I went to start my 04 Fatboy this afternoon, only to find my battery is dead. It wouldn't even turn the lights on, dead. When I hooked up jumper cables to it, I could turn on the accessories/headlights. The battery is about 3 years old and I had no issues at all two days ago when I went to ride.
I now have it hooked to the tender, hoping it will charge. When I turn the switch, the tender doesnt recognize its attached, but when it's off, it shows it's charging.
My question/worry is could it be the regulator? I had planned on trading for a new SGS next week, so the timing for this is horrible. For those of you who are familiar with battery systems, what do you think this is and what are your recommendations? Thanks in advance...

 

I doubt that a battery tender will be able to help you much. A tender is designed to maintain a charged battery, not to recharge a drained one.

If I were you I would pull it out and take it to your local auto parts store. There they can properly charge it and test it's condition. You can't diagnose a charging issue without a properly charged and functioning battery.

 

good advice above.


tender maintains a charge

charger charges

jump starting can destroy your charging system

pull the battery, charge it, test it and check the cables too.

mike

 

Mike, I've seen a lot of your posts, and you always seem to have
the right answer, and provide folks with lots of help.
Thanks for your contribution to the forum!
peace

 

Please enlighten us how?

 

If you jump start the bike with out the car (truck) running should not have a problem. It it is running and when you get the bike started the alternator puts out 2 or 3 times more amps than the bike charging system. It could over power the system and fry a regulator or stator. It may not but why take the chance.

 

The regulator has a diode in it, that only allows the current to flow one way(from the regulator/rectifier to the battery) it is not possible for the current to flow to the regulator/rectifier by jump starting.

 

Thanks for the input guys. I pulled the battery and took it to have it charged. Brought it home and it fired right up. It will stay on the tender while not being ridden. Hopefully there will be no more issues as I plan on trading it very soon for a SGS.

 

When the battery is duff (technical term for dead), there can be 3 reasons:

1.) bad chemistry, sulfated plates etc. it is just worn out

2.) open circuit; a 12 V battery has 6 cells which internally have a buss bar or "jumper" wiring them in series- on occasion, these may break or part.

3.) shorted; an internal short circuit- in which case the battery may burn.


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or discharged;

a.) battery drained by load being left on

b.) discharged because of electrons flowing between the poles through dust on the battery case

c.) bad chemistry

d.) etc.



If the battery is "jumped" and the motor started, the charging system is now being asked to supply power for the bike and lights- and also the drag of a discharged or duff battery.
If the total load exceeds the capacity of the charging system, it may overload and fail.

and a $100 problem becomes a $600 problem


this also applies to automobiles, although most automobiles have the alternator where it can be cooled by air ( most have a cooling fan built in) and have an alternator of much higher capacity.

I would only jump my own bikes if I had first diagnosed the fault or if I was stuck in BFE.
More than one rider has been to the autoparts store and rigged up a battery on the pass seat with bungee cords and extended cables.

on one of my old Panheads, I had a 9 volt battery clip and in emergency could run the ignition system off of that for about an hour ( no lights)


some of you may have seen my post last year on a neighbor who spent $1300 on repairs, when the fault was a $12 cable. the bad cable caused intermittent resistance/ open circuit and burned up a couple of charging systems and 3 batteries


mike

 

Thats exactly what it is designed to do, + there would be current going into the bike battery, from the vehicle you are jumping it from.
The alternator on my bike pushes 45 amps, and I'm sure the regulator is designed to cope with that.