Sold/Expired WTB custom step-up converter (6Vout, 1A max)

[utomatoe]

I'm looking to buy a custom made stepup converter from someone skilled in electronics/soldering (I'm no good at soldering SMDs).

Looking for:

Power a 6V, 1A max draw device from a set of batteries (Say 2AAs or 4AAs).

I'd like it to be voltage regulated to a consistent 6V and current limited to 1A or less, 800mA is acceptable.

Size isn't an issue, so if there are no SMT-sized voltage regulators out there, i'm open to that as well.

 

[LED_ASAP]

You probably should give more details about what you want to drive and what the end application will be.

 

[ZuluWhiskeyFox]

In this vain I too would like a step up converter. What I have in mind is as follows:
-OAD 3 cell Batteries would be 3 "D" cells
-Hotlips for heatsink, there is lots of space behind the hotlips for a converter to be potted in.
-Luxeon 5 watt, white light

Some kind of kit would really turn me on. I'm quite capable at soldering stuff. My weakness is knowing what components will do the job. Also don't know how to make the circuit boards.

cheers,
zwf

 

[utomatoe]

[ QUOTE ]
You probably should give more details about what you want to drive and what the end application will be.

[/ QUOTE ]

Well, it's not a light, so I just realized there is a non-lights b/s/t forum.

It's to drive a small external network switch, which has a DC convertor rated for 6V/1A, but in the field, I'd find it more convenient if I could power it off a set of batteries.

 

[wasabe64]

Wow, that's a tall order.

How long would you need to keep this switch running reliably? I think that you should forego the idea of running that switch from 2xAA or 4xAA unless it is for a VERY short period of time. A network switch is very power hungry and when the batteries are under load, there will be a significant voltage drop.

I don't think that the switch would function reliably for very long.

I suggest that you start off with a 6v battery config that it is capable of supplying adequate current. There should already be a voltage regulator in the switch, all that the switch requires is a steady 6v in and all the current it needs.

 

[utomatoe]

An hour or two is sufficient runtime. I was thinking of using 4 AA NiMH, but that gives me 4.8V, so I need a stepup.

If I use alkalines, the voltage will drop overtime, I know the switch has tolerance to voltage variances, but I don't know how tolerant it is, hence the need for a regulator to stepup the voltage when the battery voltages drop.

It's max rating is 1A draw on a 5port. If I only need 4-5, hopefully the current will be around 800mA? Less if I'm only using 2-3 ports?

 

[balrog]

zwf, I'm looking into doing something like this right now. I just need to get a hold of some nicely binned Luxeon Vs and away I go. I'm going to tinker with some Luxeon IIIs whilst waiting. Aside from your 3D M@glite, Luxeon V, hotlips-D, wire and tools you can do it with the following:
- ECan
- BadBoy blank + 0.12 and 0.15 ohm SMT resistors
- Arctic Alumina Epoxy

The 0.12 and 0.15 ohm resistors on the BB blank will give you a BB750 which should be nice and bright, not sure what runtime will be like and how long it will be regulated for though. I need to tinker with the current to find a good runtime/brightness compromise. It's possible to make it as a drop in module to fit a 2D, 3D or 4D m@glite. All the info you need about the BadBoy can be found in the Sandwich Shoppe threads.

Also, check this thread to see how it is built. Be sure to check dat2zip's post as it shows pictures of the Ecan and convertor in the hotlips-D.

BTW, if you find any nice binned 5W Luxeons, let me know where you got 'em. /ubbthreads/images/graemlins/wink.gif

 

[utomatoe]

Well, size doesn't matter, it's not for a flashlight, so I was hoping I could use larger components and reduce the cost...

 

[LED_ASAP]

Why not just get a 6V SLA? You can get such a battery for less than $10 in surplus stores. Then add a 6V wallwart and a small resistor for float charging (choose the resistor to charge at 0.05C or less), that should be good enough for a few field tests.

 

[utomatoe]

SLA?

Well I'm worried about how tolerant the device will be to drops in voltage over time. I'm thinking maybe 5 x 1.2V NiMH AAs, which don't drop in voltage that much until they are near death... that should be ok, the device will probably have a 3-5% tolerance in voltage fluctuations...

 

[LED_ASAP]

I haven't personally used a SLA, but I believe their discharge curve is pretty flat (2V per cell nominal, 1.8V end-of-discharge, which is the same 0.2V voltage drop as NiH/NiCd).

 

[utomatoe]

Well, in keeping it simple, I already have a charger for AA batteries and probably smaller than an SLA. I don't know much about SLA, is it rechargeable? I wouldn't have a charger for it anyways. I might actually have a 12V SLA lying around from a dead UPS...

 

[LED_ASAP]

SLA is rechargable, and one particularly good thing is it can hold the charge very long---like 50% charge after a year or something like that. If the "dead UPS" has been lying around for a while, the battery is probably dead, too. Lead-Acid batteries particularly don't like over-discharge.

 

[IsaacHayes]

SLA = sealed lead acid battery. Like a car battery...