How do I wire up 12v headlight on Sabvoton 72100

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wice.lt   10 µW

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How do I wire up 12v headlight on Sabvoton 72100

Post by wice.lt » Jan 17 2022 1:12pm

New build and can't figure out how to power on my headlamp. I have a 12v LED light that I would like to use. From what I gather there are 2 options. 1 figure out what wire to use to energize a relay that would kick in DC2DC converter to run 12v or option 2 how to figure out the UKC1 monitor "headlight" button. Documentation is not clear. Thanks in advance. My battery is 72v.

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amberwolf   100 GW

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Re: How do I wire up 12v headlight on Sabvoton 72100

Post by amberwolf » Jan 17 2022 8:01pm

You'll need a DC-DC converter that can output the current your headlight requires, at minimum, that takes it's output from your main battery's output. If you use the headlight all the time, just wire the DC-DC input side to the battery on the controller side of the main battery power switch (if you have one). If you prefer a switch, then you can get handlebar-mounted (or wherever you want) switches to control the input to the DC-DC from the main battery. Just get one that is not "momentary" (or else you have to hold it down to keep the light on).

IF you prefer to use the existing headlight function, and there's no documentation for it, you'll have to testing to determine both how to use it and how to wire it.

For the UKC1 button, which wire that comes out of it or it's wiring harness changes state when you use the button to change state of the headlight function? THat's the wire that you will use to control the DC-DC that powers the headlight. How that control will work depends on how the UKC1 control wire works.

Set your voltmeter set to 200VDC. Black lead to battery negative. Red lead to first unused wire coming out of the UKC1's wiring harness. Power system on. OPerate the headlight button. If teh wire being monitored didn't change voltage even a tiny bit, it's probably not the right one (depends on how it works). Red lead to next unused wire. Operate headlight button. Etc.

When you find one that changes voltage only when the headlight button is operated, that's the one the button is controlling. If it changes from around 0v to some higher voltage (probably either 5v or the battery voltage), then this can be used to drive a relay to switch the DC-DC on. It is probably a very low-current signal, so directly driving a DC-DC or headlight from it may damage it.

Once we know what signal it makes, we can figure out a control method using it.
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wice.lt   10 µW

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Re: How do I wire up 12v headlight on Sabvoton 72100

Post by wice.lt » Jan 26 2022 9:48am

Thanks for suggestions. I ended up running 72v to the switch at a handlebars that in turn powers on the DC2DC that then powers the light. I did try to find a wire that would send me any reliable voltage to power on the relay, but all the wires coming from the controller were either 72v or 3v or 5v, but the 3 and 5 were some sort of signaling wires, because once I connected them to the solid state relay it was pulsating. Hope this will be of help to someone. I can not believe that there is not a better way, but it will have to do for now.

xylene23nyc   10 mW

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Re: How do I wire up 12v headlight on Sabvoton 72100

Post by xylene23nyc » Feb 26 2022 1:06am

wice.lt wrote:
Jan 26 2022 9:48am
Thanks for suggestions. I ended up running 72v to the switch at a handlebars that in turn powers on the DC2DC that then powers the light. I did try to find a wire that would send me any reliable voltage to power on the relay, but all the wires coming from the controller were either 72v or 3v or 5v, but the 3 and 5 were some sort of signaling wires, because once I connected them to the solid state relay it was pulsating. Hope this will be of help to someone. I can not believe that there is not a better way, but it will have to do for now.
I'm waiting on my Sabvoton 72100 to go with a 72V battery and 72V to 12v DC-DC for lights. What wire from the controller did you use to get 72V to the switch on the handlebars that turns on your DC-DC? Did you need to use a special high voltage/high amp switch? Do you have a link for the switch you used?

Thanks in advance

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