Saturday, April 7, 2018

Testing the BQ-CC65 NiMH battery charger from Panasonic

Just spent a night testing Panasonic's flagship charger BQ-CC65 that I bought from ebay (my friend helped me with this since I don't have a credit card). I'm no expert in chargers but I will try to cover as much as I can based on my testing result.Background:
- I have 10 rechargeable AA cells, with 2 of them are from Kodak (bundled with my Canon Powershot A1400), and 8 of them are Eneloop.
- The Kodak cells are rated at 2100mAh, while the Eneloop cells are rated at 1900mAh.
- I mostly use my batteries for my camera.

- I previously used a Kodak charger (again bundled with my A1400 camera) that can hold up to 2 cells, then a Chinese charger named MP-805 ( that my old man gave me. I also tried a Panasonic BQ-CC18 that I borrowed my friend last year.
+ I used the Kodak charger for about a year on the Kodak cells and 4 Eneloop cells. During that timespan I grew suspicious that the charger was faulty due to a constant heating issue: It always took like 12-14 hours to fully charge my batteries (the charger was rated as 0.25A), and yet they all felt burning hot after charging. Later I brought the charger to my old man and he quickly identified that it has a faulty circuit and gave me the MP-805 to replace it.
+ After 2 years of using the MP-805, the thing gave me suspicion again but I had no possible method to confirm. Rated at 0.5A, it seems to charge much faster than the Kodak, but has a glaring issue: If I leave my batteries in the charger after they are fully charged, when I come back (can be 12 hours later), all of them feel just as hot as with the Kodak charger.
+ For once I borrowed my friend's Panasonic charger. Being a slow charger, all batteries felt just a bit warm after charging. The thing felt better but was slow and it wasn't mine anyway.

- In the end I had multiple issues:
+ All of my batteries grew worse quickly after using just a few times, while Eneloops are reputed to last very long.
+ I didn't know exactly what was wearing down my batteries. The prime suspect was the charger, but it could also be the camera since I may take up to 2000 pictures in just 2 days, and I heard that digital cameras mainly operate at 1.5V, which is higher than typical rechargeable cells.
+ I needed to know how much capacity my batteries have left to decide if I should throw away my batteries, and I'm not geeky enough to set up a complex circuit board just to measure them. That just feels too messy for me.

The solution I came up with was a smart charger with LCD display, but it wasn't until 2017 that Panasonic had one. Finally, when the BQ-CC65 became available in Europe in Jan 2018, I decided to give it a shot.

It took a whole month for the charger to arrive since it was shipped from Lithuana to the US, then from US to my country. My first impression was that the packaging was horrible. The back side of the plastic cover was broken as soon as I applied just a little pressure, and I had to use a nail clipper to cut off the parts that seal the cover before I could open it.

The charger has 3 modes: Charge (default), Refresh and USB Output. I haven't used the USB Output feature, and I'm sure I don't need it because I already have dedicated chargers for that.
- For the default Charge mode, you can switch the LCD display between voltage and charge time. There's no mAh for this.
- To have mAh display, you must use the Refresh function. I had to look up the manual to find out how to use it. Basically you hold the Refresh button for a second until the Refresh text appear on the LCD screen, and you shouldn't remove or add more batteries if you see Discharge on the screen.
- Once the Discharge text appears on the screen, you can switch the display to mAh and Wh. I'm no expert but I find it reasonable as a method to measure battery. Apparently the whole process take 14 hours with 4 batteries inserted.
- Unlike low-end chargers, you can charge 1 cell at a time, which is nice if you have wireless mice.

Testing result for Refresh function on my batteries:
- Kodak cells (unused in a very long time): 1 cell couldn't be analyzed (see video), so I think it was damaged beyond repairable. For the remaining cell, it took 2 hours to charge from empty to full, then a few more hours to fully discharge. After that I went to sleep and when I woke up, it was fully charged and the reading showed 1431mAh. During the charge time the battery was burning hot, but after that the temperature dropped dramatically to just a bit warm, and when I woke up, I could just feel very little heat from the batteries.
- First 2 Eneloop cells: They started as 1.38V, and after 5 minutes they were at 1.5V, but apparently the reading was wrong because it dropped later and only stabilized after 20 minutes. After an hour of charging, the discharge kicked in. At the time of typing this review, the display showed 250mAh discharged. More updates coming later.

1. First 2 Eneloop cells (these are probably my oldest cells):

- 1 hour to charge from 1.37-1.38V to full
- Total time to fully discharge: More than 5h10m for cell #1 (was at 2064 mAh discharged at 5h9m), and 5h4m for cell #2
- Total time to fully recharge: 92 minutes for both cells

- Capacity measured after discharging: 2086 mAh (cell #1), 2031 mAh (cell #2)
- Voltage at the time of fully discharged: 1.04V (cell #1), 0.98V (cell #2)
- Voltage after fully recharged: 1.43V (cell #1), 1.45V (cell #2)

2. Another 2 Eneloop cells:

- 78 mins to charge from 1.3V to full
- Total time to fully discharge: 4 hours 52 minutes for both cells (actually I lost track of individual cells and only managed to record when the recharging started again)
- Total time to fully recharge: 1h37m (cell #3), 1h22m (cell #4)

- Capacity measured after discharging: 1930 mAh (cell #3), 1946 mAh (cell #4)
- Voltage when the batteries were fully discharged and the recharging started: 1.18V (cell #3), 1.16V (cell #4)
- Voltage after fully recharged: 1.46V (cell #3), 1.5V (cell #4)

It's also interesting to note that cell #3 was at 1.49V near the end, and then it gradually dropped to 1.46V. The maintenance charge signal was also activated during that span.

- Contrary to my expectation, my Eneloops cell are all in good condition, with capacity over 1.9k or even 2k mAh.
- In average, it takes about 8 hours to refresh Eneloop cells, including:
+ Less than 1.5 hours to fully charge the cells.
+ About 5 hours to full discharge the cells.
+ About 1.5 hours to fully recharge the cells.
- The charger starts with fast charge, but slows down at the end, and completely stops at full charge, unlike cheap chargers because they simply don't stop charging like they are advertised. As a result, with this charger, charged cells will drop temperature quickly to just a bit warm. Meanwhile, with shitty chargers, they will be hot 12 hours after fully charged because such chargers will overcharge the batteries.
- 1.3V is where batteries stop working on digital cameras, but they should still have plenty of energy left. It's just that cameras require higher voltage to operate, not because batteries are almost empty.
- Battery percentage reading on camera is completely bullshit. It's better to display the voltage to know when to replace batteries.

In overall, it's a good charger, allowing you to safely charge Eneloop cells in just 90 minutes. It also helps you analyze and measure actual battery capacity.

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