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Old Mar 20, 2012, 05:44 PM
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England
Joined Nov 2005
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Flight pack voltage too high for DS821s and TM1000 ?

Hi

I'm using a five cell Eneloop pack in my Toledo Special with Spektrum DS821 servos, an AR8000 and a TM1000.

I've low charge rate topped up the pack for a couple of hours.

The DX8 is now showing that the flight pack voltage is at 7.2 volts. Is this too much for the servos and the TM1000 ?

Thanks
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Old Mar 20, 2012, 06:15 PM
Registered User
Dallas, TX
Joined Jan 2010
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The servos (and everything else) are rated for use with a 5 cell pack.

Your voltage will not hold that high once it is under load.
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Old Mar 20, 2012, 06:54 PM
AndyKunz's Avatar
Illinois
Joined Sep 2001
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The AR8000 and TM1000 work just fine up to 9.6V I think. Check the specs, but it handles 2S LiPo easy.

Andy
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Old Mar 21, 2012, 07:32 AM
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United States, UT, Salt Lake City
Joined Oct 2007
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The ENELOOP cells are really not a good choice as rx pack.

They are excellent tx cells .
The chemistry of the ENELOOP , offers extended shelf life and very good low load performance .
You really should be looking at cells which will provide power under under heavy loads.
As a rule, AA cells in NIMH do not have the same discharge abilities to withstand loads as compared to the 'short ,fatter cells .
Check with local suppliers who offer cells made for rc cars . There are a number of HD cells available which are better suited to rx pack use.
The batteries you select can make or break your 2.4 system.
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Last edited by richard hanson; Mar 21, 2012 at 07:41 AM.
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Old Mar 21, 2012, 02:59 PM
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England
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Thanks for the replies.

The pack is sold as an RX pack.

http://www.overlander.co.uk/batterie...h-rx-flat.html

Flying today, the voltage was recorded at a minimum of 5.8 volts.
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Old Mar 21, 2012, 03:52 PM
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richard hanson's Avatar
United States, UT, Salt Lake City
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Quote:
Originally Posted by netdudeuk View Post
Thanks for the replies.

The pack is sold as an RX pack.

http://www.overlander.co.uk/batterie...h-rx-flat.html

Flying today, the voltage was recorded at a minimum of 5.8 volts.
That is a surprise ,as the specs on those cells showed fairly high impedance -
see if you can contact battery suppliers who have tested these in high drain conditions
The recorded voltage means nothing -I probably have 3 dozen ENELOOPS of newest types and they work extremely well in low load applications -
It's the instant high loads that will cause a problem. They have an internal resistance of 25-27 milliohms
THAT IS TOO HIGH!
If you would go to their site and read the voltage depression on loads you would se that they are NOT rx type cells -
IFyou have only very low loads on your servos -you may be OK -but they are simply not intended for this purpose
go the Hangtimes site and read up on cells .
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Old Mar 21, 2012, 09:43 PM
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United States, TX, Round Rock
Joined Dec 2004
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I can also confirm that Eneloops and any other LSD NiMH cells are not good as receiver packs unless they power only the receiver and not the servos. I lost a plane to that. The LSD cells have a high impedance and quickly lose voltage when constantly loaded with higher amps.
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