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Discussion Starter #1 (Edited)
Last week I had a stuck starter relay, killed the battery. Today I tapped the relay and got it to function properly again and gave the bike a jump.

It’s idles strong for a few minutes but after, starts hesitating and eventually dies completely.

Runs strong with 12v coming from jumper cables so I’m assuming it’s a stator issue.

Battery voltage rose by 1 or 2 volts each time I ran the bike (so there’s at least enough current generated to charge the battery) but not enough to run for more than a minute or so without 12v assist

Any thoughts about potential voltage regulator or coil issues that can disguise themselves as a stator issue?
 

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A dead battery will give you bad readings.
You most likely dont have enough battery power at idle to keep the motor running.

Charge the battery first, and if its 3 years old or more maybe a new one?

Cant find charging problem with a dead battery!
 

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Discussion Starter #3
A dead battery will give you bad readings.
You most likely dont have enough battery power at idle to keep the motor running.

Charge the battery first, and if its 3 years old or more maybe a new one?

Cant find charging problem with a dead battery!
Oh ok so you’re saying stator charges battery first before sending power to coils? That would make sense and might give me the symptoms I’m seeing too
 

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Oh ok so you’re saying stator charges battery first before sending power to coils? That would make sense and might give me the symptoms I’m seeing too
Not exactly... Here's a brief rundown in some simpler terms and ideas...

The stator doesn't decide which part gets how much power, it simply generates it. Much like a car's alternator, it doesn't generate it's full capacity at idle. The engine has to be turning faster to make the full output capacity of the stator. If you've ever had an alternator tested while it's on the car, there is a point in the test where you have to bring your engine speed up to a certain point (usually 2000 rpm). This makes sure the alternator is turning fast enough to give it's full capacity for an accurate test.

Electricity in itself can be thought of as being lazy. It takes the path of least resistance.

Also, a battery can develop what's known as a surface charge. This is where a good battery shows a good voltage until a sustained load is connected, then it quickly drains down and shows it's true depleted state. This is why a good battery tester (such as they have at auto parts stores) have a system built in that will put a load on the battery to check it's true condition.

So now you have a dead battery, which is acting like an electricity sponge soaking up as much as it can, and a stator not putting out it's full capacity (bike at idle), and there's simply not enough juice to run everything else (coils, lights, gauges, etc). That's why you're able to idle for a moment, then it dies. The reason it can idle for a moment is the surface charge.

If you've ever had to have a jump start in your car, and the person told you to go drive around for a while (20 mins, 30 mins, etc) the reason for that is when driving, your alternator is turning faster, and putting out more juice, so it gives time for your battery to charge.

Best bet: Charge the battery overnight on a trickle type charger (1.25 amp max). This would allow you to fully charge the battery and get accurate testing done.

One other possibility that might work for you (if you don't have a charger) is to hold the bike running at a higher rpm than idle. I'm not saying redline type rpm, but maybe 1/4 throttle.... You'll have to let it run for a while (30 mins or maybe longer), but it might help get you going again. That would simulate the driving around time I mentioned in the car scenario.
 

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Discussion Starter #5 (Edited)
I’m familiar with surface charges and experienced it when I first tried trickle charging. After 3 hours it read 4 vdc but dissipated after reinstalling.

I think a lost a couple cores or fried something when the relay shorted. Thankfully there was a load to turn so I’m hoping it didn’t do much more damage but I think replacing the battery is the first step here.




But here’s where I get confused: maybe my trickle charger isn’t compatible (10a 6v/12v variable) but after an attempt over overnight trickle it doesn’t “activate” when I clamp the terminals and plug the charger in

When I first jumped the bike with 0vdc reading from the battery... after a 4 minute run it read 1.6vdc. After the second jump it read 2.6vdc.

Maybe the stator is fine but I just need a new battery so its not stealing necessary current to run
 

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Does your charger auto sense the battery voltage? I ask because we have one charger at the shop that does, and we have to be careful with it when charging a very low battery.

When a battery is below 6v, it will automatically try to charge at the 6v setting, not 12v. If you are experiencing the same type of issue, your battery will not come to a full charge unless you find a way to make the charger sense something above 7v.

Before replacing the battery, try boosting your battery to above the 7v line. There are a few possible ways to do so:

1: Jump the bike again, and hold the rpm above idle for a while. High enough that the bike will stay running on it's own. If needed, you can leave the jumper cables connected to your booster battery for a bit to assist things.

2: Take the battery to an auto parts store. Most offer free battery charging, and have the trickle chargers to properly charge your battery at the 12v level. Not sure what's available in your area, but here in central FL, all the major chains have this (Autozone, Advance Auto Parts, Napa, O'Reillys, even Wal Mart if it has the tire and service center).

3: Hook jumper cables from your booster battery to your dead battery and try your trickle charger again. This might, or might not work, but costs nothing. Basically, it will possibly trick your trickle charger into seeing the higher voltage from your booster battery and activating, but allow the current to charge your dead battery first (remember the sponge effect I mentioned earlier?). This doesn't work all the time, but when I've tried it, I'd guess about 70% success rate. I most often use it for riding mower batteries, but the same principle applies...

One last request: Please fill in your profile, at least with your bike's info (year, model, etc). I had to go back and dig through posts to find what model bike you had...
 

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When I first jumped the bike with 0vdc reading from the battery... after a 4 minute run it read 1.6vdc. After the second jump it read 2.6vdc.
?????

Do NOT boost a battery that has a possible internal short.

Get the battery tested!
 

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?????

Do NOT boost a battery that has a possible internal short.

Get the battery tested!
Earlier in this thread, and in another thread posted by OP, it was brought up that the battery had drained due to a stuck starter solenoid. Otherwise, testing the battery would have been my very first suggestion :grin2:
 

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Discussion Starter #9
?????

Do NOT boost a battery that has a possible internal short.

Get the battery tested!
No indication the battery ever shorted. I think it’s just dead and my trickle charger is car-type 10a only so I’ll need to find another way of gettin it charged in the future.

Bought a new battery today and got her running. I’m hearing what I might call the “spaceship” noise so tomorrow before work I’m going to take a voltage and current reading from the line side of the ignition coils and see if I’m getting nominal voltage and current from the stator.

I’d rather avoid a stator replacement but I hear “rick’s” is the shit so I’ll slap one in there if need be and hope for a couple years of care free riding.
 

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Discussion Starter #11
1. The readings you gave indicate otherwise.
2. What do you mean by "ignition coils"?
3. You do not need to take current readings. Voltages will suffice.
If the battery is depleted and it slowly rises from 0-1.2v and then 1.2 to 2.8v after short runs with a jump start does that indicate a short? Sounds like it’s picking up charge. At any rate I’m going to bring it to my local shop soon and see if they can test it.

And I read that the stator should be putting out 54v? I’ll check that too
 

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Oh ok so you’re saying stator charges battery first before sending power to coils? That would make sense and might give me the symptoms I’m seeing too

Electricity in itself can be thought of as being lazy. It takes the path of least resistance.
I used to say the same thing but then someone pointed out that it is not quite correct.

Electricity takes all paths available to it, just that current through each path is inversely proportional to the resistance of that path.

Not intended to be a dig, just might be helpful in certain troubleshooting situations.
 

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If the battery is depleted and it slowly rises from 0-1.2v and then 1.2 to 2.8v after short runs with a jump start does that indicate a short? Sounds like it’s picking up charge. At any rate I’m going to bring it to my local shop soon and see if they can test it.

And I read that the stator should be putting out 54v? I’ll check that too
Personally, I'd just stick with having the battery tested first. After you have the battery sorted out and reinstalled, measure the charging voltage at the battery at idle and various higher RPMs. If there is a problem with the charging voltage at the battery then you may need to go upstream.
 

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Proportional to resistance means the path of least resistance.
ALL parts hooked up will get a percentage of the current.
Electricity will flow to all parts of the system, until it encounters a resistance and the least amount of resistance will get the most current.
That's why when a power wire is rubbed bare and it contacts the frame you get the most amount of current flow from the least amount of resistance, the bare wire, and blows the fuse. Nothing else will function because the current flows freely to the frame through the low resistance path and forcefully blows the fuse.
So if it can find a lower resistance path it will go that direction easiest and the most forceful.

Also a trickle charge WILL NOT change up a dead battery.
By itself it does not have enough power output (amperage) to get the battery up to a healthy state.
Neither does the charging system on the bike.
If your battery is that dead the stator and its friends can not charge the battery up fully.
And on a bike you want a fully charged battery.

Charge it fully off the bike and then proceed.
AND dont charge at anything other than 12 volts!
A 10 Amp charger is not a trickle charger. Anything under 2 Amps is a trickle charge.
To charge the battery you'll need a motorcycle charger that outputs about 4-6 amps.
A car charger is for bigger batteries and outputs as you said 10 amps. That much output is too much for a bike battery.
More info here -
https://www.batterystuff.com/kb/articles/battery-articles/battery-basics.html

And no don't measure current - Can be dangerous!
 

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Proportional to resistance means exactly what it says. Current in each path is proportional to the resistance of that path, not the path of least resistance.

It may seem like semantics to some but it is not. It is the fact of the matter and very important for certain troubleshooting
situations.

The attached example using LTSpice shows it clearly. 10V source with parallel resistances R1 - R5 in Ohms. Blue text shows the total current and the current in each branch.

For the techno heads this is modeled with infinite current available (meaning no value entered for series resistance of V1). Putting in a series resistance value would change the total and individual branch currents, but would not change the proportional relationship of currents through the branches.
 

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And, regarding battery charger, usually it is not so much being too small, eg. trickle charger, but these days more so that most are electronically-controlled and will not "kick in" if the battery voltage is too low. Of course, a trickle charger isn't necessarily the best tool for charging a completely dead battery especially if its a high capacity battery but most MC batteries aren't that large.

It's handy to have around an old school charger with a full manual mode for those occasions where the battery voltage may be below an automatic charger's threshold voltage where it wont even try to charge.
 

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If the battery is depleted and it slowly rises from 0-1.2v and then 1.2 to 2.8v after short runs with a jump start does that indicate a short? Sounds like it’s picking up charge. At any rate I’m going to bring it to my local shop soon and see if they can test it.

And I read that the stator should be putting out 54v? I’ll check that too
If a battery is good, only depleted, it takes only a short time to bring the "open circuit" voltage up to 12v. Now, under load, the battery voltage will drop because it does not have full capacity (dead).

I said POSSIBLY a short, did not say it was shorted. A battery test will show that up.
When one puts a heavy drain on a battery and kills it dead, it MAY suffer internal damage and that is the end right there. RV batteries are constructed differently inside to allow for the above conditions and not suffer. Not so, automotive style batteries.

If the battery has an internal short and it is boosted, you risk a battery explosion. Not a pretty sight.

You check charging voltage and if it falls low, then go ahead and check stator and reg/rect for faults (check both).

If you need help with that, post back.

As an add, a motorcycle charging system can charge a dead battery. If it cannot, there is something wrong.
 

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And I read that the stator should be putting out 54v? I’ll check that too
Keep in mind that the alternator output is AC, not DC. You'll be reading before the rectifier. Also, the spec is 54v or better at 3,000 rpm. You'll need a tach to measure that accurately.
 

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As suggested previously, just start by checking the battery charging voltage. If that's OK you are done.

If you start with stator voltage and that's OK, and odds are it is, you still have to check the battery charging voltage / regulator.
 
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