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Old Sep 21, 2006, 07:36 AM
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Joined Sep 2006
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Question
Somone explain maH to me please... i think ive got it..

So we have an 8 pack which is 9.6V and the maH ranges from say 1800-3600maH
What does this mAh mean? Ive heard an analogy that its like gallons of fuel?
So am i right in saying the Mah value just tells us how long that battery can last for???
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Old Sep 21, 2006, 07:42 AM
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Ace in the hole's Avatar
MICHIGAN, USA
Joined Sep 2004
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Correct, mAh is the capacity of the pack.
A 3600 mAh pack will last aprox. twice as long as an 1800 mAh pack in any given application.
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Old Sep 21, 2006, 07:48 AM
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MAH is the slow discharge rate of a battery spec not at a hi-discharge rate spec

U can expect a 2200 mah rechargeable NMHie to give U 2.2 amps for an hour if your digital camera only only uses 2.2 amps or less

don't expect any 2200 mah battery to put out 22 amps for 10 minutes, why , the hi-discharge curve is different due to its hi Ri ( internal resistance )
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Old Sep 21, 2006, 08:29 AM
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Staffs, UK
Joined Nov 2003
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Quote:
Originally Posted by hall woo
don't expect any 2200 mah battery to put out 22 amps for 10 minutes, why ,
Because 10 times the current only gives you 1/10th of an hour which is 6 minutes not 10 .

Yes liltbrockie, mAh is the capacity. Greater capacity = longer run time.

BTW the correct "spelling" is mAh (capital A, lower case m and h) but it doesn't much matter. We understand most variations, but it is a bit odd to see 3 different versions used in one short message .

Steve
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Old Sep 21, 2006, 09:16 AM
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Slovakia
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Allthrough it is not exact, assuming that liltbrockie is not familiar with electronics, I should say that:
Double capacity means allmost double run time. A bulb taking 1.8A will light 1 hour on 1800mAh , but two hours on 3600mAh pack.
Running twice / triple... harder (current in A amperes) lasts allmost one half , 1/3 .... and so on.

With equal pack type, the power for which is pack suitable is adequate to its capacity.
Warning posted in previous posts are saying that it is not exact and pack types are very different. For example AA cell 2500mAh is often hardly suitable for 2.5A, but high current type 1000mAh cell is suitable for 20A without troubles.
You should know that load suitable for 3600mAh pack will probably overload and destroy 1800mAh one ( if power was near rated maximum)

"C" is commonly used to determine possible load. If pack is "6C", it means that it can deliver six times higher current thant is its capacity. 3600mAh and 6C means 21.6A , it will last 10 minutes (1/6hour). However, the same motor with 1800mAh pack will draw the same power and it means 21.6A / 1800mAh = 12C, Time of run is 5 minutes, but if this pack is not capable of 12C load, it will overheat and die.
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Old Sep 21, 2006, 09:17 PM
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Fenton,MO USA
Joined Aug 2005
1,238 Posts
This might be helpful to you.
If you know what your amp draw for motor is use this Calculator to
see how long your pack might last.

http://www.lcrcc.net/electric_calcs.htm
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