Circuit to Maintain 1 amp?

[Justintoxicated]

Hi,
I'm building a few 3C mags up and im putting a decent amount of money into each light. I plan to eventualy run them on NIMH Batteries and use a Lux III white in one and a Lux III Cyan in the other.

I NEED a circuit that will keep these babies at at least 1 amp untill the cells are nearly dead, I do not care if they are overdriven a bit off the start so long as I can maintain 1 amp. a Buck/Boost would be better but hey, I'll be hapy with regulation!

Anyone have any ideas????

Can anything be made at the shoppe like this?

 

[Justintoxicated]

Nothign can do this? I don't know enough to wire up one myself or I would!

 

[CNC Dan]

You could run two BB500s in paralell.

 

[Justintoxicated]

will the 2 BB's be able to deal with the initial current of over 1 amp?

This is kinda expensive since I would need 4 of them for both lights together?

 

[CNC Dan]

each BB500 will output 500ma. If both connected to the same LED in paralell, the total current will be 1000ma or 1amp.

I don't know what you mean by "initial current of over 1 amp".

 

[Justintoxicated]

well 3C will Provide more Current than 1 amp initialy. I don't care if the LED is overdriven at first so much, but would like to maintain 1 amp for as long as possible. Basicaly I don't want the light dim as teh batteries get weaker, I did not like this affect in my DD lights, I find myself replacing the batteries long before they are 1/2 dead.

I guess I "COULD" just use NIMH and DD? But woulden't I still need some sort of a boost after their voltage drops somewhat to maintain teh 1 amp pull??

 

[wasabe64]

Be careful with the BadBoys, if your Vin exceeds the Vf of the LuxeonIII, you could damage the convertors. If you make the mistake of using primary batteries, you will definitely exceed the Vf of the diode and lose the convertor. Even using NiMH batteries, you are very close to that gray area where the BB could cook. J-binned Luxeons have a Vf of 3.2-3.5v, K-binned have a Vf of 3.51-3.75v.

You could alternatively use a DownBoy(s) in this configuration to build a current-regulated light.

Here's the Link to Wayne's convertor comparison chart.

The only thing you would sacrifice by going DD is consistent brightness, meaning that the lights will gradually dim over time during operation.

A current-regulated convertor such as the BB or DB will maintain consistent brightness by supplying the set current until the battery voltage falls below a certain level. The convertor then drops out of regulation and DD's the diode.

 

[IsaacHayes]

You'll need to ask dat2zip or someone who knows if pumping this much voltage and power through a BB would fry it or if it will just DD until it needs to boost.

Then I'd buy a BB blank and select the correct resistors to make it a BB1000. Then select the 3.00 option to have dat2zip solder them on for you. Check out the cart it and youll see what I mean. You could make it a BB900 if a BB1000 would be too much for it? You'll need to pot this for heat management too, as it will get hot.

 

[Justintoxicated]

wasabe, thats exactly my concern. I would love to make a BB 1000 if that is possible, I could probably sodler the resistors myself but maybe I would jsut have it done for me. But I need to make sure that it will DD if the current exceeds 1 amp.Or else I could possibly make it a BB 1100???IS this even possible?

Potting it should not be a problem, unless I have to use 2, I belive it could be potted inside the bottem of the hotlips HS? I hope i can get something like this worked out soon, I have a hotlips with glowpowder just waiting to be stuck in my Pewter mag 3C. I jsut can't find a circuit that will work under these conditions.

dat2zip is this possible??!?!

 

[dat2zip]

Fresh Alkaline C cells is probably 1.6V/Cell or higher. That's 4.8V or so. Assuming 150m ohms internal resistance and a nominal battery draw of 1.5A shows a battery voltage drop of .675. 4.8V - 0.675 = 4.125.

If you had a high Vf LED with a Vf of say 3.9V you could squeek by in this configuation. My calculator shows the single converter will drop out of regulation around 2.8V. That's well below the 1V/cell under load and should provide constant regulated light for the duration of battery life.

Since output is 1A, the converter efficiency is around 80% and would drop as battery voltage dropped to 75% or so at the end of battery life.

If you used two converter boards, efficiency would stay in the 80-85% efficiency for most of the battery life.

The calculator can be found at www.anlighten.com/shop/test.php

 

[IsaacHayes]

Would a wizzard be able to be configured to handle this?

Or a DB and a BB 1000 hooked together somehow?

 

[Justintoxicated]

/ubbthreads/images/graemlins/frown.gif I dunno the Vf of the LED's yet, but I doubt I the Voltage of the LED will be that high. Also I want to be able to use NIMH rechargables or alkalines...

Is there enough room in the hotlips C for 2 BB 500's?

 

[Doug S]

[ QUOTE ]
Justintoxicated said:
Hi,
I'm building a few 3C mags up and im putting a decent amount of money into each light. I plan to eventualy run them on NIMH Batteries and use a Lux III white in one and a Lux III Cyan in the other.

I NEED a circuit that will keep these babies at at least 1 amp untill the cells are nearly dead, I do not care if they are overdriven a bit off the start so long as I can maintain 1 amp. a Buck/Boost would be better but hey, I'll be hapy with regulation!

Anyone have any ideas????

Can anything be made at the shoppe like this?

[/ QUOTE ]
Given that your intended power source is 3XNiMh, I would say that using a low Vf bin Lux III [J or lower] with a low dropout linear current regulator such as an LM334 based circuit would just the ticket. Efficiency averaged over battery discharge will beat any stepup/stepdown option. Likely >95%.

 

[Justintoxicated]

Doug I have no idea what that means lol, Im not afraid to solder stuff myself as log as it is not too tiny, and I have some easy to folow diagram that has been translated into ters i can understand with simple voltage and power formulas. Due to lack of time I'd love for someone else to do the work on this circuit I would need, unless it is something as simple as soldering the right ohm resistor.

I figure there has to be something out that would work nicely for this setup. I have made a couple LM317 based circuits, but these are not suitable for a flashlight as they are horribly inefficent!

 

[Sway]

I would like to do the same thing with some 3C and 3D lights just using Alkies to keep it simple and give them to family members.

A lot of this stuff is over my head, OK just about all of it so somebody will have to /ubbthreads/images/graemlins/twakfl.gif and tell me what I need if it is possible to do and get several hours of regulated light......

Later
Sway

 

[NewBie]

I think a TPS61030 would work, as I've been able to hold 1.6A. Plus my Mag 2AA NiMH (1800 mAH as I recall) gets an hour of runtime at 1A to the Luxeon, and the converter cuts out around 1.8V, perfect for the NiMH cells.

 

[Justintoxicated]

so where do I get this thing??? and how do I set it up to work?

 

[dat2zip]

Maybe two Wizards in parallel. Each one set to 0.5A to handle 1/2 the load per board.

 

[Justintoxicated]

Wayne, that sounds like a really interesting idea. WOudl they both need to be Potted? I was going to pot whatever board to the hotlips but I'm not sure how I could Pot them both.

How hard is to to convert a wizard to .5 amps? How efficient would this be roughly?

 

[gadget_lover]

When you put two wizards in parallel, it seems like you can use the jumper pins from the sandwich kit to connect them together, no?

Daniel