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  #1  
Old 02-27-2009, 03:10 AM
tudelft
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Default kWh to Ah

We want tot store 479,45 kwhrs of energie with sure of 12volt 1766 Amp hour batteries.

Our question is how tot convert 479,45 kwhrs to Ah

And how many batteries do we use?

I know this formula but donít know how to use it the other way around

kilowatthours = (amphours * voltage) / 1000

Thank you in advance for helping us
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  #2  
Old 02-27-2009, 04:03 AM
JohnS JohnS is offline
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Default Re: kWh to Ah

Quote:
Originally Posted by tudelft
We want tot store 479,45 kwhrs of energie with sure of 12volt 1766 Amp hour batteries.

Our question is how tot convert 479,45 kwhrs to Ah

And how many batteries do we use?

I know this formula but donít know how to use it the other way around

kilowatthours = (amphours * voltage) / 1000

Thank you in advance for helping us
Just rearrange algebraically to solve for amphours:

amphours = 1000*kilowatthours / voltage

Is the comma being used as a decimal separator above? If so, it looks like you need 23 batteries.
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  #3  
Old 08-10-2010, 10:03 AM
BigGreenDog
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Default Re: kWh to Ah

Okay, I think I understand this. Can someone confirm my math?

I have a scooter with a 14AH 48V battery. I want to know how many kWh it will take to charge the battery from 0 to full capacity ( I know I will never get it to 0, but just so I understand the math).

Here is the formula I copied from previous emails:

kWh = 14AH x 48V/1000

My math says this equals .26kWh which seems like nothing. Did I do this correctly?
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  #4  
Old 08-10-2010, 10:47 AM
JohnS JohnS is offline
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Default Re: kWh to Ah

Quote:
Originally Posted by BigGreenDog View Post
Okay, I think I understand this. Can someone confirm my math?

I have a scooter with a 14AH 48V battery. I want to know how many kWh it will take to charge the battery from 0 to full capacity ( I know I will never get it to 0, but just so I understand the math).

Here is the formula I copied from previous emails:

kWh = 14AH x 48V/1000

My math says this equals .26kWh which seems like nothing. Did I do this correctly?
Something must have gone wrong. I get 672 Wh or 0.672 kWh.

As a practical matter, that is what is stored, or you will get back out, Batteries are not 100% efficient, you will probably have to put in 20 - 50% more than that. so figure 0.8 - 1 kWh.
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  #5  
Old 05-02-2011, 04:25 AM
Unregistered
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Default Re: kWh to Ah

I have 40 nos 40 watt bulb connected to batteries of following composition.
3 banks of (parallel) of 6 batteries in series,each batteries consist of 4 v 200 ah.please confirm it is sufficant for how many hours and also the battery charger capacity,
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  #6  
Old 05-02-2011, 06:07 AM
JohnS JohnS is offline
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Default Re: kWh to Ah

Quote:
Originally Posted by Unregistered View Post
I have 40 nos 40 watt bulb connected to batteries of following composition.
3 banks of (parallel) of 6 batteries in series,each batteries consist of 4 v 200 ah.please confirm it is sufficant for how many hours and also the battery charger capacity,
Assuming the batteries are sufficiently matched that they all fully charge, your net battery is 24 V, 600 Ah for a total power of 14400 Wh
Your load is 40 x 40 W = 1600 W
Estimated time = 14400 Wh/1600 W = 9 h to full discharge
Note that full discharge is highly inadvisable as it shortens battery life. Recommend no lower than 50%, thus 4.5 h.

You should plan to recharge at about a 10 h rate so a 60 A charger (approximately) should be used.
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