SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old May 25, 2013, 05:11 PM
Registered User
Albany, NY
Joined Oct 2010
81 Posts
Question
Spektrum DX7 Battery Replacement

Where do I get a replacement battery for my DX7 radio. It's not holding its charge the way it used to. Spektrum doesn't make them any more (Ni-MH AA 1500mAh 9.6v). Should I try Hobby King? I know everybody is going to say go LiPo but I want to be able to use the plug as it is for charging, and I don't want to get into making a lot of modifications. Radio still works great.
TX79 is offline Find More Posts by TX79
Reply With Quote
Sign up now
to remove ads between posts
Old May 25, 2013, 06:26 PM
Tye
Chacotoma, NM
Joined Jan 2004
706 Posts
Radical R/C.
starzak is offline Find More Posts by starzak
Reply With Quote
Old May 25, 2013, 06:50 PM
Registered User
Joined Aug 2005
957 Posts
I've been buying these. The packs built from 2,000ma Eneloops work great.
http://www.hangtimes.com/txpacks.html
t.edwards is offline Find More Posts by t.edwards
Reply With Quote
Old May 27, 2013, 02:06 PM
Crazy Foamie Builder
JettaManDan's Avatar
United States, MD, Lexington Park
Joined Jan 2010
914 Posts
i know you want to still use the charge port but i really recommend going lipo....you can get a pack from valuehobby.com for it that is a 2600 mah pack..and it already has a JST pigtail on it..so all you do is remove the battery cover and hook up your lipo charger to it..literally that pack will last you so long it is incredible...I charged my radio pack like once a month with flying every weekend...i highly recommend it...

Dan
JettaManDan is offline Find More Posts by JettaManDan
Reply With Quote
Old May 27, 2013, 08:16 PM
Marion
USA, NC, Hillsborough
Joined Oct 2003
1,018 Posts
2,000ma Eneloops work great.
Marion is offline Find More Posts by Marion
Reply With Quote
Old May 28, 2013, 05:36 AM
Registered User
Ken Myers's Avatar
Commerce Township, MI
Joined Aug 2001
4,416 Posts
2000mAh Sanyo Eneloops are a great way to go for transmitter batteries. You can still use the standard 'wall wart' charger, and no hassles about charging LiPos. I get my packs from NoBS Batteries, as mentioned earlier in this thread.
Ken Myers is online now Find More Posts by Ken Myers
Reply With Quote
Old May 29, 2013, 01:34 PM
AMA 1042906
swimmer's Avatar
United States, KS, Derby
Joined Mar 2008
1,142 Posts
Quote:
Originally Posted by JettaManDan View Post
i know you want to still use the charge port but i really recommend going lipo....you can get a pack from valuehobby.com for it that is a 2600 mah pack..and it already has a JST pigtail on it..so all you do is remove the battery cover and hook up your lipo charger to it..literally that pack will last you so long it is incredible...I charged my radio pack like once a month with flying every weekend...i highly recommend it...

Dan
Been trying to decide on a battery replacement for my DX7. Took your advice and ordered the 2600mah lipo from valuehobby.com today. Do you full charge your transmitter battery or stop at 11 volts or so as I don't know the ability of the DX7 to handle a full charged lipo? Basically the reason I'm going with a lipo is that I like the idea of infrequent charging.
swimmer is offline Find More Posts by swimmer
Last edited by swimmer; May 29, 2013 at 01:48 PM.
Reply With Quote
Old May 29, 2013, 01:47 PM
Dude, I do fly all day long!
rcalldaylong's Avatar
San Jose, California
Joined Dec 2007
5,830 Posts
some have had great success with Lipo.. My old JR 72mhz ran on Lipo for more than 3yrs before I sold it off and never missed a beat.

Then when I got my DX7, I did the same thing, and after 6 month or so, I started having mysterious crashes about once every 10 or so flights (total lost of link during takeoff). Had to send it in to Horizon for repair. I also notice my DX7 would run pretty hot at the top of the air vents... (coincidence...maybe...maybe not) BTW - Horizon swapped out the rf deck and I haven't had a crash since.

To each his own, but I'll never use a full 12.6 Lipo on an unmodified Tx.

Listen to the others and use eneloops. I did and haven't looked back. On a full charge I fly 6 hrs+ and still only down to about ~10.5v. I'm sure I can easily get another 6+hrs or more. I fly thermal planes sometimes and can be out for a long long time.

DX7 replacement batteries using Sanyo Eneloops (2 min 57 sec)
rcalldaylong is offline Find More Posts by rcalldaylong
Reply With Quote
Old May 29, 2013, 01:51 PM
AMA 1042906
swimmer's Avatar
United States, KS, Derby
Joined Mar 2008
1,142 Posts
Quote:
Originally Posted by rcalldaylong View Post
some have had great success with Lipo.. My old JR 72mhz ran on Lipo for more than 3yrs before I sold it off and never missed a beat.

Then when I got my DX7, I did the same thing, and after 6 month or so, I started having mysterious crashes about once every 10 or so flights (total lost of link during takeoff). Had to send it in to Horizon for repair. I also notice my DX7 would run pretty hot at the top of the air vents... (coincidence...maybe...maybe not) BTW - Horizon swapped out the rf deck and I haven't had a crash since.

To each his own, but I'll never use a full 12.6 Lipo on an unmodified Tx.

Listen to the others and use eneloops. I did and haven't looked back. On a full charge I fly 6 hrs+ and still only down to about ~10.5v. I'm sure I can easily get another 6+hrs or more. I fly thermal planes sometimes and can be out for a long long time.

http://www.youtube.com/watch?v=KkOOEt0asMk
Eight 1.5v enerloops equals 12 volts. What is the difference? If there is an internal voltage regulator in the DX7 it may be creating the heat you describe so stopping the lipo charge at 12v should give consistant performance as the enerloops. Am I missing something here (just asking and glad all is ok with your DX7 now)?

Your RF board replacement is interesting. I had to have mine replaced, crashes just as you described with total loss of control, also sometime back and have always used the stock nimh pack. Searching reveals Horizon has replaced a lot of RF boards in DX7's exhibiting the same issues as yours and mine. By the way, my DX7 was about a year old when I started having the problem and again using the stock nimh battery only. Since that $70.00 RF board replacement, plus shipping, I have had no more problems.
swimmer is offline Find More Posts by swimmer
Last edited by swimmer; May 29, 2013 at 02:18 PM.
Reply With Quote
Old May 29, 2013, 02:00 PM
Dude, I do fly all day long!
rcalldaylong's Avatar
San Jose, California
Joined Dec 2007
5,830 Posts
Quote:
Originally Posted by swimmer View Post
I do see an issue when charging to full charge, 12.6v, but what if the lipo battery is charged to only 11 volts?

Your RF board replacement is interesting. I had to have mine replaced, crashes just as you described, also sometime back and always used the stock nimh pack. If you do a search like I did you will find Horizon has replaced many RF boards in DX7's. It appears to be a widespread problem with these transmitters.
at 11v the Lipo is practically empty...which would defeat the purpose in the first place.
rcalldaylong is offline Find More Posts by rcalldaylong
Reply With Quote
Old May 29, 2013, 04:17 PM
AMA 1042906
swimmer's Avatar
United States, KS, Derby
Joined Mar 2008
1,142 Posts
Quote:
Originally Posted by rcalldaylong View Post
at 11v the Lipo is practically empty...which would defeat the purpose in the first place.
I would think with the low amp rating of a transmitter that even at 11v there would be plenty of flight time comparable to nimh batteries. The only way for me to determine what is best for me is to try. Obviously there are many opinions. Will do more research as I won't risk my aircraft or transmitter.

Thanks.
swimmer is offline Find More Posts by swimmer
Last edited by swimmer; May 29, 2013 at 04:39 PM.
Reply With Quote
Old May 29, 2013, 05:23 PM
Dude, I do fly all day long!
rcalldaylong's Avatar
San Jose, California
Joined Dec 2007
5,830 Posts
Quote:
Originally Posted by swimmer View Post
I would think with the low amp rating of a transmitter that even at 11v there would be plenty of flight time comparable to nimh batteries. The only way for me to determine what is best for me is to try. Obviously there are many opinions. Will do more research as I won't risk my aircraft or transmitter.

Thanks.
@11v you have less than 10% left in the tank
http://www.rcgroups.com/forums/attac...mentid=3842605

Seriously, go eneloops...you won't regret it. Eneloops will get you close to 1000 charges if not more.
rcalldaylong is offline Find More Posts by rcalldaylong
Reply With Quote
Old May 29, 2013, 05:34 PM
Registered User
pda4you's Avatar
USA, TX, Trophy Club
Joined May 2002
14,479 Posts
If you want a more modern battery without the slightly higher voltage of the LiPo batteries you can use a 3s LiFePO4 pack. They work great and working voltage is 9.9v.

LSD AA's are certainly good too and can be charged with the stock charger.

Mike
pda4you is offline Find More Posts by pda4you
RCG Plus Member
Reply With Quote
Old May 29, 2013, 09:08 PM
Registered User
United States, KS, Arkansas City
Joined Oct 2012
112 Posts
+1 on the life po4 !!!!!!!! I have been using them for about 3 yrs. now and have allmost changed my whole fleet to life. Just have to take off the battery cover door and plug in the balance wires not a big deal and no fear of burning anything down or having it puff from being fully charged and getting too hot !!
johnfly1234 is offline Find More Posts by johnfly1234
Reply With Quote
Old May 29, 2013, 09:23 PM
AMA 1042906
swimmer's Avatar
United States, KS, Derby
Joined Mar 2008
1,142 Posts
Quote:
Originally Posted by johnfly1234 View Post
+1 on the life po4 !!!!!!!! I have been using them for about 3 yrs. now and have allmost changed my whole fleet to life. Just have to take off the battery cover door and plug in the balance wires not a big deal and no fear of burning anything down or having it puff from being fully charged and getting too hot !!
Will consider the life P04 battery.
swimmer is offline Find More Posts by swimmer
Last edited by swimmer; May 29, 2013 at 09:54 PM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Sold Spektrum DX7s DX8 2000 MAh NiMH battery - $16 Shipped CONUS parkflyer215 Aircraft - General - Radio Equipment (FS/W) 0 Apr 20, 2013 05:31 PM
Sold FOR SALE: Spektrum DX7 Transmitter w/LiFe battery superjon Aircraft - General - Radio Equipment (FS/W) 2 Apr 10, 2013 06:23 PM
Question Two DX7 battery replacement questions Bombay Radios 8 Apr 06, 2013 08:51 AM
Help! Issues with Replacement Battery for Spektrum DX7 Rob Knox Batteries and Chargers 10 Feb 01, 2013 08:33 PM
Wanted Spektrum DX7 replacement battery jetboy11914 Aircraft - Electric - Batteries & Chargers (FS/W) 7 Sep 13, 2011 11:17 PM