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Posted By: Ryan_Helms Please Help Wiring DCDC Buck Converter - 06/15/22 03:05 AM
Hello I am currently building an Ebike and have been working on this for weeks my main wiring diagram is not in this picture but this is a simplified wiring diagram for a part that I am very confused on the DC to DC converter.

Converter I am using-

Now I am wondering if you have any questions, comments, thoughts, concerns, or tips. And is this wiring diagram correct.

Explanation of diagram-

Basically straight out of battery we have 72vDC and 150A of power. The main load of this battery is my Ebike controller which send power to my motor. Halfway through the connection I have a ferrule on the positive and negative line which allows the buck converter to get power. If my calculations are correct then there should be 72v and 1.75A of power running through that line. I got these numbers knowing that watts on both sides of buck converter are the same so 12V x 10A = 120W output. Then 120W/72V = 1.666A input. 1.666A/.95 efficiency = 1.75A input. I put a circuit breaker 32vDC 12A on the load side of the Buck converter because it says that this converter can take a max of 10A input or output doesn’t matter just can’t take more than 10A. Since this is Buck converter not a Boost the Output side will reach 10A much faster than input for example when the input of this converter is 72v 10a the output would be roughly 12v 57A. I put the circuit breaker on the positive line. Is the placement of the circuit breaker good? Then I have a 10A load on the buck converter output side. Load will probably more like 7.5A but for simplicity in this diagram I went for 10A.

TL:DR: is this wiring diagram correct. I would appreciate it though if you could read above what I typed.

Wiring diagram-
Posted By: gfretwell Re: Please Help Wiring DCDC Buck Converter - 06/15/22 05:58 PM
That looks like it will work but I doubt you need anywhere close to 120w for LED lights on a bike. What does the MFG say about input protection? With that many amps available from the battery I would put some kind of protection on the input and those conductors, near the tap, if it was just a fuse.
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