heated grips to shut off when the key is turned off?

[dean owens]

hey guys and girls,

i have heaters under my grip puppies. the rocker switch is very sensitive and i'm always paranoid i'm going to leave it on (or accidentally switch it on getting off the bike). i'd like to wire the hot so they get power when i turn the key. what is my best option? i have some basic electronics understanding, but know very little about auto electronics. any help you could give will be greatly appreciated.

 

[RJ2112]

You need to add a relay to the line feeding power to your grip's switch. You want to have the power feed accross the Normally Open contacts, so any time the coil is unpowered, the switch is open and the grips get no juice.

The coil for that relay can be tapped into the lead going to your headlight's low beam, so the power for your heater is only going to be applied when the headlight is 'enabled'. It's got relays on their line as well.... they don't come on until your motor is running.

The other side of the relay's coil line should be tied to ground, with enough resistance on it to limit the current drawn through that leg to what is required to energize the coil.

Without knowing what the coil requirement is, it's hard to say exactly how much resistance should be there; but it's going to be on the order of 30-50 Ohms.... could be hundreds of Ohms, if the coil will actuate on milliamps.

Once you know how much current your particular relay's coil needs, to work..... divide 12 volts by that current.... that value is the maximum resistance you need. Add that in series with the coil, to ground. Bundle it up and have peace of mind.

Unless you routinely 'kill' your motor with the kill switch......

 

[tom5796]

Simple explanation that works for me: splice hot wire to low beam, connect ground to frame (I use one of the tank bolts).

 

[Motogiro]

A relay with a 12 volt coil rating, and contact rating that meets or exceeds your grip current rating will be fine.

 

[alanrim]

For our GSR we got a headlight relay (4-pin) from Ebay. Doesn't really matter what bike it is off (as long as it is 12v, eg most modern bikes), seems to be a lot of Honda ones kicking round. Often they are in a rubber boot which you can fix fairly easily, the rubber helps give a long life.

Real good thing about proper bike relays, they are able to take the voltage and vibration present on a motorcycle.

 

[Motogiro]

Dean Owens,

Here's a little schematic that you might use for your grips.
If the rest of the years of the FZ6 are the same you should be able to find a green with black tracer striped wire, that is the wire that feeds your low beam in the left side of the fairing. You can test this wire to make sure.This is the wire you can use to power your relay coil. The relay coil shouldn't have anywhere near enough current draw that it would unduly effect or load down that circuit. When you turn the ignition off that circuit shuts down with the exception of when the engine is running and you hit the kill switch. Same as the way your headlamp works.

You'll run a fused wire from your battery to the normally open contact on the relay. The other switched contact goes to your grips or other device.This is the basic circuit that you can use to power many devices you might add to your bike. The only thing you want to make sure to do is use a relay with a 12 vdc coil and contacts that will carry at least the amount current required for the grips. For example if you're using 5 amps of current I'd use a contact rating of 10 amps.

The only other advice is route the wires safely and securely to avoid the surprise of a pinched shorted wire later on.
I've attached a PDF.
Have fun!

 

[dean owens]

thanks guys. i am wondering why tom's explanation isn't the go-to explanation? he's suggesting tapping off the same wire you guys are suggesting, only there's no relay in there. what does the relay do that simply tapping into that wire doesn't do?

honestly, i want to do it "right" but i was hoping for something easy. for example, i know justing (jman) wired his angel eyes for his projectors off the starter relay. i was really hoping i could just tap into that wire. but i don't know what that wire is. i know where that relay is, but i don't know what wire to splice into.

anyway, if going this relay route is the proper route i'll do it. i'd just like an explanation as to why i need it rather than simply splicing into a wire.

thanks

oh, and thanks for the schem. it'll come in handy when i actually have the relay.

 

[RJ2112]

The main reason to add another circuit to carry the current for the grips/what have you, is to avoid the extra current flow on the headlight wiring. If you are running the OEM single low beam, 55/12= about 4.5 amperes. With the dual headlight mod, just adding the second 55 watts, doubles the current running through that same wire. Now, you're at 9 amperes. What is the safe amount of current the present wiring can carry?

Grips will probably be in the same sort of range as the headlamps; 50-100 watts.

I would expect them to draw at least 4 amperes, and possibly as much as 9.

If you run an isolated circuit, you have good reason to assume your OEM wiring is not at risk...... and your additions are protected, as well.

 

[Motogiro]

The reason you need the relay is because you can't hook the heated grips up to a lower wattage circuit. Well you can but...... They draw more current than most any device on your bike, so you need a high current source. If you used a lower power circuit on the bike it would blow a fuse, effect the circuits sharing that line, or worse cause a fire. You also want it to be switched. This is why we're using the headlamp circuit. The Headlamp circuit is only being used as a source of current for the relay coil which uses very little power. The coil operates the contact assembly in the relay which passes the high current needed to run the heated grips, directly from the battery, which is a high current source. In essence the relay contacts are acting as a slave, carrying the heavier load that the other circuits in the bike would not. All the coil in the relay does is create a magnetic field that pulls the contacts closed. The contacts carry the heavy load.
I'm willing to bet the 10amp relay w/12 coil at Radio Shack will be cheap and easy to get locally. I think I remember RS having and automotive application type relay...

 

[Motogiro]

This will work fine:

12VDC/30A SPST Automotive Relay - RadioShack.com

 

[macem29]

brain fart, sorry

 

[krid80]

This will work fine:

12VDC/30A SPST Automotive Relay - RadioShack.com

these are good, there is also a smaller alternative in the drawers too which makes mounting easier. use solder!

I worked at Radioshack for four years before coming to the motorcycle dealership. I am actually working seasonal back at radioshack for extra Christmas cash.

Makes me wanna build stuff like.... all the time!

 

[Motogiro]

these are good, there is also a smaller alternative in the drawers too which makes mounting easier. use solder!

I worked at Radioshack for four years before coming to the motorcycle dealership. I am actually working seasonal back at radioshack for extra Christmas cash.

Makes me wanna build stuff like.... all the time!

I know! I worked seasonal at RS and have a little background in electronics. Used to also do automotive electrical. Don't like crawling under any more. Would do it on bikes though and I'm thinking about it......$$$$$

Here in SoCal we have riders year round that could use help....

Looking forward to maybe seeing you on the big ride this spring/summer? Uh Oh! Highjacked the thread! :hijack:

 

[dean owens]

ok. thanks guys. that makes since why i need a relay now. as i understand i'm still pulling my power for the heaters from the battery. but i'm pulling the power for the switch for the relay from the headlight low beam.

to answer some of you guys questions about power consumption... this is what i have
Complete Motorcycle Hand Warmer Kit w/ Round Rocker Switch
down the page it says that they draw 3 amps (36W) on the high position. on the back of the package it says maximum 20 watts at 14 volts. and the resistance is 9.6 ohms and 19.2 ohms for the throttle side and 7.2 ohms and 12.8 ohms for the clutch side.

does that info change any advice given so far? should i still stick with that relay from RS?

the smaller alternative that was mentioned... same ratings as the one linked? and i plan on soldering everything up. no point going through all this trouble and not doing it the right way.

thanks guys for your help.

 

[RJ2112]

No change in advice for anything we've said so far... the only other point I wanted to 'touch' was the wire tapped off the starter....

That one should be fine; a strater is a high current circuit, and needs to be fused and wired for the peak current flowing. Since the stater is not in operation for very much of a bike's operating time, it should be okay.....

It would work, but it would not offer as much protection as doing this with the relay that has a switched source for it's coil. If you tapped into that circuit, the grips would have power avialable as soon as you turned on the key. Not a bad deal for Halos, they are LEDs with low current draw, and somone may want them on with the bike off.

From the low beam circuit, the signal is not available until after the bike starts..... they cannot draw the battery down with the bike off.

 

[dean owens]

rat shack didn't have a smaller relay that fit the same parameters so i just got the standard auto relay.

quick question... i have some 14awg auto wire. is that fine? not enough? or overkill? i won't get around to this tonight anyway so if i need some different wire i can pick it up tomorrow.

thanks guys.

 

[krid80]

rat shack didn't have a smaller relay that fit the same parameters so i just got the standard auto relay.

quick question... i have some 14awg auto wire. is that fine? not enough? or overkill? i won't get around to this tonight anyway so if i need some different wire i can pick it up tomorrow.

thanks guys.

where did you mount your switch?

 

[dean owens]

zip-tied to my handlebars. for what it's worth, the stock wiring for the grips themselves is 22awg, maybe 20awg. the wire they provided for power is maybe 16awg, but probably 18awg if i had to take a guess.

 

[dean owens]

since i'm asking so many questions...

take a look at the second switch on this page.
Switches for Motorcycle Electrics, cheap worldwide shipping.
would that handle my hand warmers? it has an off/low/hi switch just like my rocker switch, only it looks better.

i plan on getting a stebel horn but would really like to be able to keep my stock horn on a separate switch to be able to use it every now and then when i see someone on campus. if that switch would handle my heaters i could wire the stock horn to it and put the stebel on the stock switch. and it would hopefully be a cleaner look.

thoughts?

 

[dean owens]

ok, this is a bump on...

quick question... i have some 14awg auto wire. is that fine? not enough? or overkill? i won't get around to this tonight anyway so if i need some different wire i can pick it up tomorrow.

and a stab at answering my question.

if the warmers are 36 watts divided by 12 volts i would think the switch needs to be able to handle 3 amps. so this switch being 5 amps means i should be safe. correct?

also, how do you figure out the amperage needed for the relay?