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working out voltage and amp on batteries?
Wondering what formula I can use to answer this question.
Q. 5 AA batteries each rated as 1.5V and 1000mAh are connected in series.
a) What is the total voltage supplied by these batteries.
I'm guessing to work out total voltage you do 1.5 x 5 = 7.5volts.
b) What will be the ampere hour rating of this series combination of batteries?
For this I think you do 1000 x 5 = 5000mAh? I'm not sure on that
c) Can these batteries provide enough power to drive a mechanical motor that requires a constant 8 amps current supply for 15 minutes if each of the 5 batteries rated at 1.5v and 2000mAh.
Not sure how I would work that out. Really appreciate any help.
I think I got part a working correctly. Not sure on the rest
3 Answers
- 7 years ago
You have an inconsistency in your question, in part c). You have stated that the batteries have a capacity of 1000mAh, then in part c) you have rated the batteries at 1.5v and 2000mAh.
I think that you mean they are rated at 1.5v and 2000mA MAXIMUM CURRENT. This is quite high for an AA battery, but is possible, and if this is this is the case, then it means that the maximum current you can draw from the 5 batteries in series is still 2000mA, or 2 amps., at 7.5v.
Connecting the batteries in series increases the voltage, but does not increase the current capability, so you still have 1000mAh capacity, but it is at 7.5v, and you can get it as 2000mA for half an hour.
Therefore you can not get 8 amps from this setup for any length of time. if you decrease the circuit resistance to get more current, the volts drop in the batteries will increase to the point where they will not function.
- playinmybluesLv 67 years ago
You are right for part A. For part b), if the voltage supplied is the same that is applied to the circuit, the rating should still be the rating onthe batteries themselves, 1000 mAh. However, it really depends on how much current is drawn. The mAh rating is a multiplication of the number of mA continuously supplied by the amount of time for which it can supply that current.
So dividing your required current into your battery rating for mAh should do the trick in giving you the amount of time.
