I have a 2012 road king. I have replaced the battery 2 times within the last yr. I dont ride it much but have it on a battery tinder. My green light is always showing a full charge every time I look at it. But, go to get on it and take off and it wont start. I test the battery and the charge is good but I always have a dead cell. I can see this maybe happening once but not twice in a row within a yr. I had speakers put on a couple yrs ago by a harley dealership and was wondering if maybe the grounded something? I keep seeing post on here about wires grounded could put a draw on your battery. But dont know how to go about checking this?? What would I be looking for? Any help with this would be great. Thanks

 

I personally believe the AGM or Gel batteries are far superior to the old lead acid batteries. I am now on my second Gel battery its an Odessey, this battery lasted me 9 years on a '75 Iron Head. Besides the excessive vibration I flattened the battery numerous times back when I still had the old mechanical regulator on it. I never put a battery tender on it during the winter and it would always start.

So if I were you I would first get a gel battery then see where you stand with the occasional use of the bike. I think you'll like it

 

Since you have replaced he battery twice within the last year, there is somthing else afoot here. If it were me, I would disconnect the negative battery lead and place a volt ohm meter, in the amp position, between the negative terminal and the negative cable and see if there is any current draw at all from the battery with the bike totally turned off and switch off of course. If there is no current draw, I mean zero, then you need to suspect either your stator or your voltage regulator. Also check to ensure your connections are tights on the battery terminls.

You said that if you take it off of the tender that is showing green and the bike does not start....What does this mean? Is the starter turning over the motor and you get no fire? Or do you mean that nothing is happening at all? You need to me more specific about your symptoms.

 

when you do get it running you need to check out your charging system.there's more to this story.

 

I wrote this for a similar post. Most of the information comes from the Electrical Diagnostic Manual.
If anyone see's errors or a better way to test let me know and I'll make the changes.

Harley Davidson Charging System description and testing






Description:
The charging system consists of 3 major parts:

1- An Alternator that generates single phase or three phase alternating current, (AC).
The Alternator has 2 parts:





Rotor:
Attached to the primary side of the crankshaft. The Rotor has a series of permanent magnets and rotates around the Stator at engine speed.

Stator:
Attached to the crank case and has a series of wound wire coils. The Rotor fits over the stationary stator. As the Rotor spins around the Stator the rotating magnetic fields induce Alternating Current in the stationary coils. The Stator’s coils are arraigned so the AC output is either single or three phase.

2- Voltage Regulator, (VR), rectifies the Alternating Current, (AC), from the Stator to Direct Current,(DC), and limits the voltage output to a value close to 14.5 V DC.

3- Battery, a 12V rechargeable storage device used to supply power to the bikes electrical circuits.

As shown in the schematic the charging system includes insulated conductors and connectors carrying current from the stator to the VR through the main fuse to the starter and on to the battery positive. The VR negative lead and the battery negative lead are both connected to Chassis ground.
This system can be checked with a few easy tests using a digital or analog Volt–Ohm Meter.


Testing:

Connectors and cables should be checked and cleaned first. Loose and corroded connectors, terminals and grounds can cause high resistance, impeding current flow. Check cables for broken or rubbed insulation and check continuity to make sure the conductor is not broken inside the insulation.
Coating connectors with dielectric grease will keep moisture out and reduce corrosion.
Use the schematics in the HD Electrical Diagnostic or Service manual to determine the location of additional connectors.


Battery testing:

First check and clean battery terminals, Battery cables and ground connections. To check cables, disconnect one end and Ohm out, wiggle while testing. Cables can and will corrode and the evidence can be concealed under the insulation.

If you are unsure of the battery’s condition charge it fully and take it to an auto parts store and have it load tested.

Voltmeter test:
Connect voltmeter positive to positive terminal on battery and voltmeter negative to battery negative terminal.
12.7 v = 100% charge
12.6 v = 75%
12.3 v = 50%
12.0 v = 25%
11.8 v = 0%

Watch the battery voltage when you start the bike, if a fully charged battery falls below 9.6 volts it’s time to replace it.
If a well charged battery runs down after the bike sits for a short time, perform a current draw test. Set your meter to read 10 amps current. Pull your main fuse and insert the meter leads. Here’s a list of components and what current they will draw in milli amps, (1/1000 of an amp) from the 2015 manual:
LHCM 0.5
RHCM 0.5
Speedometer/ IM 0.5
Regulator 1.0
ABS 1.0
BCM 1.0
ECM 1.0
Security Siren 20.0
Radio 0.5
Amplifier 0.5
CB Module 0.5

If the Battery passes all tests check the charging system.
Charging System Testing:
Volt meter set to DCV 20V scale or higher.
With the bike in neutral and voltmeter attached to the battery, start the engine and rev to 3,000 rpm. If the voltage measures 13V – 14.7V the charging system is operating properly. If less than 13V test the Stator first. If Greater than 15V test the Voltage Regulator.

Stator testing
Turn the bike off and disconnect the Stator from the Voltage Regulator.
Testing a 3 phase Stator, (A single phase stator is tested in the same manner but the plug will only have 2 sockets).
The end of the connector from the stator has 3 sockets. Set your meter to ohms and connect one lead to the battery negative. With the other lead make contact with the conductors inside each socket. You are checking for a grounded coil winding, each socket should show an open circuit to ground, no continuity.
Now take both meter leads and check resistance between each of the three sockets, 1-2, 2-3 and 1-3. The resistance should be 0.1 – 0.3 ohm.
Next check the Stator’s AC output. Set the meter to ACV 100V scale. With the Stator unplugged from the VR and the bike in neutral, start the bike. Run the bike at 2,000 rpm and check the Stator output between sockets 1-2, 2-3 and 1-3. The voltage should read approximately 32-46 Volts AC, for the 50 amp Stator. Stators with other Amp ratings will be similar.
If the Stator continuity tests to ground and Phase to Phase are good but the output is not the Rotor may be bad.

One other indication that the stator may be bad is if your primary oil smells like a burnt circuit board.

Voltage Regulator Testing

Voltage readings of 14.8V and higher indicate the Voltage Regulator is bad.
If the output is less than 13V from the Voltage Regulator to the battery and the Stator output is good, disconnect the output cable from the VR to the Battery. Check continuity between the Voltage Regulator Positive wire and the battery Positive and the negative wire and battery negative. Repair or replace cable if needed. If the cables are good and the Stator tested well replace the Voltage Regulator.

 

You say you always find a dead cell. Maybe as a simple idea, lose the batter tender. I cant help but feel people are better off without them, then with and cant imagine how many batteries lives are shortened by them.
Batteries HATE heat, tenders, if not working correctly or oversized for the job keep batteries warm all year. Never mind how many batteries are in a constant state of overcharged. Im not saying all are bad, I am just saying on average I think most people would find their batteries last just fine without tenders.

Just my thoughts, that post above me is over my head. *L*
All I know, I never used a battery tender in my life, decades of boating and winter storage etc. etc. etc. I look at vehicle batteries the same as a battery in a radio or flashlight = Disposable, change your bike battery every 3 to 4 years, skip the tender.

If that doesnt work see Vernal above this post. Wow, he is the guy to talk to for sure.

 

Your OEM lasted 4 years... a little short in my experience, especially with a battery tender, but not too bad.

It IS possible that the new battery was bad from the start, but the odds are something else is amiss.....

Seems you are overcharging the battery.....

Could be the tender, or your charging circuit.

Test the bike's charging circuit (great info in above post) and if it checks OK... I'd get a new battery tender, or at least lose the old one......

You didn't say what Battery Tender you are using.... they are not all equal.

I have used a Deltran Battery Tender Junior on my bikes, anytime they are parked in the garage. I have the OEM battery in my '12 Limited, and got 7 years from the OEM battery in my '03 Heritage.

Good luck...

 

yes ! i have had good luck using deltran battery tenders. 8 years on the battery in my suburban and 8 years on the softail battery. 12 streetglide had the factory battery when i wrecked it.

 

Can we start with an obvious question that I may have missed? Where did the battery come from? Is it the least expensive battery you could find or a quality name brand battery? Was the original dead cell battery replaced with the same brand of battery that had the bad cell?

The battery would not test good with a bad cell... would it? most bad cells produce minimal voltage, so a bad cell battery shouldn't test over 10 amps. If it test over 12 volts and has issues cranking the bike, then I would guess its a cranking amp issue for your bike. Cold weather and lack of compression releases would cause lesser CCA batteries to be unable to crank a 103 or 96 inch motor over.

 

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" lose the batter tender. I cant help but feel people are better off without them, then with and cant imagine how many batteries lives are shortened by them. '

Dude,your right on the money with that thought because i have been tracking issues with premature battery failure and more often then not people that had premature battery failure was also runing a battery tender 24/7 or close to it.

And thats not to mention the fact more often then not guys are using newer gen AGM bike batteries in thier HD's and by design AGM batteries use significantly less acid/electrolite then older gen std lead acid bike batteries did making newer gen AGM batteries with a lot less fluid/acid in them much more sensitive to over charging that can easily dry out /drive the electrolite out of the plates resulting in warping the plates causing internal shorting & bad cell or cells which is where i feel many of the premature AGM battery failures originate from.

I just posted a fairly long post in another battery thread in touring forum with more detail on how & why feel the same way you do with respect to leaving maint chargers on batteries 24/7 or close to 24/7 is in fact leading to and or directly causing premature battery failure.

And thats especially an issue with new gen AGM batteries that " by design " utilize less fluid/electrolite where over time (24/7) even a small amount of over charging can be detrimental to srv'c life on an AGM design bike battery.

Scott