Old battery tender, weak charging system, or inferior battery?

[harper]

If you think I am soliciting your opinion on whether I should use a battery tender of any kind or under any condition or if you think I am seeking your advice on what kind of battery I should have or when I should replace it, you have misread the thread title and should just hit the back button on your browser.

I have a Deltran Junior battery tender that I have used on 3 different batteries over a period of 10 years. I have a Japanese Yuasa that came with my 2006 that may be original and may be up to 17 years old on my bench that I had not charged for about a year. I have a Taiwanese Yuasa that came with my 2008 that may be as little as 3 years old and as much as 14 years old, also on my bench, that I had not charged for about a month. I currently have installed in my 2008 a Taiwanese Yuasa that is a month old.

Three days ago I went on a short errand riding in town for about an hour and never exceeded 3000 rpm for any significant amount of time. When I returned, I turned the bike off briefly and then restarted it to jockey it into position. It restarted instantly and after I turned it off a second time the panel meter read 13.2 V.

I attached the Deltran and the LED remained red for 9 hours that I know of. After 15 hours it was flashing green for an additional 3 hours that I know of when it finally switched to solid green. This is a long charge time.

I took the Japanese Yuasa off the bench and attached it to the Deltran. The LED went from solid red to flashing green in 15 minutes and from flashing green to solid green in another 15 minutes. Kind of what I would expect. I then took the Taiwanese Yuasa off the bench and attached it to the Deltran. It went from solid red to flashing green in about an hour and from flashing green to solid green in about an hour. Kind of long.

I plugged the pigtail on the Taiwanese Yuasa on the bike back into the Deltran and it went to flashing green within a minute like I would expect. Then it went to solid green within 20 minutes. A bit longer that I expected.

Was it the battery in the bike, the charging system in the bike, or an old, worn out Deltran? Is it that the Taiwanese Yuasas are really that inferior?

 

[roger dodger]

FJRs like a nice strong battery. Get a new battery (your choice of brand and material) and you will be golden!

 

[RossKean]

Interesting. My OEM Yuasa (13 years and 100,000 miles) still starts the (2011) bike OK, but it "acts" like it is maybe a 2 amp-hr battery instead of a 12 amp-hr. Still provides sufficient voltage but reserve capacity is very low. If I leave the ignition on too long (i.e. washing the bike and keeping the windshield raised), it sometimes doesn't have enough energy to start. When that happens, I can plug in a tender (NOCO Genius, 1 amp) and it might only take an hour (or less) to solid green and a good start. This is a function of a geriatric battery with low capacity, not the maintainer/charger. (Battery is clearly toast and will be changed out this year.) It might be that your Japanese Yuasa has the same issue that mine does - maintainer detects "full" voltage and goes to green quickly, but this means very little unless you know something about the available amp-hour capacity. The original Yuasa in my '07 behaved similarly - adequate voltage when fully charged but very little reserve capacity (I got 10 years and 160,000 miles out of it).

The only way you can tell for sure if the tender is working properly is to monitor voltage (and ideally current) as it is charging. If the battery is in doubt, it is worth getting a load test (fully charged battery) to see if it maintains voltage under load. Sometimes there are problems right out of the box. Might be worth doing another load test after sitting a week to see if the self-discharge rate is excessive.

I assume the new Taiwanese Yuasa was fully charged before your short errand? I have found that the initial charge of a newly activated AGM takes longer than expected. I have even taken it off the (slow) charger when light want to green and found it still took more the next day. Not so much after the battery was in use for a while.

Of course, the other thing to check is the bike's charging system. What voltage do you measure at the battery terminals:
1) Ignition off for at least an hour after it was last run?
2) At idle (1100 rpm)?
3) At 4,000 rpm?

If 2 and 3 are low, you will need to investigate connections, R/R or stator.

FWIW, I have bought two Yuasa batteries (not made in Japan). One was installed in my 2007 for a couple of years and 30,000 miles before I sold the bike and had no issues in that time. The other was installed in my BMW F700GS early last season and it has been fine so far. Anecdotal information, but at least no issues with either in the time I had them. The only thing I know for sure is that both OEM Yuasa batteries I have had have been truly exceptional. I guess I wouldn't be unhappy if the replacements lasted half as long.

Do the tests (Deltran output and bike voltage) and keep an eye on it. Might want to do at least one load test if there is a shop around who can do it. Probably a good idea to document everything in case of a need to make a warranty claim.

 

[harper]

Maybe this was some kind of fluke. Today I measured the battery voltage with a DVM directly to be 13.3V. The panel meter indicated 12.8V. I started it 4 times in rapid succession and watched both meters dip below 11V. On the 4th try I had to start WOT so I let it burn fuel for a while and watched the two meters. The panel meter was about 0.5V lower than the DVM connected to the battery. The DVM read 13.2V at 1100rpm and around 13.6V at 2000rpm and 13.9-14.0V at 4000rpm. I plugged the Deltran back in and it went from solid red to blinking green within 15 minutes and to solid green within 10 minutes of that.

 

[RossKean]

Maybe the new battery will settle in after a little while. Doesn't sound too bad now.
Looks like your panel meter is off. If they compare well directly connected to the same source the difference may be due to losses at various connections/switches.

Your voltage at the battery appears to be a BIT low, but probably enough to keep things charged, at least at highway RPM if you aren't running a bunch of extra stuff (lights, heated gear etc.). @dcarver started a VERY long thread about lower-than-ideal charging voltage on his '06. He chased a bunch of stuff.
https://www.fjrforum.com/threads/krzy8-gen2-charging-circuit.146331/
His eventual solution was to install a direct harness direct between the R/R and the battery - available from:
roadetercycle.com
(Website is a bit ugly) These guys are good and very helpful if you have questions about motorcycle electrics.
Perhaps Don will chime in here...

Consider it if you are finding your system isn't keeping your battery fully charged while riding. I wouldn't do anything unless it is getting worse over time. The clue will be plugging in your tender an hour or two after shutting the bike down after a ride. If it goes to green immediately (or in short order), you are OK. If it takes an hour or more, it would seem that voltage at the battery is insufficient.

 

[harper]

It was a fluke. I rode today on an errand 60 minutes each direction. I had the heated grips on full. The panel meter is clearly wired after the ignition switch and apparently it's behind the heated grips as well because turning on the grips drops the panel meter by 0.8V. When I returned I plugged it into the Deltran which went from red to flashing green within 10 minutes and flashing green to solid green within 5 minutes.

 

[dcarver]

Recently the 06 charging voltage was fading. Installed a new connector at RR and voila, 14.3 solid even with full load minus heated jacket.

 

[RossKean]

Recently the 06 charging voltage was fading. Installed a new connector at RR and voila, 14.3 solid even with full load minus heated jacket.

IIRC, you installed the Roadstercycle harness on that bike when you had low voltage before? So you just replaced the connector this time?