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People talk about taxing the charging system on bad battery. But with Harley are you not shunting to ground when battery is charged? Creating heat?
The rotor is turning all the time.
I have always heard this, but I am not sure. But I agree, don't jump unless you have to. I also think you are stressing a battery. Not that I have never done it when cranking when weak
You need to read was was said earlier. A shunt is a resistor. Yes, when running, the permanent magnets alway are making AC . The reference is at 2000rpm and that's a constant unlike a alternator in a car that has windings for the rotor (armature) that can be controlled.
So the regulator controls the AC by on and off thru a shunt (resistor) . It uses the AC electricity by passing it thru a resistor shunt to ground making heat.
Any time you use a battery, your draining the stored voltage and they do wear out from the constant drain and replenish. This constant chemical stress, along with factors like heat and sulfation, reduces the battery's overall capacity over time.
A start hits it with a apx 150 amp drain. And also, if you hit the start button more than once starting it, each hit is a start on the starter solenoid. Why some don't get a lot of life out of there starter solenoid and probably most replace the whole starter than.
Charging a defective or deeply discharged battery can damage the charging system, particularly the alternator. A bad battery can force the alternator to work at maximum capacity.
Adding too many accessories can burn out regulator and stator also.
Last edited by Jackie Paper; Mar 11, 2026 at 08:16 AM.
Harley sells jump packs. I have cable coming in mail today to add pigtail to bike. I mistakenly ordered noco first time. They don't don't use same adapters as other companies
Very interesting, I had never thought about a permanent pigtail for a jump pack. On group rides we often throw universal jump packs in a saddlebag just in case. Are you aware of any advantage of a permanently mounted pigtail vs. attaching to the solenoid bolt that the battery cable goes to?
Adding too many accessories can burn out regulator and stator also.
I feel compelled to chime in that us audio guys have tried our best to overtax the Harley charging system and very few have done it. On my old 2010 Ultra Classic I was running three amps, eight speakers and a DSP and at full volume didn't over tax the charging system. Once when I had a really CHEAP amp that wasn't designed with efficiency in mind I did overtax it at high volume, but dang, I only paid $120 for an amp that would put out almost 800 (dirty) watts, I couldn't complain. When I swapped that amp out with a Soundigital putting out the same wattage the problem went away. The newer Rushmore bikes have even more robust charging systems in them. It's nuts how much these charging systems can withstand.
Not scientific evidence by any means, but a LOT of real world empirical data built up over the past fifteen years or so.
I feel compelled to chime in that us audio guys have tried our best to overtax the Harley charging system and very few have done it. On my old 2010 Ultra Classic I was running three amps, eight speakers and a DSP and at full volume didn't over tax the charging system. Once when I had a really CHEAP amp that wasn't designed with efficiency in mind I did overtax it at high volume, but dang, I only paid $120 for an amp that would put out almost 800 (dirty) watts, I couldn't complain. When I swapped that amp out with a Soundigital putting out the same wattage the problem went away. The newer Rushmore bikes have even more robust charging systems in them. It's nuts how much these charging systems can withstand.
Not scientific evidence by any means, but a LOT of real world empirical data built up over the past fifteen years or so.
If you use heated gear; jackets, pants, gloves, etc.... you can easily over tax the charging system....
I have read threads over the years about stereo systems over taxing the Harley charging systems, but not being a "loud stereo" guy, I have no personal experience with big, extra amps and such....
Last edited by hattitude; Mar 11, 2026 at 09:14 AM.
If you use heated gear; jackets, pants, gloves, etc.... you can easily over tax the charging system....
Forgot to mention I have used heated grips and heated vest in the environment I described, and that was on a bike with a halogen headlight and passing lamps, not the modern low current LED lights.
I understand the numbers, I am just saying in my experience the FL charging system has proven to be extremely robust in the past fifteen years or so.
Very interesting, I had never thought about a permanent pigtail for a jump pack. On group rides we often throw universal jump packs in a saddlebag just in case. Are you aware of any advantage of a permanently mounted pigtail vs. attaching to the solenoid bolt that the battery cable goes to?
They are great. If you have a Noco jump pack, the Noco pigtail is fantastic.
The only advantages I can think of are obvious. They are idiot-proof, and you don't have to worry about shorting the positive lead to the frame, etc. when attaching to your solenoid bolt.
Not a huge concern, just a super clean setup that works great.
They are great. If you have a Noco jump pack, the Noco pigtail is fantastic.
The only advantages I can think of are obvious. They are idiot-proof, and you don't have to worry about shorting the positive lead to the frame, etc. when attaching to your solenoid bolt.
Not a huge concern, just a super clean setup that works great.
I like the concept. So one would permanently attach the leads to the battery terminals and then stow the plug somewhere, like under a side cover? Assuming you have one installed, can you post a pic? Is there a cover for the receptacle? Which charger model do you have? I happen to be looking for a new jump starter for my SG.
I added this pigtail direct to the battery on my Ultra Limited as well as my Pan America. On the Ultra, the connector exits the side cover where the tender pigtail comes out. On the PA, it is just in front of the shifter. Cheap, and has saved my a few times when the cold weather has made starting difficult. I carry a small Halo Bolt with me for various uses.
Cheers
They are great. If you have a Noco jump pack, the Noco pigtail is fantastic.
The only advantages I can think of are obvious. They are idiot-proof, and you don't have to worry about shorting the positive lead to the frame, etc. when attaching to your solenoid bolt.
Not a huge concern, just a super clean setup that works great.
The advantage is it is quick. The jump pack should be smart enough not to reverse polarity.
I don't think this is a must have. I just felt like it
It can replace tender cord. The one I bought came with adapter to plug tender in
Last edited by Rounders; Mar 12, 2026 at 11:36 AM.
You need to read was was said earlier. A shunt is a resistor. Yes, when running, the permanent magnets alway are making AC . The reference is at 2000rpm and that's a constant unlike a alternator in a car that has windings for the rotor (armature) that can be controlled.
So the regulator controls the AC by on and off thru a shunt (resistor) . It uses the AC electricity by passing it thru a resistor shunt to ground making heat.
Any time you use a battery, your draining the stored voltage and they do wear out from the constant drain and replenish. This constant chemical stress, along with factors like heat and sulfation, reduces the battery's overall capacity over time.
A start hits it with a apx 150 amp drain. And also, if you hit the start button more than once starting it, each hit is a start on the starter solenoid. Why some don't get a lot of life out of there starter solenoid and probably most replace the whole starter than.
Charging a defective or deeply discharged battery can damage the charging system, particularly the alternator. A bad battery can force the alternator to work at maximum capacity.
Adding too many accessories can burn out regulator and stator also.
My question is,does it really hurt charging a low battery. People have said it does. But if it is not charging the battery it is going to ground creating. Heat is not good. Cycle electric tout there's does not do this
Modern autos ,not an expert, but dropping the charging level when not needed. You can see this by watching volt meter
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