Motorcycle Battery Discharge rate

Forum Sponsor
Rotten_Ronnie said:
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.
Click to expand...

Older bikes and some not so old bikes, idle with barely 13V ... in that case yes you will have problem because the battery will be slowly getting depleted, but not until you start all kinds of things, like extra lights, heaters etc. and will keep idling without taking off. At some point, you will ride and the voltage will go up and your battery start charging, right? In that case your voltage should go over 14V and the battery will be getting re-charged. If you are not getting 14V min. you are having a problem in my opinion, unless it's by design, but that would be a bad design, no?
 
rpollard said:
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.
Click to expand...

Thanks, I might go there. I'm looking to buy local. I called Z1 Cycle and they said they had the battery in stock. I go there and the place is now a auto detailing place. lol. Apparently they moved to Etobicoke!

Anyone know a reputable place I can go to near Leslie and Finch???

Smutty said:
I just went through this situation. I'm willing to help and live in Etobicoke if you're interested.
Click to expand...

Thanks Smutty! But I think I just need to buy a new battery.

I had the battery on a tender over night, it only charged up to 12.7 volts. It should have gone above 13. I think the battery is toast. When I boost the battery through my car, it starts right away.
 
This will help you.....

have a read, and make a decision on what is actually going on or happening to your current battery

http://www.yuasabatteries.com/pdfs/TechManual_2014.pdf

if you have a voltmeter you can perform your own load test, as well as other test, read the article I posted above it will help you pinpoint the issue...

no sense in buy a new battery if it's not the cause of the issue, or there is anything wrong with it

do some testing......

.
 
Last edited:
I don't think he needs to test anything. He has said twice now that when he pulls the battery and puts it on the tender that it doesn't charge higher than 12.7v.

Either the battery is worn out or the tender is junk or both.

For comparison, my 2012 Yuasa battery on the Yuasa Smartshot 900 tender is maintained with 13.5v float pulses.
 
Sunspark said:
I don't think he needs to test anything. He has said twice now that when he pulls the battery and puts it on the tender that it doesn't charge higher than 12.7v.

Either the battery is worn out or the tender is junk or both.

For comparison, my 2012 Yuasa battery on the Yuasa Smartshot 900 tender is maintained with 13.5v float pulses.
Click to expand...

A 12V battery will never charge over 12.7v, ever. 13.5v is required to overcome the internal battery resistance to charge it.
 
Whats the average lifespan for a battery? Last year I bought a new to me 2007 Sportster - over the winter I had taken the battery out and charged for a day about every three weeks. But when I put it back in - it wouldn't keep a charge. It would drain overnight. I was kindof surprized but at the same time - it is possible the battery was 6/7 years old.
 
mxs said:
Older bikes and some not so old bikes, idle with barely 13V ... in that case yes you will have problem because the battery will be slowly getting depleted, but not until you start all kinds of things, like extra lights, heaters etc. and will keep idling without taking off. At some point, you will ride and the voltage will go up and your battery start charging, right? In that case your voltage should go over 14V and the battery will be getting re-charged. If you are not getting 14V min. you are having a problem in my opinion, unless it's by design, but that would be a bad design, no?
Click to expand...

This can be fixed !

How many volts per phase is your stator putting out?
 
sounds like its time for a new battery. mine sat for two weeks with no charge. and it started right up
 
Rebelrider1 said:
Whats the average lifespan for a battery? Last year I bought a new to me 2007 Sportster - over the winter I had taken the battery out and charged for a day about every three weeks. But when I put it back in - it wouldn't keep a charge. It would drain overnight. I was kindof surprized but at the same time - it is possible the battery was 6/7 years old.
Click to expand...

It's done. Sportsters come with AGM batteries which have a low self-discharge rate, but they don't last long. I use an automatic trickle charger on my Sportster over the winters and after 3 years it's having a hard time cranking the engine over. Getting a YUASA GYZ16HL for it next. Yours will take the same.
 
Sunspark said:
Why not a LiFePO4 chemistry battery?
Click to expand...

They don't like cold temps and they're double or more in price. Having to leave the headlight on for a minute or two just to warm up the battery to get enough cranking amps to start my bike sounds like a pita.
 
DJM said:
They don't like cold temps and they're double or more in price. Having to leave the headlight on for a minute or two just to warm up the battery to get enough cranking amps to start my bike sounds like a pita.
Click to expand...

It's really not PITA, but rather something you have to be aware only for the first cold start .... and it only happens when it's 5C or lower and will affect large V-Twins more than anything else ... most people will not even ride in that temperature ....

If you are looking to shave off weight from your bike, there's not much easier and better way to do it.
 
mxs said:
It's really not PITA, but rather something you have to be aware only for the first cold start .... and it only happens when it's 5C or lower and will affect large V-Twins more than anything else ... most people will not even ride in that temperature ....

If you are looking to shave off weight from your bike, there's not much easier and better way to do it.
Click to expand...

+1......but in honesty, the incentive to lose 5 or 6 pounds might only be attractive to SS riders.
 
I wouldn't agree with that, although yes SS riders are typically the group going to great length as far as lowering weight, there's many bikes which would benefit from that, depending where the battery is mounted.
 
Unless the battery is new I'd probably just replace it anyway. They're fairly affordable.
 
mxs said:
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.
Click to expand...

I think it's been established that some (if not most) motorcycles do not sufficiently charge a battery at idle with all the electrics running (headlight, taillight, running lights, etc.). If the battery is not charging while riding, then you have a problem.
 
Last edited:
You must log in or register to reply here.
Back
Top Bottom