How to repair charging system?

The original 2-stroke Genuine scooter and its 4-stroke manual and automatic offspring

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djarcadian
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Location: Houston, TX

How to repair charging system?

Post by djarcadian »

I tested my battery with a meter and it looks like the charging system isn't working. I already installed a new battery several weeks ago and it's slowly run down and I have to jump it to get it started.

Are there any good guides or videos on how to repair a charging system? I'm hoping it's just a loose wire somewhere. Not too familiar with how the Stella works.

It's a 2013 Genuine Stella.
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tenders
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Post by tenders »

It’s probably more accurate to consider the scooter’s power generation capabilities the “operating power source� (rather than the “charging system�) and the battery’s capabilities the “starting source.� Once the engine starts, the headlight, ignition, and other electrical loads take at least 40 watts of power, and quite possibly more depending on the draw of the headlight. This is 3-5 amps and the scooter’s power source is intended to provide this; the battery only does this temporarily. If the scooter’s power system were not working, it is an amount the battery could not sustain all by itself for more than an hour or two.

The power system’s excess capacity to recharge the battery is relatively meager, only generating an amp or two above the running needs to replenish the battery over time from the substantial reserve used up by the starting demand. And it only generates this amount of juice at full throttle.

A truly broken power system will leave the battery with too little juice to start the engine, and once kick- or jump-started, will eventually cause the engine to stall due to a lack of power to the ignition. If the battery takes weeks to run down, it is possible the power system is working as designed, but just isn’t being applied long enough to replenish the battery. This is a very frequent occurrence and is why people use battery tenders.

How long is the scooter being run between starts?

And what are the numbers you’re seeing on the meter? A fully charged, but not charging, battery will be about 12.3V, maybe a bit higher. Then see if that voltage increases once the scooter is started and idling, and again once the scooter has been revved up a bit (on the stand). If you see materially higher voltages after starting, 13V or a bit more, that’s a pretty good indication the power system is working. But if the battery is dead and being charged, the jump might be less. If the jumps is zero, yes, the power system is borked.
djarcadian
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Post by djarcadian »

My system shows just a little less than 13V when it's running. Maybe 12.7 or in that neighborhood (I'm not in front of it right now) but revving to full throttle only bumps it up to about 13V so very little variation.

I run it about once a weekend but I'll admit that on some weeks I only start it and let it run in neutral to keep it in good operating condition and don't even take it out. Otherwise I rarely get full throttle anyway. The battery did last a couple of months before I started having issues and had to jump it.

If I use a tender I'll probably just have to buy a spare battery and swap them out periodically. Unfortunately there's no outlet to log into where I store it.

Thanks for the advice.
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Stanza
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Post by Stanza »

You might be dealing with a voltage regulator problem, or possibly even the charging/lighting circuit from the stator. What voltage (AC) are you getting off the yellow lead from the stator? You can either measure that from the stator leads (on this bike they're to the rear, towards the back of the bike of the HT coil), or at the regulator itself.

On this bike, the lighting circuit is shared with the battery charge circuit, so if someone had installed the wrong bulb, with too high a wattage rating, you might be trying to charge a battery while also trying to drive too hungry a light bulb. Given that it's constantly a low voltage/amperage problem, you can rule out the turn signals, and focus on the headlight and tail light.
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tenders
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Post by tenders »

Seems there is a simpler explanation than a lot of failed internal parts: if you’re barely running the scooter, the battery is simply going to wither.

Charging while idling is barely doing anything. Is a small solar panel with a removable Battery Tender-style connection a possibility? These are available for under $50.

You might consider putting a switch onto the headlight so that giant power draw is turned off unless you need it. It may not be legal to drive on two wheels without an illuminated headlight.
2003stellaDave
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Post by 2003stellaDave »

Do you have a photo of the regulator that you can post here? It would help to see it.

Do you know for sure that it is the stock regulator?
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