Post by Dave B on May 2, 2019 9:53:58 GMT 1
I have taken a completely radical approach to wiring my YPVS hybrid, using a Motogadget M Unit (basic).
The M Unit requires a high current wire direct from battery positive to a terminal on top of the unit. This terminal is just a screw that holds a ring terminal, and it lies no more than a couple of centimetres from the fixing screw, which is obviously at earth voltage, since it goes to the frame of the bike.
There is no insulation on the positive terminal, no little plastic cap or anything, and it is live even with the ignition turned off. While I was riding the bike a couple of weeks ago, a screened cable that I use to connect the gear indicator slipped out of its safe place at the side of the air cleaner box (hit a pothole!), and bridged the gap between the positive and the fixing terminal, putting a full short across the battery for a few seconds.
The engine kept running, and I got home, but when I went to the bike the next day, the bike was completely dead. The M Unit was fried, would not reset, so I had to buy another. With the new one fitted, one of my LED running lights was dead, and whenever the bike revved up, the horn would blow. After a lot of messing about, checking circuits and connections, I discovered that:-
1. The battery had boiled almost dry.
2. The horn blowing was a safety feature of the M Unit warning that the input voltage had gone over 18V. So the temporary short had fried the regulator/rectifier too.
For the lack of one more tie-wrap, that was a very expensive pot hole!
My M Unit now has a nice cover over the positive terminal, made out of a little rubber bung from one of those room perfume refill bottles.
If you are using an M Unit, please be aware of this. Anything drifing about under the tank or seat could do the same.
Cheers
Dave
The M Unit requires a high current wire direct from battery positive to a terminal on top of the unit. This terminal is just a screw that holds a ring terminal, and it lies no more than a couple of centimetres from the fixing screw, which is obviously at earth voltage, since it goes to the frame of the bike.
There is no insulation on the positive terminal, no little plastic cap or anything, and it is live even with the ignition turned off. While I was riding the bike a couple of weeks ago, a screened cable that I use to connect the gear indicator slipped out of its safe place at the side of the air cleaner box (hit a pothole!), and bridged the gap between the positive and the fixing terminal, putting a full short across the battery for a few seconds.
The engine kept running, and I got home, but when I went to the bike the next day, the bike was completely dead. The M Unit was fried, would not reset, so I had to buy another. With the new one fitted, one of my LED running lights was dead, and whenever the bike revved up, the horn would blow. After a lot of messing about, checking circuits and connections, I discovered that:-
1. The battery had boiled almost dry.
2. The horn blowing was a safety feature of the M Unit warning that the input voltage had gone over 18V. So the temporary short had fried the regulator/rectifier too.
For the lack of one more tie-wrap, that was a very expensive pot hole!
My M Unit now has a nice cover over the positive terminal, made out of a little rubber bung from one of those room perfume refill bottles.
If you are using an M Unit, please be aware of this. Anything drifing about under the tank or seat could do the same.
Cheers
Dave
