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Old Aug 01, 2012, 10:54 AM
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Question

Transmitter replacement battery


What is a suggested replacement battery for a Futaba T7C? The stock Sanyo battery isn't holding a charge worth a cr@p anymore. Just a couple flights and it's down to 9.6v.

Thanks.

Bill B.
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Old Aug 01, 2012, 11:04 AM
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First off I believe that Sanyo Eneloops are the best NiMH battery to use in a RC Transmitter designed for Ni cells ,period!

Secondly when a Ni cell reachs 1.2V per cell (9.6V for an 8 cell battery ) it does not indicate that it is in fact nearly empty. There is a reason that Ni cells are listed as 1.2V nonimal voltage. They can drop to this level under load and remain there for a long period of time in fact much longer than it took them to drop from say 11V to 6.6V.

Different transmitters consume mAh at different rates however 250 mA us to be a good standard to us thus why I used it in this extended test.

https://www.rcgroups.com/forums/show...&postcount=142


First step should be to ensure that you are indeed charging them correctly and fully.


Just happened to post here a few minutes ago.

https://www.rcgroups.com/forums/show...10&postcount=5

Site at that link , Hangtime builds excellent quality SAnyo Eneloops Trans. packs.
Charles
Old Aug 02, 2012, 02:57 PM
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Quote:
Originally Posted by everydayflyer View Post
First off I believe that Sanyo Eneloops are the best NiMH battery to use in a RC Transmitter designed for Ni cells ,period!

Secondly when a Ni cell reachs 1.2V per cell (9.6V for an 8 cell battery ) it does not indicate that it is in fact nearly empty. There is a reason that Ni cells are listed as 1.2V nonimal voltage. They can drop to this level under load and remain there for a long period of time in fact much longer than it took them to drop from say 11V to 6.6V.

Different transmitters consume mAh at different rates however 250 mA us to be a good standard to us thus why I used it in this extended test.

https://www.rcgroups.com/forums/show...&postcount=142


First step should be to ensure that you are indeed charging them correctly and fully.


Just happened to post here a few minutes ago.

https://www.rcgroups.com/forums/show...10&postcount=5

Site at that link , Hangtime builds excellent quality SAnyo Eneloops Trans. packs.
Charles

edf,

Thanks for the information. I ordered a 1100 mah eneloop from Hangtime.

I'm getting tired of the couple flights & the transmitter battery being low.

Bill B.
Old Aug 02, 2012, 03:22 PM
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Quote:
Originally Posted by wjb111 View Post
edf,

Thanks for the information. I ordered a 1100 mah eneloop from Hangtime.

I'm getting tired of the couple flights & the transmitter battery being low.

Bill B.
I don't think there are 1100mAh eneloop batteries. The AA size cells are 2000mAh.
Old Aug 02, 2012, 03:28 PM
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Correct the 1100s are Sanyo Nicads and I would have spent the extra dollars and got the Eneloops.

I only use Eneloops in my Transmitters however I am a DIY type and 8 cells cost me less than $25.
Old Aug 02, 2012, 03:30 PM
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My latest batch of AA Eneloops were 1900mah.
Old Aug 02, 2012, 06:32 PM
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There are now a mininum of three different flavors of Eneloops. Thge original nonimal 1000 cycles and nonimal 2000 mAh , then came the improved 1,500 cycles ones and 1,900 mAh and then the ones rated for higher discharge rates but also lower cycles.
Old Aug 03, 2012, 04:58 AM
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There are loads of 3rd party battry pack guys out there who will make a pack up for our use. They use good cells and often will ask what capacity you want. I used a UK company to create a pack for my JR Propo .. that pack is 2300mAh and over a year later of abuse - performs as good as the day they sent it to me. $25 equivalent incl. post.

Eneloops .. yes good idea - but in fact as a Mallory Battery Tech told me - most AA NiMh are now Low Self Discharge including many of the budget AA's. I use Grundig NiMH AA's in all my gear from cameras to my Tx's ...

I get an average of 9hrs use out of my Tx's ... they hold charge for months ... I can charge them either via my Prolux auto peak charger or the old Futaba M chargers I still have. Cost ? $8 for the 8 ...

Nigel
Old Aug 03, 2012, 11:08 AM
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I agree there are some very good alternates to Enellops but considering how important a Transmitter is and that Sqanyo Eneloops will last for many years they are still the least expensive part of flying RC.

The Eneloops in my DX7 installed 2-11-09 so they will be 3-1/2 years old in 8 more days. I fly an awful lot by most flyers standards and the DX 7 has been my primnary transmitter for around 5 years now. The first batteries I put in it were Ray O Vac Hybrids and they did well and in fact were still doing well when I replaced them after justover one year of service.

I have tested some other LSD AAs and AAAs and the ones I tested here have been doing well.

https://www.rcgroups.com/forums/show....php?t=1347070

I still prefer Eneloops as they have a proven history of dependability going back for many years.


Here is my original Transmitter battery test thread her on RC Groups where many brands and capacities have bben tested. The worse ones were the Energizer 2500 and the SAnyo 2500s. Very high capacity AAs are only good for charge and use right then high drain applications. Both of these 2500s brands had very high self discharge rates and also had a high cell failure rate especially the Energizers.

https://www.rcgroups.com/forums/showthread.php?t=327288

Charles
Last edited by everydayflyer; Aug 03, 2012 at 04:36 PM.
Old Aug 03, 2012, 03:44 PM
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Well it looks like I ordered the wrong item then...


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