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Discussion Starter #1
I have a 2008 LT that I bought as a carry-over new in 2009. For various reasons, I ride it infrequently and thus need to keep it on a Battery Tender Junior. The OEM BMW battery seemed to die this spring (wouldn't hold a charge,) which seemed premature, but I went out and bought a new, appropriately-sized BikeMaster gel battery in March, and all seemed well.

Then I had a period of about four months where I didn't ride the LT, all the while it's on the tender. Tried to start it yesterday, and while it wasn't completely dead, the battery didn't provide enough juice to start it. Dash lights flash, and beeping alert happens when I push the remote switch necessary for ignition. Can't get even coax an attempt to turnover after the beeping; it just flashes and seems to need more power than the battery has.

I jumped the bike with cables yesterday and took it for about a 15-minute high-speed ride. Still wouldn't restart after shut-off, but I suspect I needed to ride for a longer period of time to have the bike recharge on its own.

Then tried the tender again, but the battery won't seem to take the charge. Tried a second tender, in case the one I was using on the LT was defective. No difference in result with an overnight charge attempt.

Have I fried a brand-new battery by letting it discharge (inadvertently) over the four months between rides? Was the battery tender I was using inadequate for such a power-hungry bike? Any advice from any of you? Could it be a defective battery that I should attempt to replace via warranty? Any advice is appreciated. Thanks!
 

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New batteries can fail

Have you checked output of alternator with bike running using a voltmeter

15 minutes would not put much of a charge back into battery and once a battery is totally discharged they will not recover fully and should be replaced, even my buddies very expensive battery on his sailboat designed for deep discharge is not supposed to be ever discharged more than 50% if long life is desired

lots of people use battery tenders successfully, I use solar panel with 12 volt regulator, same as on my trailer
 

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Battery tender will not charge a battery that is below a certain charge. Its a safety feature. You need an old 2 amp or so dumb charger without a protection circuit to charge a dead or almost dead battery, then keep it on the tender to keep the battery charged.
 

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Discussion Starter #4
mwnahas said:
Battery tender will not charge a battery that is below a certain charge. Its a safety feature. You need an old 2 amp or so dumb charger without a protection circuit to charge a dead or almost dead battery, then keep it on the tender to keep the battery charged.
I guess what has me confused is why the battery would have discharged much at all. I put the tender on it almost immediately after the last rider prior to the four-month storage. The Battery Tender Junior is only a 0.75 Amp trickle charger for 12v batteries, but its manufacturer claims it has some sort of built-in intelligence that regulates the charge based on what the battery needs. Thanks for the response!
 

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Discussion Starter #5
gary45 said:
New batteries can fail

Have you checked output of alternator with bike running using a voltmeter

15 minutes would not put much of a charge back into battery and once a battery is totally discharged they will not recover fully and should be replaced, even my buddies very expensive battery on his sailboat designed for deep discharge is not supposed to be ever discharged more than 50% if long life is desired

lots of people use battery tenders successfully, I use solar panel with 12 volt regulator, same as on my trailer
I haven't checked the alternator because the battery always seems to be fully charged after a good long ride (1-2 hours.) The problem seems to stem from the time it's sitting in the garage. I thought putting the tender on it immediately would take care of that problem. Don't know why it would have discharged with the tender on it.
 

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Not all Trickle charger are able to charge a Gel Batterie up to full load. Some of them just keep them alive.
As said before use a dumb charger for full load maybe it comes back to live

Manfred
 

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bbrunmeier said:
I guess what has me confused is why the battery would have discharged much at all. I put the tender on it almost immediately after the last rider prior to the four-month storage. The Battery Tender Junior is only a 0.75 Amp trickle charger for 12v batteries, but its manufacturer claims it has some sort of built-in intelligence that regulates the charge based on what the battery needs. Thanks for the response!
interesting.. Which plug did you use? The one by your clutch foot? Is the key in the lock position? Sometimes those contacts need to be cleaned. Also you might have a dead cell/short in the battery.
 

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My original battery purchased with bike in late 04 is still going strong!!!!!

go figure
 

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Discussion Starter #10
mwnahas said:
interesting.. Which plug did you use? The one by your clutch foot? Is the key in the lock position? Sometimes those contacts need to be cleaned. Also you might have a dead cell/short in the battery.
Didn't really use a plug, just attached alligator clips to the battery terminals. The key was in the lock position. Contacts are clean as a whistle. With battery being so new, this seems odd. Also, this was essentially what was going on with the OEM battery that I just replaced. I tossed that one, figuring it was a shot battery although only used three years.
 

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Discussion Starter #11
mreuter said:
Not all Trickle charger are able to charge a Gel Batterie up to full load. Some of them just keep them alive.
As said before use a dumb charger for full load maybe it comes back to live

Manfred
That seems reasonable. I'm going to jump it today to start it and ride for a good 100 miles or so. Maybe that will get it up there again.
 

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Discussion Starter #12
tobiwan said:
My original battery purchased with bike in late 04 is still going strong!!!!!

go figure
I think it must have something to do with the battery draining down during garage time and the tender's inability to keep it charged. I can go weeks/months without riding that bike. The tender works great on another bike (2007 HD 1200 Nightster) with original battery. That bike isn't rode any more often, either, but does have significantly less electrical gadgetry.
 

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You didn't accidentally put the key in the Park position did you..

This leaves the tail and marker lights on and will run down the battery...

I would suspect your battery tender is funky.. Get a volt meter and see what is really going on..

A better charger is probably in order for you to leave it long term...

John
 

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Discussion Starter #14
JPSpen said:
You didn't accidentally put the key in the Park position did you..

This leaves the tail and marker lights on and will run down the battery...

I would suspect your battery tender is funky.. Get a volt meter and see what is really going on..

A better charger is probably in order for you to leave it long term...

John
No, I always lock the steering and remove the key each time. I tried a second tender that I use on another bike and it didn't yield any better results. I'm at a loss...
 

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Discussion Starter #15
JPSpen said:
You didn't accidentally put the key in the Park position did you..

This leaves the tail and marker lights on and will run down the battery...

I would suspect your battery tender is funky.. Get a volt meter and see what is really going on..

A better charger is probably in order for you to leave it long term...

John
Also, not sure I'd know what to do with a voltmeter if I had one. Touch the posts on the battery for a reading? Wouldn't know what I'd be looking at, other than wanting it to be somewhere close to 12v. I'm quite sure it's not now. The question, I guess, is if the tenders are doing anything at all. Also, why having the tender on it for months wouldn't have maintained the charge in the first place. It's a six month old gel battery! Frustrating.
 

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Depending on the brand of battery tender and it's quality, you can ruin a battery with it. The tender must be a float type which shuts itself off at a preset voltage and then comes on again when necessary. Walmart has cheap digital meters in the automotive section that you can check the voltage at the terminals with the tender attached. You should see about 13.2 volts with a healthy battery.
 

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bbrunmeier said:
I have a 2008 LT that I bought as a carry-over new in 2009. For various reasons, I ride it infrequently and thus need to keep it on a Battery Tender Junior. The OEM BMW battery seemed to die this spring (wouldn't hold a charge,) which seemed premature, but I went out and bought a new, appropriately-sized BikeMaster gel battery in March, and all seemed well.

Then I had a period of about four months where I didn't ride the LT, all the while it's on the tender. Tried to start it yesterday, and while it wasn't completely dead, the battery didn't provide enough juice to start it. Dash lights flash, and beeping alert happens when I push the remote switch necessary for ignition. Can't get even coax an attempt to turnover after the beeping; it just flashes and seems to need more power than the battery has.

I jumped the bike with cables yesterday and took it for about a 15-minute high-speed ride. Still wouldn't restart after shut-off, but I suspect I needed to ride for a longer period of time to have the bike recharge on its own.

Then tried the tender again, but the battery won't seem to take the charge. Tried a second tender, in case the one I was using on the LT was defective. No difference in result with an overnight charge attempt.

Have I fried a brand-new battery by letting it discharge (inadvertently) over the four months between rides? Was the battery tender I was using inadequate for such a power-hungry bike? Any advice from any of you? Could it be a defective battery that I should attempt to replace via warranty? Any advice is appreciated. Thanks!
What make and model battery tender? My understanding is that gel batteries require a special charger as do lithium ion batteries. If your tender is for a lead-acid battery, then it likely is not correct for the gel battery.
 

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Discussion Starter #18
Voyager said:
What make and model battery tender? My understanding is that gel batteries require a special charger as do lithium ion batteries. If your tender is for a lead-acid battery, then it likely is not correct for the gel battery.
It's a Deltran Battery Tender Junior, which claims to be OK for all those things, but I wonder...I appreciate your response. Thanks.
 

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bbrunmeier said:
It's a Deltran Battery Tender Junior, which claims to be OK for all those things, but I wonder...I appreciate your response. Thanks.
Might want to check the voltage across the battery terminals with the tender hooked up. If you aren't seeing something north of 13V, then the tender may not be working, particularly if you know the battery is weak.
 

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Discussion Starter #20
Latest twist is that I jumper-started it and took it for a 115-mile ride to see if the alternator would properly charge the battery. Ride went fine, but when I pulled in the garage after nearly two hours of highway riding the hydraulic center stand would not activate (bike was still running.) Attempts to start bike after shut off by ignition were futile once again.

At this point, I'm suspecting I might have larger electrical short issues or something else putting a load on the system that will not allow ignition starts. I'm a novice at diagnosing things like this, so your informed posts are welcomed.
 
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