I have a 2006 f41 that has needed a new battery every year for some reason. The factory original battery went dead after the first year after being stored on the bike for the winter. I replaced that with a new battery from the dealer and bought a battery tender for the winter. But that battery went bad over winter so I bought a battery from "batteries plus". That one lasted the summer and I took it out of the bike and put it on a wooden shelf for the winter. So I put it back in the back last week and it wont hold a charge. I just replaced it with another battery.

Here are some basics

No "on key" drain. If I charge the battery and let it sit a week the bike will start right up. But if i ride for an hour the battery will drain and the bike will not start.

I get 12 volts consistently not running, turning the key the voltage will drop slowly.

With then bike is running i get 14 volts and even revving up to 7000 rpm it stays at 14 volts. So my thoughts are that the charging system is good


Ideas?

 

My advice for winter storage is to bring the battery inside unless you have a house-connected garage or a garage that is heat sealed and warm throughout the winter. I have know people who've had the same problems with batteries. They die in the winter if kept in the cold for the winter (even if on the tender). At least up here in the Northeast where our winter is usually 5+ months (in terms of cold air).

I bring my battery into my house because I don't have a heated garage. I usually don't put my battery on the tender until about 3 months prior to being used or if I put the battery on the tender at time I take it off, I'll charge it for a few weeks, then off, then on again, etc.

As for the issues with with a new battery and being drained after riding, my intuition leads me to believe the issue is (was) that battery or something electrical with your bike. The charging system may be fine putting out 14v when the bike is on and revving, but I believe that the charging system on our bikes don't kick in to keep the battery charged/maintained until the bike hits 4K+ RPM's while riding.

I would get your charging system checked as soon as you can so you wont get stranded on a long ride or while being far from your home.

 

I thought about rigging up a multi-meter and taking the bike for a ride so I could see the voltage while riding. I have had the battery die while I was away, but the bike compression started easy and it had no problems running. I do notice that it will not run if the battery is disconnected. Even if it is a bad battery. For that test, I started the bike then disconnected the battery. I wanted to test voltage draw at the terminals without a bad battery in line... but the bike only ran for a few seconds and killed. So it is either a bad charging system, or there is a design in the electrical system that requires the battery to be in-line. Since I went from 12 volts not running, to 14 volts while running, I assumed it was electrical design.

Well, I guess my next step will be the ride test with a multi-meter inline for the ride.

 

Sealed batteries? My EX500 battery used to run low on fluid all the time and I'd have to refill it with distilled water every 3 months or so. Sounds like your alternator is working fine if it's jumping to 14 while running. If it was a car, I'd say parasitic drain from lights or aftermarket radios, but on a bike, I couldn't imagine what else it would be.

Do you have a Cycle Gear nearby? Little expensive, but I just bought a battery with a "lifetime" warranty for $130. Dude told me if I have any problems with it, I can take it to any Cycle Gear and get it replaced. Might be worth the investment if you're going through a new battery every year.

 

It's a sealed battery so no luck there. There is a cycle gear in my area. If I have to replace it next year I will check into their deal. It would be worth the extra $ if it was a lifetime warranty.

 

Are you running any electrical upgrades like headlight upgrades or something that would use more electrical power than usual?

Take my example of why I think it could be your electrical system (if definitely not the battery).

I've had my bike for 2.5 + years. The battery that was installed was a Yuasa OEM battery. My battery has drained/recharged over 15 times since I've had it, but only when the battery is either off the bike for winter storage or when I go longer than about 10 days without riding during the warm months. Usually, to get my battery going again, I charge it up with the battery tender, ride it and its fine, until I let it sit without riding or if it is winter time.

If I ride my bike consistently (like every day or every other day or a couple times a week or anything more frequently than once in two weeks) I don't have to recharge my battery with the tender. The battery will last and start my bike just fine.

Based on the service manual, the battery has to stay connected for the bike to keep running, so I believe that test you did failed due to the way our bike is designed. I know cars can run without being connected to the battery after started.

The manual states to measure the battery voltage without being connected. Then, measure the charging voltage at 5K+ RPM. If this formula is what you test: Battery voltages < charging voltage (RPM at 5K+) < 15.5V, then the charging system is working (for this test). The other things to test would be the alternator charging coil and/or the regulator/rectifier.

This is from chapter 16 of the service manual.

No need to do the voltmeter ride test.

 

Thnaks for the info

I do not have any electrical upgrades. The bike is in factory condition minus a repair job due the bike being high sided. I had the dealer do the repairs and they put it back to factory condition. (supposedly) I was thinking they may have missed something... I do not have a service manual, but the 15volts seems a little high. I am getting a stron 14 volts while running and at high rpm. I revved it to 7 or 8k rpm and the voltage stayed at a consistant 14+ volts.

 

Click on "Service Manual" in the second from the bottom line. You can download the 2001-2003 service manual there. Mostly everything is about the same except for a change in fairings and other minor details, so I believe this can help you.

I have a 2004 F4i and have used this manual for everything that I needed to and haven't had a problem. Hopefully you will figure the problem out as I know how time consuming and mind boggling this can be.

 

Take the bikee out for a long ride, get it real warmed up then check the battery voltage with the lights on, if its not still holding 14+ volts the reg/rec is failing when it gets hot.

 

Thanks all. I did a ride test with the voltmeter in line and watched it the whole time. At idle is was about 12.25-12.5. At speed. Or 3000+ rpm I got up to 14 volts. Mostly high 13. I watched it as I put on blinkers and lights etc. No change to the readings.

When I got back I re did the idle test and it was the same. Up to 14 volts with revving. I did notice upon restart the battery took a hit and went down to 10 volts. That seems excessive. Perhaps my starter is over drawing or these are just crap batteries. But if that were the case I would imagine more people would have problems.