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### Topic: Calculation of maximum current a battery can provide (Read 236 times)previous topic - next topic

##### Aug 21, 2017, 12:37 pm
How can i calculate the maximum current a battery can provide if the only information i have is: 7.2 V / 11.5 Wh / 1600 mAh.

I know that if i can multiply C rate with Ah i can get maximum current of battery, however, most of the batteries lacks this information. Is there any other to calculate maximum output current of battery?

#### septillion

#1
##### Aug 21, 2017, 12:46 pm
Simple, you can't So the save option would be to stay under 1C.
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#### INTP

#2
##### Aug 21, 2017, 12:59 pm
Call the maker. Amp draws that are stated are a guarantee but batteries don't have predictable maximums.
Any battery that gets shorted, for example, will use up an unpredictable amount of current until it dies. And before that, you have no idea what kind of damage occurs inside.

#3
##### Aug 21, 2017, 01:40 pm
Call the maker. Amp draws that are stated are a guarantee but batteries don't have predictable maximums.
Any battery that gets shorted, for example, will use up an unpredictable amount of current until it dies. And before that, you have no idea what kind of damage occurs inside.
Can you let me know the discharge rate of NP-F Lithium-Ion Batteries?

#### INTP

#4
##### Aug 21, 2017, 02:48 pm
I see that you quoted me, but it appears that you have not read a single bit of it.

#### vinceherman

#5
##### Aug 21, 2017, 03:16 pm

Which battery are you using?
"7.2 V / 11.5 Wh / 1600 mAh." gives us very little to go on.  "NP F" is only marginally more useful.
Can you provide a link to the battery you want to use so that we are not guessing?

What are you trying to do with that battery?
Knowing what kind of current draw you are expecting will help us make recommendations.

#### androidfanboy

#6
##### Aug 21, 2017, 06:15 pm
Do you have a link to this battery so we can see? Max discharge current for lipo's depend on the application. For example, quadcopter lipo's generally tend to have very high discharge currents (like 20-25C)
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#### MarkT

#7
##### Aug 21, 2017, 06:37 pm
How can i calculate the maximum current a battery can provide if the only information i have is: 7.2 V / 11.5 Wh / 1600 mAh.

I know that if i can multiply C rate with Ah i can get maximum current of battery, however, most of the batteries lacks this information. Is there any other to calculate maximum output current of battery?
No.

You can measure internal resistance, you can even look up the datasheet, but there
isn't enough information to calculate power from capacity as they are different properties.

For instance a vehicle 12V battery and a deep cycle 12V battery might look the same, weigh the same,
have similar capacities, but one could be rated for 800A, the other for 50A...
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#### Noobian

#8
##### Aug 21, 2017, 07:04 pmLast Edit: Aug 21, 2017, 07:06 pm by Noobian
For instance a vehicle 12V battery and a deep cycle 12V battery might look the same, weigh the same,
have similar capacities, but one could be rated for 800A, the other for 50A...
You can say the same for a Lithium Cobalt cell and a Lithium Manganese cell. They both look the same in 18650 form and has same voltage but their discharge current varies substantially.

#### DVDdoug

#9
##### Aug 21, 2017, 07:45 pm
I just looked for a random battery datasheet, and it lists 3 discharge currents:
Standard Discharge Current
Rapid Discharge Current
Max Pulse Discharge Current

If that's not listed, there should be some discharge curves showing/listing current and those test-conditions might give you a good idea of the recommended limits.

This particular battery is also specified not to burn-up or explode when shorted, and the internal resistance is listed (so you could theoretically calculate short-circuit current) but it does NOT say the battery won't be damaged/distroyed by short-circuiting (it may have an internal fuse or a thermal fuse).

#10
##### Aug 22, 2017, 07:07 am

Which battery are you using?
"7.2 V / 11.5 Wh / 1600 mAh." gives us very little to go on.  "NP F" is only marginally more useful.
Can you provide a link to the battery you want to use so that we are not guessing?

What are you trying to do with that battery?
Knowing what kind of current draw you are expecting will help us make recommendations.

Thank you for your reply. I have very little information as well. The battery i am using is the camera battery manufactured by SONY with model number NP-FM55H. However, the only information mentioned on the website and battery is that i mentioned above. Here is the link for your reference.
https://esupport.sony.com/US/p/model-home.pl?mdl=NPFM55H