Battery running flat, again

[Sephiroth]

Hey, well I posted a thread before and it was advised to get a new regulator/rectifier, so I did.

No luck, still runs the battery flat.

I charged the battery full, checked the voltage when off and it was 13.5V. Is that right?

I started it up, took it a mile and then turned it off, checked voltage and it was 12.8V.

What could be wrong?

[Finglonga]

Sounds like the Altanators is not charging, how many volts when the engine is at tickover and at 4k rpm?
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Andy Sez....
F.Y.Y.F.F.

[finpos]

Certainly, check that the voltage at the battery at idle/fast idle is above the voltage at the battery with the engine off, that will give you confidence the charging circuit is now working ok.

If it is working, you may have neen unfortunate in that your old rectifier may have buggered up your battery.

But, to be honest, 12.8V sounds about right. the 13.5V figure seems a little hight and might be because it had just come off a long charge.

finpos.

[critical_technique]

just buy a new one init and charge it 4-6 hours beofre putting it in

[Sephiroth]

idles at 12.6v at 4k revvs.

Checked the voltage after a quick spin, 12.4v when switched off

[APNess]

Sounds like mine before I bought a new battery. Put on trickle charger, showed full charge, stopped to fill up for a fuel about 4 miles from home, click click click, battery not enough charge to start engine!

When hooked up to the trickle charger it would show green (ready to use) when I blipped the throttle, and dip down to orange (needs charging between 6 and 12 volts) so I knew the alternator was working and battery just leaking charge away (despite the seller having claimed the battery was new - yeah... right...)

£55 for a new one on mine (a yuasa, figured I'd go for best) but it's been spot on ever since. Left it non charging for a week, alarm on, and it cracked up first time, so problem solved for me with new battery.

Good luck!

[Sephiroth]

I put the old battery on, charged it first though.

Seemed to pull away a bit smoother, but maybe that's just my subconscious (although my girlfriend did mention it when she was on the back).

When I revv the engine the lights go dimmer.

[KatOwner]

12.6V at 4K revs sounds low...

Your battery is nominally 12V, but on open circuit, with no load, a reading of around 13V is not unusual after a fresh charge. When you rev it, though, you should see the voltage rise. When spinning at optimum revolutions, an alternator should be chucking out 14V+

Leave the meter connected and check that the voltage increase with increased revs. If it doesn't, then you have a fault with your charging system and a new battery would be a waste of cash.... it'll just die like the current one.

If the charging system DOES check out, then a new battery would be called for. Once a battery goes ( my last one only went 3 years ) they will charge ok, but won't hold a charge worth a damn.

Bring back the kickstart!

[Sephiroth]

lol I know there's something wrong with the charging system, but what that is, is what I'm trying to find out .

Thanks for the reply though.

And no, the voltage doesn't increase when the revvs increase, the opposite happens.

[KatOwner]

OK

So you got a new regulator/rectifier.... and the thing is STILL not charging....

If all the wiring in between is OK, and that there is no corrosion on the connections then the next thing to replace would be the battery. A dead battery will soak up the volts. If you can...borrow a battery to test this out ...saves money!

Re-check the voltage outputs with a known good battery, and if it STILL won't chuck out around 14V as the revs rise, then you are potentially looking at a new alternator.... and a nasty bill

[suzi_bandit]

Any idea how old the battery is?
My bike began sounding very sluggish when I was starting it. Actually had to jump start it a couple of times because the battery just died when I was unable to fire it up on the first attempt. Tested it and although it was charging up while the bike was running it was slowly loosing it's charge when the engine was turned off.
Had it replaced and was told it was about time. I hadn't actually noticed but the old battery was dated (bloody years ago ) and the new one is also dated as it is guaranteed for 2 years.
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I want a big boys bike, preferably a Speed Triple. To date I have ?7:42p stashed away to put towards one. Need to get it in the bank & earning interest asap.

[MattEMulsion]

Your bike when running should be charging the battery somewhere around 13.5v - 13.8v If it isn't then you have an alternator fault. Don't waste your time buying a new battery, if you can charge it okay and it holds its charge then it is functioning properly. The only reason your battery goes flat is because your bike is using its power and not recharging it cos your alternator is most likely knackered.
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Yamaha YZF-R6

[Sephiroth]

Yep, new battery, and old battery which has nothing wrong with it .

Thanks, all I wanted to know was whether it was the alternator or not

What would cause the alternator to go bad...?

[KatOwner]

Never had an alterntor just fail on me personally. Had one destroyd by a very inept garage using a puller to remove the fly-wheel on an old X7 Suzuki.... they used overly long bolts and put a bolt through the windings.....

I have also heard of them going as a result of overheating. Infrequent oil changes can let things get a little warm, breaking down the insulation and shorting out the coils. The wire wound round the alternator windings has to be laquered so it doesn't short itself. If the insulation breaks down, you lose a section of the primary windings, and that effectively shorts out a chunk of alternator. Can be past neglect....can be faulty manufacture....or can be just plain bad luck!

I happen to own a bike now with a reputation for eating it's own alternator..... so it's something I worry about a lot!

[Sephiroth]

Ah right, just found a new generator winding for 70 quid

[finpos]

It's easy to check the altenator windings are within spec with a multimeter. Have you got one?

You'll need to measure the resistance of each coil (look for the similar/identical wires coming from the altenator to the rectifier - usually 3 of them) with respect to each other and with respect to earth. There will be figures to compare against in the manual, but in general you should be looking for a the same value between coils and always infinite resistance to earth.

finpos.

[Sephiroth]

Right, theres two wires coming from the left hand engine casing, could that be them?

I have a multimeter.

What do I do? I'm not very bright as you can tell

[finpos]

Only two wires from altenator means one of two things:

1. Wrong wires!
2. Definintely need the manual to describe how to test it.

Can you tell me how many wires there are connected to your regulator, and what colour they all are?



finpos.

[Sephiroth]

Just so happens I have the old regulator infront of me

There are 5 wires, three yellow, which connect to one female connector and a black and white with a red which connect to another.

[finpos]

Right, it's the 3 yellow wires you care about.



set meter to read ohms (Omega Symbol), a low range eg 5Ohms.
Wave leads around in the air - the meter should say something like "OL"
Touch the leads together, the meter should say something very close to zero.


Disconnect the altenator from the regulator. Measure the following on the 3 yellow wires (Y1, Y2, Y3):

Y1 to Y2
Y1 to Y3
Y2 to Y3

all should read very similar, and should be somewhere between 0.5 and 2.5 ohms. Your manual will give you the proper value.

Y1 to EARTH
Y2 to EARTH
Y3 to EARTH

all should read "OL"

If that all checks out, the stator is probably ok.

Now your remaining two wires:

One is the wire that actually charges the battery.
The other, I THINK is a thing called a "sense" wire, which provides feedback for the regulator. So if it's not connected up properly, it may be supressing it's output. Can you find where the other ends of these two wires are going??

edit - RED is the charge wire. Test the regulator output at the regulator, not the battery,
black/white is sense??. Find out where it goes.

finpos.

[Sephiroth]

The red and black wires go into this long thick cable (where the rest of the wires are contained.

The other end of the Yellow wires go into the right hand engine casing, I haven't opened it up to check but I might be able to look at some diagrams in the manual, I'll post them up now.

When you said Y1 to earth, etc... where's the earth?

[Sephiroth]

Just realised those diagrams probably wont help at all.

I'll go try out what you said.

If it'll help you I can get pics of where the cables go and whatnot if you'd like?

Cheers

[ram_doom]

Sounds like stator coils, they often die shortly after the rectifier if thats not sorted quickly
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TL1000s, KDX200

[Sephiroth]

What do they do?

[finpos]

Altenator = Magnets + Movement + Coils. The Engine is going round, magnets don't fail (well, they do but it's normally spectacular), so if an altenator fails you can usually tell by measuring the coils. That's what the instructions above should allow you to do.

For the yellow wires, just pull off the connector block from the rectifier and measure directly from there. No need to do any more. The stator coils are on the ends of those three yellow wires.

Still need to know where the other end of the black/white wire goes, though!

Earth = battery -ve terminal.

finpos.