With the coming of shorter and colder days, we’ve been working hard on solutions so we can help extend the riding season here in Southeastern PA. We get a number of questions about heated (wired) clothing and will or won’t a bike support wired solutions. We have added standalone heated clothing to deal with the weather for our riding commuters on the bikes that we know won’t work. But, there is is a way to figure out what the system can handle. To determine what can work, I like to look at the observed voltage to see what is happening with electrics on a bike.
I had a conversation with Rick at Rick’s Motorsports Electrics (http://www.ricksmotorsportelectrics.com/) when I was looking for electric heated clothing solutions. We were talking about Hyosung’s particularly, as Rick makes stators (the thing that makes the electricity) and the regulator/rectifier (the thing that tells the stator what it should be doing to maintain battery charging voltage) for Hyosungs. Once those two, the stator or the reg/rec, are maxed out, your system is maxed out. A quick way to check this is to look at your voltage with the bike up on the center stand at idle and also with the engine revved up a bit (be careful, of course when you do this).
You can check the voltage with a very inexpensive multimeter from Radio Shack or the like (~$10). You measure the DC voltage with the multimeter at the battery on the + and – terminals. If you have a cigarette lighter adapter (like we do for the Battery Tender Jr.’s for bikes that have a lighter adapter), you just plug it in and stick the multimeter probes in the end of the lighter adapter to measure the DC voltage. We showed how to check a battery’s voltage Oct 15th, at our Maintenance Night.
The battery should be around 12.5 V at rest (bike not running). This is normal battery voltage for a 12V battery. You will see a big drop in voltage when you hit the starter. Makes sense, right? The engine isn’t running and the electrical starter, powered by the battery, is turning a cold engine. This voltage drop shows the battery is discharging and in a big way. The corresponding big amperage draw is why eventually a battery can’t turn over a non-starting motor.
Incidentally, a non-cranking motor does not mean the battery is bad. It often is just the result of the motor not starting for some other reason. You must, of course, now also deal with a discharged battery when one investigates the non-starting problem.
After the engine starts, the stator (an electricity generator) takes some of the power of the bike motor to make electricity to power the electrics (lights, turn signals, horn, etc.). The job of the regulator/rectifier is to take the AC voltage that the generator makes, convert it to DC that the battery needs and also not to fry the electrical system. Left to it’s own devices, the stator can make weird voltages that would hurt the bike – voltages like 18-19V DC. The electrical system wouldn’t survive this. We recently had a reg/rec fail on a scooter and it burned out the headlight. So, we generally see healthy voltages around 13-14.5V when a motor is running some minutes after a start. Rick said he tries to maintain 14.1V with his reg/rectifiers.
So to see what your bike can do, with the engine running, just start adding things and turning them on. Hit the horn, the turn signals, watch the voltage change so you can see how this works. Turn signals take, for example, quite a bit of power for some reason. The reg/rec will try to maintain the voltage designed into it to the limits that the stator can give you. If, with your accessories attached, you are not seeing ~13V at idle, a little more than the battery showed us at rest, you are or are close to discharging. A long time in traffic and then a stop for lunch could find you with a dead battery when you come out after eating – not enough power in the battery to start the bike. If you are not seeing ~13V off idle, that combination of accessories will not work, period.
Running a system that is always working maxed out? Rick didn’t seem to have an negative opinion about adding an accessory package that requires 100% of your stator-reg/rec all the time FWIW. I had a customer that added higher wattage headlights to a TNG Verona and we didn’t maintain 12.5V at idle but did off idle. That was four years ago…
