I need help selecting a battery!

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inevu
 
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I need help selecting a battery!

Post by inevu »

Hey guys! So I am building this robot and I need a battery to power it. I need to get the smallest battery possible no matter what the price is. I need a battery that would get me 6V and 5A constantly for about 20 minutes. So what battery should I get? Thank you very much for your help!

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adafruit_support_bill
 
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Re: I need help selecting a battery!

Post by adafruit_support_bill »

I'd suggest a 5xAA NiMH pack.

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inevu
 
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Re: I need help selecting a battery!

Post by inevu »

Awesome! How many MAH do you suggest I get? Thank you very much!

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adafruit_support_bill
 
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Re: I need help selecting a battery!

Post by adafruit_support_bill »

In theory: 5A for 20 minutes is 1667 mAh. But you will want a bit of a safety factor because:
  • 1. The actual delivered mAh is dependent on the discharge rate - (and 5A is high)
    2. You want to make sure you don't start to fade before the 20 minutes are up
    3. Manufacturers often inflate the capacity ratings.
There are plenty of packs with ratings in the 2200-2500 mAh range.

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philba
 
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Re: I need help selecting a battery!

Post by philba »

Can you live with 7.4V? LiPos will give you about twice the power density over NIMHs (or half the size). Plus LiPos have a really wide range of capacities, sizes and shapes. A 2 cell LiPO has 7.4V as it's nominal voltage and you can get them in really high capacity and/or really high discharge rates. If you are driving a motor, the higher voltage shouldn't be a problem.

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