Bench power supply for newbies

jimjones3630

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Hi all,

So, forging along after picking up some rudimentary soldering skills, cheap equipment from ebay, some PCB knowledge, rudimental understanding of MOSFETs, resistors, and capacitors started working on a simple MOSFET switch that is turned on by the M@g stock switch.

Fun so far with modding and now have picked up a used DC bench power supply from who else but ebay. My wife is beyond jealous now but it's still fun.

I've found out my 12v bulbs: 64625 flashed at 13.9v, 62138 flashed at 15.2ish volts, 64623 flashed just over 17v, 64458 took to 20.5v and it is hard to tell the difference between it and the monsterous 24v 64655 driven to the limits of my equipment which is 13amps @24v.

Only have 2 64458's so didn't take it to flash point.

Update on 64458's driven to 22.5v and held for few moments then with the next increase it instantflashed I would say between 22.5 and less than 23v.
Super white and hot, would be tricky to direct drive it on 17 cells although I've heard other doing so.

64610 flashed at 15.08v.

Bulbs connected via Kiu socket and measurements varified by DMD piggybacked to power supply which has an analog meter. For $50 I'll live with it since it has 13amps, 72v limit.

FM's new 3" reflector used pointed to ceiling. So brightness is my subjective impression.

Burn test(held piece of colored paper- actually a Hersy's wrapper to the rim of reflector) on the 138, 623, 625 are about the same taking some seconds to ignite.

64610 at 14.5v would draw smoke from the paper but not ignite.

Both 64458 and 64655 driven to above mentioned volts ignited the paper the instant it was at the rim of reflector.

Now for the liability statement you can get hunt playing with fire and electricity, water and electricity cause some really impressive results.

Jim
 
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LuxLuthor

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Jim, really great information. I tend to look in the Incand section for this info on the bulbs....so glad you linked it here.

Not sure how to compare it, because I did not check voltage at the bulb pins...afraid I would never see again. I can confirm that hot off the charger 23.6-23.7V measured at the battery pack level with 16 x Elite 1500 mAh cells in that 3D maglite that I got from Mad Maxabeam, which has KIU and some internal wire fixes to reduce resistance.

If I get brave and can wrap wires around the bipin wires, I can try and do a measurement hot off the charger when I turn it on if you want.
 

JimmyM

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The killer for the 458 on 18 cells is the inrush current at turn on. Otherwise it should take 18 cells.
The hotrater shows the following for the 458 on 18 cells (21.6V)
Watts: 223
Lumens: 14,000+
Life: 3.5
Color Temp: 3600

If it lasts for than a minute... That's Larry14K territory.
There HAS to be something wrong with the base figures on the 458. At 21.6 volts, it's making 62 lm/W. That can't happen, can it?

I really need to get cracking on that PWM soft-starter.
 
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jimjones3630

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Lux,

You know what you can do safely, I would like to know for sure as I'm working up a mod with the 64458-S using a FM Elephant host and maybe 4/5 A's since 17 or 18 would fit with the length I have.

Other will like the form of a 3D which I would have used and is about the same length of the Elephant I have.
Jim
 

LuxLuthor

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Lux,

You know what you can do safely, I would like to know for sure as I'm working up a mod with the 64458-S using a FM Elephant host and maybe 4/5 A's since 17 or 18 would fit with the length I have.

Other will like the form of a 3D which I would have used and is about the same length of the Elephant I have.
Jim

I'm waiting on the new Elite 1700 AA's to setup a 21s x AA in an Extended Elephant cranking a 64655 24V 250W
 

jimjones3630

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The 24v 64655 looked as bright as the 90w64458 driven hard. 21AA = nominal 25.2v, full charge 29.4v.

Using AA's suppose you want or have taken into account battery sag.
Even with AA's the in rush at start up think may instantflash.

Now have a larger bench supply Motorola ac, cc, fully variable 0-40v, 0-40A than when started this thread and have flashed the big 24v 64655 not much over 26v.

If I find my notes I'll post it here. You have FM's Elephant 120mm extension and deep tail cap 4px5s 18650 will fit. 18650 2600mah 4p wired in series by 5 = 21v, 10,400 Mah. Long run time.


I'm waiting on the new Elite 1700 AA's to setup a 21s x AA in an Extended Elephant cranking a 64655 24V 250W
 

LuxLuthor

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The 24v 64655 looked as bright as the 90w64458 driven hard. 21AA = nominal 25.2v, full charge 29.4v.

Using AA's suppose you want or have taken into account battery sag.
Even with AA's the in rush at start up think may instantflash.

Now have a larger bench supply Motorola ac, cc, fully variable 0-40v, 0-40A than when started this thread and have flashed the big 24v 64655 not much over 26v.

If I find my notes I'll post it here. You have FM's Elephant 120mm extension and deep tail cap 4px5s 18650 will fit. 18650 2600mah 4p wired in series by 5 = 21v, 10,400 Mah. Long run time.

Jim, thanks for saving me a bulb. Yeah it is the Elephant you describe. I'm wondering if this would be a good application to try one of those Ametherm NTC (#SL12-1R010) in the 21xAA's.
 

jimjones3630

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LL 21AA full charge 21x1.4=29.4v if target is 25v that's 4.4v difference
post#7 NL get into the math application working the specs to determine applicablity.
https://www.candlepowerforums.com/threads/170972

Hopefully Northern Lights will be out tonight and give you a first rate illumenation. I'm still digesting JimmyM discussin with NL about NTC

Jim, thanks for saving me a bulb. Yeah it is the Elephant you describe. I'm wondering if this would be a good application to try one of those Ametherm NTC (#SL12-1R010) in the 21xAA's.
 

jimjones3630

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LL, no paticular bulb. charged li-on 18650 is 4.2vx5=21, and yes nominal 3.7vx5=18.5v. Sorry if not clear. below some tech info, and link.

think would figure max volts working up a mod. since still does not account for the in rush amps and how much that would be.

http://www.batteryjunction.com/li18cyce326h.html
3. Technical Information​
3.1 Capacity Nominal : 2350 mAh (by standard charge and discharge)
Minimum : 2300 mAh
3.2 Nominal Voltage : Average 3.7 V
3.3 Standard Charge : Constant Current and Constant Voltage (CC/CV)
Current = 1150 mA
Voltage = 4.2 V​

Just checking this again, as 5 x 3.7 is 18.5V, did you mean that for another bulb?
 

jimjones3630

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LL the 24v 64655 you mention using a 21AA pak. charged volts 21x1.4v=29.4v

a 18650 li-on pak would get you closer but still over the 24v bulbs flashpoint.

thinking 29.4v AA pak even if saged after startup would instantflash.

found the tread, 64655 inrush amps measured as outlinned in this thread about 42'ish. I sacrificed a fluke fuse to get that measurement.

http://www.candlepowerforums.com/vb/archive/index.php/t-166738.html

one advantage to using 18650's in that Elephant is longer run time. 4x2600mah= 10,4000mah. 64655 amp draw is around 13A I believe. over 30min run time.
 

LuxLuthor

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That's an impressive inrush current spike. Looking at some other options. I'm a little reluctant to spend that much on that many 18650's. I'll go back to the drawing board.
 
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