FJRiders.com

Greetings, Steve (Fossil) here in Tn. New here and have a question. I have a '07 FJR that KILLS batteries. Any where I should start my search? A long-time Yamaha mechanic friend suggested the voltage regulator and said Yamaha had an issue with them basically across their range of vehicles a few years ago. Any additional info would be greatly appreciated.

Have you measured the voltage at idle and at elevated rpm?
Have you checked the stator output?
Are you using a battery tender? (not a trickle charger)
Are you sure it works properly? (more than one battery has been destroyed by a battery tender/trickle charger that overcharged the battery)
What accessories have you added and are they switched off with the ignition?
Have you inadvertently left the ignition on resulting in a dead battery? (AGM batteries don't like to be deep cycled)
If your battery is deeply discharged (by error) are you using a charger designed for automotive batteries? (One to two amp charge rate is best for MC batteries - some automotive chargers will charge at too high a rate)
Have you measured the parasitic draw? (Ignition off, ammeter in series between battery and cable)
How long before it kills a battery? (miles or months)
How much do you ride?
Are your batteries gradually losing capacity/performance or is there catastrophic overnight failure? Or have they failed while riding?
How many have you killed and what brand?

My FJRs have been kind to batteries. 165,000 miles and 11 years on the OEM on my 2007. Replaced it with another Yuasa due to reduced reserve capacity in the original, but it still worked. Sold the bike 20,000 miles later. Around 90,000 miles so far on my 2011 - still with the original battery. I never use a battery tender but do a top-up slow charge a couple of times during our long winter off-season. (early December to middle/late March)

Good luck!

fossilrider wrote: ↑Mon Oct 04, 2021 6:23 pmGreetings, Steve (Fossil) here in Tn. New here and have a question. I have a '07 FJR that KILLS batteries. Any where I should start my search? A long-time Yamaha mechanic friend suggested the voltage regulator and said Yamaha had an issue with them basically across their range of vehicles a few years ago. Any additional info would be greatly appreciated.

Steve,

That was good advice on the battery/charger aspects of this issue. A Battery Tender (or similar intelligent battery charger) is a good investment there, to prolong the life of a new battery. You want a gadget that has an automatic de-sulfating phase, when connected.

Do you have a multimeter? If not, with everything turned OFF, connect an instrument light bulb between one battery cable end and that battery terminal. If the bulb lights up or even glows (when the place is nicely dark), then you have a slow leak in the electrical system. If so, we can probably help. Beyond that, things can get more complicated.

With a multimeter, connect it to read Amps (or milli-Amps) between the battery terminal and the cable end. A reading near Zero would be a good number on the meter display, then. The bike draws a tiny amount of current when everything is OFF.

Any accessories that are not stock would be a likely place to find the problem.

Keep us posted.

FJR's and most other recent Yamahas don't have voltage regulator issues... your FJR has a Shindengen FH020AA mofset regulator..... if anything unplug the connectors, give a little spray (and blow dry) with contact cleaner, and plugging it back in will refresh the connections.

In addition to the above, I'd check parasitic draw also, but just how does it kill batteries in your case? .... if left more than a week or two in storage, you need to have it hooked up to a Battery Tender...... as Ross mentioned, AGM batteries do not like being deep cycled.... according to Yuasa, a battery is 50% discharged at 12.5V and will start to sulphate if you go below that very often.

I have 4 Battery Tenders, leave bikes plugged in all the time and haven't had a problem. What I also do is install a voltmeter on every bike I have so know the state of my battery and charging system at any time.