Bad Battery or alternator?

[amamet]

The other day I Randomly went and checked the voltage on my wife's '79 G5.   At idle it was 11.8 and @ 12.7ish with some throttle. Thought that was a little weird as I hadn't had any battery issues previously. Put it on the battery tender and didn't think about it...until this afternoon when my wife called and said the bike died on the side of the highway in jersey.   Battery is a few years old odyssey forgot what number but it's huge. (I'm away from home right now). What should I look at first?  I figured since it was charging, a little anyway, that the alternator was fine. Maybe the battery can't hold a charge anymore?  My last battery, think it was either an odyssey or a westco. Died after a year, couldnt maintain a charge. I have A gel battery in my ducati 750gt that's been fine for years. Again, what should I look at and test first
Thx
Allen

[fotoguzzi]

  What should I look at first? 
Thx
Allen

your battery tender, I never use them..especially on an oddesey.

[guzzisteve]

If you have the big 925 it should be good for at least 7- 8yrs.       It is big enough to put a car charger on it.

[amamet]

I believe it is the 925.  I only used the tender once i saw that it was under 12 volts and only got to 12.7 or 8 with some gas, @3k rpm
What does the tender have to do with the battery running out of juice while being ridden?

[pehayes]

12.7 is pretty weak for a fast throttle output.  I'd say you have a failing charge system and just ran the battery out.  Odyssey and Westco are AGM batteries and should be good for many years.  However, when they do fail it is usually a very sudden, binary failure.  It could be either, but my bet is on the old charging system of the bike.

Patrick Hayes
Fremont CA

[pete mcgee]

First off get the battery load tested, odessey or not they can still "die" young.
If its the battery, fit a new one and see what the charge vs rev volts are then, still not good?
Start with the simple and cheap stuff, clean the main earth lead at both ends, still fitted to the battery tray and frame? Move it rear wards to one of the battery tray bolts on the gearbox.
Rectifier, the main red lead on the front of the unit fits onto a spade connection pointing up so it can catch dirt/mank/roadsalt and water, remove the connector and clean the spade.
Regulator, is it still the original? Replace it with new electronic type, bear in mind that AGM batteries require a higher charge voltage than the old lead acid somewhere around 14.2 V.
Condition of the main leads is worth looking at, new is better if they are the originals.
Alternator, how are the brushes? I recently had a brush with a broken wire and had very similar voltages to what you have, really noticable with lights and heated handgrips on.
Spade connectors and wires comming off the alternator, dirty/heat discoloured?
Follow the 3wire loom back to the rectifier and clean those connectors as well.
Does the alt light still work?, if it doesnt replace the bulb.
Cheers

[HDGoose]

One cannot check an alternator or charging circuit with out a good battery.

[canuguzzi]

A battery tender will not ruin or otherwise damage a good battery, that includes an Oddessy battery. If anyone has proof that a battery tender will damage a good battery, let's dispel with all the myths that get it out in the open.

Here is yet another battery that having gone bad, was charged did exactly what damaged batteries do, leave someone stranded. The battery was toast, checking its voltage showed that.

Once a 12 volt battery is discharged to below 12 volts it has been damaged. There are all kinds of stories about recovering dead batteries and using them for 50 years but sorry to say, its just luck it still works properly.

It doesn't matter what you do, a discharged battery has been damaged, that is a fact. How long it will provide service varies but it is no longer reliable unless you consider charging it over and over again each time it leaves you stranded as being reliable.

A battery tender was not and is not the problem unless it was faulty. Trying to use a battery tender to charge a dead battery (11.8volts is a dead battery) will not recover it. No charger will recover it. Get a new one. You might have another problem that chased the battery to become discharged in the first place, you can fix that but not the bad battery.

A load tested battery that tests good can fail 30 minutes later. Load testing is often done to avoid replacing a battery under warranty. Ask the many many people who having a battery load tested got stranded. You test the charging system, not the battery. If the battery checks out at low voltage while resting, it is toast.

[nunzio]

First off get the battery load tested, odessey or not they can still "die" young.
If its the battery, fit a new one and see what the charge vs rev volts are then, still not good?
Start with the simple and cheap stuff, clean the main earth lead at both ends, still fitted to the battery tray and frame? Move it rear wards to one of the battery tray bolts on the gearbox.
Rectifier, the main red lead on the front of the unit fits onto a spade connection pointing up so it can catch dirt/mank/roadsalt and water, remove the connector and clean the spade.
Regulator, is it still the original? Replace it with new electronic type, bear in mind that AGM batteries require a higher charge voltage than the old lead acid somewhere around 14.2 V.
Condition of the main leads is worth looking at, new is better if they are the originals.
Alternator, how are the brushes? I recently had a brush with a broken wire and had very similar voltages to what you have, really noticable with lights and heated handgrips on.
Spade connectors and wires comming off the alternator, dirty/heat discoloured?
Follow the 3wire loom back to the rectifier and clean those connectors as well.
Does the alt light still work?, if it doesnt replace the bulb.
Cheers

+1

[normzone]

[amamet], I recently had battery issues. Mine were self induced though.

Check the last post on this thread -

http://wildguzzi.com/forum/index.php?topic=78373.60

Long story short, start with a known good battery (new if you must) and maybe you can save some troubleshooting time. Not that I wholly regret mine, I know more about the bike now, but the money I spent on tolls and car gas could have been saved.

[nunzio]

They make a small voltage indicator that  you can keep plugged into you battery tender cable.
I have them on all my bikes.


http://www.amazon.com/Battery-Tender-081-0157-Disconnect-Voltage/dp/B00DJ5KE9A

[HDGoose]

A battery tender will not ruin or otherwise damage a good battery, that includes an Oddessy battery. If anyone has proof that a battery tender will damage a good battery, let's dispel with all the myths that get it out in the open.

Here is yet another battery that having gone bad, was charged did exactly what damaged batteries do, leave someone stranded. The battery was toast, checking its voltage showed that.

Once a 12 volt battery is discharged to below 12 volts it has been damaged. There are all kinds of stories about recovering dead batteries and using them for 50 years but sorry to say, its just luck it still works properly.

It doesn't matter what you do, a discharged battery has been damaged, that is a fact. How long it will provide service varies but it is no longer reliable unless you consider charging it over and over again each time it leaves you stranded as being reliable.

A battery tender was not and is not the problem unless it was faulty. Trying to use a battery tender to charge a dead battery (11.8volts is a dead battery) will not recover it. No charger will recover it. Get a new one. You might have another problem that chased the battery to become discharged in the first place, you can fix that but not the bad battery.

A load tested battery that tests good can fail 30 minutes later. Load testing is often done to avoid replacing a battery under warranty. Ask the many many people who having a battery load tested got stranded. You test the charging system, not the battery. If the battery checks out at low voltage while resting, it is toast.

A true AGM battery can sometimes become useful again when hit with a 50 amp charger.

[canuguzzi]

A true AGM battery can sometimes become useful again when hit with a 50 amp charger.

Depends on how you define useful. There are no quasi AGM batteries, they either or are not. I'm not trying to be testy (an affliction since both) but the only thing that competes with oil threads are battery threads.

While it is true that a damaged battery can sometimes be recharged and you can gain some use from it, it is no longer reliable and can and often does leave people stranded.

Think of it this way, using a battery that has discharged to very low levels is like having an empty fuel tank. You can add a charge and some gas but without knowing how much gas you put in or how much charge is actually held by the battery, sooner or later you run out of gas or the battery fails you. Stranded in either case.

The lengths people will go to avoid getting a fresh battery is puzzling. Oil? Fork over the money. Filter? Only the best. Battery? Ah, throw a charge in it and go for it.

A poorly performing battery affects the entire electrical system and by itself can lead to other problem. A good battery like good oil is essential for reliability.

If you follow proper maintenance and use methods like any other component, it will give you good service apart from the outright failures that can be rectified.

How many of us would reuse a cartridge oil filter knowing that it could filter acceptably for several thousand bikes more than the recommended change interval? We wouldn't dare. When a battery is nearly discharged it suffers damage and the right solution is to change it or risk unreliability.