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Customer Review

651 of 655 people found the following review helpful
5.0 out of 5 stars Perfect combination of Smart Charger and low-self-discharge cells, December 8, 2010
Verified Purchase(What's this?)
This review is from: Sony BCG34HRE4KN Cycle Energy Quick with Refresh Charger and 4 Pre-Charged 2000 mAh AA Batteries (Discontinued by Manufacturer) (Electronics)
The charger in this package (Sony Cycle Energy BCG34HRE4KN Quick with Refresh Charger and 4 Pre-Charged 2000 mAh AA Batteries) is very similar to the old SONY "BCG-34HE" which I have used for many years, but it added several important improvements.

First, the common features for both chargers:
+ Streamlined one-piece unit with fold-in AC plugs - No need for power cords or wall-adapters!
+ Low profile design (just 1.2" thick) - Easy to fit in camera bags.
+ Accepts universal AC voltage (100-240V) - Great as travel charger.
+ Smart charger that monitors and charges each cell individually - Unlike most cheaper chargers that force you to charge in pairs only.
+ Reasonably fast charging - Charging current=1050mA for 1-2 AA cells, 640mA for 1-2 AAA cells (for 3-4 cells, the current is reduced by half). That translates to about 2 hours for 1-2 AA cells, 4 hours for 3-4 AA. This is a good balance between shorter charge time and longer battery lifespan.

In addition, the new model (BCG34HRE) offers the following features:
++ Individual battery status indicators. Let's say you're charging two AA and two AAA cells together. You can tell when the AAA cells are fully charged, and start using them right away. (Previous model has just one status indicator, which changes color only when ALL cells are fully charged)

++ You can now charge 1-4 cells, in any combinations of AA/AAA cells. (Previous model can charge 1-4 AA cells, but only 1-2 AAA cells)

++ There is a 'Refresh' function. It works by fully discharging all cells, then fully recharging them again. This can be used when you suspect some of your cells are suffering from reduced capacity.

[Aside: It is not necessary to run a discharge before every recharge. Such practice is a left-over from the days of dumb chargers. With a smart charger, you can top-off your batteries anytime, without fully discharging them first.]

The included SONY Cycle Energy 'Pre-Charged' AA cells are low-self-discharge NiMH type, similar to SANYO eneloop and Rayovac Hybrid. That means all the good things you heard about eneloop and Hybrid are true for SONY Pre-Charged cells, too. They are advertised to have a capacity of '2100mAh typical, 2000mAh minimum', and a lifespan of '1000 cycles'. Note that the 1st-gen Sanyo eneloop cells are also rated for 1000 cycles, while the 2nd-gen eneloop cells claim to achieve 1500 cycles. But realistically, most users will probably never experience this perceived benefit.

I highly recommend getting this package over similar packages such as Sanyo Eneloop 4 Pack AA with Charger. The main reason is that: the SONY charger is much better than the Sanyo MQN06 4-cell charger included in eneloop packages. The MQN06 is too slow (approximately 7 hour charge time), and can only charge in pairs. As of this writing, this SONY package is the only one that combines a high-quality smart charger with proven name-brand low-self-discharge batteries. You can use this SONY charger to recharge Sanyo eneloop or any other brands of NiMH cells, too.

[Update on July 6, 2011]
I need to point out one drawback of this Sony charger. Due to its compact design and relatively high charging current, batteries can become toasty hot _if_ the charger missed termination signal (negative dV/dt) - especially with the charger cover closed. I did an experiment by charging four nearly full Rayovac 4.0 Hybrid AA cells together (this is to force the worst-case scenario where all batteries are being over-charged), and measured the cell temperature with an infrared thermometer. The highest temperature recorded was 62 degree C, which is too hot to hold for most people. Note that this will NOT happen if you recharge partially exhausted cells (because then the charger can terminate correctly by detecting negative dV/dt). But to be safe, I recommend charging with the cover open or removed.
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Showing 1-10 of 215 posts in this discussion
Initial post: Dec 16, 2010 7:14:11 PM PST
credit risk says:
Any idea on what kind of charger the Sony BCG34HLD4KN is?

Specifically does it charge individual cells or charge in pairs.

In reply to an earlier post on Dec 16, 2010 10:07:20 PM PST
The Sony Cycle Energy BCG34HLD4KN Power Charger can charge individual cells. The charging current is a bit low at 360mA for AA (180mA for AAA). But it is a great value at the present price of $14.

Posted on Dec 22, 2010 3:44:29 AM PST
Ed Head says:
NLee I've placed my order, I hope this thing is has great has you say!

After reading a lot of your posts it's obvious you know your stuff, so I'm not worried in the slightest.

It's so hard to get good info anymore, thanks for taking the time to review all these items!

Posted on Jan 2, 2011 6:30:15 PM PST
Mark C. says:
I already own several Eneloop AA cells, and am looking to add more low-discharge cells (AA and AAA) to my cache. I'm also looking for a good smart charger, so would it be better to purchase the SONY cells separately, and then add a Maha MH-C9000, LaCrosse BC-9009, or Lacrosse BC-700 charger?

In reply to an earlier post on Jan 3, 2011 9:27:42 AM PST
Last edited by the author on Jan 3, 2011 9:32:53 AM PST
Based on my testing, the SONY Cycle Energy Pre-Charged and the SANYO eneloop cells are nearly identical electrically. So you should just look for whichever is the lower price. You can usually get a good deal on eneloop packages from Costco (Amazon prices are not as good on those). For example:
Sanyo Eneloop Ni-MH Charger and 8 Rechargeable AA and 4 Rechargeable AAA Batteries

The main reason you should consider this SONY charger mentioned here is that it make a very good travel charger. But if you have many appliances that can use rechargeable AA/AAA cells, then it is worthwhile to invest in an advanced charger such as BC-700 or MH-C9000. An advanced charger lets you know exactly how well your batteries are doing (in terms of capacity), so you can group them accordingly.

In reply to an earlier post on Jan 8, 2011 8:32:24 PM PST
[Deleted by the author on Jan 25, 2011 2:50:10 PM PST]

Posted on Jan 25, 2011 5:29:14 AM PST
NLee, will this Sony product charge the batteries too fast ?

I thought a slower rate of charge is better for the batteries long-term health ?

In reply to an earlier post on Jan 25, 2011 8:12:31 AM PST
The charging rate of SONY charger is about 0.5C (1050mA/2100mAh) when charging 1-2 cells. This is a perfectly safe rate.

It is true that faster charging rate generally means shorter battery lifespan for NiMH cells. However, the penalty is most severe when charging at current greater than 1C. For example, '15-min' (4C) or '30-minute' (2C) chargers are very bad for battery lifespan. Between '2-hour' (0.5C) and '5-hour' (0.2C) chargers, the impact is negligible.

According to spec sheet for Rayovac 1800mAh NiMH AA cell: if a cell is slow-charged at 0.1C, its capacity will drop by 5% after 200 cycles. But if the cell is fast-charged at 1C, then the capacity will drop by 10% after 200 cycles (discharge rate=1C in both cases). The difference is small enough, so it is fine to charge at 0.5C to save some time.

In reply to an earlier post on Feb 16, 2011 7:30:38 AM PST
Rob says:

You certainly have a well trusted reputation when it comes to batteries and chargers, so I'm ordering this package right now.

Thanks a lot for writing these very helpful reviews!

Posted on Feb 17, 2011 3:44:25 PM PST
Mr. NLee,

Thanks to your input, I purchased this battery charger from Amazon, and I am glad I did. It works great and the refresh function has saved 12 rechargable AA batteries I've had for over 5 years. My previous recharger (15 minute recharger from Energizer) wouldn't recharge those batteries anymore. I thought they were lost, but thanks to my laziness I never threw them away, and now they work great.

I've read your other posts about other rechargers and batteries and came to the conclusion that you are very knowledgeable in this area so I took your advice. Keep up the great work!!!

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