Switch Box for accessoires

[rpvanoyen]

Hi there,

Before I'm building (altering) the additional electrics on my bike, I like making a schematic plan in advance. That way any improvements can be made during planning, which occurs up to three times on most occasions. I like to share the plan as I have it in mind now.

The switch box is made out of ABS, mounting it to the battery access panel on a rubber backing and holding it in place with the standard rubber string. All wires from and to the battery area are lead through one rubber grommet in a drilled hole from the edge of the frunk. This way the switch box can always be moved out of the way if maintenance desires this, also the rubber seal on the panel will not be compromised. In the longest side there are 4 switches of which 3 are illuminated by a small LED when the switch is on (orange for the battery charger, yellow for future flood lights and green for GPS power). The 4th switch has no built-in LED and is for the frunk interior lights.

I use heat shrink crimp connectors (Faston), heat shrink crimp and solder wire connectors and crimp wire ends (added shrink tube if needed). The main wire boom is hold together with a spiral tube, the two wires for the frunk lights will be captured in closed tubing. Probably next week I can start with the switch box, it can be fabricated whole and connections/switches tested before going live on the bike.

 

[AsureDawn]

Looks neat, will you have a relay in addition to this switch box, to ensure everything is off when the bike is off?

 

[rymech]

Always good to plan out your wiring! Something to consider along the lines of AsureDawn, for your switched power relay you should tap into that excellent factory option subharness. I like to minimize invasive wire tapping and the setup is all there minus subharness and relay kit. Looking forward to seeing progress!

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[rpvanoyen]

Thanks for your remarks.
I had a similar setup on my first bike - without a relay, tapping into the subharness or even fuses (!) - and had no problems whatsoever, despite the longer and thinner wiring.

I do want power when the bike circuit is off, so through the subharness and relay is not an option. Each switch is double insulated and rated for 125V~16A and switched off I do not measure any leak current. Voltage drop due to wire resistance is also way below the limit. It should function just fine. Full control so to speak.

 

[Juggler]

Always plan additional space for future improvements.

 

[670cc]

I would suggest a main fuse on the wire coming off the battery. You have no protection in the circuit until past the switches. Typically the individual fuses would be at the distribution point before the switches, because at that point you have gone to reduced wire sizes. A distributor block that was also a fuse block would be ideal.

Best practice would be to place the fuse as close to the current source as possible to protect the wiring.

 

[AsureDawn]

Makes sense--guess you'd notice if the flood lights or gps were left on...maybe not the gps sometimes. The charger connector shouldn't be an issue, so that leaves the frunk light as the only real concern there.

Keep us updated.

 

[rpvanoyen]

Thanks a lot for those wise remarks. I changed the drawing;



For the main fuse I choose 20 Amps as not all accessoires are in use at the same time.
The CTEK charges with 1A and the AirMan tire inflator which is only connected occasionally at home, is rated for 10A max. Fused for 15A should be fine.
The GPS draws less than 2A (fused 3A).
The future LED flood lights would be maxed at 36 Watts (3A) so here also fused somewhat higher (5A).

Yesterday I ordered five pieces of the 16 Watts LED lights (link) to be mounted at the highest point of the opened frunk lid. No, I'm not going to mount them all there, just one would probably more than enough already (the rest is for my car trunk). Fused at 2A will be a safe decision.

The light will be mounted with sticky double sided 3M foam tape, the light itself shall be double isolated and protected against the shaken contents of the frunk during rough rides, the wiring shall be safely improved with waterproofed connections and mounted hassle free with duct-tape. And should the (Chinese) light malfunction in future, it can be switched easily with a new one.

I do have a question... Should the negative wiring for each accessoire have the same gauge as its positive wire? Does the negative get the same current as the positive one?
And just for my knowledge... Can two 2 mm2 wires handle the same current as one 4 mm2 wire? I know that when it comes to resistance the answer is yes, but how is this related to current?

That's it for now.

 

[rymech]

It is perfectly fine to use the same gauge wire for the other side of the switch or accessory. The only time you would need to up your wire size is if two accessories are using the same ground - so two positive potentials and two current draws need to be taken into account for a shared ground wire.

I'm not familiar with the mm2 designation but an engineering chart for wire sizes is the best place to look. I'll see what I can dig up, I only have American Wire Gauge charts...


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[670cc]

Looks good.

Your positive and negative wires coming and going from a device would need to be the same size. Unless the device is leaking current to ground, which would likely be a fault condition, the current coming and the current going are the same.

Your 4mm2 ground wire from the switch lights and frunk light distributor is probably a bit oversized since it's only carrying the current of 4 small LEDs, but it certainly can't hurt anything if it's too large.

 

[rpvanoyen]

Generally speaking I probably use 1mm2 (AWG 17) for the LED in the switches, 2mm2 (AWG 14) for any accessory wiring from the distribution blocks and 4mm2 (AWG 11) for the main leads from and to the battery poles. Overkill in most areas but like 670cc mentioned, it can't hurt.

Well, I'm going to practise my crimping skills now...

 

[Convict1997]

for the frunk light, I'd consider some type of auto function with a spring loaded switch that would make contact when the lid is up. Probably still keep the manual switch for if you plan to leave it open for awhile with the bike off. Similar to the options for the dome light in a car.

 

[670cc]

for the frunk light, I'd consider some type of auto function with a spring loaded switch that would make contact when the lid is up. Probably still keep the manual switch for if you plan to leave it open for awhile with the bike off. Similar to the options for the dome light in a car.

Yes, keep the manual switch. I have such an automatic level switch on a frunk lid, but once it didn't shut the light off and a dead battery was the result. Also, there are times I don't want the frunk light to come on in the dark if I'm attempting to preserve night vision.

 

[rpvanoyen]

I'm not using a spring loaded (door) switch as during daytime I need no illumination, maybe only flashing red and blue LEDs
Just a manual switch will do just fine, but thanks for thinking with me.

 

[rpvanoyen]

I've been working some time on my project and know the value of decent tools and materials. Especially setting the crimping tools at the best force takes some time, doing trials on wire pieces until the result is perfect. Then heat shrinking takes some practise too (I use a paint stripper gun), keep those wires rotating to prevent overheating and to the point where the glue reaches the end of the shrink tube. I'm quite happy with the results so far.



Checked the switches for faults (none found, LEDs are bright enough for their size, switched in the off-position, power is cut off on both poles (nice!) so no leak current).
The ABS box has its holes (took some time to get it to the desired diameter (21 mm (26/32" ?)) and cutting my thumbs twice while cutting off the residue plastic...
It probably take some fiddling to get all wires inside, guide and fix them with tie-raps. The distributor blocks get some strong adhesive backing, the fuse block get fixed with small bolts and nuts. Also I must not forget to put on the rubber wiring grommets, wiring socks and heat shrink tubing before taking the last step of connecting it all in the battery area. I check everything multiple times before doing anything and so far that worked out just fine.

When everything (in the box) is connected, I'll do a final check (attaching the main leads to an external power source and measuring the wiring outputs) before putting glue on the switches edges and snapping them in their holes. Though any wire can be renewed if needed of course.

The next few days I'll be having a happy family gathering somewhere nice and warm, so the fiddling will continue next week. Have a great weekend to y'all!

 

[rymech]

Looks really good so far! What's your choice in tooling for crimping? I was going to recommend a product but since you were practicing I figured you were being plenty meticulous!


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[rpvanoyen]

I have them from a specialized automotive shop, no specific brand, paid about €40 per tool, works good and easy. Unless you're using it daily, this quality should be fine for years.
Some crimping tools are suitable for many different kinds of connectors, but I prefer single purpose tools. Personal choice.

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[rymech]

I'll second the single purpose tools. I really like the ratcheting ones with dies in the jaws. Most are derived from aviation and produce a super consistent crimp!

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[Convict1997]

Dang. Just when this is getting good, you go and take a break. Love to see other people's wiring projects. I've very anal when it comes to wiring accessories on my machines. My goal is to always make it look like it came from the factory. If someone unfamiliar with the bike were to take a look, I don't want them to be able to spot what I have done. I'll be following your project and it looks like you'll be even more OCD with your install than I am. I've got a friend that drives me nuts with his use of wire nuts and big balls of electrical tape to secure a rats nest of wiring that he always calls me to troubleshoot when something fails. Never can understand the folks that won't put a little time and effort into their install.

 

[rpvanoyen]

Beside I like to think out and building something myself, no factory item in this electrical stuff meets my demand for an honest price. I want it to be easy to understand so when a malfunction happens, I know where to look and fix it myself.

Thanks for the nice comments, my project will continue soon.

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