I have heard that quality heated clothing controllers used an adjustable "duty cycle" to regulate temps, while cheaper ones can use a selective resistor to accomplish a similar task.
How would I go about making one & what are the pros & cons.
I understand the resistor types create a lot more load. Is that a prohibitive factor?
Anyone got a used one I can buy reasonable? They seem pretty pricy on Fleabay

the resistive ones actually limit the current getting to the heater element

so ..in fact less Power is consumed (and ipso facto -less heat ) but the current limit resistors might get warm themselves

have seen a couple of fet based regulator circuits around somewhere ...hope i can find it again

found it on line for $20 + $11 shipping. That's more than 1/2 the cost of a ready made one. Guess I'll wait & reconsider.
http://store.qkits.com/moreinfo.cfm/MX033

Using a PWM Pulse Width Modulator works well. What it does it give full power but in pulses which are timed by the modulator and can be adjusted in length (width) according to how hot you want. This way less power is consumed and there is no current limiting resistor to get hot. Albyalbatros1 built one for Nicole's heated vest not long before we went to Araluen in 2011. I have heard of many others doing the same.
If you look for a PWM on fleabay you will find them and supprisingly cheap.
http://www.ebay.com/sch/i.html?_trksid=p2050601.m570.l1313&_nkw=Pulse+Width+Modulator&_sacat=0&_from=R40

Ordered 1 from Hong Kong 7.48 free shipping, 10A

My prototype controller is ready for testing. It's rated at 10A.
If I want to measure the output changes as I turn the rheostat from low to high, might I need to put my meter in line on amps or across the circuit on volts?
Or do I need an oscilloscope to see the changes as it operates (if it does)?
Please don't tell me to just put the jacket on & feel the changes.......LOL

Could you use something like a car instument dimmer switch??? I may have just given away my electrical knowledge right there...........

You can use any number of switch set ups.
By your question I'm guessing that you are referring to the rheostat in a car that dims the dashboard lights????
At any rate, you could use such a resister device or keep turning a regular switch off & on.
In this case, I've elected to use the earlier recommended Pulse width modulator device.
My question was about how to measure the effect of the item I've assembled.
Regards, ibj...

you can measure in either of 2 ways

first you need to emulate a suitable load

do you know what the resistance of the heated thing is ?.....measure it on ohms

the first way is to put the meter probes across the load ...yes measuring volts .....do it in the ac scale (cause you have modified the dc and are now making a pulsed waveform) ...or one that closely resembles an ac voltage ... you will get an idea of the average voltage able to effect the heat creating element ...the old "ohms law" applies here given that you know the load ...ie reistance if you measure the average voltage you will be able to calculate the current or power being used by the system under test

or conversly you can put the meter on ac amps and in series with the load .....and subsequently again given that you know the resistance the average current ...you should be able to calculate that way .....

you might have to find a good load for this ......why not a standard 240 volt ....ooops... 110 volt light globe cheap as chips and able to dissapate lots of heat ....you may need a few different wattages for the test ..again use the ohms law for this calculation of peak demand -load and current that will be drawn . (so you dont over load the controller ).

look it up it isnt hard to understand ....im really quite surprised that an overwhelming number folks that build electronic stuff dont know the simple things that are the building blocks of modern understanding of things and why ... i guess its just a generational thing . oh well !!!!

good luck !

If the board you bought is able to work while in a no-load condition, then you could measure its AC output using a multimeter. As the variable control is adjusted, the pulse width at the output should change. The RMS value of the output will also vary linearly with the changing pulse width and you can observe this on the multimeter as changes in the AC voltage. Put your meter in AC volts and measure across the output. If your meter is auto ranging, that's easy; otherwise select a setting on the meter that is around 25V full scale.

Charlie & Robmack,
Thanks for all that good info!
As I'm used to, Charlie's answers are a bit technically "over the top" for me and even though I'm also "old school generational" at 65 yrs........I still don't understand if at least remember all the electrical stuff that many people tried to teach me.
I try to remember OHMs law, but even then I get confused. is it: V ./. W = A ????
Please tell me the 3 basic steps again. I'll try to look it up again.
Last time I tried to Google this stuff I got all balled up.......I had a little model train transformer.....it was rated in VA. What the heck is that????
At any rate Charlie, I don't really want actual values as much as just to get a baseline to see approx. how warm the vest should be at approx. what position on the rheostat.
I hope as Rob suggested that it'll give me some values with no load, just to prove it works before plugging in the actual vest, firing up the engine for max. voltage and letting all the smoke out of the box!

I used one of the Ebay PWM contollers for my LED driving lights. don't see why they wouldn't work for clothing.
http://www.ebay.com/itm/DC12V-24V-8A-Light-Dimmer-Brightness-Adjustable-Bright-Controller-LED-Strip-/290899999967?pt=LH_DefaultDomain_0&hash=item43bafdbcdf
I remoted the potentiometer up on the dash and potted the circuit board to make it water proof.

ibjman wrote:I try to remember OHMs law, but even then I get confused. is it: V ./. W = A ????
Please tell me the 3 basic steps again. I'll try to look it up again.

I = E / R where I= current in Amps, E = potential in Volts and R = resistance in Ohms.

Last time I tried to Google this stuff I got all balled up.......I had a little model train transformer.....it was rated in VA. What the heck is that????

VA is "Volt-Amps" which is pretty much equal to power in Watts. Technically, it is usually used to describe power in AC circuits and mathematiclly it is composed of real and imaginary power vectors. So, that's why it's much easier to remember that VA is Watts for all intents and purposes.

i was just recommending that you try it with some form of a load because without a load you may get different results , i dont know how your controller works so it could really suffer under load conditions voltage- current

maybe just put a bike turn indicator globe as a load and see how the glow changes ....its an easy thing

= ohms law

quoted from some page on the internet ....but pretty helpfull

Though not part of the original theory, in later years, we have also attributed the Power factor to Ohm as well. Power is usually abbreviated by (W) and measured in Watts. The formula generally given for Power is:
W = V x I or W = I² x R or W = V² / R. Other basic formulae involving Power are:
I = W / V or I = (W / R)₂
V = (W x R)₂ or V = W / I
R = V² / W or R = W / I²

where V = voltage (should read as "E") I= current R= resistance or ohms ...watts is normaly the sum of E x I in lots of circuits so abreviated to "va " in many cases ...its an electrical ac trade thing

depending on the temperature and insulation properties you may be surprised how many watts of power is required to heat something up ...now were not talking about a bar radiator in the lounge room... lol ...a lot less

what i can suggest is .... point reference heat is really hard to spread to where its needed without getting a hot spot

ipso facto, better to spread the heating element over a larger area or run 2 circuits so that at any one point you get a more even temperature spread and keep the overall current draw a bit lower ....all rather obvious i guess

unfortunatly i have no experience in what is needed for warming up things up there in your climates in wattage terms ... but i imagine 20 to 60 watts (2- 5 amps ?) spread over a large area ...like a jacket ? having it contuinuously variable is a bonus ....i guess when you get it right you might put some markers on the adjustment device

sorry for being a techno speak type person ...i guess its just the world that i live in

Could you elaborate on "I" from Ohms law.......I know V = Volts, W = Watts I know Resistance is Measured in Ohms. Not sure about I.
I'm gonna use this on a Gerbing's heated vest. I'll probably just plug 'er in & see if the little board goes up in smoke????
I can measure the resistance end to end on the vest. The little board is rated at 10A. I'll put an A/C voltmeter across it when I light the fire to see what I can learn.
Maybe I'll try a little bulb thing first

I = current in Amperes

V Charlie V it's E for Electromotive force You You You unlettered dolt you Bloody hell I taught you everything I know and you still know nothing.

yeah i know rick ...tell me about it ...but some folks believe its this way, and posted it on the net as reference material ,.... and some one let it slide through editing that way.
i just copied and pasted
where ever you see "V" in the formulas above you will be doing yourself a favour by exchanging an "E" in there instead

Well......no smoke came out of the box! I hooked her up and it appears to be working exactly as intended. I found it easiest to put the amp meter in line between the positive output (motor +) of the box and the positive input to the jacket cable. With the engine off, parking lights on, I had about 0.4 A with the rheostat at it's lowest setting, about 1.22A at 25%, about 2.04 at 50%, 3.74 at 75% and 3.67 at 100%. Conversely the battery voltage available was 12.24 in the lowest position, 12.13 at 25%, 11.9 at 50%, 11.71 at 75% and 11.5 at 100% (full on).
The resistance measured through the heating wire end to end of the jacket appears to be 3.35Ohms.
Does that all sound about correct????
I didn't spend any time with the jacket on, but I could feel warmth in the wires.

Seems great to me!
This is a link to the PWM I bought $7.48 w/free shipping from China.....actually arrived quite quickly to. Now I have to order 1 more for a jacket for the better 1/2!
Now if I could just find a source for both the male + female 2.5mm barrel connectors and wire end power sockets either wired (with like 16G wire)....or at least wireable for me with a nice finished look, without paying a gazillion $$$$ to buy & cut up Gerbings leads I'd be ecstatic.
http://www.ebay.com/itm/310620708441?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

sounds about right
should be a little more when engine is running ....(at about 13 .5 v? to the battery )
good work !

As the voltage goes up, the draw will go down, correct? What's the minimum gauge wire I can get away with at 10A, 12V+?

With the bike running the voltage will rise to about 13.4 and that makes the current rise but at you readings it would only go to 4 amps max so 10 amp wire is quite good for the job.

no ...not correct ...as the voltage rises so does the current ...its just a marginal thing shouldnt change by much
i always work on about .15mm of conductor for each amp of current draw ...allowing for voltage drop losses etc
so for 10 amp about 1.5mm conductor dont know what that works out to in imperial .06 inch ?
just over 16 guage ...nearly 14

Voltage is pressure, right? More pressure means you will push more Amps down the wire?
So 14G to be safe.
Gerbings heated accys. come with 2.5 mm barrel connectors and the wire looks like AC lamp cord
16Gu. With nice soft rubbery insulation. I was trying to make up some custom cords, but can't find a source for ends that are heavy duty enough that also have nice strain relief outlets attached.

wansfel wrote:I used one of the Ebay PWM contollers for my LED driving lights. don't see why they wouldn't work for clothing.
http://www.ebay.com/itm/DC12V-24V-8A-Light-Dimmer-Brightness-Adjustable-Bright-Controller-LED-Strip-/290899999967?pt=LH_DefaultDomain_0&hash=item43bafdbcdf
I remoted the potentiometer up on the dash and potted the circuit board to make it water proof.

I have used one of this with an EXO2 heated vest, and found it to work very well.

ibjman wrote:Voltage is pressure, right? More pressure means you will push more Amps down the wire?
So 14G to be safe.
Gerbings heated accys. come with 2.5 mm barrel connectors and the wire looks like AC lamp cord
16Gu. With nice soft rubbery insulation. I was trying to make up some custom cords, but can't find a source for ends that are heavy duty enough that also have nice strain relief outlets attached.

Old electronics adage:
All things electrical run on smoke, and the more smoke that leaks out, the worse they work.

Have enjoyed reading all of the posts regarding this...and has answered some questions for me.
Looks like you have done some fine work.

This crowd is pretty amazing.

I can't tell if I'm surrounded worldwide by engineers/mad scientists/avid riders/ some seriously funny and good folks, or all of above.

Am sure that it is all of the above.

wansfel wrote:I used one of the Ebay PWM contollers for my LED driving lights. don't see why they wouldn't work for clothing.
http://www.ebay.com/itm/DC12V-24V-8A-Light-Dimmer-Brightness-Adjustable-Bright-Controller-LED-Strip-/290899999967?pt=LH_DefaultDomain_0&hash=item43bafdbcdf
I remoted the potentiometer up on the dash and potted the circuit board to make it water proof.

I just bought a few of these off ebay for heated vest and grips. They $4 each including shipping from China. Hope they work.

What do you mean when you say you "Potted" the circuit board?