Boost Circuit

[Justintoxicated]

Anyone know how to build a reasonably cheap booster circuit?

I want to build a small circuit for my 3C M@G that will boost the power to 1 amp after the batteries get somewhat taxed.

I can't have my little FL7-S kicking the poop out of my Lux III now can I?

If it is too complicated where can I buy one that can boost all the way to 1 amp ?

 

[Jack_Crow]

J,
Sounds like your trying to make a current regulator, to deliver a constant 1A to your lamp system.

Your asking for nearly five watts of delivered power to your lamp.

There are many IC's avalable to do this task. Generally speaking parts are cheap and time is expensive. There are much more experienced guys on this board who can give that advice.

Im asking you to consider something. That Amp of current you want will have to come from someplace. The 4.5 volts from your 3C cell stack most likely.

If your power regulator circuit is 90% efficent you will be wasting 10% of your avalable power as heat. .1A at 4.5 volts is just under a half watt of heat.

New Cells will deliver that power until some discharge point is reached.

Then the internal resistance of the cells will not permit any more energy to be delivered (heat and chemistry limits).

At that point your light will dim out rather rapidly. Switching regulators starve out rather quickly.

The question to be asked at this point is how badly do you want to do this, and is the need worth the expense. Mods, and feeding the battery habbit.

Good luck

Jack Crow in Iraq

 

[Justintoxicated]

Well my abtteries are not deal, but I kinda want to change them anyways because the light is WAY less bright already. I meausred the batts with my voltmeter and they say 1.32V so they definately have some use on them.

I Think I would rather the light be brighter and have a shorter runtime.

Im also looking to boost 2C's to 750ma for another light,

I'll for the sake of cost, pretend that I have time. But I'm not really even sure where to buy somethign like this.

I checked the Sandwitch shop, but I don't see any of their circuits that will go this high. On fresh batts the led was brighter than my FL7-S now the Xeons bulb wins again.

 

[RussH]

You need a boost circuit as you are thinking. The best way to do that is with one of the many switching power supplies that have been discussed lately. You could do a search on this (electronics) forum for some references to schematics. Georges is selling his fairly large board set for 1 amp now and you can get that high with a BadBoy also, IIRC. However, it doesn't make a lot of sense to boost 3 C batteries (alkaline or NiMH). Consider that a boost circuit uses about 1 volt of the batteries voltage (some are lower voltage drop converters, but many are higher). This means your efficiency (70%?) is a bit lower than direct drive to start. That's why you see most boost circuits being used with one or 2 batteries. You really need it for higher output in spite of the losses. I'd build one for two cells (you'll require 1.3 amps from the batteries for a 1000ma output) as a current regulator that could also work with most 3 cell setups. See discussion regarding using BadBoy with batteries higher than Vf, and look at the Wizard board also. HTH, -RussH

 

[Justintoxicated]

wow Im a little lost now...

All I know is that my DD light is not very bright whent he LED is at 3.25V...I have the parts for a 2 cell light, I guess I'll build a 2C light with a boos circut then and check it out. I still do not see anything that says the Badmoy or Wizzard boards can be used to Drive an LED at 1 amp /ubbthreads/images/graemlins/frown.gif

 

[Burnt_Retinas]

Small circuit, three C's (preferably NiMH for me), 1A or greater ....sounds like I have what you want.

Give me a week to work out what to write in a post for it and you may be interested in a left over proto? No commercial runs here, it was just for me to get 1.2A+ from a single Li-Ion for my LIII PM6. It fits into a McModule and it'll do >1.5A, but I found the Lux vs current not to be worth it at1.5A. Settled for 1.2A. It's real nice at 1.2A, I recommend this maximum current for the LIII's - well heat-sinked of course.

Chris

 

[Justintoxicated]

Yes, yes and Yes!

Looking forward to your post, it would be great to understand enough to build one myself, Also interested in a left over prototype.

My LuxIII is an SX1J bin, so I guess I need to Overdrive it to make it bright? /ubbthreads/images/graemlins/smile.gif

Will your circuit also work with a 2C mag then?

 

[AilSnail]

justin, there is a recent thread by jarhead here on a tps61030 cirquit, a boost that can do at least an amp probably a lot more with good efficiency, past 90%.

 

[Burnt_Retinas]

Justin..

No, no go on 2 X C. It was intended for 3 - 4.2V I/P. 2 X C's just wouldn't cut it at the current drain. You need to make up your mind what you want /ubbthreads/images/graemlins/icon3.gif

AilSnail,

Yes, been following this myself. Jarheads post re tps61030 will be more efficient that what I have for a 3W LIII. My circuit was intended to boost for a 5WLS, which a tps61030 can't do, but as I'll post I decided to tinker a tad. I'll certainly be giving credit to Jarhead in post for future mods to come, but for now and until I can get better chips and this seemed to fit the bill for a 3 C boost mod as was requested.

Really though, +/- 10% for a PM6 on 1 X Li-Ion (my mod) = 45 minutes vs. 50 minutes. Would this really be noticed with 'normal' usage?. I'll still go the efficient route though, but I am eagerly awaiting the receipt of such IC's.

The reality, for Justin’s sake, is you can get something now that works, or you can build your own from Jarheads findings. Unfortunately there's nothing out there commercially available in this current/size range. I just hope Dat2/Jarhead can make commercial reality of such a converter. I'd prefer to buy than spend my time building custom circuits - it takes a lot of time.

...Where's that spellcheck button when selecting reply???

Chris

 

[AilSnail]

Burnt, any good 5w chips are certainly appreciated.
LuxIII buck as well.

 

[Justintoxicated]

Burnt, I actualy have 2, well now 3 projects to be built.

Right now im just using DD for my 3C mag with Lux III.

I was hoping to make a smaller version with a 2C light and some type of booster circuit. I want Bright and constant, I could care less if the batteries drain faster, as long as the efficiency is reasonable. It almost sounds as though I should build another 3C Lux III with your circuit, or save my extra Sx1J for a minimag. And wait for a better binned lux to use a custom circuit. As of now I want to put in new batteries ever time the brightness drops so I'd be wasting 80% of good cells anyways.

I spent the last couple hours reading all of Jarheads post and in the end I may as well have been reading a foreign language upside down in dark room with one hand tied behind my back. I would at the minimum need part #'s and a circuit diagram to make one myself I don't have 100's of hours to spend trying to learn what every part of a circuit does and why he is using each part. I would if I had time but college is more important right now. I'd rather just have a diagram where I could get the parts and solder them together and understand it better as I work on it..But I could not figure out how to hookup each part just based on a data sheet. A picture would also help 100x as jsut part #'s leaves me with no idea of the amount of space I have to work with; trying to stuff it into a 3c?

Jarheads status says Banned? Maybe thats why he has not been replying to my pm's? What happened?

Burnt,
So there are no boost circuit to bost 1-1.2 amps from 2C?
You could make me one to boost to 1.2 amps from 3C?
Would I be better off finding a better binned lux and using this one for a mini mag?
How much $$ are we talking?

Right now I have a spare Hotlips C, UCL lense, and Sx1J bin Lux III. I'm trying to decide what to do with these parts.

Let me know your opinions and I really appreciate the effort!

 

[AilSnail]

tps61030 will very likely do 1.2a from 2c.

justin, can you pm me your email addy?

 

[Burnt_Retinas]

Justin,

As AilSnail say's, perhaps the tps61030 *may* do the trick for a 1.2A from 2C. I do not have one so I do not know. I can tell you that you can expect close to 2A current drain at 3V battery voltage, this limits battery options. Like I said, what I had was intended for a 5W LED and is not targeted at a 3W from 2 batteries. Just so happens it works great from 3 X NiMH or 1 X Li-Ion. Note the current - up to 2A - any boost probably won't have much runtime from zinc/carbon batteries or even alkalines.

Note, there are always trade-offs. If you want maximum brightness, smallest size then something's got to give - eg runtime due to heat (small host) or battery capability (available technology).

My recommendation - sleep on it. Work out what you REALLY want then ask if it can be done. There's soooo much help available on CPF I'm convinced something can be done. This is the place to be.

Re Jarheads post - ???? Perhaps this is only as a consequence of CPF re-organisation of threads?

Re minimag mod LIII@ 1.2A boost - not recommended. The heat generated would be too much for the host. You'd only get several minutes of runtime at best maybe. Perhaps you can live with that?

Worth mentioning - an LIII at 1.2A or so in a Mag 2/3C host is a great throw flashlight, but a bit too tight and bright for only back-yard use.

Chris

 

[dukeleto]

I also was wondering what happened to Jarhead?

Olivier

 

[cy]

[ QUOTE ]
Burnt_Retinas said:
Small circuit, three C's (preferably NiMH for me), 1A or greater ....sounds like I have what you want.

Give me a week to work out what to write in a post for it and you may be interested in a left over proto? No commercial runs here, it was just for me to get 1.2A+ from a single Li-Ion for my LIII PM6. It fits into a McModule and it'll do >1.5A, but I found the Lux vs current not to be worth it at1.5A. Settled for 1.2A. It's real nice at 1.2A, I recommend this maximum current for the LIII's - well heat-sinked of course.

Chris

[/ QUOTE ]

I'd be interested in your left-over proto that fits into a PR head. 1.2 amps? will this support 2X 123 or 3x 123?

One another project, I planning on doing a bike light, using 3X C in a maglite host. My plans are to use an X3T, if I can ever find one. What is your recommended config for max run time and bright.

On cycling app's you cannot have too much light. However you need a decent runtime of at least 3-4 hours, 4-6 hours would be better. A buddy has a Mr bulk, 3xC w/Q bin, direct drive, it's fairly bright w/decent runtime.

 

[Doug Owen]

[ QUOTE ]
cy said:

One another project, I planning on doing a bike light, using 3X C in a maglite host. My plans are to use an X3T, if I can ever find one. What is your recommended config for max run time and bright.

On cycling app's you cannot have too much light. However you need a decent runtime of at least 3-4 hours, 4-6 hours would be better. A buddy has a Mr bulk, 3xC w/Q bin, direct drive, it's fairly bright w/decent runtime.

[/ QUOTE ]

This one's pretty easy. Take a typical C cell, like the Duracell:

MN1400 'C cell'

The answer is in either of the bottom two graphs.

If you want '3 to 4 hours', you can have one watt (or one volt at one amp average, take your pick) from each C cell. So assuming a perfect drive circuit (which DD is far, far from) you can drive an additional Luxeon with each C cell. Three cells, three Luxeons. Or one driven to three Watts. You want twice as much light from each of those three, you'll need three more C cells.

Easy.

Doug Owen

 

[Justintoxicated]

Well Im Planning on using Alkalines untill I can afford some NIMH rechargables as my thirst for this hobby grows.

I really wanted 1 amp from a 2C host, but it sounds as though this is not possible. I could do a 2C to 3x123 adapter. I believe that would be pretty simple. Just more $$$, and then I would think it would be better to DD a Lux V for even more light? Am I right?

I take my lights camping out in the desert, so the more throw the better, It is hard to imagine having TOO much light heh.

I think I just want some regulaton to keep my Lux III bright. The batteries last forever and it is still brighter than my stock mag, but I have the urge to change the batteries already, they still have 1.323 volts in them!

Would your prototype work ok with 3C alkalines? or 3x123 to drive a lux 3 or 5? I don't wanna buy a 2C host if I'm not going to be able to use it for anything.

 

[Burnt_Retinas]

Doug,

Phew, a picture speaks a thousand words. Thanks.

Cy,

Re PR head/123's - No on the 123's. A direct drive may do the trick for high currents. A boost with 2 X 123's will be almost direct drive anyway for an LIII (I assume you were referring to an LIII). It is not a config that needs a boost. A downboy perhaps?

Justin,

1A+ from 2C is possible, just not with what I have left over. It'd take a different IC as per Jarhead's approach perhaps.

You really need to get away from those alkalines if you intend to boost to any decent current. They may have good AH rate, but they can't supply high currents for very long. When you hit the high power game, you'll be so glad you switched to Li, Li-Ion or NiMH.

Chris

 

[Justintoxicated]

Yea, I jsut can't afford expensive NIMH rechargables right now.

Possibly in the future, but not just for one flashlight that I have not constructed. /ubbthreads/images/graemlins/frown.gif

So what your saying is the best thing to do is DD a lux 3 off 3C, it would nto be a good idea to attemps to boost from 2C nor would it be a good idea to use a circuit with a 3c? Im a little confused on what I should do...I still have these parts sitting aorund and from the sound of it my cheapest bet to get more light would be to go 3x123 and buy a new Lux V emitter and sell the lux III Sx1J?

I did not realize it would be so compkicated to get constant 1000MA from a battery source. I guess that is why Driect drive is so popular.....

Sounds like my absolute best bet is to DD another 3C mag, maybe get one a different color...Of course this is pointless since I already have one.....

 

[Burnt_Retinas]

It's not complicated, it's $$$$$.

If the budget is tight at the moment, you already have the the best for the least cost you can get. A converter alone is $$, then you'll need batteries to support it = $$.

Chris