KymcoForum.com
General => Technical | How To => Topic started by: mousejunks on May 09, 2017, 10:31:07 AM
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For a year, the red battery warning light would appear soon after riding at night with the headlights on. After several tests with a multimeter, this warning light only appeared when the battery voltage dropped below 12.0V volts. The battery was never more than 12.3 volts after riding it for an hour at night. This meant two things - the battery was dying or the charging system was faulty, so I investigated it.
I replaced my existing battery with a new Yuasa 12V, 8Ah, 135CCA battery. It was charged overnight before installation. After a few more night rides the warning light still came on. A quick battery test showed it had only 15% charge after riding for an hour. This meant that there was an issue with the charging system.
How to check the charging system on the DT300i:
1) Open the seat. remove the seat and then the seat bucket.
2) Locate the voltage regulator on the right hand side of the seat area, just in front of the right seat latch.
3) Disconnect the 3 yellow wires leading to the voltage regulator.
4) Use a multimeter to meaure the resistance between each of the yellow terminals of the connector coming from the generator. This should be around 0.5 ohms. If it is close to 0 ohms then there is a short circuit in the coil. If the value is high, then the coil is broken or burnt out. Also, there should be no continuity (conductive path) between the connector and the bike's frame/ negative terminal.
5) Start the bike on and measure the AC voltage between any 2 of the 3 terminals of the connector. At idle this should be 24-26 volts. At 4000 rpm this should increase to 60+ volts. The voltage should be similar across any two terminals, indicating healthy coils.
6) Turn off the bike and plug the connector back in.
7) Measure the voltage of the battery. Anything less than 12.0 indicates a flat battery.
8) Turn on the bike and rev it to 4000rpm and measure the battery voltage again. In my case it was only 13 volts. It should be 14-15 volts for sufficient charging.
After confirming that the generator was fine and the regulator was faulty, I replaced it with a new regulator from eBay. The regulator is easy to replace - there are only two 10mm bolts holding it to the frame and two connectors to disconnect. Now the battery light never comes on and the battery voltage after an hour-long ride (with headlights on, drawing 6 amps) is 13.2 volts, much better than the previous 12.0 volts. My battery tester confirmed that the battery was still 95% charged. Also, the charging voltage is at least 13.8 volts @ 4000 rpm and the headlights are brighter.
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This very good and usable information mousejunks. I know much about the functions of a gas engine, but have always shied away from the electronics for some reason. I will copy your post and insert it in my Kymco folder for further reference . That's the great thing about these forums, as they become a knowledge bowl of good information concerning our scoots. Thanks for you input.
Mac
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Really good job, Mouse! This kind of info goes way beyond the service manual!
Karl
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I do have a background in electronics, I didn't know it would be useful in real life.
Also, when I plugged my smart charger into the battery after a ride, the charger jumped straight from analysis > bulk > absorption in 10 seconds. There was no need for a overnight bulk charge like previously needed.
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I do have a background in electronics, I didn't know it would be useful in real life.
Also, when I plugged my smart charger into the battery after a ride, the charger jumped straight from analysis > bulk > absorption in 10 seconds. There was no need for a overnight bulk charge like previously needed.
Good work. Very clear and usefull. T. Y. [emoji6]
Sent from my SM-N910C using Tapatalk
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Question:
Would you recommend the ebay vendor you bought the replacement regulator from ?
I would assume it was a discount offering and great value ?
If so, after being proven, would you post a specific link to that part?
Tnx!
redk
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It was the only item I bought from the eBay seller, but it only took 5 days, not 4 weeks to get it shipped from China. Price was 27 AUD.
Here is the link: http://www.ebay.com.au/itm/Regulator-Rectifier-KYMCO-Venox-250-Xciting-300-500-Downtown-People-200-300-AU/282279929105?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 (http://www.ebay.com.au/itm/Regulator-Rectifier-KYMCO-Venox-250-Xciting-300-500-Downtown-People-200-300-AU/282279929105?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)
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the Reg is off the scooter, is there any way to test this Reg. off the scooter
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The regulator requires a 3-phase AC input up to 60V, it would be very hard to get those specific conditions for testing when the reg is outside those specific conditions.
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thanks for the INFO I will order a new one now,.
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i wanna ask about this issue, as i'm having a damaged regulator (rectifier) for the second time in less than one year, the first damaged one was the stock one after more than 2 years service (24,000 km) and the second after more than 3 years and about (36,000 km service)
the first and the second time i thought it was the battery but after measuring the diode by avometer, the regulator found to be the faulty one
i'm just wondering if this is normal that rate of damage for the regulator or is this related to any other factor in my electric circuit (i have changed the main headlight bulbs with LED type 40w each)
i found a video on youtube talking about changing the position of the regulator to have more air flow thus prevent its failure due to excess heat not dissipated
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No idea why they would fail within a year, possibly the regulator is a faulty batch or something is overheating.
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These regulators from Kymco seem to be prone to failure judging from just the posts on here. The bullet-proof replacement is the Honda reg-rectifier made by Shindengen. I think I recall 253.....gotta post on this a while back with the right numbers. The Shindengen / Honda has a larger heat sink and undoubtedly way better electronic components. One mode of failure with the Kymco regs is to destroy the stator. Peter Kapitar in Hungary made these discoveries and his mech-techs found the solution. The ebay regs are as bad as the Kymcos.
Karl
PS: Shindengen 232-12
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Thank you guys for this great info! I'm not going to wait for a failure. I'll be getting a Honda one soon to prevent a future failure of reg/rec, stator and battery.
This forum is very useful with you guys sharing your experiences.
Gramps
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hey mouse , very good information . I have the same issue and i followed your instructions . The connector is around 0.5 ohms but the O/P AC voltage is around 4v not between 24v-26v at idle and is around 6v at 4000 rpm . so Is the coil has a problem?
thanks.
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hey mouse , very good information . I have the same issue and i followed your instructions . The connector is around 0.5 ohms but the O/P AC voltage is around 4v not between 24v-26v at idle and is around 6v at 4000 rpm . so Is the coil has a problem?
thanks.
Sounds like there is a problem with the stator. The coils seem fine so their is more likely an issue with the magnet. Best to replace the stator.
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Thanks a lot @mousejunks for your valuable info! Today I had the same issue, the difference here in Sweden is that we have to drive with headlight even during daytime.
Thou driving back home I turned them off, (no battery light 👍)
So I've contacted my dealer here in Stockholm and the did not have in stock, they needed 3 weeks! And 160usd 😳
So I've ordered one from your seller for 18usd.
Thanks again mate 👍👍
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US models, lights are on all the time....when running.
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Yeah I realise that now. My DT350i low beam 55W is always on so I put in a long-life Phillips H7 globe.
It also uses a different regulator to the 300i so Kymco knew about the charging issue and fixed it. They also moved the regulator to the opposite side of the bike where the exhaust pipe heat doesn't affect it.
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Hey, thanks for the valuable info, the battery in my Downtown 125i keeps depleting as well (after about two weeks of riding, the battery's dead, I keep rotating two batteries). Next time I'm replacing a battery, I'll try following the guide, the symptoms seem similar.
I know very little about electronics, so I have a basic question - is the regulator different for different cc scoots? Can I use the same you use for your 300, for my 125?
Hope my question is relevant enough and justifies necroing this thread
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For the downtown 125i and 300i I think they are the same as it is a generic part shared across many models.
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yes the reg. are same the downtown and yager -frost are same . one has more heat sink ,must be the fix kymco did,. I attached a second Reg. on the back to double the heat sink on the Reg. seems to work,.
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yes the reg. are same the downtown and yager -frost are same . one has more heat sink ,must be the fix kymco did,. I attached a second Reg. on the back to double the heat sink on the Reg. seems to work,.
Now I remember, the heatsink is located directly above the exhaust and there is limited airflow as it is hidden under the fairing. Both these factors lead to the regulator overheating and shortening its life.