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Sold/Expired High efficient 5A/9A Buck Converter for SST-50, SST-90

Candle Power Flashlight Forum

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PayPal sent for 9A driver + shipping to Finland, 44.45 Euro.
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upd 29.04.2011: Received driver yesterday, thank you!
 
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Hi DW -

I just wanted to verify that your Paypal ID is the same as your listed email address. I'd like to order one of the 9A drivers soon. Thanks, MN
 
Hi DW,

Can I use your P7 9A driver with a potentiometer to drive 3 XML in parallel with 2 IMR cells? The 3 XML will need 3A each, so your 9A driver is perfect and the IMR will provide the amperage. Vf for 3A for the XML is 3.35V so the 2 IMRs will provide 7.4V at least. Does this sound ok?
 
As I always say: never drive LEDs in parallel on a single current source.
A slight difference in Vf of each LED (0.1V) can cause each LED getting different currents, for example:

LED1: 5A
LED2: 3A
LED3: 1A
Total: 9A

So the first LED can be overdriven and will be destroyed after some time. Then the 9A will be divided between the two LEDs left. So they will be overdriven as well. After some time all LEDs will be destroyed.
 
Thank you very much for your explanation! Guess its wiring in series now 🙂
 
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Hello,

I've finally got my driver installed to a SST90 @ 9A - impressive.

I have a question though:

What happens when the input voltage drops below 6V?

Your spec sheet states that the minium voltage is 6V, but not what happens below this.

I ask the question because I'm looking at battery options for a 2C maglite. At 3V per battery on any chemistry, the current draw is just over 6A. That's too much for AW's LiCo (PCB cuts out at 5.8A on his latest 18650's), but the LiMN would be fine. The only problem with IMR cells is they're unprotected.

If your driver cuts out at 6V, then running two IMR cells in series will be fine, as neither will drop below 3V each (assuming both cells are charged separately, same age, same production batch, same charger etc).

My bench PSU can only deliver 5A, so I cannot test this myself.

Many Thanks.
 
I don't have the driver, but I would assume that when you go below 6V, it will not be able to deliver the rated current. most likely the current will start dropping when the voltage drops, until at some point, a part of the circuit doesn't work anymore. usually this is not a good situation for the driver to be in...

Just try it and see what happens I would say ;-)
 
What amount to Paypal for 1x adjustable 9A driver with 2x pot wired, as discussed incl. shipping Netherlands?

Walter

Edit: item received
 
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OK.

After some testing....and without wishing to hijack this thread...I took a 6v SLA battery out of a 12v lantern, and hooked it up to the flashlight. I ran the battery down until it passed 6v and started taking voltage and current measurements.

The voltage and current at the battery went down to 5.3 volts and 7.2 amps before the light started to flicker and the converter started to whine.

I put a second fresh 6v SLA on the light after this to ensure it wasn't the converter overheating - and it wasn't. The light fired up without flicker on the higher voltage.

5.71v 7.1a = 40.5w
5.3v 7.2a = 38.16w

So the converter was still trying to regulate to the very end; the current didn't drop as expected, but the overall power did.
 
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5.3v is a good figure for me because that equates to 2.65v across each unprotected battery, which is well within the safe discharge level for an IMR. When the flickering starts, I'll shut the flashlight down. Just pulled the trigger on two 18650 IMRs from AW. 1600mAH will provide about 12 minutes of runtime, but that's not a problem either, as the light gets too hot to hold after 3 minutes. LOL.
 
Hello everyone.

I have used the 9A buck driver succesfully for what must be close to a year. I am wanting to build a couple more mag mods using the 9A buck with a 10K ohm potentiometer this time. If anyone can recommend where they purchased thier potentiometer, and especially any pictures of where you mounted it inside the flashlight, I would be very greatful!

Der Wichtel, thank you for the great products!
Eddie
 
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