Low Voltage at Battery
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5th Gear
Joined: Apr 2017
Posts: 9
Likes: 0
From: Simi Valley, CA
Low Voltage at Battery
2008 FLHTCU Ultra Classic - I have verified my stator and brand new voltage regulator are working perfectly, however, I am not seeing the regulator voltage at the battery (i.e, bike runs off battery). Anybody have a clue as to what I should check between the regulator and the battery? 40A fuse looks good. Is there a connector or junction box that could be culprit? BTW, battery ground to frame is solid. This one is baffling me.
Also, if anyone knows where the voltage regulator Front Dirty GND is physically located on the bike that would be awesome. That is like the last connection I need to check and I am having troubles finding it.
Also, if anyone knows where the voltage regulator Front Dirty GND is physically located on the bike that would be awesome. That is like the last connection I need to check and I am having troubles finding it.
Last edited by WildCherry; Aug 9, 2017 at 10:04 PM. Reason: More information/request for help
Road Warrior
Joined: Aug 2015
Posts: 1,712
Likes: 410
From: Puyallup, WA
2008 FLHTCU Ultra Classic - I have verified my stator and brand new voltage regulator are working perfectly, however, I am not seeing the regulator voltage at the battery (i.e, bike runs off battery). Anybody have a clue as to what I should check between the regulator and the battery? 40A fuse looks good. Is there a connector or junction box that could be culprit? BTW, battery ground to frame is solid. This one is baffling me.
Thread Starter
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5th Gear
Joined: Apr 2017
Posts: 9
Likes: 0
From: Simi Valley, CA
This all started with DTC error code of P0562 - Low Battery Voltage (I.e., the supply voltage to battery has dipped too low). I load tested battery and it is good. I removed voltage regulator and the insulation on the back of it was cracked and falling apart, so I replaced the voltage regulator with a new one. I then verified I am getting good voltage from stator >30vac to the voltage regulator and also verified voltage regulator is putting out >15 vdc. So the stator and the voltage regulator are good. However, when I run the engine at 2000 rpm, my voltage only gets up to about 12.4 vdc at the battery terminals. It should be up to at least 14 vdc at higher revs and I can't figure out why the drop. I really need to find the front dirty ground for the voltage regulator. I need to make sure it is clean and tight, but I can't find it.
Road Warrior
Joined: Aug 2015
Posts: 1,712
Likes: 410
From: Puyallup, WA
Check all the wiring, cables, etc.. Could be a bad connection or corroded cable. Check for voltage at the battery ends of the regulator wiring to see if you have 14v there. Should be a small ground wire at VR to the frame.
Road Master
Joined: Jun 2012
Posts: 1,062
Likes: 191
From: Boise, Idaho
I was having a similar issue on my bike. 2012 FLHTK. I found that the dirty ground connection was not good. I eventually ran a jumper from the dirty ground directly to the negative post on the battery. This took care of my charging problem.
The dirty ground on my bike is directly to the left of the clean ground a couple of inches. It is very difficult to see with all of the wires in front of the battery. I only found it when I removed the fuse block to check the connections for the main fuse. You can see it if you move the wiring in front of the battery some.
The dirty ground on my bike is directly to the left of the clean ground a couple of inches. It is very difficult to see with all of the wires in front of the battery. I only found it when I removed the fuse block to check the connections for the main fuse. You can see it if you move the wiring in front of the battery some.
Thread Starter
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5th Gear
Joined: Apr 2017
Posts: 9
Likes: 0
From: Simi Valley, CA
I was having a similar issue on my bike. 2012 FLHTK. I found that the dirty ground connection was not good. I eventually ran a jumper from the dirty ground directly to the negative post on the battery. This took care of my charging problem.
The dirty ground on my bike is directly to the left of the clean ground a couple of inches. It is very difficult to see with all of the wires in front of the battery. I only found it when I removed the fuse block to check the connections for the main fuse. You can see it if you move the wiring in front of the battery some.
The dirty ground on my bike is directly to the left of the clean ground a couple of inches. It is very difficult to see with all of the wires in front of the battery. I only found it when I removed the fuse block to check the connections for the main fuse. You can see it if you move the wiring in front of the battery some.
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When you pull the seat, look on the frame right behind the fuel tank in front of the battery. There are two connectors to the frame. The left is the dirty connector, the right is the clean connector. Don't mix them up.
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Thread Starter
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5th Gear
Joined: Apr 2017
Posts: 9
Likes: 0
From: Simi Valley, CA
Thanks for the post. I found my problem on Saturday. I've got some kind of short from my stator to GND. UGH! But, at least I know what the issue is now. I've ordered the stator and should have it replaced this week. I'm having withdrawals! Need to get back out on the road!
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Joined: Jul 2009
Posts: 967
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From: Reno, NV
Your Battery may have a shorted cell, more common than one would think. How old is it ? And i have seen new ones that were bad...
