Surge confusion

This a quote from a previous thred. I believe Brightnorm wrote it:

"Ok, not wanting to burn out my light I tried it with 4 lithiums instead of all 8. The light is actually a 6v light, so you have two sets of 4. Now with 8 alkaline I got 1.1amps at 5.3v With 4 lithium I got 5.5 with 1.25 amps. That is 5.83 watts with alkaline and 6.875 watts with the 4 lithiums. I can imagine if I put 8 lithiums in ther the lamp would not last long. It would be really bright though."

According to Energizer the voltage will not be higher using both sets(barrels) than just one. The only difference would be the runtime. So if 4 lithiums give 5.5V/1.25A...then you'd get the same result using 8. If this is correct the 8 Alkalines that gave 5.3V/1.1A is the same as 4 Alkalines would give. ....so i can't understand why it should be dangerous to use lithiums.

How do you assume that the Surge is a 6V light? after all 4x1.2V = 4.8V

Brock's webpage says it's a 5.3 volt light, and when a Surge has all its fresh new AA's in there neatly packed a voltmeter will read 6.0. So it can handle 6 volts and must be intended for that. I don't know why Brightnorm is worried about overvolting except maybe he doesn't want to pay for any of those $5 bulbs when they blow, which they certainly will be doing if he uses lithiums all the time. Many bulbs can tolerate overvolting but they will all blow early from the intense heat. There are graphs and charts of voltage against bulblife on certain websites, maybe you have seen them. Brightnorm was interested in using lithiums for practical things like shelf life or discharge rates. Alkalines are inferior batteries terms of general performance. Also, remember that NiCads and other rechargeables are rated for a lesser voltage than the nonrechargables, least when they are fresh. Does this help?

I sure hope Energizer doesn't really believe that adding a second set of batteries doesn't increase the running voltage. That is the reason they use 2 sets of 4 in the light in the first place. I can say without a doubt if you add a second set of batteries the voltage goes up. I am talking about when the light is running, not a straight battery voltage. The more load you add to a battery the more the voltage will drop. Adding a second set of batteries cuts the load in half, thus increasing the output voltage. If you don't believe me try running your surge on 4 batteries, then all 8. All 8 is MUCH brighter, thus a higher voltage.

Brock, I believe you're right. I have asked Energizer a lot of questions, and sometimes I get the most amazing answers. They seem to be more newbie in flashlights and batteries than me....which is kind of amusing

Ithought the double barrel was a series/parallel configuration? If so, would voltage still increase?

--dan

Open circuit voltage would not increase and is approximately 6 volts. As Brock mentioned, load voltage will not decrease as much because you have two sets of batteries providing the six volts. Due to the chemical nature and composition of batteries, they cannot provide a constant current/voltage under load and the more current a battery has to provide, the more it's voltage will drop. Having two sets of batteries in parallel, that means each battery only has to provide half the amount of current so hence the voltage will not drop as much. I think the series/parallel combination is a great idea. All the benefits as mentioned plus still smaller then say a four C light.

So a tec4 running the surge bulb will not be as bright as the surge running running on all 8 batteries because of voltage drop. Is this correct? (a post under the tec4 thread indicated that tec4 with surge bulb would run as bright as the surge itself ignoring run time).

Duh
tec4 with surge bulb has to be same as surge on 4 batteries

Well the reflectors could make a difference in the light concentration.

I think a good experiment would be to take a Surge bulb which is presumably designed to run at a higher voltage then a normal four cell 6v light lamp, put it in a four cell assembly such as tec 40 if possible and run 4 AA lithiums and see if that would make the lamp as bright as it normally would be under the surge configuration.

5 not so new AA might be just fine.(1.2x5 =6)
Linfeng

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR> So a tec4 running the surge bulb will not be as bright as the surge running running on all 8 batteries because of voltage drop. Is this correct? (a post under the tec4 thread indicated that tec4 with surge bulb would run as bright as the surge itself ignoring run time). <HR></BLOCKQUOTE>

I don't believe that's my post, but I have both the Tec40 and Surge running on the same bulb. The Surge is brighter overall, and I think Brock's explanation as to why is completely correct. I've also run the Surge on 4 batteries and it is dimmer.