wiring auxiliary lights

[SilverBullet]

I am installing two 10w LED lights as auxiliary driving lights. I will wire these directly in to the low beam power to avoid any switch and extra wiring. However I'm not sure if I can safely splice into low beam wiring without using a relay. I would like to avoid a relay if at all possible for simplicity and reliability.

I have measured the LED lights and they are together using a total of 1.1 amps. Stock 55w bulb should be using approx 4.6 amps (Amps = Watts/Volts) for a combined total of 5.7 amps. Since the stock 60w high beam bulb uses 5.0 amps with the same wiring it seems to me that the additional 700mA should not pose any issue.

Of course I'm extra careful with a new bike and still under warranty also so asking opinions from the ones here that have a solid electronics background.

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[JAG-TE630]

Hi, please tell me if you had any trouble with the bike after installation, if possible send pictures, It is always recommended to use a relay. On my last bike(klr 650) I installed extra lights,

 

[JAG-TE630]

I had some trouble with the battery because after extended hours of night riding the intensity of the lights will go down and the battery was drained, I was taking too much energy out fron the system.

 

[BiG DoM]

LED lights 9esp these) draw so little there should be no issue at all IMO. A relay generally adds to reliability.

 

[blakebird]

I've used a Fuzeblock FZ1 fuse block with built-in relay. Small and compact, easy to locate in confined spaces - and allows you to connect accessories switched or unswitched just by where you put the mini-spade fuse. I've had these on my FJR and other streetbikes, as well as a few dualsports.
http://www.fuzeblocks.com/index.php?pid=1#board

I've also used Eastern Beaver's Three Circuit Solution
http://easternbeaver.com/Main/Products/Fuseboxes/3_Circuit/3_circuit.html
Eastern Beaver also makes a compact fuse block
http://easternbeaver.com/Main/Products/Fuseboxes/PC-8/pc-8.html

 

[SilverBullet]

LED lights 9esp these) draw so little there should be no issue at all IMO. A relay generally adds to reliability.

If you are pushing the capacity of stock wiring then yes a relay will add to reliability and safety. However if not needed then an inline relay and the extra wiring required will be a negative, just more possible components to fail. Commonly available 12V relays are somewhat prone to failure. Search around though and you can find the much better $20-$30 Bosch relays.

So for example if some electronics whiz here can calculate what current the stock wires and switches can handle and it is 10amps then a no brainer and I leave out the relay. If it can only handle stock high beam draw plus say 10% safety margin then I am too close for comfort and will install a relay.

BTW these little LEDs have incredible light output!! I can't believe they are only 10W each. I will post back after the install is complete with some photos.

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[Kenneth Webb]

Using an online DC wire size calculator: 6.66 amps, 12V DC, 1 meter wire length, 3% acceptable loss, use 18 AWG. You need to figure out what wire size you have. For 1% loss you need 16 AWG, and I'm sure it's smaller than that.
Here is the link I used: http://www.solar-wind.co.uk/cable-sizing-DC-cables.html

 

[SilverBullet]

Using an online DC wire size calculator: 6.66 amps, 12V DC, 1 meter wire length, 3% acceptable loss, use 18 AWG. You need to figure out what wire size you have. For 1% loss you need 16 AWG, and I'm sure it's smaller than that.
Here is the link I used: http://www.solar-wind.co.uk/cable-sizing-DC-cables.html

Thanks for the info Ken. Equally important though is the headlight switch and other relay(s) in the headlight circuit. From past bike experience it is usually the switch contacts that are the weakest link and fry.

BTW I really love how the Husky circuitry keeps the headlight off while the starter is cranking the bike. Headlight only comes on after the engine is running, that is why I will definitely tap into it for aux light switched power. Other bikes I've had have the headlights and driving lights on while cranking and cause a bigger demand from the battery.

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[KLOC]

Headlight only comes on after the engine is running, that is why I will definitely tap into it for aux light switched power.

I'd like my relay to only get signal power when the engine is running, but I haven't been able to figure out which wire to use as a signal.

 

[blakebird]

I'd like my relay to only get signal power when the engine is running, but I haven't been able to figure out which wire to use as a signal.

When I wired a fuse block into my FJR, I didn't want any accessories coming on until the engine was running, so I Posi-tap'd the relay into the headlight wire.
On the TE 630 I'll tap the relay into the 5w running light, just to get switched power - it will come on with the key, not the headlight.

 

[SilverBullet]

I'd like my relay to only get signal power when the engine is running, but I haven't been able to figure out which wire to use as a signal.

See your owners manual, it has good details for this. Relays under your seat are for engine on power source. Pick the desired one and then use schematic with color codes to identify your tap wire for sense to your relay.

For me I want engine on but also only when select light beam is on so will tap directly behind H4 bulb connector. I want relay on with low beams and relay off with high beams.

I'm now resolved to using an extra relay just to be safe than sorry. I would kick myself in the head if I caused any kind of electrical problem on my new bike by trying to eliminate a relay (even though I think probably unnecessary).

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