How to best figure amps being drawn?

[LuxLuthor]

I'm trying to figure out why a setup of 8xAA (Sanyo 2300's) is not having a WA-1164 setup be brighter than a 4 x 14670 driving a WA-1166.

When I use the WA rerating formulas, it says the 1164 at 9.7V should be 1620 BL, and the 1166 at 12.7V should be 970 BL. However, the Mag66 setup is clearly brighter than the 1164 which is not making sense.

I'm guessing the Sanyo's are not putting out as much amp's that the rerating formula page at WA is saying the bulb needs....but how do I actually measure the amps being put out with a given set of batteries and specific bulb?

 

[fivemega]

LuxLuthor,
You need to measure voltage at bulb pins not battery terminals as.
You definitely loose some voltage at bulb because of unwanted resistance.

 

[LuxLuthor]

OK....I measured it by checking the voltage from the wires I had plugged into the tailcap plug before and after light turned on. I'll check it in the bulb bipin holes.

Still not sure how to figure out how many amps are being drawn by a various bulb/batteries combo.

 

[Flash_Gordon]

If you get a good voltage measurement at the bulb with the light both on and off that will give you a direct indication of voltage drop under load.

Calculating the current can be tough, because the only component you will know accurately is the voltage. It is better to measure the current. If you have a DVM or analog multimeter with a 10A scale you should be able to get at least a reasonably accurate current measurement. Keep in mind amps are measured in series with your DC circuit, so you will have to insert your meter leads between two components in your light.

If you have a light that is much dimmer than would be expected, most likely you have high resistance at one or more places in your light. Switches and tailcap springs are common problem areas.

Mark

 

[fivemega]

Measuring current draw is very easy.
1-Remove the tail cap.
2-Turn the switch on.
3- Select 10 or 20 amp and complete the circuit by connecting black prob to battery holder negative side and red one to edge of flashlight barrel.

Measuring voltage at the bulb is easy too.
1-Lift the bulb from socket half way up.
2-Connect volt meter small alligators to buttom of bulb pins. (make sure they don't touch each other or body and socket.
3-Turn the light on and check the voltage.

 

[nickz]

Measuring voltage at the bulb is easy too.
1-Lift the bulb from socket half way up.
2-Connect volt meter small alligators to buttom of bulb pins. (make sure they don't touch each other or body and socket.
3-Turn the light on and check the voltage.

Always remember your safety glasses during this procedure. A hotwire bulb can really pop with some power as you all know .

 

[LuxLuthor]

Measuring current draw is very easy.
1-Remove the tail cap.
2-Turn the switch on.
3- Select 10 or 20 amp and complete the circuit by connecting black prob to battery holder negative side and red one to edge of flashlight barrel.

Measuring voltage at the bulb is easy too.
1-Lift the bulb from socket half way up.
2-Connect volt meter small alligators to buttom of bulb pins. (make sure they don't touch each other or body and socket.
3-Turn the light on and check the voltage.

OK, that is the answer...thanks for making it that easy to understand. My reading at bulb is only 8.3V, so I'll do the bottom tailcap and top switch spring mods. Not sure how much those two mods reduce resistance. I'll ProGold all the contacts too.

I'm still a little surprised with 8.3V giving a rerating of the 1164 at 940BL...but it still does not look that close to my Mag66.

Also, I have a better DMM coming, but this "El Cheapo" Radio Shack $20 special only goes up to 200mA, so I can't check the current yet.

 

[nickz]

Lux,

I can say this much. My mag 85 pulls 3.12A with my sanyos (these have are a few days off the charger with no use other than a quick click on or two). With cbp1650's a couple days of the charger it pulls 3.25A.

I am not sure that was of any help as I am unfamiliar with the bulbs you are using. I find in my mag85 it doesnt show enough output difference from the cbp's to the sanyos to loose the extra run time.

The ROP hi for me is a different story. The sanyos pull 3.95A while the cbp's allow for about 4.25A. This shows a decent gain in output so I use the cbp's. Hope this helps some.

I am going to top both sets of batteries off and repeat the test. We'll see if there are any changes just to be sure.

 

[LuxLuthor]

OK Nick. Sounds good. TBH, I have not paid attention to amp output for various bulb/battery combo's because I didn't know how to test them, and still waiting for my better DMM to do it now.

 

[nickz]

Not to make more posts, but so far I have charged cbp's for the mag85 and the ROP HI. Both were charged before each test between lights with a maha MH-C801D.

Outputs were as followed for this test:

Mag85 = 3.35A
ROP HI = 4.30A
I am working on the sanyos yet ;-) Had to take few minutes to have drink and watch some TV in between!

To make the test more true, neither lights have had a switchmod done. I also have not applied any pro gold or anything like that.

 

[nickz]

WOW! It may be just my lights without mods but I see as follows:

Mag85 = 3.34A
ROP HI = 4.20A

With 2500mah sanyos!

As stated above, lights are modified as stated.

Hopefully somone can help your more than I did ;=s .

More info: This was done with each battery set charged for each light and had about a 5 second settling time for the reading. Maybe a 60 second test would be more appropriate?

 

[LuxLuthor]

When I get my new DMM, I'm gonna go on an amp testing spree....but your feedback is still useful information.

 

[jimjones3630]

Measured powerx 2300mah 9parralellx2series 11.58v, maybe month since last charge, driving a 1185 @ 3.05amps.

This light has had all low resistance fixs, switch ground, progolded contacts, tailcap, bipin by FM-not the ceramic one.

ROP LE, li 18650 2600mah x2. Measured 7.4v, close to a month since last charge, driving ROP HO @3.94amps.

The ROP has all the fixs and routinely flashes the HO bulb even when rested overnight with 7.8v measured.

Used to be able to run the Phillips 5761 in it untill after did all the fixes, I've blown so many now I've given up.

Also over fixed a 5c with 6 sub c's which blows ROP HO's and the 5761's. Put a kiu in the 5c and run 1111's which seem to like being overdriven.

So, I would do the fixes one at a time in the future. Which I plan to do with a 2cM@g to run the 5761 which is so bright and white with perfect circular beam.

Jim

 

[LuxLuthor]

I just did the tailcap spring wire fix (pretty tricky still allowing the charging post rod to make it through, and the wire inside the stock switch top spring (soldered to top & bottom caps), and Pro-Golded.

My previous 8.3V was also with 8 x AA Eneloops that have been sitting a couple weeks. I charged them up....and well....insta-flashed the bulb. Damn It! LOL!

I put in an 1185 and ran it down to 9.7V at the bipin bulb level, then put a new 1164 in, and got range of 9.56 to 9.62V at bipins...but I swear it is not brighter on whitewall than 1166 running at 12.55V (1D) or 12.68 (1.5D) lights.

The mods definitely helped, but something is off with this particular re-rating formula of the 1164. The 1166 is becoming my favorite overall bulb.