Bleah, not enough amps

reikiman's picture

Dang. The Lectra is still so close I can taste it.. but... The two major pieces left before it could be taken on the street is a) wiring the manual on-off switch I mentioned before, and b) getting the lights to work. I got the switch and am pondering choices on mounting it on the bike. But today I wanted to get into the lighting system.

The lighting system is a mess of wires in a wiring harness, and include in-line fuses and turn signal relays etc. Probably the existing wiring harness works but it looks like a mess and I keep thinking I want to cut it all out and start over. In any case I need to work out which parts of the harness go where etc.. at the end it might be a simple enough matter to find two wires for a 12v connection and the whole thing lights up. But so far it hasn't been that simple.

Anyway I tried connecting the lights directly to the DC-DC converter just now to make sure they're all working... and it gave me a chance to measure the amp load.

Wiring the lights directly was successful and the lights do indeed light. However....

The headlamp (a normal incandescent headlight) draws 4.6A @ 12v (or about 45 watts). The turn signal I hooked up (an LED unit) draws 0.6A in normal mode, and 1.5A in turn signal mode.

The DC-DC I have is home built from two individual DC-DC units. Each are 2.5A so the total capacity of the DC-DC is 5A. If you add up the amperages above it's well above 5A, powering the headlight and running lights will draw over 8A and close to 10A if a turn signal is on. Doesn't sound like I'll be able to put a stereo system on this bike... }:)

Bleah.. my DC-DC doesn't have enough amps.

The options I can think of are:

  1. Find an LED headlight that requires fewer A's and is still DOT approved
  2. I have two more of the DC-DC units, so I could wire them in and make the total be 10A
  3. Find a bigger capacity DC-DC unit.. EVPARTS has some which might work
before comments


MB-1-E's picture

I wonder if anything like this might work?

LED Pod light mod

Motorcycle Lights

Dave B

<a href=" - Bridgestone MB-1 Mountain Bike</a>

reikiman's picture

I don't know the truth.. but what I found yahoogling for various variations on LED headlights for motorcycles is.. they don't exist. There's all sorts of LED turn signals and accent lights. But headlights? Not that I could find.

I've also been yahoogling for DC-DC converters & electronics surplus dealers. The problem finding specific DC-DC converters is the many variations on them. They come in various input voltages, number of outputs, the output voltages, and power conversion. And it seems the specific thing I'm looking for is out of the ordinary, but it does exist.

The DC-DC converters I already have are Avansys AW30-48S12 with Vin ranging 36-72v and Vout 12v @ 2.5A ... I have four of them, which if paralleled together would provide 10A. That's still a bit skimpy for my bike, I'd feel better with 15A capacity. But I wasn't able to find more of these specific converters.

I did find this:-

48-12+/- DC-DC Converter (CNV035)
30 Watt DC-DC Converter

P# AV30-48D12

Input: 36-75VDC
Nominal Input Voltage: 48VDC
Output: +/-12VDC @ +/- 1.25A
Size: 3.0"L x 2.5"W x 0.50"H

I could get a couple of those and parallel them with the four 2.5A units I already have and it ought to work.

At digikey I found Isolated Enclosed DC-to-DC Converter PWR,SPLY,DC/DC,50W,12V/4.2A,
... Input Range (volts) (min-min) 36-72V Output Voltage (volts) @ Current (amps) +12V @ 4.2A ... so three of those in parallel would work.

And at newark electronics I found AEH25B48N-L — ASTEC — DC-DC Converter (Datasheet) Input range is 36-75v and output is 12v @ 20A

I want to especially point to Newark's website for DC Converters ... in most cases the dealer simply lists the converters in some random order and it's up to you to page through 10's of pages of nearly similar items looking for what you want. At Mouser Electronics they have a query function that lets you select DC-DC converters by various attributes, but I found theirs to not work very well. At Newark they have a similar query function but this one does work properly. Or it might be that Newark has stock that meets my needs and Mouser doesn't.

jdh2550_1's picture

If I remember correctly LED headlamps are a no-no as far as DOT approval goes (not sure why). I seem to remember a thread a while back on this.

John H. Founder of Current Motor Company - opinions on this site belong to me; not to my employer
Remember: " 'lectric for local. diesel for distance" - JTH, Amp Bros || "No Gas.

reikiman's picture

If I remember correctly LED headlamps are a no-no as far as DOT approval goes (not sure why).

I believe the process is that the U.S. Department of Transportation (a.k.a. DOT) approves vehicle parts on criteria like safety, complies with various requirements they've determined, etc. And that individual manufacturers have to have their products certified. etc. The crash testing that's done for whole vehicles is part of this ... but the parts themselves contribute to overall safety, right? While reading this morning I came across a page listing various motorcycle headlights, and one of them was described as not being certified (DOT compliant) but still being a very bright bulb, etc. In short.. some company would have to go through the certification process.

In the area of "it's not illegal unless you get caught" ... how likely is an non-certified light to be caught? That's rather unlikely I'd say. Except that LED lights do have a distinctive shade of white which would make it readily obvious they were being used.

At the same time there's a certain comfort in knowing the parts on the vehicle are known to meet safety criteria, right? But even so I wasn't able to find LED lights which are bright enough to be headlights, so even if I were brave enough to do it anyway regardless of the rules, they don't seem to be available.

In any case... I remember on the Xebra_EV group LED headlights had been discussed several times. The best I found was this message:

Which points at this interesting article:

That article says that LED headlights have been appearing on concept cars, and that sooner-or-later the DOT will approve some LED lights.

Fechter's picture

Is your battery 48v?

I've found some small switching power supplies designed to run off AC line power that will maintain output when powered by as low as 30vdc. These are the little power bricks that run a computer flat screen or printer type. Likely candidates will have an input rating of 100vac - 240vac. You can hook it right up to a battery and it works. You don't even need to worry about the input polarity.

Some that I tested would only work above 60v.

These things are dirt cheap and come in a variety of output voltages and currents.

Another cool thing is the input and output are fully isolated. You can safely use the frame as the ground for the output.

The actual dropout voltage will vary by model, so I only have data for the particular models I've tested. If you have one of these lying around, you might try it.


reikiman's picture

No, my battery pack is 60v. I'm not sure, but is that a typical power brick such as for a laptop? Also the label says 1.5A output current, so I'd need about 10 of these. The thing I ordered from Newark is one small unit that will do 12v 25A; looks perfect.

Fechter's picture

Yes, it's a typical power brick, switching mode power supply.

OK, it's too small for your application, but these would be great for a small scooter or bike running a 10w or 20w halogen lamp.

You can find much larger ones at some of the surplus places that might have the kind of current you're looking for.

How much was the one from Newark?

reikiman's picture

How much was the one from Newark? You can see the price through the link above... qty 1 is $113 plus shipping.

reikiman's picture

ergle... I found out this morning that Newark had canceled my order without telling me. Explanation: The manufacturer of the DC/DC I'd ordered would not fulfill an order for just one unit.

I went to Digikey to order my second choice, but no matter how many I ordered their site said the quantity could not be fulfilled.

I think a trip to halted specialties is in order. That's my local surplus electronics parts place... and they're very likely to have some of those power supply bricks that Fetcher mentioned.

reikiman's picture

Powerstream, .. has a couple DC-DC's which will work. A 36-72 volt input, 12 volt output, 12.5 amps capacity runs for $125.

45 watts seems a little light (no pun intended). I would have thought closer to 60 for a normal high-beam bulb. I ended up with a Vicor 100 watt DC-DC and plan on putting in a HID kit instead of an incandescent bulb. It should be much brighter, you can get a tint to the color and it uses about 35 watts according to the web sites.

I don't think you can get enough light from LEDs these days although converting the other bulbs to LEDs should be a no-brainer for us EVers.


For strong LED floods On EBay check Under the ( solar panal ) down about half way for low voltage 90 cell flood s

thank GOD I wake up above ground !!!!

Another VERRY bright LED comes with a lense from key s [dragon puck][linearlight optics ] probably want to talk to one of their reps or your local electric supply houses ( find the one that has sylvania )

thank GOD I wake up above ground !!!!

reikiman's picture

Are these DOT certified for use on vehicles?

Well I do not know I just saw them at Viking electric's supply and was impressed with their brite white even in the daytime

thank GOD I wake up above ground !!!!

andrew's picture

Are these DOT certified for use on vehicles?

I imagine they probably are, as they are available at auto parts stores for headlights. On their website they have some neat comparisons. I think I'll check into some for my bike.

[url=/forum-topic/motorcycles-and-large-scooters/587-my-kz750-electric-motorcycle-project]KZ750 Motorcycle Conversion[/url]
[url=/forum-topic/motorcycles-and-large-scooters/588-fixing-my-chinese-scooter]900 watt scooter[/url]
Pic from http://www.electri

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