Charging time for Ni-14WM 1400mah in Sony BC-7DC2 charger ?

[burns3016]

I have recently purchased a Sony BC-7DC2 Ni-MH battery charger (it can charge 2 Sony Ni-14WM 1400mah batteries) & I am having problems with the charging times. The LED lights on my unit come on to indicate that charging is in progress (orange lights) - however, they do not change colour or turn off etc. when the charge cycle is complete. In fact I have no way of knowing when the batteries are fully charged, short of trying various charge times & checking the battery indicator in my Hi-MD unit. I left the charger going for 20 hours & it did not turn off automatically etc. Personally, I think if I just leave it charging, the lights will stay on & charging will continue until the batteries swell & burst etc.

Does anybody know how long a charge-cycle with the Sony BC-7DC2 for two 1400mah Ni-MH batteries is ?

The chargers specs. are:

Input: AC 115 - 230V 7 VA 50/60Hz

Output: 1.2V 0.2A (or 200mah)

And the batteries being charged are the Sony Ni-14WM 1400mah batteries.

PS. I have heard that because the output of the charger is 200mah & the batteries being charged are 1400mah that it should take approx. 7 hours to fully charge. If this is correct do you double the charge time because there are 2 batteries being charged, OR halve the charge time for one battery ? OR is it 7 hours irregardless of whether there are 1 or 2 batteries being charged ? Can anybody help ?

[greenmachine]

Assuming discharged batteries to begin with:

Minimum charge:

1400mAh / 200mA = 7h

Formula to compensate for charger's inefficiencies:

1400mAh / 200mA = 7h x 1.4 = 9.8h = 9h 48min ~ 10h

Charge them for up to 10 hours, regardless if you charge one or more batteries at once. A few minutes more or less won't damage the batteries, but 20h are definitely too much.

Edited January 18, 2006 by greenmachine

[burns3016]

Assuming discharged batteries to begin with:

Minimum charge:

1400mAh / 200mA = 7h

Formula to compensate for charger's inefficiencies:

1400mAh / 200mA = 7h x 1.4 = 9.8h = 9h 48min ~ 10h

Charge them for up to 10 hours, regardless if you charge one or more batteries at once. A few minutes more or less won't damage the batteries, but 20h are definitely too much.

Many thanks Greenmachine.

[mercury_in_flames]

dont charge it too much though or it will expand and then be useless. keep an eye in it.

[bdenton]

The output is 1.2 Amps at 1.2v thus the output is 1440 MW

[greenmachine]

The output is 1.2 Amps at 1.2v thus the output is 1440 MW

I don't think so. Take a look at these pics:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...&category=20332

[bdenton]

Just got mine..different box but it looks identical except both the box and charger state 1.2 amps. Also, mine has a red charging light. Otherwise it appears to be identical to the unit on ebay. This unit has the look and feel of a Chinese counterfit and even Sony Japan doesn't list this unit on their web site.

[bdenton]

I pulled the POS open. It has one IC (LM393N) a few small caps, transistors and diods. The IC is a dual voltage comparator and could theoretically shut down charging once the voltage of each side reached a preset level. I'm not a EE so just guessing. There is no mention of Sony on the board and it's poorly made. If this circuit can put out 1.2 amps, I'll eat it for breakfast! 200mw seems much moe plausable.

I paid $30 including a NH-14MW. So realisitcaly, asuming the battery is worth $10, $5 for postage the charger is a little over priced. I'd say it is worth $8-$10 max.

But it is a cheap way to charge two batteries overnight.

Cya