Stop & Go kills my 85 Magna V45 battery.

[hondanewbie]

So recently I thought I had solved my battery charging issue. I was getting normal battery and charging system readings for two weeks! No issues. Then, my buddy wanted to get in some clutch practice on a bigger bike. He's experienced, but only on small bikes, so I was confident he wouldn't do any clutch damage. So after a 30 minute ride to his place, he got on, bike fired up just fine. After about 10 minutes of stop and go(literally, clutch out, 3 foot drive, stop) we turned off the bike. Went to start it up, and the battery sounded dead. It would try to turn over for a second, but then stop. So I gave the battery a full charge, and repeated the exact same scinario. Same results. Dead battery. Any thoughts on what might be happening here? Anywhere I can start the search?Thanks!!

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[Easy Rider]

and repeated the exact same scinario. Same results. Dead battery.

If it "hurts" when you do that, stop doing it. Seriously.
The system wasn't designed to be used like that.

But then, you should repeat the voltage measurements, be sure your idle speed is up high enough........and shop for a new battery.
Now that you have killed it twice, it might be down for the count........even if there is nothing else "wrong".

[Scrapdog2grand]

Check your 3 yellow wire stator connector as well, very common for them to burn up and cause inadequate charging.

[Easy Rider]

Check your 3 yellow wire stator connector as well, very common for them to burn up and cause inadequate charging.

Good thing for ALL Honda owners to do even if they don't notice any problems but if that is really bad, it will show up in the charging voltage tests.

[Drifter]

So recently I thought I had solved my battery charging issue. I was getting normal battery and charging system readings for two weeks!

Approx. 14 volts while running?

[hondanewbie]

Well the 3 yellow wire connection WAS the problem. It was gross. I cleaned it out, and the battery started charging normally. It was a bit low, it was charging at 13.85V. But it charged at that level consitantly, and the battery operated normally. But its just the stop and go!! And it was mentioned that it just wasn't designed for that, but what happens if you get stuck in a traffic jam, an you're forced to drive like that for an hour or more?

[slozomby]

lanesplit?

[Easy Rider]

But its just the stop and go!! And it was mentioned that it just wasn't designed for that, but what happens if you get stuck in a traffic jam, an you're forced to drive like that for an hour or more?

Maybe we need a little clarification here.
I thought you were describing a situation where the "student" was killing the engine repeatedly and needing to re-start it multiple times without actually going anywhere.
It was not designed to do that.

IF you are talking about running at idle or very low speeds for long periods, then testing the battery voltage at idle should tell that story.
Nominal battery voltage is 12.6; double check that for your battery after a full charge and sitting unused overnight.
THEN......if the voltage measured at EVERY practical engine speed (paying close attention to idle) never goes below 12.6......your charging system is OK and the battery is bad or some other connection is fuzzed up causing intermittant charging.

If the charging voltage is very close to your reference voltage at idle, then your idle speed probably needs to be turned up just a tad.
Some really OLD bikes just wouldn't charge at idle......but I don't think yours is one of them.

[Y2K]

lanesplit?

Here in WA this guy would give you an award for that lol.

[hondanewbie]

lanesplit?

What's that?

[hondanewbie]

Maybe we need a little clarification here.I thought you were describing a situation where the "student" was killing the engine repeatedly and needing to re-start it multiple times without actually going anywhere.It was not designed to do that.IF you are talking about running at idle or very low speeds for long periods, then testing the battery voltage at idle should tell that story.Nominal battery voltage is 12.6; double check that for your battery after a full charge and sitting unused overnight.THEN......if the voltage measured at EVERY practical engine speed (paying close attention to idle) never goes below 12.6......your charging system is OK and the battery is bad or some other connection is fuzzed up causing intermittant charging.If the charging voltage is very close to your reference voltage at idle, then your idle speed probably needs to be turned up just a tad.Some really OLD bikes just wouldn't charge at idle......but I don't think yours is one of them.

Yes, sorry, it was all done AT idle, we weren't turning the bike off and on. But I'll start with the full charge, let it sit over night. See what it reads. It's been raining for days with no end in sight, so timing couldn't be better!!

[Y2K]

What's that?

Riding between the cars inbetween lanes,not legal most places but it is in CA.

[hondanewbie]

SO! I thought I had it licked, went for a 2 hour ride. Half way point, stopped for coffee, bike almost didn't start, like it had a dead battery. Drove home, another hour or so, parked it. Turned it off, immediately tried to restart the bike, and the battery was dead.

SO! I tested the battery, still attached to the bike. It had a reading of 11.3V. I removed the battery, and put it on a slow charge over-night. Today, fresh off the charger, but not yet attached to the bike, the battery read 13.3V. I put it in the bike, started it, and I let it get up to temp.

At idle, it was hovering around 12.2 volts, dipping and raising a .2V here and there. As I revved the bike, I revved it up to around 5000rpm. I raised the rpm's slowly and the meter reached 13.77V when it hit 5000rpm's. They rpm's dropped back down to 1000, and the reading was 12.4V. I turned the bike off, and took a final reading of 12.2V with bike turned off.

Any thoughts??

[Easy Rider]

SO! I tested the battery, still attached to the bike. It had a reading of 11.3V. I removed the battery, and put it on a slow charge over-night. Today, fresh off the charger, but not yet attached to the bike, the battery read 13.3V. I put it in the bike, started it, and I let it get up to temp.

At idle, it was hovering around 12.2 volts, dipping and raising a .2V here and there.

I think a couple of things are happening here: An old, weak battery AND your idle speed is too low.......or you have added accessories drawing too much.

What have you done......checked connections at both ends of the main cables......checked connectors on th R/R.....????

You should get the battery load tested.
OR
Read carefully, details are important here:
Trickle charge overnight. Then let it sit unused for a few hours.
If the voltage at that point is less than 12.6 Volts, the battery is likely bad; ditto if it drops below 12.6 with just the ignition and lights on before starting.

You can't really do a good test on the charging system until you are absolutely sure the battery is good.
Sounds like yours is NOT.

If you get a new battery, it must be charged BEFORE using.

[Drifter]

http://www.electrosport.com/media/pd...ng-diagram.pdf


I am laying my money down on bad stator, but do the test and see what you come up with.