How to run 12V lighting and accessories with a 6V charging system

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Curly 64
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How to run 12V lighting and accessories with a 6V charging system

#1

Post by Curly 64 »

I discovered a "step-up" converter that will make using modern electrical items on an old bike simple. It changes voltage from 5-11, negative ground to 12v. negative ground with a maximum output of 10 amps. I'm sure they've been around a while, but I just learned about them, so I thought maybe others hadn't heard about them yet either.

I bought it for $28.99 from Amazon. I found two brands, Digiten and Smakn, that were exactly the same item with different names, but the Smakn unit was about $49. The one I got was about 3" square.

I tested it when it came and it worked just like I hoped it would. My '64 has a 15-amp generator so if I use a 12v halogen headlight it would take about 4-5 amps at 6v to run the light that takes about 2-3 amps at 12v. I put an ammeter in the line from the 6v battery supply to the converter and saw about 4 amps draw, then put the ammeter in the line from the converter to the light and the needle showed about 2 amps draw. The ammeter I had isn't real accurate, but it appeared to me if I use a halogen or LED headlight I'd be at or under 2 amps. Running LED 1156 and 1157 bulbs for the tail/brake light and turn signals should take less than that. I can use an electronic flasher for the LED's.

I also want to put a power port on the bike to be able to charge my cell phone or operate a gps if necessary.

I can have plenty of generator left to run the ignition and horn on 6v so they don't have to be changed at all, and I think I will wire a pair of spotlights on 6v that will be wired independently of the rest of the system to give me a backup system to give me lights in case the converter should happen to fail. I will not turn them on unless it's necessary. The only thing that would not look original on the bike would be the little converter.

Here's what it looks like.
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converter 2.jpg
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Mark44
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Re: How to run 12V lighting and accessories with a 6V charging system

#2

Post by Mark44 »

Nice solution! It looks like you have done your homework on the voltage and current requirements.
I wonder how this gadget works? It can't be just a transformer, since transformers require AC. I would guess that it has an inverter to convert 6V DC to halfwave AC, then a transformer to step that up to 12 V AC, then another inverter to get it to 12 V DC.
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Re: How to run 12V lighting and accessories with a 6V charging system

#3

Post by ncmc47 »

While in theory a transformer will only work on AC, how does a coil work then. Since a coil is just a transformer. Basically the voltage coming off the armature of a generator is rectified by the segments of the commutator. So basically you end up with pulsating DC, which will work a transformer. So in reality it doesn't require a rectifier.
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Re: How to run 12V lighting and accessories with a 6V charging system

#4

Post by ncmc47 »

Went back and reread Mark44's post and thought about it for awhile. I studied electron theory a long time ago. What he calls half wave DC is what we called pulsating DC. Back then we didn't have chips, still in transistor technology, and LEDs were expensive. Anything that was cheap was LCD, and tubes were still around. They may do things different today, but all that is needed is a basic step up transformer, which will work with pulsating dc, just like a coil does. Could do it yourself at home, but easier to just buy At $29.99 or what ever.
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Re: How to run 12V lighting and accessories with a 6V charging system

#5

Post by awander »

A transformer won't work here, guys. The generator may be putting out "pulsating DC", but it is instantly smoothed to constant DC by the battery.

Even if you connected a transformer to the output of the generator, before going to the regulator, I doubt it would work very well, if at all.

The converter shown above is a simple switching power supply. Looks like it could be hidden inside the nacelle if you wanted to keep things looking stock.
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Re: How to run 12V lighting and accessories with a 6V charging system

#6

Post by devon john »

i was looking for something like this to run the sat nav i.e. 12v

if this will do the trick could fit in tool box and a mini socket ,,

anyone bought one and tried it yet???

john
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Re: How to run 12V lighting and accessories with a 6V charging system

#7

Post by Mark44 »

ncmc47 wrote:While in theory a transformer will only work on AC, how does a coil work then.
The points act as a switch to turn on and turn off the voltage to the coil. As the current rises in the coil's primary windings, a voltage is induced in the secondary windings. Same thing happens when the current to the coil is shut off. Without the points opening and closing, the coil could never act as a transformer, boosting the voltage from 6 or 12 V DC up to whatever the output voltage of the coil is.
Curly 64
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Re: How to run 12V lighting and accessories with a 6V charging system

#8

Post by Curly 64 »

i was looking for something like this to run the sat nav i.e. 12v

if this will do the trick could fit in tool box and a mini socket ,,

anyone bought one and tried it yet???

john
I have a Garmin GPS so I hooked it up and it worked fine. I've used this Garmin on my '74 and it works except the vibration seems to make the electrical connection from the unit to the wire loose connection temporarily from time to time. It gives me a message that power has been lost and acts goofy. If I don't plug it in and just use it on its own battery it won't do that and it works until the battery wears down. It might be a unique problem with my unit and wouldn't do that for every Garmin. I just charge it up when the bike is stopped. Anyway, it worked with the voltage converter.
devon john
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Re: How to run 12V lighting and accessories with a 6V charging system

#9

Post by devon john »

thanks Curly
that will make it easier as i do a few miles and the sat nav is great for that last 10 mls ,,

will get and fit one

john
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Re: How to run 12V lighting and accessories with a 6V charging system

#10

Post by Frankenstein »

Curly, are you running a Fan cooled genny? Just curious what genny you have that's rated at 15 amps.
DL
Curly 64
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Re: How to run 12V lighting and accessories with a 6V charging system

#11

Post by Curly 64 »

Frankenstein wrote:Curly, are you running a Fan cooled genny? Just curious what genny you have that's rated at 15 amps.
DL
That's a very good question. The generator I have is original and I studied the manuals to find out what the amp output is but they aren't clear on that at all. I got my statement from a Cycle Electric add that stated "Cycle Electric Inc. manufacturers the model 61 6-volt generators to Harley-Davidson specifications for restoration purposes. The model 61 is rated at 15 amps and is capable of producing 20-30 amps."

In my own judgement, pushing one of these generators to 15 amps for more that a couple of seconds would be burning it up. I think even 10 amps would be a big load for it if it was run that way very long. That's why I'm trying to minimize the load I'm putting on it by using LED lights with my new system. I'm trying to stay at a maximum of about 2.5-3 amps 12v total load. If their ad is accurate and their genny is actually made to HD specs, my statement is right. If they're overstating their generator's abilities, I'm also wrong in my statement. It would be the first time, but I could be wrong...:) Jerry
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Re: How to run 12V lighting and accessories with a 6V charging system

#12

Post by Frankenstein »

Thanks, I guess I'd never read the spec's on the model 61. As an semi educated guess, I'd say that it would be capable of doing 10 amps all day without working up a sweat. The 32/52 series would. The wire gauge on the armature windings in those models is heavy enough to carry the current without overheating and I would guess the wire size didn't get smaller on the armature until they went to the 65A.
You're wise to keep the demand level as low as possible, a sure way to assure long life.
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Re: How to run 12V lighting and accessories with a 6V charging system

#13

Post by Curly 64 »

I have finished assembling the bike and have put several hundred miles on it now so I wanted to update my post about the conversion. I like it very much and am completely satisfied with the way it works. I have an LED fan-cooled headlight bulb installed in a German Hella lens housing and LED bulbs on the brake/tail light and the turn signals. I bought a special flasher for the turn signals that allows me to mix and match LED and conventional bulbs should I have a failure and can't easily replace the LED's. I hid everything in my old beat-up tool box. It was all cracked up, dented and had large areas where the chrome was gone, so I welded all the cracks, straightened the dents and put some wrinkle black paint on it for a different look.
I was able to stay very close to the original wiring diagram by using trigger wires from the different functions to operate 6 volt cube relays to turn on and off the 12v circuits. Each of the three systems are protected with a 10 amp circuit breaker, the turn signals, the brake light and the headlight. I didn't need a relay for the turn signal circuit because I can use the ignition switch power wire for the trigger so any time the ignition switch is on the converter turns on and can power the turn signals. I ran a trigger wire from the brake light switch to turn the brake light 12v circuit on when I push the pedal, and the ignition switch headlight circuit is the trigger for the headlight relay.
I used two toggle switches for the passing lamps and left them on 6v with 30Watt bulbs so I can use them as daytime running lamps, one or both at a time and as a back-up system for night time if my main headlamp fails. It's just to help me get home
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Re: How to run 12V lighting and accessories with a 6V charging system

#14

Post by Frankenstein »

Very Tidy, Nice installation.
DD
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Re: How to run 12V lighting and accessories with a 6V charging system

#15

Post by Buddhahoodvatoloco »

Impressive, Impressive, great job, description and details.
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