Ideal cells for a Mag85?

Hallis

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Hey guys, I know there has been quite a bit of Mag85 discussion lately thanks to Wilkey, js, bwaites, and a few other people giving us great gifts of wisdom and enlightenment.

One of the things that i havent seen a lot of coverage on is batteries. I know that NiMH's are the thing to use and are a pretty economical way to do it with 3aa-D adapters or one of fivemega's custom 9aa-3D (which is just sickening in how nice its made). The only thing generally said about the cells themselves is that you want to stay under 2200mAH as far as capacity rating goes since the bigger cells have trouble meeting the amperage draw from the big 1185. Wilkey is packaging some CBP1650's with his "Polaris" turnkey units that are available for signup. He chose these because they are able to deal with really high current. And rightfully so, they should fit the application well. But, i cannot look past the fact that they are in fact 1650mAH cells and as a result wouldnt have good runtime in a Mag85 or really much else, (ive got some 1500's that i have to charge every few days with just random normal use of my digital camera which is getting to be a pain)

Basically what im looking for is a battery that could be a happy medium, say 2000mAH or somewhere there about or suggestions about a higher capacity cell that could meet the Mag85's required draw. And also, where to get them. Fivemega seems to like the Sanyo 2300's. At least those are what he pictures with his 9aa-3D adapters. Will those meet the current draw and if so where can i pick them up?

My old Maha 2200's are going to get rolled over from flashlights to consumer electronics duty, like my digital camera.

Sorry for this being so long-winded.

your input is greatly appreciated guys.

Shane
 
Think I can only answer one of your questions regarding the Sanyo 2300's. I am using 9 of them with my MC85 and it works well. They are all fitted in 3x 3AA-D cell holders. I don't have a runtime chart for it though.
 
Define noticeably yellow? I use industrial Sanyos and they seem to lask forever.
 
According to Wilkey the Energizer/Sanyo 2100mAh available at Target, Walmart etc. are the best balance of runtime/current that he has tried...

That's good, I have 12 stashed as of this moment!

Goota LOVE /ubbthreads/images/graemlins/buttrock.gif the fact that they are available locally!
 
Hallis, and anyone else,

First, please read Ginseng's masterful High Current v. High Capacity Cells - Updated thread.

But the short of it is this: a cell's capacity rating is figured by measuring the maximum constant current that a cell will deliver over 10 hours and by then multiplying that by 10. Thus a 2100 mAh AA cell was able to deliver 210 mA over 10 hours.

Got it?

But this DOES NOT tell you what the cell will be able to do when trying to dump all of its' charge in one hour, or 30 minutes, or 15 minutes. As bwaites has recently pointed out, a cell can be designed for either high capacity OR high current but not both at once, although you can have a cell that splits the difference.

High capacity cells have higher internal resistance, and thus when asked to deliver high currents, they will not come anywhere near to their rated capacity.

High current cells look less appealing because their capacity is lower, but when being asked to deliver lots of current, their capacity stays more or less the same.

An example: the high rate KAN 1800 4/5A's which I used in the TL mods will still deliver 1800 mAh at a 2 amp draw, which equals an over 1C draw. Some other batteries which I tested, however, dropped from 1750 mAh (at .1C) to 1500mAh (at 1C).

Quite an eye opener, isn't it?

Part of the reason that 1800-2000 mAh AA batteries drive the 1185 for longer, is because they are not driving it as hard. A high or medium high capacity battery's voltage under load will sag when being asked to deliver a lot of current (such as the 1185 demands). When the voltage sags, then the current also goes down. There can be an incredible difference. For example, the KAN pack will drive the WA1111 at 7.0 volts half-way through the run, but the other batteries can barely hold 6.0 volts. This translates to a HUGE drop in light output.

That said, however, the advantage of having some non-trivial amount of internal resistance in your circuit is that it will prevent insta-flashing over-driven lamps at turn on.

This is why the Tiger85, which runs 9 KAN 1050 2/3A high-rate NiMH cells, will blow the 1185 1 out of every 3 or 4 times that it is turned on fully charged hot off the charger, and why the Mag85 running the usual 2000 mAh Maha's, will not. It also means that the Tiger85 is brighter. hehe.

There are very few things in this world where one number will tell you the whole story, and battery capacity is certainly NOT an exception to the rule.

OK. Now. If it were me, I'd be inclined to use whatever Wilkey is recommending (Maha 2000 mAh, IIRC) because he has extensive experience with this light and knows what he is talking about. The CBP 1650's are awesome, awesome cells, but they will have a good chance of blowing the 1185 if the light is turned on hot off the charger.
 
I just switched from the Energizer 2100's to the Ray-O-Vac IC-3 2000 nimh batts and have been extremely pleased with their performance - especially in terms of brightness. What an improvement! Plus with the IC-3 charger, in a very short time, I can be ready for more light-time fun...I've kind of been getting impatient with the overnight charger.

greg
 
Greg,
I just switched to the La Crosse charger, that give among others things "capacity".
I was surprised to learn that some of my 1800 mah batteries were only at 1000 mah!!!
And some that I was using on my camera had less than 500 mah!!!!
I put them in the refresher mode, that will charge and discharge them until they attain maximum capacity.
What an eye opener charger!!
Juan C.
 
This is what I received from Wilkey last November as a rough guideline. I too have been pleased with my Rayovac IC-3 2000mAh batteries in my Mag85.

-------------------------------------

I have found that the following is a decent guideline for optimizing power, runtime and stress on the batteries.

Current of 0-750mA, use the highest cap cell you can find
Current of 750mA or higher, use 2300mAh
Current of 2000mA or higher, use 2200mAh
Current of 3000mA or higher, use 2100mAh or less
Current of 3200mA or higher, use 2000mAh or less
 
*nods* that is some of the most helpful info yet, that thread by wilkey about the head to head test is good and all but doesnt really tell me much about the Mag85 compatability. And, since they're 4/5AA's it would mean having to build a pack and get a charger that could charge them. More of a pain then im looking to get into.

Question is, Sanyo or Maha? price isnt the concern but reliability and quality is.

Shane
 
Hello Shane,

I am glad you brought this up.

I started testing alkaline batteries because I was trying to develop a testing methodology and I was curious if there were any differences.

After finding differences, I moved on to 123's. I found out there were differences there as well.

My goal all along is to gather information on rechargeable batteries.

I am currently finishing up my charger testing. The best battery in the world is only as good as the charger you use to charge it up on. I am pleased in finding that there are several good chargers available. I am also learning that most chargers will do a good job if given a little extra time on charge as long as they don't "cook" the cells in the process.

The next chapter is to test a variety of brands of rechargeable batteries.

I only have a few brands, so once again I will be asking people to let me "borrow" a couple of cells for a few days for testing.

I believe we have a variety of uses and in some cases high capacity cells will work the best, and in other cases high current cells will work better.

With this in mind, I am planning on testing at several current draws. Probably start at 0.5, 1.0 and 2.0 amps, and go from there.

As always I am shooting at a moving target. There are too many brands out there and the battery manufacturers are continuing to try to "improve" their cells through changes in chemistry to get an accurate assessment. I am hoping that trends will develop similar to those found in the Alkaline and 123 Battery Shoot Outs.

I also know that my results may be off a bit because of a lack of statistics. However, I do not have the time, resources, or the test set up to do 1000 cells of each type under each current draw and retest every 6 months. I have found the other testing to be useful in spite of its limitations, and believe this round will be useful as well.

I know Wilkey, Jim, and Bill have done a fair amount of testing on high current cells and we will be comparing results. I also know that there are others with test equipment that I may be able to talk into "sharing the load."

I believe I have a method that addresses the variables that I can control and the results should benefit the CPF community.

Tom
 
Well, i would send you some cells to test but i have no clue how old my maha 2200's are or the care or lack thereof they were given prior to me owning them. I think im just going to buy Maha 2000's, Unless Sano 2000's are more high current friendly.

Shane
 
Welllllll,

The BEST NiMH cell I've found to drive ANY bulb is the Aero 4000MaH 1/2D cells. They present an interesting problem though, you've got to use a BIG Mag to use them for the 1185 and only slightly smaller bodies to use them for the 1111, 1274, and so on.

That said, if you want maximum brightness, the 1650AA's from CBP are easily the best in the AA category.

Maximum runtime with AA's is another game though. A high quality consumer cell, such as the Energizer 2100 seems to be the best compromise. It's not as bright as the 1650's but runs close, and picks up roughly 7-10 minutes of runtime, though if you look at maximum brightness at each level (the 2100s don't start quite as bright), there is probably only 2-3 minute difference.

Bill
 
I wouldn't mind running the CBP1650's in my mag85 but wont they run a much higher rick of flashing the bulb?

Shane
 
Out of curiosity, has anyone tried charging a pack of the Rayovac IC-3 batteries in a holder like Fivemega's new 9 and 6 cell holders using a charger like the SuperNova ?
Larry.
 
I would like to share with you a note I sent to Wilkey regarding the CBP 1650's...

Hi Wilkey – Thought I would tell you how those CBP 1650's handled an uninterrupted runtime of 30 minutes in the MAG85. I myself was most impressed. It ran really bright up until about 25 minutes and than the last 5 minutes the bulb began throwing a yellow beam. It was as if the bulb was dropping out of regulation that is how dramatic it was in my opinion. At the end of the 30 minutes the lamp was still throwing but a weak yellow beam. This is running off x8 hot off the charger. I took a reading of the cells at end of test and they held 1.13v.
 
Not bad. At 25 minutes, that's 1312mAh at 1.91C, At 30 minutes, that's 1575mAh at 1.91C. I suspect the voltage is holding really well. It's quite normal for true capacity to diminish as C rate goes up. If we take 0.9V per cell as the cutoff, then I think we are getting pretty close to full capacity as the WA01185 will be quite dim at 7.2V.

All in all, pretty good. If it survives 9 cells, it'll be pretty bright right to the end at 8.4V.

Wilkey
 
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