aiyoh....so easy....
first... get
THIS. im using this to power a usb port under my seat, my motowolf phone holder that has wireless charging along with a pair of led spotlights. or u can DIY this with a 30A automotive, bosch style relay and one of those multiport fused distribution blocks. personally, id just get this, much smaller package and neater. downside is 20A which is actually more than enough based on my usage... looks to be ok with urs too. same thing i posted in 1st post of this thread. just make sure to tap the acc wire to a keyed power source so it turns off when u turn off the bike.
then connect 1, 2, n 4 to it.
for 3, wanting to get the quadlock-like cable is just over complicating things. keep things simple. a USB port in a waterproof location along with a longer USB cable (which i believe the sjcam case u mentioned has, coz my SJ4000 case cable is really friggin long)... basically u can use 4 with a long usb cable. again, i used to run this with a powerbank in a ziplock bag in my jacket pocket. lasts the whole 10 hour day ride....rain or shine
i also saw the design of the
quadlock cable. i wouldnt trust it for waterproofing on the source side even if its using the target side design. why? coz the target side has a "hole" for the cable to plug. while most, if not all USB A ports are flush with the surface, so theres nothing to plug. even usb C ports as source are flush with the surface so no actual hole to plug.
also, if u plan on getting the SJCAM waterproof charging case... u cant change the cable without damaging the waterproofing. its kinda embedded in the screw on cap n kind of a tight fit. so ur stuck with that cable anyway.
for the fuse box i mentioned, connect all wires and route them where ever u need in advance. if any unused, just tape/heatshrink it off first at least itll be accessible later on when u need it. no need to open up everything n reroute new wires bla bla bla.
for carplay/ android auto... my friend bought the greenyi. he also uses a cheapo RM30 bt headset (non intercom). everything runs well together... he normally uses it for GPS while listening to music.
Remember...keep it simple. Recognize when u may be overcomplicating things and look for a simpler solution. Sometimes itll just appear
1. Power splitter box you mentioned I had bought it last year. Recently bought another type, smaller unit. Gonna use it to supply to spotlight and USB charger.
2. SJCAM C200 Pro. Supplied with "waterproof" cable at target side. I think workable by hiding the connector away when not in use. Also possible to use a powerbank in jacket if I wanted to mount it on my helmet.
3. Carplay / Android Auto. The default connection is Phone --> HeadUnit --> Helmet Comm. Helmet is not connected to phone. This is where the complicated part comes in. Most HU does not use proper BT profile. When connected to comm, your comm unit will turn to 1:1 connection and you won't be able to connect and talk another rider. What's prefered is Headunit <-- Phone --> Helmet comm. I am trying to test this when I have the opportunity on phone side, see if I can redirect audio through another BT device.
4. Cabling. Yeah, intend to just lay them down first.. if you know how interesting and fragile is it opening up those fairing, you won't want to do it a 2nd time