Battery of 1 Amp & 2 amp effect on resistor parameter

Status
Not open for further replies.

rajaram04

Advanced Member level 3
Joined
Jun 17, 2012
Messages
871
Helped
6
Reputation
12
Reaction score
5
Trophy points
1,298
Location
earth
Activity points
7,687
Hello sir

I ve two batteries of 4 volts 1 amp & i am connecting them in series so as to obtain 8 volts

Now i am connecting several White LEDs in parallel & each LED is having a serial resistor of 220 ohms 1/4 watt

Here i am getting sufficient bright light .

Now i am replacing both the batteries with 4 volts 2 amp.

So in this case what would be the resistor parameter ?

is the value remain same ?
 

Do you mean batteries rated at 1Ah and 2Ah? (Not 1 amp and 2 amp. Ah="amp hour") Batteries do not come rated in 'amps'

The capacity of the batteries will make no difference to your calculations of series resistor. It is only the voltage that is important for that.

There is a proviso: that the battery you use is capable of supplying enough current to run all of the LEDs without its voltage dropping too quickly. You do not say how many LEDs you have and what current they draw, or what type of battery, so we cannot calculate this.
 

If total voltage is 8V @ 2A than No change required for resistor
 







50 White LEDs with 25 mA current rating & battery is small pillar type black colour

i am not i n my lab.at present so ll post the picture later
 

50 LEDs at 25mA each = 1.25A

If you are using high current capable batteries, then you will get away with it but if not, then neither battery will like having that amount of current drawn from it for long. For general batteries it is best to stay under 1/5 of the amp hour rate, so a 1Ah battery should be run at 200mA or less. 1/10 rate is even better. That said, some batteries are designed for higher loads. Li-ion can take a much higher load, for instance.

That is not to say that you cannot do it, but the batteries might not live very long and will not give their rated capacity.

If you use alkaline batteries, their voltage will drop very quickly under that load, but I guess you are using lead acid (from the 4V) which will cope a little better.
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…