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lipo transmitter batt

Old 07-23-2010, 09:04 PM
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bbrown2828
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Default lipo transmitter batt

ok guys i have a 3 cell lipo in my transmitter I was wondering how low to let this thing get before i need to charge it
Old 07-24-2010, 09:16 AM
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KW_Counter
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Default RE: lipo transmitter batt

A 2000 mAh 11.3 volt LiPo won't last as long as a
2000 mAh 9.8 volt NiMH. So you need to charge more often.

Additionally, LiPos have a steep discharge curve.
This means they hold their voltage for a long time and drop off suddenly.
Taking loaded readings won't help as much.

I use 2000 mAh NiMhs and charge before each flying session.
I will do the same when I switch over to LiFes.
Why take the chance on a crash because I was to lazy to charge?

I hope this helps,
KW_Counter
Old 07-24-2010, 12:30 PM
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Default RE: lipo transmitter batt

ORIGINAL: KW_Counter

A 2000 mAh 11.3 volt LiPo won't last as long as a
2000 mAh 9.8 volt NiMH. So you need to charge more often.

Additionally, LiPos have a steep discharge curve.
This means they hold their voltage for a long time and drop off suddenly.
Taking loaded readings won't help as much.

I use 2000 mAh NiMhs and charge before each flying session.
I will do the same when I switch over to LiFes.
Why take the chance on a crash because I was to lazy to charge?

I hope this helps,
KW_Counter
I'd like to go the life route for my TX also. Which TX are you using and which life cells do you plan on using? Just curious to know what will fit. I'm using a DX7 with a poor performing 1500 NiMh. So I'm going to need to replace the battery and would like to go with Life/A123, but just not sure what will fit. Thanks.
Old 07-24-2010, 12:32 PM
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ndb8fxe
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Default RE: lipo transmitter batt

duplicate.
Old 07-24-2010, 02:32 PM
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Default RE: lipo transmitter batt


ORIGINAL: KW_Counter

A 2000 mAh 11.3 volt LiPo won't last as long as a
2000 mAh 9.8 volt NiMH. So you need to charge more often.
I haven't seen this at all on pairs of IDENTICAL radios otherwise.

Not only do the NiMH tend to self discharge at a faster rate, but the LiPo packs seem to yield more "safe" flying time.

Though the BIG problem with the LiPo's is once you hit that voltage curve "knee", you have SECONDS to get your plane down... whereas with a NiMH pack you have minutes... so it is better to keep those LiPo packs charged and not let the voltage drop past 10.4v... if it gets that low it's time to recharge.

FYI I'm using 2600mAh LiPo packs on most of my JR gear.


I've tested the new 9503 2.5gHz DSM/2 units up to 16v for long durations with no problems what-so-ever.

Yet I've seen an 11.1v LiPo RX pack blow a recent vintage 2.4gHz Futaba's input circuit... go figure.


Old 07-24-2010, 06:34 PM
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Default RE: lipo transmitter batt

What would you consider I set my low transmitter voltage at with a 2S LiPo.
Old 07-25-2010, 08:39 AM
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Default RE: lipo transmitter batt

ndg8fxe,
Actually, I am planning on going to LiFe for my receiver packs.
I will go to LiFe in the xmtr when my pack dies and I can find a LiFe
that will fit.
Everything said about LiFe in a xmtr is also true in a rcvr.
Good Luck,
KW_Counter
Old 07-25-2010, 03:23 PM
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Default RE: lipo transmitter batt


ORIGINAL: TigerI

What would you consider I set my low transmitter voltage at with a 2S LiPo.
I would never use 2S LiPo's in a TX, as the TX expects 9+ volts.

Normally eight 1.2v NiMH or NiMH cells are supplied with your TX ( 9.6v total ) so the 7.4v output of a 2S LiPo pack does not cut it!

My JR's shut themselves off around 8.8v or so... if I recall correctly.

Old 09-27-2010, 12:09 PM
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Default RE: lipo transmitter batt

I have a friend that wants to change his Eclipse transmitter battery to a Li-Po battery. Has anyone done this, and what are the results?

Thanks,
Larry
Old 09-27-2010, 12:23 PM
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Default RE: lipo transmitter batt

Hobbyking carries transmitter Lipos in 3 cell. There is some risk in using them, the voltage is considered too high for many computer radios and needs to be lowered. Also there is a concern that you can accidentally chage them through the charge port with a non lipo charger.
Simple solution is to install a .50 cent diode in the positive battery lead that will drop the voltage by .7 volts and prevent charging the battery back through it.
To charge the battery you simply open the back cover and charge through the balance port, I have an inexpensive Turnigy balance charger for this and it works great.
Most of my radios are now Lipo.
Old 09-27-2010, 01:36 PM
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Default RE: lipo transmitter batt


ORIGINAL: opjose


ORIGINAL: TigerI

What would you consider I set my low transmitter voltage at with a 2S LiPo.
I would never use 2S LiPo's in a TX, as the TX expects 9+ volts.

Normally eight 1.2v NiMH or NiMH cells are supplied with your TX ( 9.6v total ) so the 7.4v output of a 2S LiPo pack does not cut it!

My JR's shut themselves off around 8.8v or so... if I recall correctly.

Not all TX. Spektrum DX6i uses only 4-cells (4.8V). But yes, for a standard 9.6V transmitter, don't use a 2S - not even sure if it would turn on?
Old 09-27-2010, 02:36 PM
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Default RE: lipo transmitter batt

I've installed the Hobby King LiPo's on MANY JR radios without any problems...

However a friend installed one on his Futaba and fairly quickly had problems because of the higher voltage. He had to get his transmitter serviced to fix the problem and was told that the Funtaba's could not tolerate the higher voltages.

The JR's seem to handle the higher voltage w/o any problems what-so-ever and I've been using LiPo's since they first became available a few years ago.

It's nice to be able to quick charge your TX in one hour or less, and having it work practically non-stop all weekend.

As jeffie8696 mentioned, you should NEVER charge the LiPo pack with the standard charger. It behooves you to install a plug to remind you not to use the port if you go with LiPos.

I don't know about Hitec TX's though...

Old 09-27-2010, 03:58 PM
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Default RE: lipo transmitter batt

This is what I recommend to those who go lipo with their TX. Open up the transmitter, and turn the charge jack 180 degrees. This will offset the charge plug and make it impossible to connect to the standard TX charger.

Saying Lipo's don't last as long as a nimh is wrong. I get far more time out of my lipo pack and if only flying a few times a week, I can go atlaest a week or two before recharging. I never let the pack go much below 10.5v before charging. My JR XP8103 has been using a lipo for 3 years with no problems at all, I just bought a 9303 that I plan to switch to lipo as well. I too have heard of issues with Futaba and a 3s lipo.
Old 09-28-2010, 01:03 PM
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Default RE: lipo transmitter batt

In reguards to using Li-Po batteries in Futaba transmitters, I have been using a 11.1 volt Li-Po 2500mha battery in my Futaba 10CAP 2.4 gig transmitter for a year now. I have not had a problem. I think most transmitters that are having a problem with Li-Po battreis are analog transmitters and not digital......

Larry
Old 09-28-2010, 01:33 PM
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Default RE: lipo transmitter batt

Nope, my friend had his 2.4gHz TX blown by a LiPo TX pack I gave him to try in that same radio!

In his case it happened a day or two after he started using the LiPo pack.

I even gave him a balancing charger to use with his pack.

Old 09-28-2010, 09:10 PM
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Default RE: lipo transmitter batt

The simple .50 cent diode trick will eliminate the possibility of charging through the port and also decrease the voltage by .7 volts so the voltage regulator in the radio is not overheated.
Old 10-01-2010, 07:57 PM
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Default RE: lipo transmitter batt

I use 2000 MA. NIMH batteries on my RX, and on larger planes I use 2 Batteries and 2 switches. I use a JR 9503 with a 2500 MA,Nimh battery on the TX. I use a wall chargerto charge all the batteries with no problems. I didbuy a 2500 MA Lipo, 3 cell brand new for the TX, but decided not to use it. It is a Light Max 2500 11. 1V, 03 series, which is anew battery, I have had it about 4 months , never used. If you want it , I'll sell it to you dirt cheap!!!!!!!!
I am lazy, and don't like taking the battery out or making special plugs for Lipo's, I like simple, get er done stuff with no problems.
Old 10-01-2010, 08:02 PM
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Default RE: lipo transmitter batt

When my transmitter batts die I find it much cheaper to replace them with an inexpensive lipo. Ionly spent like $7.50 .
Old 10-01-2010, 08:17 PM
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Default RE: lipo transmitter batt

Jeffie:
I get a kick out of guys like you, I really do. If you have a $2000.00 airplane and you only spend $7.50 for a battery, good luck.!!!!!!!! I'm laughing as I type. If you want to fly cheap at a reasonible cost, that's OK, but when you have 1K or more in a plane, that is an idiot mentality and short lived.That is just my opinion, but flying R/C planes, you do not go the cheapest route my friend on batteries. If it fails, your plane is destroyed, there she goe's!!, oh, you may luck out now, but I guarentee your plane or boat, car, whatever,it will not last very long,
Old 10-01-2010, 08:33 PM
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Default RE: lipo transmitter batt

Well since being disabled and not working for 3 years and not approved for disability yet I have to save every penny. I do not own a $1000 plane, to me a $100 plane is plenty.
There are so many companies out there selling product they rebranded and jacked up the price on you are probably buying the same thing just paying twice as much as you need to.
But if it makes you happy to do that and you think that you are getting so much more because you spent a whole bunch of money drive on.
Old 10-01-2010, 08:34 PM
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Default RE: lipo transmitter batt

In response to your question, I would not let the battery get below 9.8 volts. It is simple to recharge a battery, why take a chance and press your luck??? Just recharge the thing and your good to go.Simple to do, and about 1/2 hour time. How long doe's it take to repair a plane?
Old 10-01-2010, 08:35 PM
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Default RE: lipo transmitter batt

ORIGINAL: FLAPHappy

Jeffie:
I get a kick out of guys like you, I really do. If you have a $2000.00 airplane and you only spend $7.50 for a battery, good luck.!!!!!!!! I'm laughing as I type. If you want to fly cheap at a reasonible cost, that's OK, but when you have 1K or more in a plane, that is an idiot mentality and short lived.That is just my opinion, but flying R/C planes, you do not go the cheapest route my friend on batteries. If it fails, your plane is destroyed, there she goe's!!, oh, you may luck out now, but I guarentee your plane or boat, car, whatever, it will not last very long,

Cheap does not always mean bad quality... I paid only 16 bucks a piece for my TX Lipo packs and have used one of these cheap lipos for nearly 3 years in my TX before wearing it out. Assuming that expensive = quality is not wise in my mind. No matter the price, batteries should be cycled and tested before putting into use, once proven, proper care and charging is the key... If a lipos puffs, toss it and get another, at the lower price, it's no big deal. Bottom line, both expensive and inexpensive gear can fail, spending more money on something is seen by some as insurance, but to me, it is all relative and dependent on proper care and simply paying attention to the condition your gear BEFORE it leaves the hangar, let alone the ground.
Old 10-01-2010, 08:48 PM
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Default RE: lipo transmitter batt

Jeffie:
My response was not intended to degrade anybody. I regret your disability and money problems, many people have them as well. If you fly and can only afford so much, you spend as much as you need to have fun and nothing more. I did not know about your disibility when I typed my response, and I hope you acceptmy apoligy to you. I had no idea on your situation. I am truely sorry my friend for my statement directed towards you.
Anyway, have Fun, that is what this hobby is about!!!!! Fly like you have wings my friend..

Old 10-01-2010, 09:19 PM
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Default RE: lipo transmitter batt

ACS:
Your statement is OK. Everybody has their opinion on certain subjects. It is like the Gas and Oil , what type is the best, what not to use etc.
It never ends, and it will not, same goe's for batteries and everything else, radios servos etc.
I will say, from my own experience, using cheap tools is a waste of money period, They break, shatter just do not hold up to torque or anything else, cheap pot metal, poor construction. I will pay more for a tool that works and doe's not break the first time I use it.
Batteries: there are many people that discuss this, and the pros and cons of both. I am not a scientist, but I only use what what works for me, without any problems. I do not want to introduce any problems I am not familiar with nor understand. I like the plain and simple, if it works, I use it. If it fails,I 'lltry to find out what the problem was and double test,my change,before comitting.
You are absoutley correct, any gear can fail at any time. Batteries, etc. It happens in everyday life, but I tend to use the best I can afford without going overboard on cost. I have used cheap batteries in cars and trucks, and they don't last as long because of the temperature changes in the area I live. A cheap battery, when it's 20 below Zero, is no time for a battery to go dead. I want the best I can get,. Have to get to a medical facility now, right now, the battery clicks, it's dead. Maintance is very important on batteries, but you have to be consistant, in recharging, and in my opinion, I have tried cheap batteries, they just don't cut it for longevity in the long run.

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