Electronics, Lighting, & Gadgets - Rechargeable AA batteries? Best deals, best brand?

I run a dinotte powered by AAs and would like to have an extra set of backup batteries. Regular ones sap too quickly (manufactor doesn't recommend 'em anyways). Any suggestions? Sonys on dealextreme seems steep....

i use AAA rechargeable batteries, tenergy brand from http://www.batteryjunction.com/aaponiba.html here. they seem to live up to their claimed capacity and i have encountered no problems. i would guess their AA ones would be good as well.

Tenergy's work fine, but I have had better runtimes with Duracell 2650's or the Titanium 2700's from Batteryjunction..

Sanyo and Maha both make highly rated batteries.

I have 4 AA Sony rechargeable Nimh 2500mAh, and 4 AA Energizer rechargeable Nimh 2500mAh. I have 2 Fenix LD20s, 2 AAs each, and the batteries work great, they seem to be lasting the manufacturers estimated run times, plus a little. Thats at about 38 degrees out, we'll see when it gets colder.

I used these batteries a few times a few years ago, then they sat, say 3 years. Now I use them every day, its a 1hr commute each way, and on the way home there are NO street lights on my route so I have the LD20s on turbo or high the whole time.

Duracell rechargeables seem to work well, and they make a low-self-discharge (LSD) version (which has a very reduced tendency to lose charge over time). I've used Duracell non-LSD rechargeables, and they seem to self-discharge at a very low rate (at least in my experience).

Sanyo Eneloops enjoy a very good reputation, and they're also LSD-type batteries. You can buy them at Costco as a set (charger and AA/AAA batteries). If you're in Canada, Real Canadian Superstore sells "rebadged" Eneloops under their President's Choice label. IIRC Costco sells their set for ~$40 CDN (charger, four each AA/AAA), and RCS sells two AA's and a charger for $25 CDN, with packs of 4AA costing $15 CDN.

Note that LSD batteries usually have lower rated capacities (2000 mAh as ooposed to ~2500 mAh), but not self-discharging is often a good trade-off.

For AA NiMH rechargeables, I've had good results with the 2700 mAH capacity PowerEx line from BatteriesPlus (http://www.batteriesplus.com/pc-36025-36025-MHRAA4.aspx). For backup batteries, I don't trust rechargeables. I keep a set of AA lithium primary batteries (Eveready or Duracell - watch for sales). Excellent shelf life, capacity and low-temp performance vs. NiMH (including the LSD cells). I move them over to a less-critical use when done with them on the bike.

Of the AA batteries I've tried, the Sanyo and Maha 2700s last the longest. I bought them on-line. The Enloop batteries hold a charge longer in storage -- that is, if you carry extra batteries as spares -- but the regular 2700s I believe will last longer if you use them right after charging.

I run a Dinotte powered by AAs and would like to have an extra set of backup batteries. Regular ones sap too quickly (manufacture doesn't recommend 'em anyways). Any suggestions? Sony's on dealextreme seems steep....

I use these and carry a charged set for my Dinotte.

Amazon.com: Sanyo 277265 Eneloop Power Pack with Battery Charger, 8 AA & 2 AAA Batteries Plus 4 C & 4 D Size Adapter (CostCo Kit #2): Electronics

Since you're keeping them in your bag for possibly weeks as backups, you really want low self discharge cells. Sanyo Eneloops are probably the best, but Tenergy are cheap. I've seen them 24 for $30 up on eBay.

I don't buy anything but low self discharge cells anymore. The capacity isn't quite as good but in general I lose more than that amount before I use it anyway with regular cells.

I'm with ItsJustMe ... I'm a huge fan of the Eneloops and other low-discharge batteries, for exactly the same reasons he gave.

And lately, Frys has had the Rayovac 4.0 batteries on sale for about $4 for a 4 pack, so I'm totally set on AA and AAA batteries for a while. I haven't really had time to fully check these batteries out, but so far they seem just as good as the Eneloops.

(Precharged is basically the same as low self discharge -- they can't really be sold precharged unless they're low self discharge, and it's something that people actually understand, though it's really the low self discharge rate that's important. Did that even make sense? :))

For regular use the Sanyo 2700 and Duracell 2650 seem to be tops in consistency and capacity (http://www.candlepowerforums.com/vb/showpost.php?p=920843&postcount=1); with Accupower, Titanium and Powerex being very good as well.

There are 2 ways to view a "back up set". If you pull set A to recharge, rotate set B from backup into the light and then store the recharged A set as back up, you can just get a 2nd set of cells. Whether you rotate after each ride or each week both sets would get exercised periodically, the back up set would be fresh and you'd have maximum capacity available. This keeps both sets in peak condition (which can be helpful when you forget to recharge) but might be a chore depending on where you stash the second set.

If you want to regard the second set strictly as backup and not bother 'rotating', then LSDs are the way to go as you wont have to worry about topping them off more than once/2ce a year. In LSDs, Eneloops and Imedion are both very highly regarded with Imedions having slightly more capacity for the same price. Accupower are also very good (same rated mAh as Imedion and their C and D cells are fantastic). LSDs are cheaper than regular NiMH ($13 vs $10 for the Sanyo, for instance) but capacity is less (about 70%) as well.

How long and how frequently you use the lights shoud be the determining factor. I use Accupower LSDs in the lights on the bike I ride much less often, but strictly high cap rechargeables on the 'main' bike. I am a big fan of LSDs but <1h 20m runtime wouldnt cut it.

HTH

I think i ll go with Sanyo -- to rotate between two sets (I already have a set). Will get AA lithium primary batteries (as a pure back-up).

Thanks!!

I purchased three dozen AA's from http://www.greenbatteries.com/, I'm very impressed with the quality so far.

Will get AA lithium primary batteries (as a pure back-up).Thanks!!
Dont skimp on the Lithiums, stay away from off brand/Chinese ones unless you research them. The cheap ones can come seriously overvolted. It is not uncommon for the cheapies to run 1.8V or higher. Your Dinotte expects 4.8V/5V but with these it could be getting as much as 7.2V (4*1.8V)!.

I have some I got for just that reason - grab and go backups for the Dinotte. However, after 4 in a row showed 1.95V (!!!!), I set them aside for other uses.

I use a Fenix L2D as my main bike/running lights, and I've become a big fan of the low self-discharge (Eneloop) batteries. My Duracells and other non-LSDs lose 50% of their charge in a few days, so it takes a pretty substantial charging before each use on/off the bike. The 2000mA eneloops definitely don't last 2/3rds as long as a 2700mA Duracell; closer to 85%, so it's not a bad tradeoff, since the one day you forget to charge your Duracells teh night before, you'll be out of luck.

A healthy NiMH cell should only lose about 1% of its capacity per day. Higher capacity cells sometimes lose a little more the first day or two then 'settle down', but weak cells tend to have a higher overall discharge rate. Healthy cells should take close to 2 months before they discharge to 50%. Some tests (http://www.candlepowerforums.com/vb/showthread.php?t=115650) indicate the self discharge rate may be less than 1%.

NiMH cells which are simply topped off fail three times faster than those which are periodically 'excercised' or discharged to 1v then recharged. Cells which are recharged and used daily can fail at a rate of nearly 50% per year. Weak cells paired with good ones will make them both seem weak.

If you have a good charger, you can try to 'refresh' or 'recondition' them (of course, if you have a good charger, you know this, but it is actually for those who do not ;) ). I have a set of 8 Fujicell AAAs which are about 4 years old. All the cells still have a cap of 735mAh +/- 50 except one which was 580mAh. It took about 6 refresh cycles (discharge then recharge) but it now reads 750mAh.

I buy all my batteries from dealextreme.com and they've been fine. The buyer reviews there are very helpful with sorting the good batteries from the bad ones (of which there are many).

A healthy NiMH cell should only lose about 1% of its capacity per day. That's perhaps right for NiCd batteries, but NiMH cells (before the low self-discharge variety) lose far more than this -- perhaps 3%/day, and even more the first day or two.

Now, this doesn't mean they're totally dead after 34 days (it's a rough rule of thumb, and the rate slows as the battery becomes more dead), but they're pretty close to it.

Sanyo 2500's if you change them often. The Eneloops for long term slow discharge backups.
http://www.users.on.net/~mhains/Reviews.html

That's perhaps right for NiCd batteries, but NiMH cells (before the low self-discharge variety) lose far more than this -- perhaps 3%/day, and even more the first day or two.

Now, this doesn't mean they're totally dead after 34 days (it's a rough rule of thumb, and the rate slows as the battery becomes more dead), but they're pretty close to it.

I think it's more than that, even for LSD.

My Eneloops come off charger at ~1.43v, and are down to 1.35-1.38v the next day. But it'll take them maybe a year to get to 1.25v after that.

Regular NiMH discharge much faster. Basically you need to recharge them after a week if you need more than 1.20-1.25v.

Eneloops are worth the additional cost just for the lack of hassle. I bought 24 Eneloops in AA and AAA a year ago, all are still good. I highly recommend them.

The capacity ratings are exxagerated by all mfgs - they're practically meaningless. I have some 2700mah Sanyo non-LSD from Batteryspace, and they don't even last as long as the Eneloops rated at 2000mah. Go figure. Also, 2 of the 8 died within a week.

I got a lot of junk from Batteryspace on my last order 8 weeks ago - buyers beware.

I noticed Thomas Dist has AA eneloops @ 4 for $9.47 after coupon code. Best price I could find, even cheaper than buying 8 AAs.

My Dinotte works fine with eneloops, or anything else for that matter as long as 4s V> ~4.0v.

I also agree that the Eneloops seem to last as long as, if not more than the 2700mA batteries despite the fact that Eneloops only say 2000mA. My Fenix runs equally well on both and I can't notice a significant dropoff with the Eneloops compared to the others.

I also agree that the Eneloops seem to last as long as, if not more than the 2700mA batteries despite the fact that Eneloops only say 2000mA. My Fenix runs equally well on both and I can't notice a significant dropoff with the Eneloops compared to the others.

I've noticed a significant difference in runtime between Sanyo 2700 and Eneloops if both batteries are used freshly charged and discharged within a week. The 2700s run for quite a bit longer. Cheaper 2700s will probably be similar to Eneloops.

FWIW, the lights around my house that aren't drained quickly use Eneloops.

That's perhaps right for NiCd batteries, but NiMH cells (before the low self-discharge variety) lose far more than this -- perhaps 3%/day, and even more the first day or two.
No, 1% is the commonly stated general rate for NiMH which has been conditioned, charged and then allowed to settle a bit. The NiCd rate is 30% less. They do loose the most the first day (as do LSDs) but settle down after that.

Outside a lab with less care given them, the rate probably IS higher, but the link I provided showed a real world test where the rate was .7% per day. Since the LSD rate is simply low and not 0, given the 300-500mAh head start, it should take weeks at least for the non LSD to catch up. If your cells are loosing more than 25% capacity in the first day or two crystalline formations have taken over and it is time to discard them.

Wiki: (http://en.wikipedia.org/wiki/Nickel-metal_hydride_battery#Self-discharge)
"NiMH cells historically had a somewhat higher self-discharge rate (equivalent to internal leakage) than NiCd cells. The self-discharge is 5–10% on the first day and stabilizes around 0.5–1% per day at room temperature."

I buy all my batteries from dealextreme.com and they've been fine. The buyer reviews there are very helpful with sorting the good batteries from the bad ones (of which there are many).

The eneloops are fake. Not LSD. :mad:

I have also tried some Rayovac LSD batteries and their run time was significantly shorter than my Sanyo 2700, Maha 2700 and DuraCell 2650 batteries. I also have some Rayovac AAA batteries that are a good option in LSD because I use them in my rear blinky lights (PB Superflash), which don't draw much power and only need to be replaced every couple of months or so.

No, 1% is the commonly stated general rate for NiMH which has been conditioned, charged and then allowed to settle a bit. The NiCd rate is 30% less. They do loose the most the first day (as do LSDs) but settle down after that.

Outside a lab with less care given them, the rate probably IS higher, but the link I provided showed a real world test where the rate was .7% per day. Since the LSD rate is simply low and not 0, given the 300-500mAh head start, it should take weeks at least for the non LSD to catch up. If your cells are loosing more than 25% capacity in the first day or two crystalline formations have taken over and it is time to discard them.

Wiki: (http://en.wikipedia.org/wiki/Nickel-metal_hydride_battery#Self-discharge)
"NiMH cells historically had a somewhat higher self-discharge rate (equivalent to internal leakage) than NiCd cells. The self-discharge is 5–10% on the first day and stabilizes around 0.5–1% per day at room temperature."

I've seen those stats about the NiMh discharge rate being 1% or something really low, but I definitely find this not to be the case in real-life experience.

I have run 3 different sets of AAs - Duracell 2700mA, Tenergy 2400mA, and Sanyo 2700mA in the past 3 years, all of which have been charged using a high quality Lacrosse charger. All 3 brands lose 20% of their charge in the first 5 days, and nearly 50% of their charge after 2 weeks of non-use. I've judged this by both real-world use with a Fenix flashlight as well as the amount of mA readings per recharge on the Lacrosse.

The Eneloops do drop off about 10-15% in the first 5 days, but after that they seemed to hold 80% max charge for 2-3 months, which I found impressive. All 3 other brands above were down to <25% after 2-3 months.

At least for me, there was a BIG difference between the stated lab testing of NimH and my real-world experience. I actually had bought all 3 different brands (I have over 4, if not 6 of each brand) because I thought I might have gotten a "defective" batch since they were discharging at rest so much faster than the lab tests showed.

The Eneloops do deliver, though. Oh, as well, there is a "Eneloop-like" brand called "Energyon" (blatant ripoff of design) that looks identical to the Eneloop and I ordered through batteryjunction that seemed to function identically to an Eneloop in my experience.

I have run 3 different sets of AAs - Duracell 2700mA, Tenergy 2400mA, and Sanyo 2700mA in the past 3 years, all of which have been charged using a high quality Lacrosse charger. All 3 brands lose 20% of their charge in the first 5 days, and nearly 50% of their charge after 2 weeks of non-use.

Higher capacity cells to use a thinner separator to make room. This makes them more vulnerable to damage from things like overheating, overcharging, deep discharging, rapid draining, charging at too high a rate and dropping (how many bumps on a bike equates to a drop?). They also tend to have a somewhat shorter service life.

The Fenix is driving your cells two or 3 times harder than the Dinotte. A number of flashaholics have noted that LSDs seem to be better suited to flashlights compared to higher capacity cells. It has little to do with the self discharge rate, but the design of lower cap cells able to deliver the required current. A quick test shows my 2xAA Q5 draws 3 times the amps as my Dinotte. I dont know how many amps equates to 'driving them hard', but it is more wear and tear than other systems.

It seems quite likely that the combination of things including driving high cap cells harder than it might like combined with normal bike usage over 2-3 yrs have caused your cells to age and develop a higher SDR. My S/2700s go for a ride within 3-5 days of charging but I dont see anywhere near a 20% loss beyond the initial settling down loss.

'Normal' cap cells would seem to be a better bet in flashlights since they appear to handle the higher drain rate. Given the marginal price difference there isnt much reason NOT to go with an LSD for a flashlight. But other applications can make use of higher cap cells.




The Eneloops do deliver, though. Oh, as well, there is a "Eneloop-like" brand called "Energyon" (blatant ripoff of design) that looks identical to the Eneloop and I ordered through batteryjunction that seemed to function identically to an Eneloop in my experience.

Sanyo makes well over half of all batteries. Especially in the early days, nearly all the LSDs were licensed and relabeled Eneloops.

La Crosse Technology's AA-AAA charger is one of the best. A good charger being the most important factor IMHO for getting good battery performance. Don't get hooked by going out to Wally World and buying one of their skanky "home chargers"....

For batteries, you cannot go wrong w/ Sanyo 2700's.

I agree, every time I've heard someone say "I tried rechargables but they suck" it turns out they've got a crappy charger.

Higher capacity cells to use a thinner separator to make room. This makes them more vulnerable to damage from things like overheating, overcharging, deep discharging, rapid draining, charging at too high a rate and dropping (how many bumps on a bike equates to a drop?). They also tend to have a somewhat shorter service life.

The Fenix is driving your cells two or 3 times harder than the Dinotte. A number of flashaholics have noted that LSDs seem to be better suited to flashlights compared to higher capacity cells. It has little to do with the self discharge rate, but the design of lower cap cells able to deliver the required current. A quick test shows my 2xAA Q5 draws 3 times the amps as my Dinotte. I dont know how many amps equates to 'driving them hard', but it is more wear and tear than other systems.

It seems quite likely that the combination of things including driving high cap cells harder than it might like combined with normal bike usage over 2-3 yrs have caused your cells to age and develop a higher SDR. My S/2700s go for a ride within 3-5 days of charging but I dont see anywhere near a 20% loss beyond the initial settling down loss.

'Normal' cap cells would seem to be a better bet in flashlights since they appear to handle the higher drain rate. Given the marginal price difference there isnt much reason NOT to go with an LSD for a flashlight. But other applications can make use of higher cap cells.




Sanyo makes well over half of all batteries. Especially in the early days, nearly all the LSDs were licensed and relabeled Eneloops.

I like your thinking, but I have definitely been watching my batteries, from the day I got them to now, a good 1-2 years later (depending on the battery), and even when the batteries of any brand were 1-4 weeks old, they demonstrated the same big dropoff in charge when sitting around unused, particularly in the first 10 days. While the Fenix may be a harder driver, I don't think they're damaging my batteries significantly; I honestly can't tell any decrease in performance or charge holding a year later, or when I compare my newer ones to the older ones. (I can definitely notice that the Eneloops do much better holding charge after the first 2-3 days, though.)

Sanyo Eneloops enjoy a very good reputation, and they're also LSD-type batteries. You can buy them at Costco as a set (charger and AA/AAA batteries). If you're in Canada, Real Canadian Superstore sells "rebadged" Eneloops under their President's Choice label. IIRC Costco sells their set for ~$40 CDN (charger, four each AA/AAA), and RCS sells two AA's and a charger for $25 CDN, with packs of 4AA costing $15 CDN.



The charger included in the Costco kit leaves much to be desired because it's a timer based charger and requires the cells to be charged in pairs. This is not ideal.


La Crosse Technology's AA-AAA charger is one of the best. A good charger being the most important factor IMHO for getting good battery performance. Don't get hooked by going out to Wally World and buying one of their skanky "home chargers"....

For batteries, you cannot go wrong w/ Sanyo 2700's.

Specifically, the 900 and the 9009 are the better ones. The 700 is a less expensive version not as good even though it came out after the 900. Another charger to consider is the Maha MH-9000. More features and can charge at a higher rate than the Lacrosse when there are four cells.

The charger included in the Costco kit leaves much to be desired because it's a timer based charger and requires the cells to be charged in pairs. This is not ideal.

"Not ideal" is an understatement. Such chargers are useless and only serve to further peoples ideas that rechargable batteries are not good.

Pick up a charger that uses the phrase "negative delta V", and that has a separate charging channel for each cell. You don't even have to spend that much, I picked up a package including such a charger AND four AA low-self-discharge store-branded cells for $18.