Have I got this right ?? Less lux from 5761 ver 1111

[Anglepoise]

Have I got this right??

My tests were with a Mag2D, with FF 6AA> adapter .

Batteries were Elite 1700 AA NIMH. Hot off charger 8.4 volts.

Both Phillips 5761 and WA 1111 both flashed.

****

After draining batteries to 7.9 volts, I got the following.

With WA 1111, Vb sagged to 7.1 volts, while drawing 3.7 amps.
Predicted lumens .....772

With Phillips 5761, Vb sagged to 6.1 volts, while drawing 5.0 amps.
Predicted lumens .....765

So with this setup, light output is almost identical but I guess the 5761
will fall off quicker so the preferred bulb would be the WA1111.

 

[LuxLuthor]

Something is not quite making sense in terms of the flashing....but I am assuming you have some resistance in your setup that will drop the battery voltage. Most Mag's have at least 200 mOhms. What was your light setup?

If you compare their tested profiles from this thread, they are not that close in output.

You do need to address their narrow acceptable voltage ranges, and especially the intitial high startup voltage spike. This is why some use the NTC, AW's D/C multi-level brightness driver/switch/bulb holder, or AWR's HotDriver.

 

[Anglepoise]

Something is not quite making sense in terms of the flashing....but I am assuming you have some resistance in your setup that will drop the battery voltage. Most Mag's have at least 200 mOhms. What was your light setup?

If you compare their tested profiles from this thread, they are not that close in output.

You do need to address their narrow acceptable voltage ranges, and especially the intitial high startup voltage spike. This is why some use the NTC, AW's D/C multi-level brightness driver/switch/bulb holder, or AWR's HotDriver.

Sorry.....I did not explain myself correctly. I am not concerned about the flashing. I have taken out quite a bit of resistance from the switch and tailcap, and have some NTCs on order.

What interested me was the fact that both '5761' and 'wa1111' bulbs put out almost the same lumen output ( projected) when batteries had dropped to Vbat 7.9volts. I was presuming for more output from the '5761' but the extra load sagged the batteries down more so lumen output ( projected) was similar.

Just an observation that might help others with battery choice.
Even with 6, Elite 1700 AA NIMH batteries, they have not got enough grunt when used with '5761' for anything over 750 lumens ( projected ) .

 

[EvilLithiumMan]

Something isn't right with your cells. According to the discharge curves at www.cheapbatterypacks.com the Elite 1700 can handle a 30 amp load. No way the 5.5A load of the 5761 bulb is going sag them that much. Either a cell has failed or somehow the resistance in your setup as changed. I'd double check everything.

 

[Anglepoise]

Something isn't right with your cells. According to the discharge curves at www.cheapbatterypacks.com the Elite 1700 can handle a 30 amp load. No way the 5.5A load of the 5761 bulb is going sag them that much. Either a cell has failed or somehow the resistance in your setup as changed. I'd double check everything.

Good suggestion.......I will re do my simple recording of Vbat,Vbulb and current draw and let you know. I purchased the Elite cells for the very reason I would not get too much voltage sag.

 

[mdocod]

try again with freshly charged but rested cells on an NTC, the 5761 should win in overall output by a decent little margin. Are you using a ceiling bounce or other lumen box method to insure there isn't much effect from beam differences?

 

[Josey]

There is too much slop in comparing bulbs at different voltages and amps and trying to force them into some "predicted lumens."

You're driving the 1111 at 26 watts and the 5761 at 30 watts and so their light output should be similar. But both these bulbs are in different positions on their efficiency curves -- the 1111 at high efficiency and the 5761 at low efficiency.

Yes, the 5761 is about the same on predicted lumens (which is a loosey goosey concept), but it is way underdriven at 6 volts.

 

[Anglepoise]

,.... but it is way underdriven at 6 volts.

Yes...I am looking into this, as its about a volt lower than I hoped for.

Thank you all for your helpful comments.

I will check if the extra resistance is in the circuit ( my soldering ) or one of the new Elite 1700 batteries are not up to snuff.

 

[rizky_p]

something definately not right with your battery, my Elite 1700 holds above 1.2v each under 10Amps load..

 

[Anglepoise]

Presuming that one of my 6 batteries might be the cause of my low Vbat,
has anyone got a suggestion as to how to isolate the faulty battery.
They are all new in the last week and have only been charged once.

 

[SilverFox]

Hello David,

"only been charged once..."

Hold on a moment. In a multi cell application, you need to make sure your cells are reasonably matched. This is usually done by looking at the discharge capacities of the cells you are going to use, after then have been formed and have a few charge/discharge cycles on them.

Breaking new cells in usually uncovers under performers, so I would start there.

Tom

 

[Anglepoise]

Well I took everything apart and carefully cleaned all connections.
On reassembly the output with the 5761 looked greatly improved.

The measurements also were drastically different and improved.

7.87 Vbat
7.36 Vbulb ( measured at the charging jack on FM's 2D > 6aa adapter)
7.01 Vbulb ( measured across bi pins on bulb )
Current draw 5.28 amps.

Thanks again for all the helpful and encouraging remarks and suggestions.

Still got lots to learn but enjoying the great output from a modded hotwire
light.

 

[FILIPPO]

elites are good batteries!
I read all the thread and at abuot 1/2 I started to have some doubts on elites 1700...(that I have just bought...)

happy to know everything is now Ok with your light!

:twothumbs

 

[Anglepoise]

elites are good batteries!
I read all the thread and at abuot 1/2 I started to have some doubts on elites 1700...(that I have just bought...)

happy to know everything is now Ok with your light!

:twothumbs

Yes......I am delighted with the performance I am now getting.
Have no idea what I did wrong. I think a bad connection somewhere
or a dry solder joint somewhere in my heavily modded switch.

 

[LuxLuthor]

As Silverfox has said many times, you MUST cycle/condition new NiMH cells before you can optimize them, or even weed out underperforming cells.

When I have talked to Mike from Cheapbatterypacks.com about this, he says no matter what brand he has been able to obtain for high current output, there is always a percentage of cells that do not perform as well as the rest. That is why I started cycling and testing all the cells before I make them into packs. I can tell when I get one that is not of high quality within two cycles, and set them aside.

I have also seen that these high current cells do better charging with a lower range of current....i.e.) 1500mAh Elite 2/3A with 0.4 to 0.6A; 1700mAh Elite AA with 0.5 to 0.8mA charging current. Then there is the separate issue of doing a periodic "conditioning" charge of 0.1C (i.e. 100-200mA charge rate) for 15 hours.