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Author Topic: NimH vs Li-Ion  (Read 5143 times)

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Offline vidamTopic starter

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NimH vs Li-Ion
« on: July 13, 2008, 05:34:19 PM »
I have a choice between NiMH and Li-Ion and right now the only difference is the cost and 2500 maH difference.

http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=2281
http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=537


http://www.onlybatterypacks.com/showitem.asp?ItemID=11074.37
http://www.onlybatterypacks.com/showitem.asp?ItemID=11115.12

The charger for the NiMH is much more expensive than the Li-Ion.

Is 2500 mah a big sacrifice to make? I couldn't find any equivalent Li-Ion for 10,000mah.




Offline airman00

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Re: NimH vs Li-Ion
« Reply #1 on: July 13, 2008, 06:05:15 PM »
you know lithium ion explodes easily and needs a special charger , right?
Check out the Roboduino, Arduino-compatible board!


Link: http://curiousinventor.com/kits/roboduino

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Offline vidamTopic starter

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Re: NimH vs Li-Ion
« Reply #2 on: July 13, 2008, 06:08:26 PM »
Airman,

yep I'm aware of it. And I checked that these batteries have built-in protection. And the charger is made especially for this battery.


Offline airman00

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Re: NimH vs Li-Ion
« Reply #3 on: July 13, 2008, 06:15:38 PM »
Airman,

yep I'm aware of it. And I checked that these batteries have built-in protection. And the charger is made especially for this battery.



aight then


whats your application for these batteries? its hard to tell if that current difference is important without that info.
Check out the Roboduino, Arduino-compatible board!


Link: http://curiousinventor.com/kits/roboduino

www.Narobo.com

Offline vidamTopic starter

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Re: NimH vs Li-Ion
« Reply #4 on: July 13, 2008, 06:19:09 PM »
It has already been calculated that 10,000mah hours would last about 50 minutes using the NiMH 12Volt battery for this robot application. I'm just wondering how much time I lose with a 7500mah Li-Ion.  The robot application is a 30 lb robot with 4 powered wheels that is running in differential drive. Robot must travel at 1-2 mph for at least 1 mile.
« Last Edit: July 13, 2008, 06:20:01 PM by vidam »

Offline Soeren

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Re: NimH vs Li-Ion
« Reply #5 on: July 13, 2008, 09:03:36 PM »
Hi,

I have a choice between NiMH and Li-Ion and right now the only difference is the cost and 2500 maH difference.
[...]
Is 2500 mah a big sacrifice to make? I couldn't find any equivalent Li-Ion for 10,000mah.

With lithiums, you will save some weight, but at 30 lb it probably doesn't make that much of a difference.
Lithiums will have a shorter life (i.e. less cycles) given a reasonable amount of care to either kind.
Lithiums will be more predictable since they have a very low rate of self discharge.

Would the lower capacity be enough - now as well as when the battery is worn a bit?
Did you consider paralleling 2 batteries of 5Ah each?
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline junior000

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Re: NimH vs Li-Ion
« Reply #6 on: July 13, 2008, 11:56:02 PM »
hey,

     can we use li-ion batteries for for applications where the starting current is relly high(dc motors for example).i was told that using li-ion for such applications is not advisible.is it true?
view my tutorials at


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Offline bulkhead

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Re: NimH vs Li-Ion
« Reply #7 on: July 16, 2008, 12:45:13 AM »
Look at the current ratings (average continuous, and peak, if available) to make sure you're requirement doesn't overload the battery.  Even if they don't explode, they can overheat and melt as with NiMH.

If weight isn't much of an issue look into 6V/12V/24V lead acid batteries.  Sealed ones won't leak acid/gas while charging.  "AGM" type lead acid batteries have lower internal resistances and can provide very large currents.  They will be heavier than NiMH but more cost effective.

Offline vidamTopic starter

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Re: NimH vs Li-Ion
« Reply #8 on: July 16, 2008, 10:42:38 AM »
Look at the current ratings (average continuous, and peak, if available) to make sure you're requirement doesn't overload the battery.  Even if they don't explode, they can overheat and melt as with NiMH.

If weight isn't much of an issue look into 6V/12V/24V lead acid batteries.  Sealed ones won't leak acid/gas while charging.  "AGM" type lead acid batteries have lower internal resistances and can provide very large currents.  They will be heavier than NiMH but more cost effective.

I now plan on keeping the 3- 12 volt sealed Lead acid batteries. I *was* trying to reduce weight, but you guys kind of scared me out of using Li-Ion and Ni-MH. ( Leaks gas and acid, blows up. Gees )

 


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