Extra Electrical Loads

[Centex]

More than once I've read posts on C10 forums indicating that lots of folks think they can 'by-pass the J-box' by connecting extra electrical loads (lights, heated gear, etc) directly to the battery.  Slybones first made me aware of the error in this logic on his ZZR alternator upgrade webpage.

I've prepared some simple schematics to illustrate his point, which I think is important for C10 modifiers to understand.  The 'alternate wiring' mentioned below is described in Slybones' ZZR alternator upgrade page and on a new page about alternator wiring in general.

First two pics, the OEM wiring setup compared to the Alternate wiring setup with the engine off (or at idle where the alternator output is less than the battery voltage).  The current-load connected directly to the battery does not go through the J-box; the J-box is only involved for those circuits that are 'hot' depending on the ignition switch position (clock and OEM accessory leads with switch-off, some lights with switch-on, all OEM circuits with bike running at idle).





Second two pics, the OEM wiring setup compared to the Alternate wiring setup at 'cruise speed' (engine RPM sufficient that the alternator output exceeds battery voltage.  This is where you want to be 90% +/- of the time when riding so your battery stays healthy).

With OEM wiring, the current-load connected directly to the battery comes from the alternator through the J-box; the J-box is involved in all loads because the alternator output all goes through the J-box.         

With Alternate alternator wiring, the alternator output is not routed through the J-box; the only current routed through the J-box is that needed for loads on the OEM fuse block.  Aux loads that are connected to the battery (or the starter solenoid stud) do not go through the J-box, presumably reducing stress on that sometimes problematic component.




The point is to advise folks that with the original alternator wiring they are not 'saving the J-box' by connecting their extra loads directly to the battery.  Contrary to what some seem to think, for all practical purposes any added electrical load goes through the J-box when riding the Connie.  Nothing wrong with that electrical scheme, I just think folks should know how it really works.

 

[George R. Young]

Here's a schematic for the post-'93 Concours, courtesy of Guy B. Young, no relation.
http://web.ncf.ca/ag136/junct2bnewc.gif

Looks like if you hook a load directly to the battery, additional current flows through the J-Box main fuse from the alternator to the battery/load, but the load current does not flow through any of the J-Box relay contacts.

[syntor]

Yes Centex you are correct, don't take your extra loads off the battery.

 My solution (with the ZZR alt) is to simply take the extra loads straight off the alternator. No mods at all to the OEM wiring is required.

[Tele130]

My daughter is the electrical engineer in the family,......................I gave her all the smarts .  All I'd like to do is to have a centerlized location for hooking up any acc (Driving Lights, heated gear......etc). 

Would this work?
http://www.amazon.com/Blue-Sea-Systems-5029-Block/dp/B000MMH1GC

Tap power from The "J-Box" or the factory fuse Block?


Yes, I'm an electrical dummy.

[Daytona_Mike]

Sorry , I have to completely disagree  and the reasoning is very simple.  Your alternator can only ever out put  the same max amps ( and not very much at that) and never any more then that which is what the J-Box fuses and the stock Connie wiring is designed to handle.
We  all   hook up up more lights , heated grips , air horns and so on and so on and those  combined amps   can and  many times will  (like at idle and  also while riding down the road ) pull more amps than the alternator will ever put out specially the big pulses like  when you hit hard by switching on HID  ballasts and also air horn pumps.
 So your best to pull that extra power directly from the battery and by pass the j-box and alternator. The bigger gauge  wiring hooked to and at the battery can handle these extra loads and pulses but  the j-box  and stock wiring cannot.  This is why all directions for  fuse  box add on  panels (like Murph's)  and extra lighting harnesses (like Hella and any HID kit)  tell you  hook directly to the battery. Your best to pull down  (overload) the battery  and not the alternator because if you overload  the alternator  then the alternator wiring will in turn pull from  the battery through the j-box and because  the J-box  normally would never see that extra  heavy load it  would in turn now  blow the fuses in the j-box or possibly melt the stock Connie wiring which was never meant to handle those extra amps.
Oh , I forgot to mention. The above is the  same reason why all engine starter motors pull directly off the battery

[Tele130]

Thanks Mike. Even though I'm very slow in the electrical department, what you said makes sense.

[GeeBeav]

The above is the  same reason why all engine starter motors pull directly off the battery

When you go to start your car or bike, the alt is not turning, no output.
The starter is connected to the battery for that reason.

[Daytona_Mike]

When you go to start your car or bike, the alt is not turning, no output.
The starter is connected to the battery for that reason.

Duh! no kidding.  However if the alternator  wiring could handle the loads AND it was better to do so why would you not see  all loads hooked to the alternator?

[Centex]

Sorry , I have to completely disagree  and the reasoning is very simple..... 

I'd like to understand which of the current flow diagrams you disagree with / think is technically incorrect?

Please note that I never suggest or show the physical connection of the added load to anything other than the battery (though it could as well be connected to the starter solenoid stud where the battery connection is made).

I simply point out that for the normal operating condition (running with the alternator output meeting the current demand), the current for those added loads connected directly to the battery does indeed flow through the J-Box (diagram 3).

Again, I'm not saying that's a fatal flaw, I'm just saying it is a fact that should not be ignored.

Hopefully the J-Box and alternator harness are designed to carry that additional load on an ongong basis.  However, Some types of J-box failure and alternator harness failure (brown connector meltdown) suggest (IMHO) that owners should be particularly attentive to maintenance of those components when additional loads are connected to the battery.  Telling yourself that these components are "by-passed" when additional loads are physically connected to the battery (in addition to being incorrect when looking at the flow of current in the system) might lead to complacency in that regard.

BTW, I agree that in the case you describe where the bike is running and a short-term load exceeds the alternator output capacity ... the maximum output alternator current flow is still as shown in diagram 3 (through the J-Box), but the battery condition goes from "charging" to "power source" (discharge) as long as the battery is able (until it is depleted) or until the load is reduced to within the alternator capacity.  That's when you hope your alternator circuit connections are at their cleanest, tightest and least-oxidized condition 

[Daytona_Mike]

The current does indeed flow through from the alternator through the all the fuses in the fuse box (which is called  J-box)  which is just fine and should be left that way because there is no way around that even if the battery needs charging or anything else is added to  the battery.

This too is correct:   Please note that I never suggest or show the physical connection of the added load to anything other than the battery (though it could as well be connected to the starter solenoid stud where the battery connection is made).

Drawings one and three look correct (but most of the OEM  the fuses are inside the J-box)
Are you saying that current flow through the j-box which is most of the time would be better off by passing the J-box? The answer is no.
You need the flow to go through the j-box. Your not going to wear it out or over load it  how ever we already know the stock mechanical relays  are a weak spot and sometimes the cladding has cracked  where  the solder needs to be re flowed but we have not seen any issues with how the alternator is wired and you cannot by pass the J-box and you certainly are  not going to wear out the wires and fuses because more is flowing  this way then that most of the time and then some of the time.
Please do not be concerned about the  'Direction' of flow as it is inconsequential and has not  had any effect on things like the 'brown connector meltdown' issue. That issue will happen whether you change the direction of flow or bypass the j-box or not.
 
Look at the schematic,  moving the BK>>WHT wire  (output of the alternator) from the  bottom of the J-box the  to the starter relay  is electrically the same connection and all  the current will still  flow through the j-box the same as before, your just moving the  output of the alternator from pin 3 to pin1 and that current  will continue on to CR1 (main relay) the same as before so nothing would be accomplished.
Also look at the W/R wire going from pin 1 to the start solenoid. That wire can handle the alternators max  output but cannot handle the max amps the   battery is capable of out putting.
You could take the BK>>WHT wire from the alternator and hook it directly to the battery and  the flow will still  travel back up through the J-box again  but not doing any thing except changing flow direction along a  wire which does  not effect the  wire.

[timsen84]

Great conversation! Warm & Safe (heated jacket & gloves) says connect to Battery "it is a clean source of power". Adding Driving Lights & 12V Power Socket. As long as each of these has an in line Fuse why not connect all three directly to Battery? Is there a numerical limit of direct to Battery lines?

[timsatx]

Why not save the connections made directly to the battery and install an auxiliary fuse panel? Then you only have one connection the the battery and you can still hook everything up.

[timsen84]

The Aux Fuse Box is a great idea. Also install an in-line switch under the side cover (Murph's Knobs) as a Master Switch. Turn it off so driving lights will not get switched on while I'm away. 12 or 14 gauge wire.

[Daytona_Mike]

The Aux Fuse Box is a great idea. Also install an in-line switch under the side cover (Murph's Knobs) as a Master Switch. Turn it off so driving lights will not get switched on while I'm away. 12 or 14 gauge wire.

Yup you are correct. If you buy Murphy's aux  fuse box it has a relay to turn the fuse box on and off for you automatically.

[kzz1king]

Does the Murphs have an inline fuse for the feed to the relay (not the trigger)? I built my own and did not install an inline between battery and relay. Concerned if the relay should fry it could cause a short?
Wayne

[Daytona_Mike]

Does the Murphs have an inline fuse for the feed to the relay (not the trigger)? I built my own and did not install an inline between battery and relay. Concerned if the relay should fry it could cause a short?
Wayne

It sure does. A master 30amp fuse for the inline wire from the battery to the relay.

[kzz1king]

It sure does. A master 30amp fuse for the inline wire from the battery to the relay.

Well, now mine does too!
Wayne