Using a LIPO pack in a X9303, dangerous?

[Air_Screw]

Hello,

I just upgraded from a XP9303 to a X9303. I was using a TrueRC 2500mAh 11.1V 3S1P TX LIPO pack in my XP9303 with no issues. When I received the X9303, I took the lipo pack out of the XP9303 and put it into the X9303.

While reading the X9303 manual, I came accross the following Q&A on page G26:

Q: Can I use a 3-cell Li-Po pack in my transmitter
A: No. All current JR and Spektrum transmitters are
designed to operate using a 9.6-volt transmitter pack.
A fully charged 3-cell Li-Po pack puts out 12.6 volts.
This higher voltage can overload the power-regulating
transistor causing damage and or failure, possibly
in flight. Many of our customers have experienced
failures using 3-cell Li-Po packs and their use in JR
and Spektrum transmitters is highly advised against.
The X9303 2.4 system will operate for over 15 hours
using a 2700mAh Ni-MH battery.

Can anyone confirm that using a 3 cell lipo pack in a X9303 will cause damage and or failure? I really like the amount of time I get out of the lipo pack, but not at the expense of damaging my new TX.

Thanks in advance for any assistance.

Regards,

Air_Screw

[Pinecone]

You don't believe the manufacturer?

They would know about any failures.

I don't see lipo in the Tx. You can get 2500/2700 NiMH packs. You can charge them safely in the Tx, using the charge port. You don't have to worry about leaving the Tx on over night or even a few days. And you get the same amount of flying time as 2500 Lipo.

[WayneBrown]

been using a 3s1p lipo or li-ion in my transmitters for years with zero issues.
12.6v fully charged is within the acceptable limits, although to the high side of the spectrum.

[Air_Screw]

Pinecone: No, I guess I don't alway believe manufacturers.

The manual refers to "All current JR and Spektrum transmitters". I know from personal experience that no issues were observed with using a 3 cell lipo in my XP9303. Additionally, many other XP9303 and Spektrum DX7 owners in this forum have also successfully used lipos in their TX's.

So, I'm wondering if there are any other X9303 owners out there using 3 cell lipos in their TX.

Regards,

Air_Screw

[BarnOwl]

The only danger is there is no voltage protection so if you leave the Tx on by mistake your lipo will drain all the way to the point of puffing and maybe even worse.
I strongly suggest building at least a bright led in the tx (http://www.helifreak.com/showthread.php?t=49174)so you can see when the thing is on. I waysted an expensive lipo this way and fortunately the pack only puffed but I learned my lesson here.....

[th3tick]

I've been using the Rodney Corp. LiIon, which seems to have all the advantages of LiPo without the danger of BOOM. It doesn't have the drain rate of a LiPo, but for a Tx, you don't need it.

You do have to be careful not to over-drain the pack, but only to avoid ruining it, I believe.

I have one in my DX7, and being able to leave it and have it hold voltage, or charge it at 1C both are huge advantages in my book. I plan to get one for my X9303, should it ever get here ;)

John

[Pinecone]

OTOH you don't really know if there are not hidden issues using the lipo, like reduced component life, or even that some of the "glitches" seen aren't from too high of voltage.

You have some data points, JR/Spektrum seems to have more, and bad ones.

But again, I don't see the purpose of lipos in a Tx.

[kingiggy262]

I have been using a TrueRc lipo pack in my DX7 for a while now with no issues either. For safety I added a 1N4001 diode in line to drop the voltage going to the transmitter by about 0.75 volts. This way the lipo is only giving around 11.8 volts rather than 12.5 volts when fully charged.

[ryanc]

I have been using a TrueRc lipo pack in my DX7 for a while now with no issues either. For safety I added a 1N4001 diode in line to drop the voltage going to the transmitter by about 0.75 volts. This way the lipo is only giving around 11.8 volts rather than 12.5 volts when fully charged.

I was also thinking of adding a diode to drop the voltage. As my background is not EE, I do not know
much about circuits, etc... I have a few questions about adding a diode, and if any of you could answer them, I would be very much appreciate.

1. Do I add a diode on the positive side of the battery? So it would be...


(+) ------|<|-------------- (+)
transmitter battery

(-) ------------------------ (-)



2. 1N4001 drops about 0.7v. If I want to drop about 1.4v, do I connect two diodes in series? So it would be...



(+) ------|<|--|<|--------- (+)
transmitter battery

(-) ------------------------ (-)



3. Do we have any (or negative) side effects if we connect a diode or two to drop about 0.7v to 1.4v?


I may also apply the same techniques to decrease the RPM of computer fans, as they make too much noise.

Thanks

[Rodney]

Well the hidden issues must just be with LIPO's as the Ions are working great.
The reason to use them is so you dont have to charge at the flying field or at an event even if it is 30 days long.

[Pinecone]

How many mAH are you LiIon?

I have a 2700 mAH NiMH pack in my 9303.

[th3tick]

The one I got from him is 2000mAh. I would say, however, it seems to last longer than the 2500mAh one I have from JR due to it not draining while the Tx is turned off.

John

[kingiggy262]

I was also thinking of adding a diode to drop the voltage. As my background is not EE, I do not know
much about circuits, etc... I have a few questions about adding a diode, and if any of you could answer them, I would be very much appreciate.

1. Do I add a diode on the positive side of the battery? So it would be...


(+) ------|<|-------------- (+)
transmitter battery

(-) ------------------------ (-)

2. 1N4001 drops about 0.7v. If I want to drop about 1.4v, do I connect two diodes in series? So it would be...



(+) ------|<|--|<|--------- (+)
transmitter battery

(-) ------------------------ (-)

3. Do we have any (or negative) side effects if we connect a diode or two to drop about 0.7v to 1.4v?


I may also apply the same techniques to decrease the RPM of computer fans, as they make too much noise.

Thanks

The way I added mine is just like you have in the first diagram. And adding the diodes in series as you have in the second diagram should drop the voltage by about 1.4 volts as you wanted. :thumbup:

I haven't had any negative side effects from doing it and I don't believe that you could unless you soldered the diode wrong or shorted some wires. I could see negative side effects happening if the battery was added with the full voltage load being put on the transmitter though.

[Rodney]

yes these IONs are 3s2p 2000mah.

[Pinecone]

I still don't see the big deal about charging the Tx pack every so often? I cahrge mine about once a month when not using it heavily.

Plug it in one evening, take it off the next. Heck we have to charge Rx packs or main pack anyway.

[Rodney]

Its not thats its a problem. Its just that it is one less thing to worry about. If you dont charge it the night before you fly you really dont matter as long as you charge it at least once in the last month or so.
Its just a convinence that some folks like and may not be for others.

[Air_Screw]

Seems like there is enough of a demand that the good folks over at FlightPower are now marketing a TX specific 3S lipo battery (EVO-TX).

http://www.flightpower.co.uk/Products/Product_Info.asp?item=EVOTX-15003S-SPEKTRUM&cat=Evo_TX

Regards,

Air_Screw

[Rodney]

Let me know how the flight power fits.

[DavKhy123]

I have a Flighpower EVO-TX Li-Poly in my 9303 and it works great. A perfect fit and I only charge once every three weeks. From Dreamworksrc.com. They are, I think some where around $60.00. They have the ThunderPower balance connector and I use one of FMAdirects Cellpro chargers. The battery is designed to fit and work with the Spectrum radios and JR radios. The li-poly pack fits perfectly in the place of an 8 cell square pack. They also have a pack that will fit most Futabas also. The batteries come with the correct plug to fit in the radios, like the JR pack comes with the little white plug that fits the same place as the original battery. It is suggested that you rotate your original charge jack in the transmitter so you cannot accidently insert the original charge plug. You must take the battery cover off to charge through the balance connector.