do I need a new battery?

[lele]

seems that after 4-5 days I do not run the bike, my yuasa voltage drop to 12.6/12.65 volts.I hear the starter crank it quite slowly...time for a new one? I don't want have surprises

 

[Bill Lumberg]

How old is the battery? I've had both mysterious and non-mysterious (like yours) problems disappear more than once by replacing the battery. Of course, I've had symptoms remain after replacing a battery too, but it was time for a new battery anyway.

 

[lele]

I bought the bike 5 years ago used with that battery installed on.And I don't know if it has been changed before.

Unfortunately on yuasa battery there is no manufacturing date printed

 

[Bill Lumberg]

Odds are that battery is ready for replacement. Any electrical anomaly on a bike with a 5+ year old battery and I'm replacing the battery. Smarter folks may go through more diagnostics.

 

[ERS]

My 2cents says if the old battery is 5 years old and you have issues with starting, then the first thing to do is replace the battery. If the new battery solves the starting issue then you are good, If the symptoms continue you now know the battery is not the cause.

 

[lele]

I have issue with starting only when the voltage drop a little after few days of inactivity. I read somewhere FJR ECU drain a small amount of energy when the bike is off..

 

[RossKean]

Not enough parasitic drain to significantly deplete a good battery in a few days. If the battery capacity is WAY down, it might be an issue. It is more likely that the self-discharge rate is higher than it should be coupled with reduced capacity/partial sulfation etc. Likely a good time for a new one.

 

[ionbeam]

Yes, there is a tiny current drain (parasitic loss) when the key is off, it is caused by little things like keeping the clock circuit live to retain the time.

If the bike is always started and run for at least a few minutes or more in warm weather or even longer in cold weather, if the voltage is always >13.2 volts when running, the battery is being sufficiently charged. If the battery fails to retain this charge either the battery is bad or there is something drawing a small amount of power when it should not be.

Edit: I see Ross already said this while I was typing. So, to this I will add: If a battery is let get to a low state of charge and then quickly recharged it will develop small dendrites, sort of like microscopic stalagmites which start to short the cells together and causes the battery to self-discharge. The charging system of the FJR will quick charge a slow cranking, low voltage battery which contributes to growing dendrites.

 

[mcatrophy]

As others have said, there is a small current draw by the bike. I measured my 2014 just for fun (linky, it was less than the minimum current my meter would measure, below 10uA (ten millionths of an amp). I would expect your 2001 to be higher than this, maybe even as much a 1mA (one thousandth of an amp). This wouldn't discharge your battery significantly over several weeks.

One test you could do is to disconnect the battery after it's been fully charged, leave it disconnected, measure its terminal voltage (say) every day. If it continues to drop noticably after the first day, it is self-discharging and needs replacement. If it maintains its terminal voltage, maybe there's something on the bike pulling too much parasitic current.

You could, of course, measure this current as I did.

 

[lele]

yes I think is self discarging..need to be replaced, money money money everyday!

 

[RaYzerman19]

A more significant indicator would be a load test on the battery, but I suspect at that age, a new battery is a worthy upgrade. While the bike is in storage, it only takes a few days to discharge to half charge (12.5V) and if this has happened a few times, the battery will start to deteriorate (sulphation). It is best to keep it on a maintenance charger like a Battery Tender.

 

[HotRodZilla]

At least 5 years on a motorcycle battery? Get a new one.

 

[lele]

yuasa or another brand?

 

[Mihalis fjr]

Oem GS from your Yamaha dealer is very very good!Seven years in mine and works great..

 

[redzgrider]

"Oem GS from your Yamaha dealer is very very good!"

Interesting observation. BikeBandit lists it at $130. That's not the worst battery value I've seen.

 

[kieefjr]

I've got 7yrs out of one of mine, always on a trickle charger when parked more than a few days.

Id give your weak battery a good charge then make sure a trickle charger is on it when parked.

My Dad had a battery that lasted 10yrs so proper care is the key.

.

 

[RossKean]

Oem GS from your Yamaha dealer is very very good!Seven years in mine and works great..

I don't think that the Yuasa battery you get from your North American dealer is the same as the one that comes OEM. That said, I think the Yuasa from the dealer is likely to be pretty good.

So far, I have 9+ years and 160,000 miles on the OEM one. Never been on a tender.

 

[lele]

now that battery is off from the bike since 10 days and still be on 12.72-12.70 volts. I'm too stupid to understand if must be replaced or not....just becouse I don't know the real drop of voltage of a good battery after few days

 

[Mudslide Miller]

Get a new battery and keep it on a trickle charge as Kieefjr suggested. My bikes live on a trickle when I'm not riding.