused circuits. Red also charges battery through 15 amp MAIN fuse. EXTRA Fuses are not required on charge output.

Charge output is greater than the chemical battery can ever supply. Therefore, charge output is running the bike.



[ATTACH=CONFIG]61734[/ATTACH]

Starter circuit is different. It is momentary, until motor spins stator magnets... "starting" is the only time "+" is supplied by battery...that is, when it "flows out" of battery.

Yes, you're right nothing damageable is between the reg and the fuses. I will stick to the oem wiring for this .

[Brendan W]

In <my> opinion (for what that's worth ), the frame could be used as the "single-point ground" as long as you can GUARANTEE that there is a corrosion-free path between any of the devices and the ultimate ground to the battery.
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That's the way I look at it. At every connection into and back out of the frame you have three, possibly four, dissimilar metals just waiting to have the galvanic talk with each other plus they are out of sight which is out of mind. My SPG is one of the start relay mount screws.