BC-900 Overcharging?

[Porter]

Greetings all. This is my first post on CPF, although I've been lurking for quite some time. I've really learned a lot about flashlights, batteries and electronics here. Granted,a lot of it is over my head but my many thanks for the wealth of information from all you brainiacs out there .
I am recharging some Titanium 2600 batteries on a BC-900 charger at 200 mA. Number 1 is reading full at 416 mAh, #2 is still charging at 701 mAh, #3 is full at 316 mAh and #4 is full at 404 mAh. Am I correct in assuming these numbers are really 4160 mAh, 7010 mAh, 3160 mAh and 4040 mAh since the display is only 3 digits long? Wouldn't this mean that the batteries are being way overcharged or am I reading this wrong? Thanks in advance to all who can provide any insight on this.

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[wptski]

Your 416mAh is what it reads. The capacity readout will change to Ah when above 2000mAh. If your charging at 700ma and it was full at 416mAh, press Display a few times to see how long it took, it'll be a fraction of an hour. Charging capacity is normally not exactly correct becasue of heat loss.

 

[Porter]

Thanks for the reply wptski. I'm not sure I follow you. Isn't 2000mAh the same as 200Ah? I'm topping these batteries up after being stored for about a month. I'm charging at 200mA. #1 is full in 2:09, #2 is still charging in 4:27, #3 is full in 3:16 and #4 is full in 4:04. Does this sound right? Thanks again.

 

[jayflash]

Your readings are correct, assuming a full charge a month ago.

Milli = 1/1000. So 2Ah = 2000mAh. Your cells may benefit from several charge/discharge (reconditioning) cycles to equalize them.

Welcome to the CPF, porter.

 

[Porter]

Thanks jayflash. Following the advice of some on this board, In order to condition them, I ran them on the refresh cycle at 500mA charge and 250mA when I first got these batteries. This took several days. I've used them very little in the 3 months I've had them, just topping them up once a month. What do you think could be the cause of them becoming so unequal?

 

[Long John]

Hello Porter

Welcome at cpf. I would charge them in "Testmodus" at 700 mA.
So they will be charged at first with 700mA and then discharged with 350mA, automatically. After that they will be charged at 700mA and at the end blinks the capacity in Ah and Full. In your case it needs about 13-14 hours for the whole process. So you can be sure, what's the capacitys of your cells.

Best regards

____
Tom

 

[Flash007]

I have buyed the BC-900 some days ago (v32).

For the moment, I have no problem. Seems to be an excellent charger.
I use refresh test at 700/350mA.

With Ansmann 2300mAh accus, I have 2,28Ah to 2,32Ah when fully charged.
With Energizer 2500mAh accus, I have 2,27Ah to 2,34Ah when fully charged.

Ansmann 2300mAh look to be very good accus !

 

[Flash007]

The Lacrosse BC-900 have 1999 count for the capacity display.

If your accu is 1980mAh, you'll see 1980mAh displayed in the charger
After 1999 mAh, you'll see, for an accu with 2150mAh, 2,15Ah displayed in the charger.

 

[Long John]

My results with Sanyos 2700mAh batteries after "Testmodus" are between 2,80 and 2,93 Ah. Great batteries:thumbsup:

Best regards

_____
Tom

 

[Flash007]

I own too the Conrad Charge Manager 2010, with discharge/charge curve software RS-232.

I'll do the capacity test in this charger and see if there is any difference with the Lacrosse BC-900.

 

[Porter]

Thanks Long John and Flash007. I am charging my second set of Titanium 2600's at 200mA. #1 says full @414mAh, #2 says full @301mAh, #3 says full @376mAh and #4 is still charging @578mAh. They've been charging for between 1 1/2 hrs. and 3 hrs. Does this mean I only have 414mAh, 301mAh, 376mAh and 578mAh available in a 2600mAh capacity battery or is this the amount of mAh i just added to the battery to bring it up to 2600mAh? How do I tell what the total capacity of each cell is? Thanks again.
Flash007, I like that Conrad Charge Manager 2010. Where and how much?

 

[Long John]

Hello Porter

I forgot, welcome at cpf. I have heard, to charge high capacity AA-cells with about 200mA can be a problem.


The only way to see the capacity of the cells is the "Testmodus" with the LaCrosse. Therefore it's necessary to discharge the cells under controlled conditions. You can now stop your charging process and set the charger at the test modus. I prefer the 700mA setting for my 2,7 Ah Sanyos.
After you have start this process, the charger will charge your cells with 700mA and discharge them with 350mA. After that it will charge them to full with 700mA and at the end the display shows you Full/and the capacity in Ah.

It needs about 13-14 hours.

Good luck and best regards

____
Tom

 

[wptski]

Thanks Long John and Flash007. I am charging my second set of Titanium 2600's at 200mA. #1 says full @414mAh, #2 says full @301mAh, #3 says full @376mAh and #4 is still charging @578mAh. They've been charging for between 1 1/2 hrs. and 3 hrs. Does this mean I only have 414mAh, 301mAh, 376mAh and 578mAh available in a 2600mAh capacity battery or is this the amount of mAh i just added to the battery to bring it up to 2600mAh? How do I tell what the total capacity of each cell is? Thanks again.
Flash007, I like that Conrad Charge Manager 2010. Where and how much?

It means that you added that much mAh to the cell but like Long John states charging high capacity cell at 200ma can be a problem. They may terminate early or miss termination! Charge at 700ma or higher to insure proper termination.

 

[Handlobraesing]

Hello Porter

I forgot, welcome at cpf. I have heard, to charge high capacity AA-cells with about 200mA can be a problem.


The only way to see the capacity of the cells is the "Testmodus" with the LaCrosse. Therefore it's necessary to discharge the cells under controlled conditions. You can now stop your charging process and set the charger at the test modus. I prefer the 700mA setting for my 2,7 Ah Sanyos.
After you have start this process, the charger will charge your cells with 700mA and discharge them with 350mA. After that it will charge them to full with 700mA and at the end the display shows you Full/and the capacity in Ah.

It needs about 13-14 hours.

Good luck and best regards

____
Tom

I use a different way to check capacity and it's especially useful for evaluating other chargers' effectiveness.

Charge batteries in a charger of your choice and let them rest about an hour.

Put the batteries in BC-900 and cycle through the modes until you come across "discharge refresh" and select the current closest to C/5 rate (500mA for 2,500mAh and above cells).

Check the mAh after the first discharge cycle is complete (5 hours, +/- depending on current you chose and actual capacity of battery). Check on it no sooner than the end of first discharge cycle, but before the second discharge cycle ends (12-15 hours)

 

[Porter]

Thank you Long John and wptski. I finally get it.

 

[coppertrail]

I ran into a similar situation over the weekend. I charged some new Powerex 2700 AA cells in the BC-900 @ 200 mA. This didn't cut it, it couldn't detect the voltage correctly, and terminated the charge early. I put the batteries in my Maha MH-C204W charger, and it charged them to full capacity.

A rule of thumb learned: when choosing charging currents on the BC-900, choose the current that's higher than .1 of your batteries total capacity. In my case:

.1 X 2700 =270 mAh. Since the BC-900 doesn't have a 270 mA charge setting, I would choose the 500 mA current to charge.

 

[wptski]

I ran into a similar situation over the weekend. I charged some new Powerex 2700 AA cells in the BC-900 @ 200 mA. This didn't cut it, it couldn't detect the voltage correctly, and terminated the charge early. I put the batteries in my Maha MH-C204W charger, and it charged them to full capacity.

A rule of thumb learned: when choosing charging currents on the BC-900, choose the current that's higher than .1 of your batteries total capacity. In my case:

.1 X 2700 =270 mAh. Since the BC-900 doesn't have a 270 mA charge setting, I would choose the 500 mA current to charge.

Using 200ma on new cells in the BC900 v32 units has caused several to overheat and melt! Best to use .1/C for 16 hours on the first charge if possible. You can use a BC900 but time it as it may miss the termination point. It may terminate early which is possible also!

 

[Porter]

Thanks wptski and coppertrail, I'm learning more every day and tuition is free! It doesn't get any better than that.