Battery problem?

[Johny_me]

Hello

A week ago i noticed that the Horn on my 750x started to sound strange. Dumb me, i thought it was caused by the rain that fell that week. 2 days ago the bike didn't start due to low battery.

Yesterday I took the battery out and charged it.after full charge and 1 hour, with a multimeter, i measured 12.72v... bike started ok and this morning the battery had 12.7, 12.68v. So i guess its good.

When idleing i measure 12.5ish V and if i increase the rpm to 3000/3500 i starts to go up, slowly. 30seg at Those Rpm and it reaches 12.8/ 13.0v... i guess it continues to rise but seems too slow, doesn't it? Shouldn't be higher when idleing?

Does this seems fine to you? What are your measures?

I bought the bike new, made 1 year this month. Has 22000km. I have h4 led headlight bulb, 2 10w led auxiliary Lights, frunk 12v socket and Garmin GPS charger, all connected to the acc harness. I use it daily to go to work, 25km.


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[HarveyM]

I think that's low. Honda says the battery should be 13 to 13.2 volts fully charged. If your battery is bad it's hard to check your bike's charging system but my feeling is running voltage should be above 13 volts at idle with a good battery. I'll try to get some measurements on my 750 today.

 

[lootzyan]

You should have 14-14.5 V +/- charging voltage from alternator almost all the time when engine is running.
Your charger/maintainer should be able to give about 13.8 V charging voltage.
Battery should be charged ones every 2-3 weeks for minimum 6-8 hours.

 

[Old Can Ride]

The more you ride, the longer the battery will last. If the bike sits, the battery will give you fits.

 

[casualmatt]

At idle my charging system puts out about 14V. Yours does seem low. My commute to work is 12 miles each way so once a week i put it on a charger overnight due to the fact that rides of that short distance might not recharge the battery to full after taking out the charge of starting the bike. Kind of like taking a sip of water from a glass every day but only putting back in a half a sip. Eventually you will run out of water in the glass.

 

[HarveyM]

I just checked mine. The battery was at 12.7 volts. At idle the voltage was 14.4 volts. This is on a 3 month old 750 DCT.
Good luck with yours!

 

[ste7ios]

Battery's condition affects the readings of the charging system. So we can talk only about the battery.

(That's why any test of the charging system need a fresh new battery and 5000 rpm [generator's max. output])

Your battery seems to able to keep about 70% of its named capacity. Not bad.

It's always a good idea to monitor the battery and the charging system to avoid any (bad) surprises...


Take a look at Yuasa's Technical Manual to have an idea about AGM batteries...

 

[ste7ios]

I think that's low. Honda says the battery should be 13 to 13.2 volts fully charged. If your battery is bad it's hard to check your bike's charging system but my feeling is running voltage should be above 13 volts at idle with a good battery. I'll try to get some measurements on my 750 today.

It's 13.0V for Yuasa, Varta & other (always refer to the manufacturers instructions), when they're new / fresh.

As the battery deteriorates this number will be lower, and lower... At 12.5V and lower you must consider to replace it because there is not enough juice to start he engine at a cold night...

With a healthy charging system we must always see a charging voltage > battery's voltage.

The ideal charging voltage for an AGM is 14.4V

 

[Johny_me]

Problem solved (i guess)
Today tried to look out what was going wrong. Took off the front sprocket cover and look at the cables and there was a cable with 3 yellow wires inside that was touching the Chain. Then i Isolate the wires, checked the voltage at idle and was higher than 14v

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[lootzyan]

...there was a cable with 3 yellow wires inside that was touching the Chain...

It's hard to imagine how this happened. Any wires are pretty far from chain.
And there supposed to be curved chain guard... Did you lose it?

View attachment 31662

 

[Johny_me]

Mine don't look like that...they were more loose

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[lootzyan]

But you knew where to look or... just a hunch?

 

[Johny_me]

Just a hunch... i took the cover out several times to clean, it was near the alternator... i thought it could be wire between the cover and the engine.

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[NCX19]

Dirty connectors at the battery will contribute to a non-start, yet lights/horn work.
How the battery is stored in the off season (needs a maintainer, or plates will sulphate). Same for inadequate use in season.
Some chargers have a recondition setting to try to repair minor sulphating.
Internal leakage can happen suddenly due to plate failure, lowering the capacity and terminal voltage.

Try a battery tester (load type) to see what its condition is.

 

[TacomaJD]

Dirty connectors at the battery will contribute to a non-start, yet lights/horn work.
How the battery is stored in the off season (needs a maintainer, or plates will sulphate). Same for inadequate use in season.
Some chargers have a recondition setting to try to repair minor sulphating.
Internal leakage can happen suddenly due to plate failure, lowering the capacity and terminal voltage.

Try a battery tester (load type) to see what its condition is.

Hello. Please look at dates on the thread you reply to. This thread is 3 years old, and others you've posted on recently have been several years old too. Welcome to the forum, look around at some of the more active threads, just check thread dates before replying.