Wiring up my lights (Step down transformer)

[Pwnlord187]

Hello fellow ebikers. I am currently wiring up my lighting and considering using my main battery for my lights as my external died on me in the night which was a buzzkill (4x18650's) the lights im running are as follows, 1x 18W led headlight and 2 x all in one led strips (using only left and right lights on the front of course)

I have a 60v to 12v step down transformer from an old scooter i had, but curious where i should put an inline fuse when installing it, would i put one between the battery and transformer? Or one just after the transformer? Or both? And what rating fuse ? would i need to use a 120V50A fuse in and 120V5A fuse out? (My controller is rated at 50A output, 1500W)
Also, im assuming id need to use heavy duty cables and connectors if I were to split the power from the main cable from my battery? (So it wont interfere with the draw my controller needs?)

And one last thing.. my controller, has an option to output for lights using the lcd backlight switch to activate its power, however the guy who sold it to me (hallomotor) said its only for 5W of led lights. And I could not find any documentation anywhere that says this..I guess Ill just assume that is correct and not bother with that feature.

If any of what I said is incorrect, or if theres anything else I should know, please comment
Much appreciated
Chris

 

[Ianhill]

Place the fuse as close to the battery as possible take a new feed if possible try not to cut any wires or add more connections than needed, The cabling only needs to be thick enough for the current handling of the lights so 1.0mm stranded would be more than enough for 3 amp at 12vdc or 40w of led, If the controller does have a light feature for 5w led check the voltage you could use a suitable relay and trigger the larger lighting through it for less switches check the output of the dcdc convertor and fuse it with maxi blade fuses at its max output and go from there.

 

[Pwnlord187]

Ok great. Thanks for your reply. Basically, ive already cut the power wire from the XT plug from my battery, to the controller to put on the right plug type, i was thinking of just disassembling my patch job (2 x butt connectors crimped, hot glued and wrapped in electrical tape) and adding/changing to the best way to splice and split this line..was thinking of ring connectors and a terminal block because i already have the parts, but could pick up something different if there is a better way
Cheers

 

[Pwnlord187]

Also the voltage out from the controller for the LEDs isnt stepped down at all (i assumed it would be for 12v initially, and ended up just frying my lights on round1) so id have to step it down myself, but if i use a relay for the headlight, would i need to add a 2nd transformer for it, or somehow run it through the same one?
(think i gotta grab a pen and paper here, haha)

 

[Ianhill]

Also the voltage out from the controller for the LEDs isnt stepped down at all (i assumed it would be for 12v initially, and ended up just frying my lights on round1) so id have to step it down myself, but if i use a relay for the headlight, would i need to add a 2nd transformer for it, or somehow run it through the same one?
(think i gotta grab a pen and paper here, haha)

Use a multimeter and test it may be a battery feed or anything upto 48v but test is best, small 48v relays are available its best to use a purposed one as a 12v relay in 48v will draw a fair bit of power, get a basic schematic together its priceless for looking over to simplify the system.

 

[kneedeep]

Personally I would put a fuse between the battery and transformer to keep the battery safe and a fuse after the transformer to keep the led safe from surges. Also the transformer will have a no load rating (the amount of power used with no lights or other power draws). So take your no load draw and add you draw from your lights to determine the wire fuse and switch size. Also switch prior to transformer so the no load draw does not drain your battery on daytime rides.

 

[Pwnlord187]

Thanks. Good advice regarding the switch as well, was about to overlook that one

 

[Pwnlord187]

I am not too familiar with relays and have minimal experience with them other than wiring up relay flashers. However I do have a basic understanding of what a relay does.. but unsure how to install/wire one ill have to look it up. So with this idea/config, would i be running everything right from the battery to transformer, but using the relay just to trigger it all on from the system switch? Or wire just the 18w headlight seperate from the controller, and use the relay to activate it with the other lights?

 

[Pwnlord187]

Maybe draw a picture and upload it?
(If im asking for an inch , and now a mile forget i asked, all good)
thanks

 

[Ianhill]

Maybe draw a picture and upload it?
(If im asking for an inch , and now a mile forget i asked, all good)
thanks

I'll try my best to help, I thought you have the display for controller and could activate lights through it you could use that by just energize the hold on coil on a 4pin relay with the controller led feed, then just run a feed fused from battery to lights through it, when you turn lights on it all should play nice and light up, select as low a power coil as you can for the voltage you need, the led light won't be inductive so its a light load for a relay to switch.

 

[Pwnlord187]

cool that makes sense, thanks

 

[Pwnlord187]

i guess I'd still need the step down transformer in the circuit, and a switch for it.. Im just going to use a dedicated switch for the lights I think.. maybe I'll revisit this in the future though

 

[Pwnlord187]

Pieced this together last night. Any issues or suggestions before I install it please let me know!
Thanks
(Need to add a fuse by the battery , assuming a 50A car fuse would be what i need, just dont have one yet, also the terminal block was rated for 30A, but an 8-bay that i cut in half, and double stacked the mounting plates on the far left and right sides, where the battery connects to the controller)
Cheers
(The right side of the image got cutoff on my phone, but saving the pic seems to display in full)

 

[Ianhill]

Volts*amps =watts 50amp way to high

 

[Pwnlord187]

Alright. I just assumed since my controllers max amp draw is 50A thats what id need. But had a feeling something was incorrect there
What size would you reccomend?

 

[Pwnlord187]

My controller reads almost 2000W when its maxed out, and I have a 52V battery, so.. ok 40A then. Thanks for noticing