Rechargeable AA batteries

[KeithG]

"eneloop is good" is not always an accurate assumption. There are 11 different versions of AA sized "eneloop" brand batteries. Those are made by at least three different manufacturers (Sanyo, Panasonic, and Fujitsu). Given the huge variation in Eneloop branded batteries, some may be great in his strobe, others may not - assuming the strobe even likes 1.2v batteries in the first place.

The point in my post was to say that looking at the battery specifications will be a more reliable indicator than the brand on the label of that battery.

Eneloop is a brand name. The brand was originality owned by Sanyo but Sanyo was bought by Panasonic (2009 or 2010?). Due to antitrust issues the Sanyo battery stuff was then sold off to Fujitsiu. Maybe...
The Evolution of eneloop and Fujitsu Rechargeable Battery | Famcart News BLog

 

[tbone1004]

@giffenk
charging NiMH batteries at 1C is fine as long as it is on a smart charger. Probably want to charge close to 0.5C if there isn't a temp monitor on it, but if yo'ure careful you can charge at 1C. I wouldn't want to charge any faster than that and apparently you're supposed to fully discharge them before you charge them that quickly.

 

[victorzamora]

I'm missing the point in some of these posts. Is the point to save a few cents on each cell, or to have a reliable, proven, power source? Even if real Eneloops were twice the price of (say) Amazon Basics, who cares? In the scheme of things, you are talking about one of the most minor costs of diving, but a critical part of diving, especially underwater photography (which is what this thread is supposed to be about). Would you be looking for the cheapest possible o-rings for your gear, or is a few cents more worth the peace of mind?

I initially recommended AmazonBasics not on price, but because they actually performed better in the tests I saw performed ~18months ago. If AmazonBasics are, in fact, manufactured in the same factory right beside of the "good" Eneloop cells then you can bet your butt I'd save the pennies and go with the same cell for cheaper.

I took it back because some testing showed that maybe the AmazonBasics cells weren't as good.

 

[KeithG]

@giffenk
charging NiMH batteries at 1C is fine as long as it is on a smart charger. Probably want to charge close to 0.5C if there isn't a temp monitor on it, but if yo'ure careful you can charge at 1C. I wouldn't want to charge any faster than that and apparently you're supposed to fully discharge them before you charge them that quickly.

You are using lingo I do not understand. I have an old time Lenmar charger thay charges 4 AA's in less than an hour. that is all I know. This works great if you screwup and need to recharge during your SI. the eneloops seem to survive this.

 

[tbone1004]

@giffenk
C rates are used to discuss the charging and discharging speeds of batteries. 1C is fully charged in 1 hour, 0.5C is fully charged in 2, 2C is fully charged in half an hour. It's a good way to normalize this information.

Say you have a 2ah battery, and a 2a charger. it's going to charge it in 1C. If you put a 4ah battery in that charger, it will charge it at .5C or C/2 which is a slower rate. It's a good way to match charger size to battery size.

Right now I'm converting a DPV to LiFE. They have a max charge rate of 1C, but finding a 40a charger is a bit impractical. I'll be able to reasonably get a 10a charger so will charge at C/4 which is plenty quick, and is worth paying a bit more money vs a 4a charger which would be C/10 and take overnight to charge the battery

 

[fmerkel]

C-rating is related to amp capacity > a 2000mA battery is 2.0A so is 2C.
'High performance' NiXX batteries (like for RC cars that use up a pack in 10-15") can charge OK at 1-2C, BUT, they are not long lived batteries.
More standard performance AA/AAA batteries are better charged at 0.5-1C. High rates of charge lead to heating which is an enemy of longevity. A hot NiMh is a dying NiMh.
In a nutshell, your Lenmar fast charger may be useful, but at the price of battery life. Now you know, you choose.
(Those old 15 minute NiMh chargers were positively destructive).

Since Panasonic took over Eneloops the equation has changed. There are a number of different variations (Japanese being better than Chinese eneloops). Same for Amazon Basics-initially they were 'stock' 2000mA Eneloops with a different shrink wrapper. A number of other companies did this re-branding also.
Now, you may or may not get real Eneloops when you buy Amazon Basics. From my most recent checking....not.
I have both Eneloops and older Amazon Basics. Near as I can tell they are the same product.
Imedions and Fujitsu are both good batteries also and work fine in strobes.

 

[tbone1004]

@fmerkel incorrect

c rating is a ratio of charge/discharge rate to battery capacity and has nothing to do with their actual capacity.

 

[fmerkel]

@fmerkel incorrect

c rating is a ratio of charge/discharge rate to battery capacity and has nothing to do with their actual capacity.

I was simplifying. Good enough for most people. Hoards of folks are still mighty confused by [nominal] 1.2v vs. [alkaline] 1.5v.

 

[tbone1004]

@fmerkel voltage has nothing to do with c rating. you made a very factually incorrect statement by saying that C rating is the amount of amps a battery has, which has no thread to the truth. C rating has nothing to do with the actual rating of the battery. 1C is 1C whether it is 1mah, 1ah, or 1000ah. Your statement implies that 1ah-1c, 1000ah=1000C, which is completely untrue

 

[kelemvor]

I've never heard of C rating before this thread, but I already love the idea. If manufacturers include that bit of data with their products the world will be a better place. I bet it will be hit or miss, like lumens for lights.