Modifying 35w ebay ballast questions

[liteitup]

Ok well i looked high and low and on this particular ballast there is no pot anywhere to be found. Morepower had the 55w ballast which has the mounting tabs molded on which is supposed to have the pot.

Now for the GOOD NEWS!!! Ballast is currently running at 51 watts input (as opposed to a measly 32 input watts stock). I did have it as high as 70 watts input. more on that later.

Some numbers to crunch:

Stock ballast 13.5 volt input, 2.42 amps input. 32.67 input watts.

Modified ballast 13.02 volts input, 3.94 amps input. 51.29 input watts.

51 watts was attained by soldering 2 additional 0.05 ohms resistors on.I test fired it with a total of 3 extra resistors and got 69 watts input!! Assuming 75% efficiency (low side probably?) thats 51w at the bulb! Not bad for an el cheapo ebay ballast. I only ran it for a minute like that as i dont want to burn it up at a level im not going to be using it at.

Modded 6 resistors 11.92 volts input, 5.8 amps input. 69.13 input watts.

These ballast were going to be paper weights, but i am glad i can now put them into service and get atleast 35watts at the bulb out of them with im assuming some decent reliability!

Ok here are some beamshots from an old 4 wheeler reflecter that reflector is pitted and lens foggy.. lol
51watt

stock

now i need to go to digikey and get myself some more resistors. I stole the resistors from the other ballast to test with lol...

 

[liteitup]

More beamshots for fun lol...

lens removed from old reflector gives quite a bit better light output.

modded ballast on left, stanley HID light on the right! 6k bulb vs stanley 8k (love that stanley )

Head on shot... stanley on right

 

[liteitup]

Measured today getting .42 amps at 101 volts t the bulb. 42 watts at the bulb. 83% efficient. not bad.

 

[SirJMD]

Measured today getting .42 amps at 101 volts t the bulb. 42 watts at the bulb. 83% efficient. not bad.

Actually, its 99% efficiency!
You can do a quick test to see if im right: (0.42*101)*0.99 = 41.9958W

If its really 99%, its quite damn impressive.

 

[BVH]

Efficiency is measured using input Power (probably near 55 Watts in this case) vrs output power - as measured - 42 Watts. 42 Watts to the bulb is very typical of 55 Watt rated Ebay type ballasts.

Not sure why the POB looks like it's producing so much less light than the Stanley which is putting out about 34 Watts to the bulb, IIRC?

 

[SirJMD]

Efficiency is measured using input Power (probably near 55 Watts in this case) vrs output power - as measured - 42 Watts. 42 Watts to the bulb is very typical of 55 Watt rated Ebay type ballasts.

Not sure why the POB looks like it's producing so much less light than the Stanley which is putting out about 34 Watts to the bulb, IIRC?

As i read it, he got 42.42W at the bulb, and meassured 42W - or did i miss something?

 

[BVH]

1. Input Volts x's Amps = Input Watts
2. Output Volts x's Amps = Output Watts

To find efficiency, measure total power consumed by the ballast (1.) and Total power provided to the bulb (2.) Then divide 2 by 1.

Liteitup, opps, your ballast is 76% efficient.

Now there are also some factors I've been made aware of that need to be considered when the output is AC. There's things like sinewave and others that need to be calc'd in. But for our purposes, it's close enough.

 

[joedm]

wow.. how many what's is your lamp shade?

 

[joedm]

ok, ok, I'll play as well.... :nana:

This is my cheap chinese 35w ballast:

Are those the resistors I see?

And what do we have here:

ok now...

Someone can tell me where to measure, when to measure, i.e. how do I measure output at the bulb when this thing is fired up? (without toasting my nuts that is).

 

[joedm]

oh well.... looks like I took one for the team....

I had my meter in series on the bulb side trying to measure the output Amps..
Flicked it on and saw the numbers go up.... and then the meter turned off..

No more meter...

Good news though..
Adjusting that pot does the trick..

first I turned it clockwise 1/4 turn and the ballast switched off??
Then I turned it off and on again (after returning the pot to it's orignal position).

The I tried anticlockwise, and lo and behold.... boosted output!!! :twothumbs
How much by??? no idea.. until I get a new meter.
But my eyes can tell and it's daytime here.

Video is here:

http://img682.imageshack.us/i/p1050316.mp4/

 

[BVH]

Joedm, see my thread here for how I measure Watts to the bulb. Hint...the Voltmeter does not get connected until after the strike to avoid the 25KV or so and high associated current.

http://candlepowerforums.com/vb/showthread.php?t=243509

Any chance there's a blown fuse inside the meter?

 

[IgNITEor]

jodem, please thank your meter for us. For it's sacrifice, so that all of us can succeed in future tweaking of willing 35-Watt ballasts. Thank you, too.
This is a great experiment to witness.

 

[BVH]

:mecry: To the sound of TAPS in the background

 

[liteitup]

1. Input Volts x's Amps = Input Watts
2. Output Volts x's Amps = Output Watts

To find efficiency, measure total power consumed by the ballast (1.) and Total power provided to the bulb (2.) Then divide 2 by 1.

Liteitup, opps, your ballast is 76% efficient.

Now there are also some factors I've been made aware of that need to be considered when the output is AC. There's things like sinewave and others that need to be calc'd in. But for our purposes, it's close enough.

Not sure how you are calculating efficiency but :

((output)/(input)) * 100 = efficiency %
(42 / 51) * 100 = 82.35% (i rounded up before). Not sure where your getting 76%.

your right about measuring it with a multimeter though, not an exact science. And yes dont measure volts until its been running for a minute to be safe... too bad that multimeter got ruined

Also you said something in another post about a POB putting out a lot less light. Im assuming your talking about the Power On Board hid spotlight? I only have the stanley. In the beam shots i was using the 880 series bulb in an old 4 wheeler headlight which has potted faded chrome and a foggy lens. It sucks up the lumens lol, thats why its no where near as bright as the brand new stanley at 35 watts

 

[liteitup]

Lets see how many brave people we can get in here to open and mess with their ballasts! Id love to see how many different configurations there are of these ebay ballasts going around and how each one can be modded differently.

Oh and do be careful around these things when they are on lol... i touched part of the circuit board completely by accident and my thumb got nice buzz through it! I dont know if i would go adjusting pots when the ballast is running. Some parts of these ballasts run at very high voltages before its outputed to the bulb. A screw driver makes nice conductor if you make a stray movement!

 

[BVH]

Trying to think of a way to explain it better. If a ballast is pulling 100 watts DC from it's power supply as measured in its input wires and it is only providing 76 Watts to the bulb as measured at the output wires, then it is only 76% efficient. 24% of the input power is being used to power the ballast components and wasted as heat.

So if this particular ballast if pulling 55 Watts from its power supply and it is only providing 42 Watts to the bulb, then it is only 76% efficient. 42 Watts is only 76% of 55 watts. 13 watts is being used to power the ballast components and wasted as heat.

Does this help?

 

[liteitup]

Trying to think of a way to explain it better. If a ballast is pulling 100 watts DC from it's power supply as measured in its input wires and it is only providing 76 Watts to the bulb as measured at the output wires, then it is only 76% efficient. 24% of the input power is being used to power the ballast components and wasted as heat.

So if this particular ballast if pulling 55 Watts from its power supply and it is only providing 42 Watts to the bulb, then it is only 76% efficient. 42 Watts is only 76% of 55 watts. 13 watts is being used to power the ballast components and wasted as heat.

Does this help?

i think your misunderstanding. this ballast is pulling 51 watts modified at the input. Its not a 55w ballast but a "35" watt that only pulled 32 watts unmodified.

 

[BVH]

That would explain the difference. I thought it was pulling 55 Watts input.

 

[liteitup]

That would explain the difference. I thought it was pulling 55 Watts input.

glad were on the same page now.. lol

 

[joedm]

So.. I'm thinking of re-potting these ballasts now, but still want access to the pot. Any opinions on whether I should use a tube down to the pot and use thermally conductive epoxy around the tube?

Also, Since I've removed some of the old potting compound, is it worth while trying to use a bit of aluminium to sink some heat directly from some of the other components to the side of the ballast? and then pot over that?

The small trimpot is so small that I'm reluctant to try soldering anything to it.