-=what converter do you suggest me?=-

[MatajumotorS]

I need Buck - Boost converter 18mm diameter max for driving Seoul led at 1000mA from one 18650 Li-On. What do you suggest me?

 

[MatajumotorS]

Re: what do you suggest me?

:bump:?

 

[PhotonAddict]

There is a Wizard 937 from the Shoppe which would get you pretty close to 1000mA. I think the newer GD board is only available in 500mA at the moment but you might have better luck asking about this in the "The Sandwich Shoppe" section of the forum.

1000mA is a lot from a buck/boost IMHO. I imagine efficiency would be a little lower than usual. I imagine the Vf of the led would be quite high at those drive levels as well.

 

[cryhavok]

If you are going to drive it from 1 18650, you won't need any boost function, as the Vf's of these leds should stay below the 3.7V of the 18650. I think you are better off with a DownBoy

 

[chris_m]

If you are going to drive it from 1 18650, you won't need any boost function, as the Vf's of these leds should stay below the 3.7V of the 18650.

Except that 3.7V is only the nominal voltage - you get useful energy from a 18650 LiIon down to 3V, and if pulling 1A from a single cell it will drop below the Vf of the LED before you have used half the energy available.

 

[tebore]

Except that 3.7V is only the nominal voltage - you get useful energy from a 18650 LiIon down to 3V, and if pulling 1A from a single cell it will drop below the Vf of the LED before you have used half the energy available.

But that's what you want. It's acting as it's own low voltage cut off. When you see noticeably dimmer you'll know to charge the cell.

 

[cmacclel]

I would suggest Goldserves Flupic driver. It has 1.2amp max and a fully adjustable Low and High then other bonus's include strobe and beacon modes.

Mac

 

[Nereus]

I have no experience with GD500 converter, just down/badboys/sharks. But IIRC, you can change the current sensing resistors of GD500 converter and make it GD1000. There should be a formula on Sandwich Shoppe website that tells you which resistor you need. But ask Wayne for a "guru opinion" before you proceed... You don't want to release the magic smoke

-N

 

[Nereus]

Ok, found the equation: Output Current formula: 0.05 / Rsense = Iout.

So basically you want the sense resistor to be 0,05 ohms to get 1 amp out of the converter. Actually you don't need to remove the old resistor. Since the basic setting for the GD500 is 0,5 amps, the standard sense resistor should be 0,1 ohms. Just add another 0,1 ohm resistor on top of it and there you have it: GD1000 (That's what I've done to customise my own converters). Just remember to ask Wayne if the converter can handle 1 amp output.

-N

 

[PhotonAddict]

+1 on Mac's suggestion. The output will drop a bit as the voltage of the battery drops with a flupic but if you are intent on driving it at 1000mA it won't last much longer with a buck/boost and the gradual dimming would give you advance warning to charge the battery. With multiple levels it will also be useful for other tasks where 1000mA would be too bright.

 

[MatajumotorS]

Thanks for replies, now i got it, and i need to decide