Lowest cost Low Self Discharge

My 1.5 year old has enough battery powered toys that were needing to re-chargeables for them. I want some cheap bulk ones so when they get over discharged and one reverses or something I can toss them without being out too much. So what are the cheapest out there?
I can still get the Eneloop 4 packs at HHGreg for $7.99 so thats about 1.99/cell.

Would go with the Eneloops - you may find others just slightly cheaper but the Eneloop seem very good (certainly better than the Hybrio batteries I tested them against).

Wish we could buy them for less than $2 a cell in the UK - typical prices here are about £2 a cell (i.e. double) unless Amazon does another of their good deals on the 8 packs.

You probably won't find them a LOT cheaper, but I have found the Uniross Hybrio to be about the same performance as Eneloop for a little less money.

Hybrio's can be found for as little as $9 plus shipping if you shop around. They seem to be better than the eneloops according to
this review
Scroll down to 2100mah, and you'll see links to the out of pack and charged capacity.

cam94z28 said:

Hybrio's can be found for as little as $9 plus shipping if you shop around. They seem to be better than the eneloops according to
this review

Click to expand...

Looking at the voltage graphs, I would disagree. Indeed, the Hybrio dropping under 1.0V per cell a little over a quarter of the way through their discharge is quite pathetic, and would cause much electronic equipment to turn off.

http://www.users.on.net/~mhains/Tables/swiff/SanyoENE 2000V12.swf
http://www.users.on.net/~mhains/Tables/swiff/Hybrio2100V-12.swf

The cell to cell capacities of the Hybrio cells are apparently also more variable, although those results do make me wonder about channel 3.

http://www.users.on.net/~mhains/Tables/swiff/SanyoENE 2000Cell.swf
http://www.users.on.net/~mhains/Tables/swiff/Hybrio2100Cell.swf

Personally in the tests I have done I found the Eneloops to be superior and the actual 'tested' capacities were almost identical (even though Hybrio claim 2100mah vs. Eneloop 2000mah).

Believe Sanyo also claim a lower self discharge rate for their batteries.

TorchBoy said:

Looking at the voltage graphs, I would disagree. Indeed, the Hybrio dropping under 1.0V per cell a little over a quarter of the way through their discharge is quite pathetic, and would cause much electronic equipment to turn off[.....]

Click to expand...

What is the lower voltage graph showing on the Eneloops? Out of pack voltage? If the upper graph is the same test as the Hybrios, then you are correct. The eneloops maintain higher voltage much longer, but the Hybrio's have a much longer(216.91 vs 241.5 minute) overall runtime.

Indeed, it would appear that not all LSD cells are the same. Read this:
http://64.233.183.104/search?q=cach...-self-discharge+nimh&hl=en&ct=clnk&cd=8&gl=uk
It says that both Sanyo and Matsushita/Yuasa have separately developed LSD technologies. Also that Sanyo's has a lower sef discharge rate. It makes me wonder if, currently, these are only two technologies and that most of the cloners are, in fact, Matsushita devices. Here is a copy of the Matsushita patent:
http://www.patentstorm.us/patents/7022434.html

cam94z28 said:

What is the lower voltage graph showing on the Eneloops? Out of pack voltage? If the upper graph is the same test as the Hybrios, then you are correct. The eneloops maintain higher voltage much longer, ...

Click to expand...

If you compare http://www.users.on.net/~mhains/Tables/swiff/SanyoENE 2000V.swf and http://www.users.on.net/~mhains/Tables/swiff/SanyoENE 2000V12.swf that does seem to be the case.

cam94z28 said:

... but the Hybrio's have a much longer(216.91 vs 241.5 minute) overall runtime.

Click to expand...

As I mentioned, not if your equipment turns off because it wants cell voltage of at least 1.0V. I'm really surprised any quality NiMH cell would have a voltage that variable, so the graph is not quite believable. I wonder if there were bad contacts when the test was run.

The voltage graph for Hybrios off the shelf is much more consistent. Clean contacts on that test?
http://www.users.on.net/~mhains/Tables/swiff/Hybrio2100V.swf

Is the loaded voltage of off the shelf Eneloops really that low? With the specified setup of a 10 ohm resistor, an average voltage of 3.8V for the set will give a current about 380mA, which for just over three hours works out to 1170mAh. Again, not quite believable, as it compares to an average 1438mAh for 400mA tests I've done on off the shelf Eneloops using a MH-C9000. :ironic:

Furthermore, there's no mention of energy (watt-hours) that I can see.

I ended up going with the Rayovac Hybrids. They are readily available at wal-mart for $9, and are also 2100mah. After shipping online i would have paid about $5 more per 4 pack and had to wait for shipping. I'd rather pay tax than shipping. I'll have to see how they do, though. I wonder if theres a voltage graph of these anywhere. They were holding around 1600mah out of the pack. I can't find a date code on them, so I have no idea how long they have been sitting.

According to this site, the hybrids ranked much higher than spec (2376mah). There are no graphs to back it up, and I can't access his methodology page, even after creating an account. From reading around the forum though, and this thread, they come in slightly over spec.

cam94z28 said:

There are no graphs to back it up, and I can't access his methodology page, even after creating an account.

Click to expand...

On http://www.rechargeable-battery-rev...sts/rechargeable-battery-fixed-load-test.html he indicates he discharges to 0.8V but he doesn't say at what current. Should I be worried by this comment on that page?

The resistor must be of an appropriate size ( wattage ) to ensure that energy is not lost due to heat.

If you short a battery with a resistor, where is that energy going to go except as heat? A few too many typos on that site, too.

cam94z28 said:

I ended up going with the Rayovac Hybrids.

Click to expand...

Mine have been working well. The two I have been using since March tested yesterday at 2140 and 2130 mAh (1000 charge/500 discharge test on my BC-900). I bought 4 more today and ran the same test on them straight out of the package. Results were: 2090, 2100, 2130, 2120.

TorchBoy said:

On http://www.rechargeable-battery-rev...sts/rechargeable-battery-fixed-load-test.html he indicates he discharges to 0.8V but he doesn't say at what current. Should I be worried by this comment on that page?

The resistor must be of an appropriate size ( wattage ) to ensure that energy is not lost due to heat.

If you short a battery with a resistor, where is that energy going to go except as heat? A few too many typos on that site, too.

Click to expand...

Perhaps someone has done it already - but I may just run a few Hybrio batteries and Eneloop batteries through some charge discharge cycles on either my C9000 and CBA-II to get some actual capacity figures and discharge graphs to compare.

barkingmad said:

Perhaps someone has done it already - but I may just run a few Hybrio batteries and Eneloop batteries through some charge discharge cycles on either my C9000 and CBA-II to get some actual capacity figures and discharge graphs to compare.

Click to expand...

Tom has tested the Eneloop pretty well - https://www.candlepowerforums.com/threads/79302 - but I haven't seen any graphs for off-the-shelf performance except for one Flash graph linked above, and as I said, the voltage looks a tad low on that.

I tested around 1950mah average, on my C-9000. This was the second discharge i did after discharging out of pack, and recharging. I did not document the numbers for each cell on this discharge, but I will document the next one. I did document the out of pack discharge which was at 1amp. My second discharge (above) was at 500ma. Not sure if this will skew my results. Hybrids are supposed to hold up to higher discharge rates.

Out of the pack discharge capacity, the first discharge(1 amp) showed:
1604, 1621, 1597, 1615

I have no idea how long they sat on the shelf, and there wasn't any kind of date code that I could find on the batteries or the packaging. These will probably self-discharge twice as fast as eneloop, but having to charge every 6 months isn't bad considering their price.

I found a review on amazon showing the Rayovac Hybrids had higher initial capacity, and an identical self-discharge rate as the eneloops after 62 days.

You'll have to scroll down to:

Rayovac Hybrid - Battery 4 x AA NiMH 2000 mAh

http://www.amazon.com/gp/cdp/member-reviews/AOEAD7DPLZE53/ref=cm_pdp_about_see_review/104-3116722-7290337?ie=UTF8&sort%5Fby=MostRecentReview

Hybrio's - $8.95 before coupon and shipping:
http://www.batteryjunction.com/hybrio.html