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Discussion Starter #1 (Edited)
and left my key "on" in the garage overnight after checking miles ridden yesterday. Battery is 100% dead and I just hooked my Battery Tender Junior up to it. Battery Tender Junior is flashing red indicating "Charging" and I just want to confirm that my Battery Tender Junior has the "oomph" to fully charge up my completely dead battery. Any guestimates as to how many hours it might take? I was hoping to ride today...:headbang:

Thanks for any insights.
 

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In my opinion, you will not be riding today. Also, that battery tender is not designed for slow charging a flat dead battery. It is for maintaining a charged battery or charging a battery with 11.4volts or more. You are probably shortening the life of the charger.

I think you ought to decide if it is better to hook up to a proper motorcycle battery charger (off the bike) or just replace the battery. Don't charge the old battery at more than 2 amps. Certainly don't charge it in (hooked up to) the bike.

2c...


From the book: (my bold)

Therefore, a fully discharged 15 Amp-Hour battery will
take approximately 16 hours (to charge)


WORKING WITH A DEAD BATTERY OR A BATTERY WITH A VERY
LOW VOLTAGE:
If you try to charge a dead battery having a voltage below 3 Volts, the
BATTERY TENDER® CHARGERS will not start to charge because an internal
safety circuit prevents the battery chargers from generating any DC output
voltage.

NOTE:
If a 12 Volt, Lead-Acid battery has an output voltage of less than 9 volts when
it is at rest, when it is neither being charged nor supplying electrical current to
an external load, there is a good chance that the battery is defective.
As a
frame of reference, a fully charged 12-Volt, Lead-Acid battery will have a reststate,
no-load voltage of approximately 12.9 volts. A fully discharged 12-Volt,
Lead-Acid battery will have a rest-state, no-load voltage of approximately 11.4
volts. That means that a voltage change of only 1.5 volts represents the full
range of charge 0% to 100% on a 12-Volt, Lead-Acid battery. Depending on
the manufacturer, and the age of the battery, the specific voltages will vary by
a few tenths of a volt, but the 1.5-volt range will still be a good indicator of the
battery charge
 

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If it were me I would jump it from my car or truck, then go for about a 4 hour or so ride, and you'll likely be fine. It's freakin' beautiful around here today, don't waste it like I have to!
 

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I agree about not wasting the day, but really don't like the idea of charging a battery that is that dead with the bike's charging system. To each his own though. YMMV, and all that...
 

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Accidentaly turned the key to the park light position and left it on for about 12 hours.
I just got a jumpstart from a car and drove for about 1 hour.
No porblems afterwards.
 

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If you jump start your bike from a car I would be very careful. The amperage in the car battery is significantly higher and can fry electronics on your bike.
 

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Discussion Starter #7
"I think you ought to decide if it is better to hook up to a proper motorcycle battery charger (off the bike) or just replace the battery.

A new battery is $80 and this one is a year old, an appropriate charger from Harbor freight is $32.

Is the life expectancy of my current depleted battery compromised by killing it as I did? Is it worth recharging?

Should I just pay the stupidity tax and buy a fresh battery?

Thanks.
 

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Regardless of all the other factors to consider, yes, the battery on the bike now has a shorter life expectancy. If it were mine (and it did recover) it would be living in my lawn tractor from now on.

Maybe I just don't like pushing motorcycles home anymore...:yesnod:

How many volts are you now reading across the terminals? That may help you to decide.
 

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Discussion Starter #9
Regardless of all the other factors to consider, yes, the battery on the bike now has a shorter life expectancy. If it were mine (and it did recover) it would be living in my lawn tractor from now on.

Maybe I just don't like pushing motorcycles home anymore...:yesnod:

How many volts are you now reading across the terminals? That may help you to decide.
1.96V

Sounds like I should just replace it?
 

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No expert on the subject, but I would just ease the battery up with the Battery Tender to anything more than 11.5V measured with the Battery Tender disconnected, jump start it from a car without leaving the cables connected any longer than necessary, go enjoy the day, put the Battery Tender back on it when you get home.
 

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I dont understand why you would waste money on anew battery if the one you have is only 1 year old. Draining a battery to no life and recharging does wear on a battery. My brother in law who tested batteries for Toyota as a quality engineer said they would see an average of 4-5 full drains and recharging beofre a battery would no longer hold a charge. However that was an aver, some go more and some go less. There are alot of variables to batttery life like temperature stored, change in temps, charging, etc.....I would just charge the one you got. That being said, if you want to go riding today it aint gonna happen with a battery tender Jr. Your best bet is to jumo the bike and ride but you do take a risk that the battery will no longer take a charge. Ride for a acouple of hours, go home, turn it off and see if it starts. The other note of being carefull of a cars battery is correct. I learned the hard way on that one. I jumped my BMW K1200LT off a ford f-150 while running. It started but as I got down the road every piece of electrical equipment died one by one as I went down the road, eventually hitting the fuel injection and dying. It took a tow truck and alot fo work at the dealer to fix it. It would have cost 2k dolalrs if warranty didnt cover it. If you are going t ojumo off a car make sure the car is not running and try to find the smallest car battery around like out of a geo tracker or honda civic,etc... I do know guy with bike like the LT that have alot of sensitive electronics that will never jumo their bike off a car. Howeve I dont see alot of that type of stuff on a strom. Good luck.
 

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The only problems with jumping a bike off a car or truck are if the polarities are crossed, a cable is carelessly shorted or the donor vehicle has a bad charging system. The first two are handled by being careful and the last by not running the donor engine. Current is based on load. A properly connected big 12V battery on a car that is not running cannot overwhelm a properly functioning bike electrical system.
 

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You have two choices. Get an "intelligent battery charger" and recharge the battery (it takes 5 times as long to recharge a battery properly as it did to discharge it) until it is 12.7 or so and holds that charge for 12 hr. (still at 12 .3 or more), (you should let the battery rest after it is charged from the v level you stated anyway) or get a new battery, which you should probably put on charge (same intelligent charger) for 3-4 hr. If your battery was OK before this incident it will be OK after it. I would only jump start a battery in an emergency. (be careful, jump starting a battery can create an emergency.:yikes:) http://www.batteryuniversity.com/partone-13.htm And how to start your bike when the battery dies in an emergency. http://motorcycle-maintenance-repair.suite101.com/article.cfm/motorcycle_maintenancerepair
 

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Caution

Don't risk the electrical system of the bike by jump starting it and having the bike charge a dead battery. That could be more expensive than a replacement AGM battery at Walmart for $65. Get a new battery if you want to ride now otherwise a 3A charger would be next best option. I'd pull the positive terminal on the bike to to isolate it again to protect the bike's $$$ electrical system. It will probably take about 4-5 hours at 3A to get the battery charged. I wouldn't charge it faster no would I try to use a trickle charger that maybe puts out 300ma maximum on a completely dead battery. Batteries need more of a current jolt than that when dead. An yes, the battery has been a bit compromised and its' life has been shortened since it isn't a deep cycle battery.
 

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If you jump start your bike from a car I would be very careful. The amperage in the car battery is significantly higher and can fry electronics on your bike.
So let me get this straight you are in the middle of nowhere you left your key on at the camp site,over night and so all you have is a car to help you get it started ,A) walk forty miles to the nearest M\C shop B) jump it with the car, to me that is a no brainer, I have jumped mine several times from my 3\4 ton truck. with no problems, the bike has never seen a battery tender. and I have zero charging problems. and I have been a auto, moto mechanic way before the Battery university came about in 2003
 

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I did a similar thing when I was finishing up my winter maintenance. I left the key on, headlights on, after I couldn't get the TBS. I came inside to check out here on Stromtrooper, got carried away, and an hour later realized the battery was dead. Took me all of 10 minutes to jump it from my Tahoe, most of that was in finding the cables (they were underneath our camping gear from last year which was underneath a kayak which was blocked by 3 pieces of sheetrock).

I've jumped pretty much all of my motorcycle batteries at one time or another (as well as my tractor battery a number of times).

You have shortened its life, that much I will attest to. I needed more than 4 hours of riding to get it back though. I have a digital meter on the bike so I know when the battery is fully charged.
 

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So let me get this straight you are in the middle of nowhere you left your key on at the camp site,over night and so all you have is a car to help you get it started ,A) walk forty miles to the nearest M\C shop B) jump it with the car, to me that is a no brainer, I have jumped mine several times from my 3\4 ton truck. with no problems, the bike has never seen a battery tender. and I have zero charging problems. and I have been a auto, moto mechanic way before the Battery university came about in 2003
Well Steve I said be careful not don't do it. You may do whatever you would like with your bike. I don't care. I have seen a fried starters and two ignition boxes. None of them on my bike but none the less I did help them get the bikes back together. So as stated before be careful if you do this.
 

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There is nothing wrong with jumping a bike battery from a larger vehicle as long as polarities are correct. Voltages are the same, or close enough anyway. Just don't be a doofus and hook + to - and you'll be okay. There's really not much to it.

I sure hope you didn't waste this day away reading this thread. I couldn't enjoy it, my septic tank had "issues" I had to take care of today. :headbang:
 

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Discussion Starter #20
Thanks guys for your input. I got an appropriate battery charger and the battery has been on it for the last few hours. Looks like I'll be riding tomorrow. I was forced to ride my bicycle :yikes: today instead so the day was not wasted. Got some exercise and enjoyed the weather.
 
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