Step Down EV battery voltage for lights, alarms, etc

General Discussion about electric vehicles.
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Pegasus195
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Step Down EV battery voltage for lights, alarms, etc

Post by Pegasus195 » Nov 15, 2017 11:03 am

So I've been looking for ways to power my headlight for my ebike DIRECTLY from the battery, with a device through it probably. These days, I power my ebike with 1 18650 cell, and needs to recharge it seperately. I want to have an output from my battery (48v) step down to 5v for some low voltage uses such as phone charger, alarm, lights, horn, etc. I found a step down board called lm2596, but It's limited to 50v, while a fully charged 48v battery can go up to 54.8v, and I'm afraid of damaging it. Maybe some ebike controllers do have a 5v output for these, but I'm using some chinese bldc controller, that seemed lack of this feature. Maybe any other solutions you all have? Hope I can find a way...
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350W Prototype ebike
1500W Custom Full-Aluminum Motorycle-killer(ongoing)
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2.2KW electric vehicle (ongoing)
Custom electric skateboard (ongoing)
Recommend me some ideas, I got 6 unused (yet) ebike hub motors, and 2 unused(yet) Motorcyle/scooter hub motors

kdog
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Re: Step Down EV battery voltage for lights, alarms, etc

Post by kdog » Nov 16, 2017 5:57 am

Try an AC-DC smps ( wall wart) of suitable voltage and amps on the out put. plug AC side into main battery, if it doesn't work battery voltage might not be high enough. I run my lights directly off my ebike battery... Works great.

captain387
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Re: Step Down EV battery voltage for lights, alarms, etc

Post by captain387 » Nov 16, 2017 6:29 am

Some wall warts will work, and I have done this in the past.
If you are looking to go with the LM2596 for size try searching for LM2596HV aka High Voltage.
This will take the upper limit to 57v
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wturber
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Re: Step Down EV battery voltage for lights, alarms, etc

Post by wturber » Nov 24, 2017 10:41 pm

I use one of these - which puts out 12v.
https://www.amazon.com/gp/product/B0151 ... UTF8&psc=1

I further down-convert to 5v for USB based devices using a car accessory plug to USB adapter.

This version goes directly to 5v if you have no use for 12v.
https://www.amazon.com/uxcell-Converter ... 60+v+to+5v

Note that the electronics are potted in epoxy. So these are pretty waterproof.
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Pegasus195
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Re: Step Down EV battery voltage for lights, alarms, etc

Post by Pegasus195 » Nov 25, 2017 7:59 pm

Thanks all, those information are very helpful
DARE TO EXPLORE EV
My Projects:
350W Prototype ebike
1500W Custom Full-Aluminum Motorycle-killer(ongoing)
500W electric scooter (ongoing)
2.2KW electric vehicle (ongoing)
Custom electric skateboard (ongoing)
Recommend me some ideas, I got 6 unused (yet) ebike hub motors, and 2 unused(yet) Motorcyle/scooter hub motors

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