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Esprit Model . Thunder Power RC . Mikado Modellhubschrauber

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Radio - Servo - Gyro - Gov - Batt > Difference between Ni-Cad and Nimh?
 
 
Secret Squirrel
Key Veteran
Location: New Zealander living in Melbourne, Australia

Hi guys,
I just got a couple of 2400mah batteries from Cyberheli. I've already got a 2700mah one as well.

My question is: the 2700mah one is nice and light and made up of 4AA cells, which I assume are Nimh cells.

The ones from Cyberheli are big heavy D Cell mothers. There is a NOTICEABLE weight difference (not that I'm too worried about that). I'm assuming they're Ni-CAD

However, I was wondering, what is the difference? Will one 'last' longer than the other? Does it take longer to charge the one/other?

Any info would be greatly appreciated.

Regards,
Si

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Simon Lockington
06-24-2002 Over year old.
HOMEPAGE  
 
 
Twobeers
Key Veteran
Location: Toronto, Canada

The 2700 will last longer. You shouldn't push either one harder than 1.25A if you are charging them in the heli with the supplied charging jack off of your on/off switch. The switch is rated at 1.5A. You will get more flying time per charge with the 2700. Now for the big debate, NiMi's don't like high current applications v.s. NiCad's. I assume this is for your reciever and gyro. No problem there, thats not a high current application. If its for an electric motor that draws in excess of say 10A then go for the NiCad's. To charge up the 2700ma pack at 1.25A after 4 or 5 flights will take about 45-55 minutes. If you want to charge it faster than that - then think about putting in a wiring harnes directly onto the battery pack (the same type of connectors that they use for electric airplanes.) Then you would be able to push them much harder during recharge. Anyways IMHO 45-55 minutes is plenty fast enough, it gives you a chance to relax and mingle with your fellow pilots.
06-24-2002 Over year old.
 
 
rickc
Elite Veteran
Location: Creve Coeur IL. (Peoria Area)

Hello Si,

I'll give you my take on your question. I own three 2700 NiMh packs; I have one in my Voyager. You can charge the Expert 2700 pack at 2 amps safely if you have a good peak detector. I charge mine at a C/10 rate most of the time and have had great results. The 2400's you received are Sub C cells. They can deliver high amounts of current and can be charged at 4 to 5 amps. I have a Logo 10 on its way, it should be delivered tomorrow and the motor and controller combo I chose with use 12 cells either 2400 nicads or 3000 NiMh cells. The 3000's NiMh are fairly new to the RC circuit, they just been around a few years now. The newer NiMh cells can deliver high amounts of current like nicads. If your just going to use them for a receiver pack my choice would be the 2700 pack due its weight savings versus capacity. NiMh do not develop memories the way the older Nicads did. No need to cycle the NiMh cells except to check for rated capacity.

Rick
06-24-2002 Over year old.
HOMEPAGE  
 
 
Twobeers
Key Veteran
Location: Toronto, Canada

Just picked up a new 3800ma "A" size pack. Seen those yet?
06-24-2002 Over year old.
 
 
Secret Squirrel
Key Veteran
Location: New Zealander living in Melbourne, Australia

Quote 
Just picked up a new 3800ma "A" size pack. Seen those yet?


Holy cow... Do you jump start your truck with that bad boy?

So it would seem the consensus is that for an RX battery, the NIMH type is 'better'?

Si

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Simon Lockington
06-24-2002 Over year old.
HOMEPAGE  
 
 
DangerousDick
Veteran
Location: Cheshire, England

'Better' is up for debate, the thing you have to watch with the NiMH's is the fast drop in power at the end of the charge - if you're watching the checker on your ship and you decide you have enough for that 'one last flight' you will be surprised at how quickly they go down. NiCAD however have a more gentle discharge curve and allow more confidence once you leave those first couple of 'greens'.

Hang on a minute - nearly 4A of capacity who's bothered about discharge, those things should last all day long
06-24-2002 Over year old.
 
 
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GrandRC . CanoMod . Futaba-RC

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Radio - Servo - Gyro - Gov - Batt > Difference between Ni-Cad and Nimh?
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