Ed

I've been using the same battery in my transmitter for the past 4 years, and it's still testing over 80% capacity when I cycle it. Is there any need to replace it ?

ed

BuschBarber

My Feedback: (2)

Even if you are still getting acceptable capacity, aging batteries can lose a cell and then you lose the signal, without warning. Batteries are cheap enough now where the risk is not worth taking. I change batteries every two years.

Jezmo

I'm not one who subscribes to the newer is better theory as I've just had a high quality top brand battery pack (transmitter) go bad in less than six months. I was VERY fortunate that it showed up on the ground. On the other hand, my original DX7 battery is still going strong after 4 years. I've been flying RC for about 40 years now and one can imagine I've had my share of battery failures. (It actually hasn't been all that many, you could count them all on one hand.) My experience has been that "total cell continuity failure", which creates an open circuit, is rare and the most common failure I've run into has been a cell rapidly getting weak causing the voltage to drop faster than normal. This is normally noticed before it causes catastrophic loss, at least in my case it has been. I do own a West Mountain Radio CBAIII battery analyzer and use it to help spot a pack headed south although a good computerized charger with discharge capabilities will work well too. Just my two cents.

Rodney

As long as you are occasionally cycling it and getting adequate time, keep it as it is a known good performer. A new one could fail the first time you had to depend on it. When it need replacement, consider the Eneloops from Sanyo which are a big improvement over the older NiMh's and NiCad's as they have a much lower self discharge rate. Always cycle a new battery a couple of times to make sure it is giving the specified capacity.

forrest gump

Its time to change the battery when it no longer lasts long enough for a full flying session plus a little programming time.I always run two batterys any way for my tx.This allows me to flatted the one in the tx using foamies after a couple of weeks flying.This way the batt in the tx always gets good cycle use and having the spare in my tx case allows flexibility.I.e....I dont need to top up a tx batt if a lot of programming is required which will shorten its cycle life...fg

BuschBarber

My Feedback: (2)

I forgot to mention that I use LiPo batteries in all my transmitters. They hold their charge gor months, they charge in less than an hour, they do not require cycling, and they are light. If you feel your Tx voltage is too high, you can always chatge to a lower voltage or install one or two Diodes, inline with the red bat lead, todrop the voltage.

If you have good LiPo chargers, like the FMA 4S or 10S, you will never need to use NiCad or NiMh again.

Eneloops are OK for Tx's, but they still take longer to charge.

I have been using LiPo and LiFe, for Rx batteries, and LiPo, for Tx batteries, for the past 4 years, without an issue.

dirtybird

My Feedback: (5)

Disadvantages for using Lipo's in the transmitter:
1) They must be removed for charging.
2) They need a special charger.
3) If the transmitter is inadvertently left on you could lose the battery and possibly the transmitter.
4) If the transmitter is stored in a hot place the battery will deteriorate. (in the car in the hot sun).
5) If the transmitter is to be stored for a period the battery must be removed and discharged.

For all this, all you get is some larger capacity and less loss of charge over time.

Lipo's have their place, but that place is not the transmitter.

Rodney

Excellent comments from Dirtybird, my sentiments exactly.

AERORICH73

Hi fellows: I have delt with the same problem, and have come up with a plan that follows what has been said about NiCd batteries. If on a cycle test, the capacity drops 10%, replace it. Ok, great, but what happens in the long run when the batteries still show no 10% loss? I cycle my older batteries three times to see if the same capacity reading comes up using an ACE Digit Pace II equipment. There are newer cyclers in the market place today, BUT the LiPo battery types are moving into our hobby in leaps and bounds. I am sticking with the NiCds for the RX position, but the cost of the NiCd for the TX has gone above my budget; so a FeLi has been ordered for my TX. Yes, removing this battery is a wise idea. Some laptop computer batteries have caused house fires something we really do not want to experience. This TX square battery being replaced is some 8 years old.

Cheers!!!

aerorich

AndyKunz

Alternative 1: Purchase a radio which supports in-system charging of LiPo, such as Spektrum DX8 or DX10t.

Alternative 2: Modify the battery hatch to provide a charge port w/o having to open the hatch.

Most modelers (numerically) have changed over LiPos. Nowadays, a NiMH charger has become the "special" charger.

Also, with a modern radio designed for LiPo use, no special charger is needed if it is integrated into the radio.

The DX8 and DX10t include an obnoxious, loud warning that sounds when the transmitter has been inactive for a period of time (10min default). The DX8 and DX10t batteries include a special circuit which disconnects them from the load when the voltage reaches 3.0V/cell - still above the damaging point.

How does one lose a transmitter?

NiMH cells also degrade with extreme heat like that. So does the lead acid cell in your car (hence the reason for Mercedes to locate them away from the engine compartment.) This is a FUD argument, not fact.

Must? Not necessarily. The alternative is to use your transmitter more (my approach), or store it in a relatively discharged state which is easily accomplished by being lazy and not charging it late in the flying season.

The truth is, NiMH cells are also prone to self-discharge (much quicker) and like to leak inside radios. I've seen plenty of electronics with corrosion due to leaking NiMH, NiCd, and dry cells. The answer to self-discharging NiMH cells is to put them on a timer to trickle charge a little a day/week.

In short, if you use a radio designed for LiPo's, there is nothing you need to do special to care for them.

I pushed very hard for LiPo in the DX8 based on these facts.

Andy

Magnum RC

The airplane will only fly as well as it's weakest link when ever it shows up.....

BuschBarber

My Feedback: (2)

1) Big deal - Remove the battery once a month to charge
2) Most chargers handle NiCad, NiMh, and Lithiums but some do not. Many people are flying Electric as well as Gas/Glow and have Lithium chargers.
3) It is a small risk that may result in a dead battery but not likely a damaged Tx. It is worth the risk.
4) I keep my Tx's in a foam lined case which keeps it out of the sun and heat. If I do have it out of the case, it sits under the wing, in the shade
5) In 4 years of LiPo Tx use I have never had to take the battery out during long periods of non use.

Stay with the old technology batteries if you want but do not discourage others from enjoying the freedom from endless charging.

dirtybird

My Feedback: (5)

Freedom from endless charging?
Is that what you think you are gaining?
I have news for you. The aircraft uses the energy - not the battery. You will charge the same no matter what kind of battery you use.
I have a Multiplex EVO that came with a NIMH battery when I bought it in 2007. The battery has never been out of the transmitter. I sometimes leave it in my car that sits in my garage in Phoenix while I go to Seattle for the summer. If I had a lipo in there I could possibly lose my transmitter, my car and my house.
I charge it about once every six weeks. I don't fly a lot but I do a lot of testing which can use it more than flying. I charge it in the transmitter with the charger that came with the radio. It doesn't need a fancy balance charger that costs an arm and a leg.
If you think there is a small risk then you should read the "Lipo fires are real" thread in RCG.

BuschBarber

My Feedback: (2)

I understand your concerns. I have seen LiPo fires. The instances where this has happened most often result from using improper charging techniques or batteries that have been damaged in a crash. We all put cell phones to our ears, powered by Lithium batteries, and never think twice about the battery catching fire.

I have struggled with NiCad and NiMh batteries, for the past 33 years, and spent endless hours charging. I have seen the batteries self discharge sitting on the shelf and been frustrated because I could not fast charge without the charger False Peaking or the batteries heating up.

The quality of Lithium batteries has been vastly improved. I picked up one of my Lithium chargers, an FMA 4S, for $50, and my FMA 10S charger for $100. The Lithium batteries you can buy now are as cheap as NiCad/MiMh, charge in 15-30 min, and the charge last for months. I use Lithiums as Rx batteries and Tx batteries, for the past 4 years, without issue. I fly electrics with 7.4v to 50v without issue.

The technology is solid. It is not difficult to operate safely with these batteries and they save me a lot of time and aggravation.

dirtybird

My Feedback: (5)

I would never buy a cell phone that had a lipoly in it.
Fortunately most of them have a LIFE battery and that is a different animal. You should consider one of those for your transmitter. LIFE batteries don't have the low internal resistance that a lipoy does but you don't need that in a transmitter.
The prices you quoted for FMA chargers were for refurbished units. I don't think they are still available. I had to pay $189 for my 10s when they were new. They have a new 10s available now. I bet you are not going to get that for $100.

slarty

Oh goody... here we go again.... the magic of LiPo cells....

Nice sales pitch there Andy..

Once again I have just repaired a JR transmitter (that was designed to use NiCad or NiMH) that was used with a LiPo pack. Excess voltage caused a transistor to short out, luckily no secondary damage was done. IF you are going to use higher than designed supply systems, please fit diodes to drop that voltage down to an acceptable level.

BuschBarber

My Feedback: (2)

I respect your opinions. Cell phones use mostly Lithium Ion batteries, which are very similar to LiPoly. I do use LiFe and LiPo Rx batteries. I realize that thr prices I quoted were for Refurb chagers, but I was just illustrating that they were not very expensive. I feel they are some of the best chargers on the market.

Bottom line is that I have had years of experience with these batteries and they have improved to the point where they are reliable and safe to use.

BuschBarber

My Feedback: (2)

I agree that for Tx's that were not designed for LiPos, using 2 Diodes to drop the voltage a bit is cheap and easy protection. You can always just charge to 11.7v, as well.

dirtybird

My Feedback: (5)

You are correct cell phones use Lithium Ion cells. And they are similar to Lipoly's but they have one important difference. They are not so likely to explode.
a123'S are also similar to lipoly's but there is never been a case of those exploding. They can also be charged faster than Lipoiy's, are not subject to damage when stored at higher temperatures, do not need to be discharged for storage and are good for many more cycles than either Lipoly's or lithium Ions.

BuschBarber

My Feedback: (2)

Personal experience has taught me that ,properly handled, modern LiPos can be just as safe as any other type of battery chemistry. A few years ago I might have agreed with you, but chargers have improved as well as the quality of the LiPo packs sold. Many of my fellow club members and I use foam lined cases to store and transport our LliPos. LiFe batteries are lower voltage and can be used without voltage regulators in many cases. It is more difficult to monitor the Discharge rate of LiFe so they require different techniques in that regard.

nonstoprc

My Feedback: (90)

I started to use lipo packs (5000mah 10cell) for power, and 480mah/790mah TP rx packs for receiver/servos, on my pattern airplanes this year. The frequency is use is pretty high (about 50 flights @ 7 minutes each per week).

I feel Lipo batteries are pretty safe to use. These batteries do require special attentions/precautions. I strictly stick to the following practices: balanced charge, pull them out of plane to charge, store in room temperature in a fire-proof case, never drain them to zero volts, never drop them, and charged to 50% during off seasons.

I do not let them sit in a car parked outside in hot weather for long time either.

BuschBarber

My Feedback: (2)

I always disconnect the Rx batteries at the end of the day.

nonstoprc

My Feedback: (90)

I do that before leaving the field. All batteries are put in a storage case during the transportation.

dirtybird

My Feedback: (5)

Quite a bit a bother for what you get.
And still there have been cases where they have exploded even after all of these precautions.

nonstoprc

My Feedback: (90)

Yeah. I agree and it is called life.