Dorcy 1AAA Battery Life

It's been over a year since I bought my first Dorcy 1AAA - and a few days ago I noticed that my at home EDC, which was still on its original battery, was starting to look dim. So I did a quick side-by-side comparison with the other Dorcy 1AAA (#2), an Ultra-G and an ArcAAA - which are all about the same ballpark brightness.... and yes my Dorcy 1AAA (#1) was indeed dim.

So I put a new battery in -
I know, big deal.....

Actually I put the new battery in my out of the house EDC Dorcy 1AAA (#2), and put that one's in my Dorcy 1AAA (#1) -
I know, BIG deal.....

Except - I had one of those old fashioned NiCad (C/10 trickle) chargers (bought in the mid-80's) that claimed to "recharge" disposable batteries - more like "resucitate" -
according to all I've read - there are warnings that disposable batteries may explode if recharged.

But the charge rate was so low and the charger basically retired/unused - that I thought what the heck, and put that near exhausted "dim" battery in to charge - but watched the time and monitored its temperature. The instructions said 2 hours so that's all I did - the battery was not hot. I put the "recharged" battery back in my Dorcy 1AAA (#1) and was surprised to find it was back to full brightness doing the same comparison as before - I even swopped the batteries between the two Dorcy 1AAA's to check.

That was two days ago - the resucitated battery is still going strong - and the Dorcy 1AAA (#1) has been used as my normal at home EDC - probably a bit more since I keep checking its brightness - which does not seem to have diminished.

Disclaimer - I am not suggesting anyone else do what I did, as I considered it risky -
for the 30cents for a new AAA - it's just not worth it - it's stupid to risk an explosion or fire.

That charger I guestimate does something in the region of 50-100mA charge rate - it's a 5-8 hour charger for mid-80's NiCads -
this is real low compared to modern chargers for NiMH - especially fast chargers......

The exercise really only goes to show that an LED flashlight lasts a long time on a single battery under my typical at home EDC usage.

Note: Roy's runtime for the Dorcy 1AAA on an alkaline was just under 4hours to half brighness.

The dorcy is one of the kings of single cell sipping. I have one that can fire up from a little over 0.5v. It doesn't take much to get a dorcy to go for an hour about 100ma or so so if the charger can manage to restor twice that much over a 5-8 hour period you can get a few hours more back. I have too many AAA nimh and excessive amounts of AAA alkalines that recharging alkalines isn't worth the trouble for the return. I have rechargeable alkaline AAAs and I would guess recharging alkalines would be similar to recharging them with the exception of very few recharges and capacity decreasing each charge to nothing really quick. I used to have a 6v flat battery for a remote that cost $4.00 or so to replace and went out in 6 months. I would hook it up to a power supply and recharge it manually overnight and get it to run another 3-4 months perhaps the first time and a 1-2 months the next time then a few weeks. I ended up soldering 3AAAs in a makeshift pack and using that instead costing 1.00 vs $4-$5.

If the dorcy circuit was closer to 75% efficient I would just use one for a nightlight hooked up to a resistor and single cell batteries in parallel to use them up,

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Lynx_Arc said:
The dorcy is one of the kings of single cell sipping. I have one that can fire up from a little over 0.5v. It doesn't take much to get a dorcy to go for an hour about 100ma or so so if the charger can manage to restor twice that much over a 5-8 hour period you can get a few hours more back. I have too many AAA nimh and excessive amounts of AAA alkalines that recharging alkalines isn't worth the trouble for the return. I have rechargeable alkaline AAAs and I would guess recharging alkalines would be similar to recharging them with the exception of very few recharges and capacity decreasing each charge to nothing really quick.

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Thanks so much for your very informative reply.

I really just did my recharge of a disposable alkaline out of curiosity - understanding the risky nature.

Exactly as you say - it's not really worth the effort - it's certainly not worth the risk for the 30cents .

I was just surprised that I could resusitate the low battery to what appears to be a "full charge" level.

I probably wouldn't try to recharge it again - and will see how long it lasts......

call me "cheap" /ubbthreads/images/graemlins/grin.gif

Thanks

Cheap is good because it leaves you more money for more flashlights.

I have one of those rechargers. I quit using it after a battery exploded in a gameboy I was using after it had been recharged. No damage was done but it was a large enough explosion that it blew the battery cover off the gameboy and stung my hand pretty good.

Needless to say the recharger has been sitting in a drawer ever since.

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gorn said:I have one of those rechargers. I quit using it after a battery exploded in a gameboy I was using after it had been recharged. No damage was done but it was a large enough explosion that it blew the battery cover off the gameboy and stung my hand pretty good.

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I recall one occassion when I was over zealous in recharging a disposable AAA alkaline -
and it "exploded" -
well, really it was more of a rupture accompanied by a Pop sound.......

But that illustrates the risk involved even with a C/10 low trickle type charger delivering only about a guesstimated 50-100mA -
wouldn't like to think what one of the modern fast chargers might do.........

When I was a kid my dad bought one, and I recall us using it a few times. Then I don't know what happened to it. A few weeks ago a friend of mine gave me a ad with one that cost about $20. He thought I would be impressed, until I explained that it was only good for a few charges, and I read somewhere they may cause batteries to leak and ruin things.

About 5 yrs ago I bought a d cell flashlight with a solar charger built into it. It also came with a set of battery adapters. The instructions said it will charge any kind of battery including non-rechargeable. As you may have guessed by now. It was ruined by a set of regular batteries leaking, so much that they were like glued inside the light. I just threw it away. I paid the overpriced price of about $43.00 for it. You live and you learn.

I would say if you could reasonably recharge alkalines without the problems of leakage etc... the ones worth considering are the C and D cells because they cost a lot more than the AA/AAA cells. I tried recharging a 9v battery the other day and it didn't work. They are perhaps the most expensive of *common* batteries.

Lynx;
To recharge that regular alk 9V, -I prefer to call the process "rejuvenation", you definitely need a smooth, ripple free maximum of 15-20mA. Anymore than that will ruin the battery in short order. I have been doing this procedure for a lot of years-with a custom-built charger.
-The cost of 9V. being what they are.

However, these days, I don't even consider it necessary anymore, because of the availability of 8.4V & even 9.6V NimH.

I think some alkaline 9v cells take a charge better than others, and nimh cells are really not suitable for occasional use devices such as a DMM or clock radio backup battery. I once had a TI-30 calculator in high school that ate 9v batteries so much that one test I had in chemistry I sat a 6v lantern battery down on the table wired to the calculator. I never bought a battery again for that calculator and still have it sitting in a drawer.

I have found (in most cases, that the NimH works out OK for those low drain apps. because it's usually at least 6-8 months before the NIMH self drains enough to make any difference at all. -I've used AAA NIMH and 9V.NIMH in a couple of my DVMs with no problems at all. I simply check them under load every 6 months or so. I have been using NiMH for seven to eight years now. Extremely rarely have the cells become anywhere near completely drained after only 3-4 months.

So many people are under the very mistaken impression that any NimH will automatically self-drain in only a few months. Wrong.

-Remember, it's the loss (in %) that actually gets smaller and smaller as time goes on, because that percentage loss is always based on the REMAINDER of the capacity -and NOT by the original rated capacity.
So it's simply not true that NiMH cells are no good for everyday use.
-of course common sense Would preclude using these type batteries in seldom used items like emergency flashlights etc. /ubbthreads/images/graemlins/tongue.gif

I hate checking batteries in stuff, that is why I put disposable cells in stuff I know will take years to drain alkalines in so I don't have to worry every 6 months. I figure before I put a nimh 9v in my DMM I would consider a lithium instead.

My local dollar store has 3 carbon zinc 9v bateries for, well, a buck.

With the low drain applications I have (spare DMM), even the charger for 9v NiMh would never pay itself off. Lets face it, with the low drain devices that take 9v batteries, even alkalines are a little overkill.

The reason I use alkalines is they tend to leak less often than heavy duty cells and have a longer storage life. I could get 9v nimh because I already have a charger for them but unless I find myself draining a couple every few months it isn't worth paying $5 each plus $5-10 shipping and then have to recharge them 2-3 times a year perhaps when they self drain too low.

Just an update -
I had occassion to take a comparison beamshot of my Dorcy 1AAA (#1) on its original battery resuscitated back in December/2004 (as reported in the opening post of this thread) compared to my very slightly brighter/better Dorcy 1AAA (#2) with a fresh battery and was surprised to find they were about the same -

Comparison beamshots of the two Dorcy 1AAA -


Just a comment about the step-up semi-regulated circuitry of the Dorcy 1AAA -
I am VERY impressed with the circuit of this cheap flashlight - because that is the original AAA battery in the Dorcy 1AAA (#1) that has been "recharged"/resuscitated using a couple hours on a slow (C/10?) charger back in Dec/2004 - over 5 months ago! - as can be seen in the comparison beamshots - it is almost as bright as my Dorcy 1AAA (#2) on a fresh battery (amazing).

Try taking the tailcap off the light and measuring the current draw there on both instances to see what the difference in current is. On a new alkaline my dorcy draws about 190ma of current. I don't think the circuit regulates any, it just boosts with a startout overdrive and sags with the battery as it dies. Personally I wouldn't risk recharging an alkaline battery as it tends to greatly increase the chance of leakage.

[ QUOTE ]
Lynx_Arc said:
Try taking the tailcap off the light and measuring the current draw there on both instances to see what the difference in current is. On a new alkaline my dorcy draws about 190ma of current.

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I just measured my Dorcy AAA with a fresh alkaline. It draws 350mA. On a used Alkaline measuring 1.3v it draws 190 mA and it's still fairly bright. I wonder if the circuitry is different or it's a normal variation between production samples.

It could be last time I measured the battery wasn't new. needless to say I get about 3 hours or so off a AAA alkaline
and I have the older version of the dorcy. At 350ma input it must be pushing at least 60ma to the LED if not more.

[ QUOTE ]
Lynx_Arc said:
Try taking the tailcap off the light and measuring the current draw there on both instances to see what the difference in current is. On a new alkaline my dorcy draws about 190ma of current.

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Thanks for the suggestion.

I used my old Russian analog multimeter (I don't know how accurate it is - as it's old - been through hard work and the closest analog scale ranges are 60mA (too low) or 600mA (not enough differentiation).

But my Dorcy 1AAA (#1) on the resuscitated battery draws 120MA. Dorcy (#2) on fresh(er) battery draws 140mA.

Swapping the batteries around Dorcy 1AAA (#1) on the fresh(er) battery still draws 120mA and Dorcy 1AAA (#2) also still draws 140mA from the resuscitated battery.

So the lower current draw of my #1 could explain why it is not quite as bright as my #2.......

However because you reported drawing 190mA from a fresh battery and nikon reported 350mA(!) my readings seem low - then I realized my "fresh"(er) battery wasn't that fresh - it may have been fresh(er) over 5 months ago when I changed to it - but it probably isn't now.

So I took a fresh battery out of a pack and measured that - it drew 240mA in both Dorcy 1AAAs - but there was a strange effect - the initial reading was about 200-220mA and it moved up to 240mA.

Although the fresh battery does show brighter (not surpisingly) the old resuscitated battery isn't so dim that it was really noticable in isolation - one can quite obviously tell when beams are side-by-side, but I could be fooled when viewed separately - well I obviously was /ubbthreads/images/graemlins/blush.gif

New Battery vs. Old Battery


Swapped batteries around -



[ QUOTE ]
Lynx_Arc said: Personally I wouldn't risk recharging an alkaline battery as it tends to greatly increase the chance of leakage.

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I agree - I've said as much quite clearly earlier on in this old thread of which you were part of -
it's simply not worth the risk for a 30cent battery that lasts nearly a year for my usage.

That resuscitated battery was charged just out of curiosity on that occassion as described earlier in this thread, and it has lasted well over 5 more months without any signs of being too obviously significantly dimmer......

like I said - regardless of whether the circuit does any true regulation - I think that's still pretty amazing....... for a circuit in an under $6 flashlight.

The dorcy AAA is a great light, I recommend it as a starter light for anyone wanting to get into LED lights. I tell them they can take batteries out of dead remotes and clocks and run the light for perhaps an hour or so for free because the light literally sucks batteries down to half a volt. I had a tv set with a remote that used a 6v flat battery that cost $4 I *recharged* using the same method a few times myself. I ended up soldering 3AAA cells together to replace the funky battery which worked just as good and cost about 1/3 as much. What would be more amazing is when circuits similar to this get into $2 led flashlights and start ending the incan as the cheap light of choice. I once thought of using the dorcy circuit in a 2D light driving perhaps a dozen 5mm LEDs.