Looking for some advice on how to proceed with diagnosing an issue.
Last year I purchased a Chinese electric motorcycle. Overall, I love the motorcycle, but it's definitely Chinese. It's basically one of these: https://longzustar.com/electric-motorbike/electrical-racing-motorcycle-price.html
At least, the name Longzu Star appears on the motor and brake reservoirs. The motor is this guy:
https://www.qsmotor.com/product/17-inch-12kw-hub-motor/
So here's my question: there's a JD1912 12V relay under the seat. When it gets 12 volts of current, it allows the battery current through. When this relay is functioning properly, I turn the key, the relay closes, there's a beep from the controller, and the motor works. If the relay doesn't close, no beep, no motor, but the 12V system does still get power (lights, turn signals, speedo cluster all function).
I'm looking for insight into what conditions will cause this relay not to get the 12 volts it needs.
Here's what has happened:
Data point 1 -
Forgot to cover the motorcycle overnight while charging and it got rained on. Charge completed just fine, but relay wouldn't close. Voltmeter showed voltage varying rapidly between 5 and 9 volts. Which, notably, is not 12. Replaced the relay and the issue persisted, so I'd say the relay was doing its job and is not the problem. A couple hours later, voltage was varying between 7 and 10, and relay started showing signs of closing and opening. Getting closer. I let it sit overnight in the garage to dry out, and by morning the relay closed and stayed closed, and everything worked perfectly. So, I told myself, make sure that thing is always covered.
Data point 2 -
A week or so later, there was another heavy rainfall overnight while bike was covered (and not charging, which might be important?). The next day around 1:00, I uncovered the bike, spilling a gallon of water that had pooled on the cover over the gas tank. Bike started right up, I felt vindicated.
Data point 3 -
A few days later, I plug the bike into the charger and cover it, making sure the cover is over the charging plug (an Andersen connector) and the charger itself is closed in the garage. It rains overnight, but I'm not concerned because the motorcycle is covered. Go out around noon to go for a ride, and the relay isn't closing. Put it back in the garage and let it sit overnight, and the next morning it starts up no problem.
Does anyone know what this relay is likely to be responding to? Like, what is making the voltage drop, and is there anything I can do to protect it? My first thought is that some connection somewhere could use some lithium grease to keep water out of it, but I'd rather have some idea which one.
Some thoughts:
If it was simply that the bike was getting wet, then why did the issue happen when it was covered? The cover is apparently good enough that a gallon of water will remain pooled on it for several hours, so it doesn't seem likely that it leaked through. Is there something about it being plugged in during the rain? My cover did extend over the connecter, but maybe water splashed up under it somehow?
Any advice welcome, and please let me know what additional info I can provide.
Last year I purchased a Chinese electric motorcycle. Overall, I love the motorcycle, but it's definitely Chinese. It's basically one of these: https://longzustar.com/electric-motorbike/electrical-racing-motorcycle-price.html
At least, the name Longzu Star appears on the motor and brake reservoirs. The motor is this guy:
https://www.qsmotor.com/product/17-inch-12kw-hub-motor/
So here's my question: there's a JD1912 12V relay under the seat. When it gets 12 volts of current, it allows the battery current through. When this relay is functioning properly, I turn the key, the relay closes, there's a beep from the controller, and the motor works. If the relay doesn't close, no beep, no motor, but the 12V system does still get power (lights, turn signals, speedo cluster all function).
I'm looking for insight into what conditions will cause this relay not to get the 12 volts it needs.
Here's what has happened:
Data point 1 -
Forgot to cover the motorcycle overnight while charging and it got rained on. Charge completed just fine, but relay wouldn't close. Voltmeter showed voltage varying rapidly between 5 and 9 volts. Which, notably, is not 12. Replaced the relay and the issue persisted, so I'd say the relay was doing its job and is not the problem. A couple hours later, voltage was varying between 7 and 10, and relay started showing signs of closing and opening. Getting closer. I let it sit overnight in the garage to dry out, and by morning the relay closed and stayed closed, and everything worked perfectly. So, I told myself, make sure that thing is always covered.
Data point 2 -
A week or so later, there was another heavy rainfall overnight while bike was covered (and not charging, which might be important?). The next day around 1:00, I uncovered the bike, spilling a gallon of water that had pooled on the cover over the gas tank. Bike started right up, I felt vindicated.
Data point 3 -
A few days later, I plug the bike into the charger and cover it, making sure the cover is over the charging plug (an Andersen connector) and the charger itself is closed in the garage. It rains overnight, but I'm not concerned because the motorcycle is covered. Go out around noon to go for a ride, and the relay isn't closing. Put it back in the garage and let it sit overnight, and the next morning it starts up no problem.
Does anyone know what this relay is likely to be responding to? Like, what is making the voltage drop, and is there anything I can do to protect it? My first thought is that some connection somewhere could use some lithium grease to keep water out of it, but I'd rather have some idea which one.
Some thoughts:
If it was simply that the bike was getting wet, then why did the issue happen when it was covered? The cover is apparently good enough that a gallon of water will remain pooled on it for several hours, so it doesn't seem likely that it leaked through. Is there something about it being plugged in during the rain? My cover did extend over the connecter, but maybe water splashed up under it somehow?
Any advice welcome, and please let me know what additional info I can provide.
