Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

Electrical advice: heated glove modification

Discussion in 'Modifications and Projects' started by mattb, Mar 23, 2011.

  1. G'day All.

    A challenge for the electricians among us:

    With the cold coming I've been looking at cheap options for heated gloves in preference over heated grips. The cheapest option is an independant-battery heated glove - say with a D cell battery in each glove. A glove hooked into the bike's battery would be much better, but they're much more expensive. Having almost no electrical knowledge, I'm wondering if it would be possible to convert an independent-battery heated glove into one that is wired into the bike's battery, and if so could you offer come basic instructions? I see modules for sale that go from the battery and include a temperature controller, into which the glove plugs, but I'm assuming I need something between that and the glove to moderate the electricity....


  2. Everything about this seems like a bad idea.
  3. What is wrong with heated grips. They are cheap enough to install on multiple bikes. With a relay and a few bits of wire you'll be set for less than $20
  4. Seems like you'd get quite electrocuted quite quickly.

    You'd need something to step down the current and voltage to run the D battery powered ones from the bikes battery, and somewhere to plug them in safely.

    I'm sure there'd be a way to use the battery powered ones with rechargable batteries and have a charger hooked up to the battery. Like a 12V outlet in a car.

    Or you could just get heated grips.
  5. Could be done quite easy. D cells are about 1.5V. If they are temperature controlled you will need to find out the voltage range it can tollerate on the input. You can either find a 1.5V Zenner and a resistor(my google search showed a few results) Or build a voltage divider (a quick google will give you pages on how to calculate resistors) in a seperate box with plugs.
  6. I'm thinking not heated grips because the back of your hands get quite cold. Plus, I'd like to stick with my thick foam grips on my vibratory big single.

    Thanks for giving me a start there Killbot; and Joel - a charger: there's an approach I hadn't thought about!
  7. No reason a potentiometer wouldnt work for temperature control, but id add it to the circuit after you get the maximum voltage down via solid resistors (to the spec 1.5v).
    You also need to consider the level of current from the battery of your bike (lots of amps) vs the D cell (milliamps).

    edit: nearly forgot, go talk to dick smith people or jaycar or whatever your local electronics people are, letting them know what you need so you dont get something that cant handle the voltage or current, and likely melt = bad.
  8. Just going to have a dig at this.

    Circuits will have a certain resistance, set by the wires and elements etc. If the voltage is steady at 1.5V, theoretically the current should remain steady as well. Can someone verify this?
  9. Yes you are correct Lilley, Ohms Law (Voltage = Current x Resistance) If the voltage is maintained at a fixed value and the resistance doesn't change the current remains the same.

    D Cells have a surprisingly large current capacity, an Alkaline Long Life for instance is about 17000 milliAmp-hour. You bike battery probably 12000 milliamp-hour (12 Ah). The bike battery has a higher voltage so it stores much more energy however and can discharge it at a much faster rate.

    Putting the 12volts of your battery across the gloves if they are rated for 1.5 volts will be very warm for a little while and then smoke will come out and they will stop working. As others have said, if you intend to do this you need to reduce the voltage to the 1.5 volts the gloves are rated for.

    Some above have suggested resistance in series, commonly known as a voltage divider. This will work but making a couple of assumptions, that the glove uses 10 watts of power.

    10 watt / 1.5 volts = 6.6 amps.

    If you use a resistor to drop the voltage it needs to be able to drop 12 volts - 1.5 volts = 10.5 volts at 6.6 amps or approximately 70 watts. So this is not effective because your gloves use 10 watts but the dropping resistor 70 watts, a total of 80 watts. Not good, a resistor to handle this would be bulky and this is inefficient as most of the energy you are using is heating the dropping resistor and putting a heavy load on your electrical system.
    Other mentioned a Zenner diode combination. This is known as a linear regulator and is more efficient than the plain voltage divider but you still need a dropping resistor and it still ends up taking much of the energy. Again inefficient.

    The method generally chosen for this type of situation is a Switch mode regulator, the same type of regulator used in most electronic equipment, computers etc. Something like THIS would possibly do what you want but you need to do some investigation first of the gloves, the number and type of batteries they have, their current draw etc.
  10. Matt fill your gloves with extra strength denco rub - just dont scratch your testicles with your bare hands later :)
  11. Damn i forgot about a voltage regulator... much better idea!
  12. Why not?





    ... that's why not.
  13. Should be pretty easy, basically what cjvfr said, if you get a glove with a temp controller built in, you just need to supply it with the right voltage & enough current & you're done.

    If you don't want to use a switchmode power supply, you can build a reulator circuit to give you a fixed voltage, you could get away with 1-3 components if space is an issue, minimun would be the regulator & possibly some capacitors across to smooth out any ripple in the voltage.

    Voltage regulators are a couple of bucks from Jaycar, you just need to get one that can supply enough current, which will depend upon the current draw of the heating circuit.
  14. My advice would be to buy better winter gloves, and carry your summer gloves with you if you really need to.

    If you really don't want to do that, go with this option:
    Only find a much smaller unit that has a fixed output voltage to match your requirements. The example cjvfr gave is way too big because it has selectable voltage output.

    But really, the money you save by buying cheap battery powered gloves is going to be eaten into with any alternate power supply solution, and you will end up with a second rate result. Buy better winter gloves or proper 12volt heated gloves.