Grip Heater power draw

[farmerj]

While searching here revealed some good threads about Grip heaters, they were largely on kick start bikes and my question wasn't answered.

The stator puts out about 70W. Grip heaters use approx. 35W. I'm guessing I won't be able to run my headlight when I'm using the Grip heaters (?). That leaves 35W to charge the battery.

How many watts does it take to keep the battery charged for starting system use? I don't want to draw the battery down too far and damage the starter with low voltage. Is 35W enough?

Thanks,

Jeff

 

[Anders]

While searching here revealed some good threads about Grip heaters, they were largely on kick start bikes and my question wasn't answered.

The stator puts out about 70W. Grip heaters use approx. 35W. I'm guessing I won't be able to run my headlight when I'm using the Grip heaters (?). That leaves 35W to charge the battery.

How many watts does it take to keep the battery charged for starting system use? I don't want to draw the battery down too far and damage the starter with low voltage. Is 35W enough?

Thanks,

Jeff

Grip heater power usage can easily be adjusted / reduced by inserting a resistor in series with the heaters. Some heater foils also have two different circuits, one full effect and one approx half effect. I have just installed KTM-branded heaters, they have a 2 Ohm series resistor for the low effect setting. I use this togehter with a half effect headlight, or full effect grip heat, or full effect headlight, all controlled by a pair of switches.

How many watts it takes to keep the battery charged cannot be answered accurately. It all depends on the outside temperature, how heavy the starter motor have to pull, often you start compared to how long time you ride etc. Also, other loads (rear light, headlight, fan etc) will have an impact.

Here is an example calculation:
The generator on my bike outputs approx 14V. If you have 35W for charging, that would mean 35/14 = 2.5A. If you then have a battery of 6-8AH (typical for a Li-ion battery) it would take 2-3.5 hours to fully charge the battery.

So the quick conclusion would be that if you drain the battery when you start it, you would have to ride for a at least a couple of hours using the 35W grip heaters before the battery again is fully charged. However, if your starter and circuit is working flawlessly, the battery will of course not be fully drained by just one start.

 

[Neil E.]

I have the Oxford brand grip heaters on my GG. At first I ran them on DC power, but they would draw the battery down after an hours riding. I then changed them to run on AC power and they work very well with no loss on the normal DC charging. I have a switch for ON/OFF and they work at full output.

 

[farmerj]

Thanks guys, your responses give me the confidence to give it a try without much worry, and I'll set it up as AC!

Except I don't know how to do that! I was just going to hook them up to the battery.

Neil??!

Jeff

 

[Anders]

I have the Oxford brand grip heaters on my GG. At first I ran them on DC power, but they would draw the battery down after an hours riding. I then changed them to run on AC power and they work very well with no loss on the normal DC charging. I have a switch for ON/OFF and they work at full output.

I can add that my 2015 EC200 has no starter and no battery. I run the heaters on DC, using the headlight supply. The 14V I mentioned, is 14V DC, measured at that point without any load.

 

[Neil E.]

Find the yellow wire coming off the stator and connect there. Use a switch for on/off. Other side of heaters to chassis ground.

 

[farmerj]

Thank you!

 

[Neil E.]

I can add that my 2015 EC200 has no starter and no battery. I run the heaters on DC, using the headlight supply. The 14V I mentioned, is 14V DC, measured at that point without any load.

This works well because you don't have a battery. The heater load probably only reduces the voltage a slight amount. With a battery installed, the heater load could be enough to slowly draw the battery down.