15 minute charging tips

[degarb]

I assume that overheating can hurt the battery, but I cherish my 15 charger as one of the best $30 I ever spent. It makes so manythings possible that were impractical before. (I would buy a 16 AA 1 hour charger, but not a 8 cell 1 hour.)

I have seen numerous batteries cease to quickcharge. I assume this due to heating during last charge. So, I have been experimenting placing the batts in freezer 15 minutes when ever practical before charging.

The other experiment is to remove the plastic labels, then permanent marker label them (clear nail polish to lock in the marker.). This should lower temp by making the fan pass air over metal not an insulating label (thin vinyl glove is how I keep 3 degree burn off my fingers when hotgluing.).

Any one with other tips or comment on these experiments. (though the proof will be if I see any impovement on percentage of cells that stop quick charging.)

 

[degarb]

The other comment on the 15 min charger is in my experience, 100% of Duracells 2650 (made in japan) work out the package in it, %25 of the Energizers 2500's (china) fail, and %50 of the Kodaks (2000 china fail out of the package.

 

[half-watt]

i have two 30min Duracell chargers that can charge either AA or AAA cells. yeah, not 15m, but at most 30m (sometimes less) if the cells are "fully" discharged to the point that they are of no practical use for most lighting applications.

these chargers keep the cells pretty cool by the use of a FAN built into the 4cell charging units. the FAN continue to blow air after charging for a period of time.

immediately after charging, no perceivable warmth is apparent if the cells are held in the hand. they appear to be at or about ambient room temp.

have been using the same 8 2500 mAh duracell AA cells for over two years now and haven't lost one yet. i also charge other cells in these two chargers.



so, why not use a small BOX FAN (or any fan) to blow cooler ambient room temp air over the cells while you charge them? this would help to keep the cells cooler.

 

[degarb]

i have two 30min Duracell chargers ... why not use a small BOX FAN (or any fan) to blow

The Energizer has a fan like the Duracell. I suppose one could supplement, but would need to be practical.

I was wondering if the 30 min chargers ever reject cells like the 15 min charger (I think based on internal resistance, per thread about tricking unit.) If not, I might buy one to supplement the 15 min charger. At walmart, the 30 min charger is same price as the 15 min. So, It makes more sense to own one of each than two 30 min chargers, especially if removing the insulating labels may be all needed to safely use the 15min.

 

[MrAl]

Hi there,

Here is the thread that talks about fooling the Energizer charger to work
with cells that have somewhat higher internal resistance, which is what
prevents some cells from charging (the red LED blinks when you put one
of these cells into the charger).

http://candlepowerforums.com/vb/showthread.php?t=157139

The modification is quite easy, and the only thing to remember really is
that the spacers that separate the two circuit boards can come out when
you take the top board off so it's best to carefully remove them and put them
into a small box or something like you would use to hold small screws.
Getting one of the spacers back in is a matter of lift both boards while
sliding the spacer back in with needle nose pliers or something like that.
After it's in the right position, you can push the boards down a little and the
spacer will stay in place until you can get the screws that hold the boards
down screwed back in.

As the update shows, a small slot cut in the side of the charger (either or
both sides) allows the quick insertion or removal of the insulating card (can
be a simple index card slice made with scissors) so that you can choose to
convert either 1,2,3, or all 4 bays into one half charge rate bays which allows
the higher internal R cells to be charged without causing the red led to blink.
The remaining bays (1 to 4) keep charging at the highest possible rate, so
you can mix cell types too.

It's interesting that this mod does not work with the Duracell 15 min charger
because it uses a different technique to select between AA and AAA cells.
I believe the Duracell could be fooled too, but it would take a little rewiring...
The AA negative terminals on the charger would have to be disconnected,
and connected instead to the AAA negative terminals. If you want to switch
back you'd have to use one switch per bay, and each of those switches would
have to be rated for about 10 ams DC (and low voltage like 12vdc).

 

[degarb]

So far, I have been using all these strategies in this thread to keep my batts cool as possible in the 15 minute charger. ("Fooling" for all mere top-off's, removing heat insulating battery labels for better cooling, & occasionally, freezing them before charging,)

But what about making a heat sink to touch part of batts opposite of fan. Obviously, to work well, you need no labels on the batteries. This would need to 1. not conduct electric 2. conduct heat well 3. not obstruct flow of air. ... so far, I found the easiest thing is a glass or coffee mug set on horizontally placed charger on batteries.

I haven't tools to see if my heat sinking is significant. But since it doesn't take any effort and doesn't appear it will slow air-flow, might be worth it.

Also, I suppose one could come up with a really thin re-mountable battery label insulator to be replaced after charging that could be used many times. This is needed for only one of my flashlights (Dorcy 1 watt 3 AAA Nichia) where the batts touch each other and side of light. I haven't come up with anything practical other than tape. But a thin plastic with low tack glue would work better.

I have designed glove liner for winter, and found the thinnest, most heat insulating material, is latex or vinyl (despite limitations on sweat breathing/air pockets or vacuum insulation takes space so isn't really thin). So on batteries, the plastic battery label is an enemy of heat dissipation and should be removed if quick charging. Also, I use vinyl gloves when hot gluing to prevent blistered fingers and pain.

 

[degarb]

So far the heat sink idea is keeping my bats really cool, and subjectively I think they might be charging to a higher capacity.

I tossed out the the idea of using a glass to cool bats, as the center is empty. So, I switched to a refrigerated 2 in diameter jar of preserves set on the charging batteries. Testing side of bats touching jar with lips (negative), it is cool. While the positive side not touching the jar burns the lips.

Then I tried this with frozen jar, with a final ability to touch entire battery with lips and no discomfort. Then, ultimately I tried wifes 1 lb cylinder of frozen turkey. This touches entire battery side and melts the ice of the turkey. The result is nearly cool batteries at end of charge. Problem solved; just don't let the women in you house find you doing any of this..