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HELP please!! with Li Ion battery Answered

1 st question:
i have a 7.4v 2200mA li ion battery. my ip camera takes 5v 2amps
what color resistor should i use and how many ohms?

2nd quesiton:
i have a class 2 battery charger 12 volts 300mA is it good to charge my 7.4v li ion battery?

3 Replies

user
iceng (author)2011-11-07

Just because the camera sometimes uses 5V 2A max or some times 100 ma.
You cannot pick a single resistor to reduce the voltage from the 7.4V supply..
At 2A the resistor needs to be 1.2 ohms,
at 100ma the resistor needs to be 24 ohms.
you need a 5V regulator like an 7405 or an LM317.

NO, unless you put a resistor in series and watch the temp continuously.

A

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user
dwstar79 (author)iceng2011-11-08

That makes so much sense. I went and ordered the 7405 from digi key. And will use it and soon as it comes in.
Thank you so much for your help. :)))

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user
iceng (author)dwstar792011-11-08

Hope you ordered more then one, I usually hook it up wrong the first time ;-)

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