Introducing the Sparck Moto FB-11

[Tim]

Well I knew the length of the wire makes a difference, but I didn't think it would make that much of a difference on these short runs.  But I suppose every watt counts!

[Sonreir™]

The switches have a much greater impact than the wires, in practice, but it all adds up.

Lets say you're running a headlight with a high beam resistance of 3.5Ω...  At 14V that works out to 4A, or 56W.

Same headlight, but now we add only .7Ω for resistance of wire and switches.  Our voltage regulator is still keeping us at a steady 14V, so when resistance increases, it's Amps and Wattage that drops.

I = V / R.

Down to 3.3A now and that puts us close to 47W.  Lost 10W due to resistance.

And I don't think that .7Ω number is unrealistic for a standard setup, either.  I just measured a few wires, connections, and switches.  The switches I have in stock are adding about .2Ω per switch and each crimped connection is adding about .03Ω.  When you consider that most stock setups take the flow of current through the ignition switch, fusebox (twice), and several connectors, a straight shot from a relay is looking better and better.

[eyhonda]

Nice intro, Matt!  Much cost savings can be realized by not populating the full board.   As an idea, you can offer different levels/versions off the same PCB.   If you only want one switched relay circuit, offer a version without the other two relays and fuse sockets inserted.   As a correction, there are five ground taps not four (unless one is used for the off board relay).    Some of the smaller singles may only need a fourth of the capability.   Granted it will still be the same size for a base version, but the price can be lower.   Maybe set up 3 or 4 levels of build, based on the number of switched relays.    But at first we really need to beta test these parts to check current handling and overall reliability.   The components are already automotive spec'd.   It is the board that I designed that needs to be field tested before production release.    It sounds like we have a few willing testers though!

Edit:
Just to add to Matt's response on current draw and voltage drops.   The worst voltage drops/high resistance points are those old bullet connectors.   Any place with a loose connector will have a big resistance that increases voltage drop with current.  Off the top of my head, the on board relays have a 150 ohm coil that only draws 80 ma thru your switch.   If your battery is at 14 v, add up all the voltage drops and you are likely to be in the 11 volt range to your headlight.  With a relay circuit, it will drop much much less.

[Sonreir™]

As a correction, there are five ground taps not four (unless one is used for the off board relay).

Counting is hard... 

[Keiff Hardcore]

yes, all those little bastards add up.

i honestly dont get why there are so many dedicated grounds on bikes. it seams wasteful.

oh and it would be realy cool if you did a DIY kit that included wiring and maybe a few other bits so the entire conversion could be done with one purchase.

[irk miller]

It would seem that cleaning up the wiring with a system like this will also improve connections. Old, bent, loose or corroded stock connectors, can produce heat that also increases resistance.  Clean, efficient wiring has no faults.

[Rich Ard]

I haven't put the harness back on my Viragostrosity yet either, and will be doing so in the next month or so. Would definitely be in for the cost of testing.

[Mydlyfkryzis]

I haven't put the harness back on my Viragostrosity yet either, and will be doing so in the next month or so. Would definitely be in for the cost of testing.

Remember, the gray wire with the white stripe is not the same as the gray wire with the white stripe.  Also, the gray wires are ground, but not the gray wires. 

I know why you would never pass the bomb squad disarming test.....

Wiring must be one of the most challenging aspects....

[Rich Ard]

No problem at all. I just stop when the fire gets too hot.

[Mydlyfkryzis]

No problem at all. I just stop when the fire gets too hot.

Ha!!

[coalnation]

 

[canyoncarver]

Sonreir and eyhonda, this is seriously cool.  Put me down for one when ready.  I'm interested in what sort of cases you'll have also.  Will the onboard relays be replaceable ?

[Sonreir™]

Sonreir and eyhonda, this is seriously cool.  Put me down for one when ready.  I'm interested in what sort of cases you'll have also.  Will the onboard relays be replaceable ?

Not easily, no.  Relays have a pretty long life though.

[Ellwood]

I would be in on one of these also. The kit with some wire would be great too... Sourcing out all the little stuff zaps what's left of my brain. And as a man I get tired fast when shopping.

[AgentX]

Sonreir,

So the off-board relay, run by your key switch or toggle or RFID or whatever, controls the power main from the battery to the switched circuits, and a separate lead from the battery supplies the always-powered circuits? 


This looks awesome!!