Motorcycle Battery Discharge rate

Alvito

Well-known member
Hey,

My battery was charged to 12.7 volts. Over the past two days it has gone down to 12.4 volts. Is this a normal discharge rate? Or should I be looking to pick up a new battery?

Thanks fellas!
 
Down to 12.2 volts tonight. Tried to start the bike and it was a no go.
 
Try starting it with a car battery providing a boost. Do not have the car turned on at the same time!
 
Try recharging it as well. If it continues to drop dead in a day, you will need a new battery. Also see if there are any accessories that are being left on.
 
I had a problem with parasitic drain, a load placed on the battery by a faulty ignition switch. I was able to repair it by spraying contact cleaner into the ignition lock.

I found it by removing a battery cable and placing an amp meter in series to determine that the drain was in excess of 200ma. I was considering placing a kill switch in line with the battery until I sorted out the problem.

Hopefully yours is an easy fix, perhaps you could borrow a good battery for a couple of days?
 
Sounds like OP has a voltage leak someplace, unless he has some sort of alarm system etc. he has not mentioned.
 
How old is the battery. You might have two issues....


1. Battery is old is discharging - a load test will tell you if that's the case.
2. YOu might have a parasitic draw - a test will tell you if that's the case.

Both cases - a few tests would determine w hat the cause is.
 
Try starting it with a car battery providing a boost. Do not have the car turned on at the same time!

I can start the bike with a boost from my car. Went for a 15 minute ride to try to charge the battery - I don't think that was long enough.

Try recharging it as well. If it continues to drop dead in a day, you will need a new battery. Also see if there are any accessories that are being left on.

I charged it for 3 hours, checked the voltage and it was 12.7 volts so I stopped it. Should I leave it with my automatic charger overnight or do I risk doing damage to the battery?

Sounds like OP has a voltage leak someplace, unless he has some sort of alarm system etc. he has not mentioned.

No alarm system or accessories.

How old is the battery. You might have two issues....


1. Battery is old is discharging - a load test will tell you if that's the case.
2. YOu might have a parasitic draw - a test will tell you if that's the case.

Both cases - a few tests would determine w hat the cause is.

The battery is at least two years old. I bought the bike in 2012. Maybe it is time for a new battery. Will Z1 Cycletech have a machine to check the health of the battery? I will call them tomorrow if no one has an answer for me here.
 
I had a similar problem, until I realized I was idling it too much, and the headlight, running lights, tail light, plate light where draining the battery. Most motorcycles don't recharge a battery a low idle with so much electrics turned on.
 
I had a similar problem, until I realized I was idling it too much, and the headlight, running lights, tail light, plate light where draining the battery. Most motorcycles don't recharge a battery a low idle with so much electrics turned on.

I boosted it with my car battery again. It started first shot. I rode on the highway for about 10 minutes, and then back on local roads. I stopped to buy bananas, realized I had no money. Went to start the bike again and I realized my battery is toast and wouldnt turn over the bike.

I don't know how to push start my bike, so I walked it home. I was only about 300m-400m away from home. But something I don't want to do again. Going to try to buy a battery tomorrow or Saturday. lol.

Thanks for your help guys!
 
I boosted it with my car battery again. It started first shot. I rode on the highway for about 10 minutes, and then back on local roads. I stopped to buy bananas, realized I had no money. Went to start the bike again and I realized my battery is toast and wouldnt turn over the bike.

I don't know how to push start my bike, so I walked it home. I was only about 300m-400m away from home. But something I don't want to do again. Going to try to buy a battery tomorrow or Saturday. lol.

Thanks for your help guys!

1. Glen @ FS Motorcycle can load test it. IF your battery is staying below 12V is prob. is toast.
2. 10mins isn't enough time for it to charge up - if you've had to boost it.


First thing you should do is, charge your battery out of the bike.- and get it load tested. It will tell you if t he battery is at fault or not.

If your battery passes - it might your bike might not be charging. If you are semi skilled with a volt meter...you should be able to check easily.

Lastly if you are lost - ask a GTAM member or me if we can help :D
 
I had a similar problem, until I realized I was idling it too much, and the headlight, running lights, tail light, plate light where draining the battery. Most motorcycles don't recharge a battery a low idle with so much electrics turned on.

regulator/rectifier of most motorcycles should be able to charge the battery AT ANY RPM...higher the RPMS, the more the heat released from the regulator circuit...some one correct me if I'm wrong plz...
 
How'd you check the voltage, is there a gauge or did you use a digital multi meter? could be crossed exposed wire or damaged battery from age and wear. Also could be a regulator/rectifier issue, as its common with some other bikes like the older R6.


well **** lol I didn't see previous post.

Disconnect the battery for a day then reconnect and see if its lost some of its charge. If it hasn't than you know something is draining it and you can buy a $10 multi meter to hunt down the source.
 
Last edited:
regulator/rectifier of most motorcycles should be able to charge the battery AT ANY RPM...higher the RPMS, the more the heat released from the regulator circuit...some one correct me if I'm wrong plz...

The optimum point is at least quarter of the tach. It doesn't charge at idle

Sent from my tablet using my paws
 
1. Glen @ FS Motorcycle can load test it. IF your battery is staying below 12V is prob. is toast.
2. 10mins isn't enough time for it to charge up - if you've had to boost it.


First thing you should do is, charge your battery out of the bike.- and get it load tested. It will tell you if t he battery is at fault or not.

If your battery passes - it might your bike might not be charging. If you are semi skilled with a volt meter...you should be able to check easily.

Lastly if you are lost - ask a GTAM member or me if we can help :D

FS Motorcycle is a little bit out of the way. Could I take my battery to a car mechanic with a battery tester for cars? Okay, I'll put the battery on the tender over night.

How'd you check the voltage, is there a gauge or did you use a digital multi meter? could be crossed exposed wire or damaged battery from age and wear. Also could be a regulator/rectifier issue, as its common with some other bikes like the older R6.


well **** lol I didn't see previous post.

Disconnect the battery for a day then reconnect and see if its lost some of its charge. If it hasn't than you know something is draining it and you can buy a $10 multi meter to hunt down the source.

I used a multimeter.
 
FS Motorcycle is a little bit out of the way. Could I take my battery to a car mechanic with a battery tester for cars? Okay, I'll put the battery on the tender .

The car mechanic can probably test it, but when he tells you it's dead you gotta go to FS anyway. Of course you can always go to crappy tire or walmart...


Sent from my iPhone using Tapatalk
 
I had a similar problem, until I realized I was idling it too much, and the headlight, running lights, tail light, plate light where draining the battery. Most motorcycles don't recharge a battery a low idle with so much electrics turned on.

I would disagree with that .... healthy battery and healthy charging system will not drain battery just by idling (not speaking aboutthe fact that you ride not just idle, right?).

Hookup a voltmeter to your bike and measure the voltage when idling, it should be at 13.6V minimum and will go over 14 as you increase RPM. If not you have a problem someplace.
 
Motorcycle alternators and regulators are useless at idle

That's been my experience as well. At idle with no accessories running, it might break even, but most likely will not charge until you are 1/4 throttle or more.
Pulling the battery and charging it separately sounds like the way to go.

Starting with my KLR I've been installing volt meters on the bike. An led indicator that tells me if I'm undervolt, breaking even or over volt. When I tour I run a heated jacket, grips, gps and highbeams. It's peace of mind to know that I won't be bump starting it when I get there.

Check eBay, you can get them from $6 and up.
 
Just got a new battery today at Royal its no tax, mine died after 10 years. They have three levels some for about 60 some for about 100 and then lithium at around 200.
Just thought I'd let you know about the sale.
 
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