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Old Aug 26, 2014, 11:19 AM
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Do you lose range if you use a lipo pack in your Transmitter

I was told today at my local hobby shop that if I put a lipo pack in my transmitter I would lose range. Is he just blowing smoke to get me to buy an over priced $50.00 nimh tx pack or is this true?
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Old Aug 26, 2014, 11:23 AM
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DonA's Avatar
United States, CA, Placerville
Joined Feb 2006
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Your transmitter doesn't know what type battery is supplying power. As long as the max voltage of the battery is within limits for the transmitter, the battery type should not effect range in any way.

Having said that, some transmitters have built in low voltage detection that may not match the discharge profile of the alternate battery. You need to check what the voltage limits and at what voltage the transmitter will give a low voltage warning.

Don
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Old Aug 26, 2014, 11:26 AM
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Thanks Don, that is what I thought. I will check I have a Spectrum DX7 that is a few years old I will check the specs and see.
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Old Aug 26, 2014, 12:41 PM
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United States, UT, Highland
Joined Jun 2006
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As a general rule, if your tx did not come with a LiPO battery (which is a relatively recent event) the manufacturer will not warranty anything that's had a LiPO installed.

Your DX7 fits in that category.

Some folks don't care about manufacturer's recommendations and do it anyway. Be aware that if you do convert, you MUST make sure you have a way to limit the voltage from the LiPO as it will be higher than the NiMH. Also, you will not be able to charge the battery inside the tx, it must be removed.

My suggestion would be an Eneloop pack which will be in the price range you mentioned but those batteries are an extremely low self discharge NiMH cells and work great for tx's. You can also use your factory walwart to charge them.

Finally, it's always confused me when guys spend a lot of money on RC stuff which all depends on the batteries used and how they are cared for and charged or cycled, then they buy the cheapest batteries they can find.... JMHO.
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Old Aug 26, 2014, 01:05 PM
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I also hold the opinion that Eneloops are easier to deal with when it comes to TX batteries.

However, the TX electronics work on 5V and the RF circuit on 2.4Ghz radios works on 3.3V, so anything above that level will do. Should your radio work with linear regulators, more voltage will mean more heat, but I have yet to hear about a TX where this caused problems. Old MHz gear was sometimes directly powered from the battery voltage, and here it had a considerable influence.
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Old Aug 26, 2014, 01:29 PM
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If the battery voltage is not within the operating voltage range of the Tx then the Tx may not work at all, or may be damaged due to over voltage.
But one thing is for sure it wont operate at reduced range.. So yes, the guy in the shop was blowing smoke.
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Old Aug 26, 2014, 01:31 PM
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I agree that for most it's best to stick with LSD Nimh for "legacy" 8 cell transmitters.
Having a more modern Tx designed for 6 cells (Futaba 8FG) and having user adjustable low voltage makes a 2S lipo designed for transmitter use a good alternative to the stock 6 cell Nimh pack for me. When using a Lipo in a Tx the most important consideration is making sure the battery is designed for low drain use and has low C rating of around 5C, since low C rated cells are more stable than high C rated cells, and they're not as finicky about being left fully charged for long periods of time.
I have 3 seasons now on a 2S Lipo from Value Hobby and it's still going strong.
I prefer charging up the lipo with a Cellpro Multi4 at the field during a lunch or coffee break to remembering to put it on the overnite slow charge for an Nimh battery.
Pete
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Old Aug 26, 2014, 01:46 PM
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What about those LiPo packs from Hobby King that they say is for the DX8? I have one in mine and it is definitely higher voltage. The Tx seems fine but I don't want to do any damage to it long term. Is this pack OK?
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Old Aug 26, 2014, 01:57 PM
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The Northeast Kingdom, Vermont
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The HK DX8 battery is a 2S Lipo, so exactly the same voltage as the optional Spektrum Lipo, just a LOT cheaper. The important fact is that the DX8 is designed for 2S Lipo operation as well as 4 cell Nimh, so no problem.
Pete
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Old Aug 26, 2014, 03:00 PM
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Aberdeen
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Yes, as noted above, the DX8 is designed for a 2s LiPo. i used my DX8 with the Turnigy LiPo all the time I had it and it worked great. You just need to go into the setup and select LiPo.
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Old Aug 26, 2014, 06:34 PM
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United States, UT, Vineyard
Joined Dec 2011
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I used HK's TX lipo packs in my old DX7s and DX8.....they work OK but there are some quality issues. In my DX9 I run a Pulse TX 4000mAH Lipo (about twice the cost of HK junk). When it comes to Lipo batteries Pulse is one of the best IMO!
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Old Aug 26, 2014, 09:12 PM
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Joined Oct 2010
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As long as you get a battery with the voltage in the proper range the low battery alarm can be re-set on the DX7 for LiPo use. There is a You-Tube video that shows you how.
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Old Yesterday, 08:05 AM
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Barbados
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Yes endloop batts are a much better solution than OEM nimh batts,the newer Tx's are lipo compatible as my A9 radio,i use lipo's because I use lots of 2s batts and the Tx batt goes on in parallel with flt packs,ever so much more convienent for my uses.My Tx lipo came from RC Accessory and it's been great 2yrs.
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Old Yesterday, 09:26 AM
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Georgia
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When it comes to Lipo batteries Pulse is one of the best IMO!

All the Pulse Lipos I bought ballooned while at 3.85 volt per cell storage.
(Two green, two red)
Two had never been flown. (5S,6S, 5000mah
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Old Yesterday, 10:04 AM
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Mark Wood's Avatar
United States, CA, Bear Valley Springs
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Quote:
Originally Posted by chuck75 View Post
When it comes to Lipo batteries Pulse is one of the best IMO!

All the Pulse Lipos I bought ballooned while at 3.85 volt per cell storage.
(Two green, two red)
Two had never been flown. (5S,6S, 5000mah
That makes them the best? Easy to please, are ya?

mw
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