TideFlyer

Apologies in advance if this is not the right forum, but I figured someone here could advise. Have a 600 mAh NiCd in my Futaba 2.4 6EX. I`m considering replacement with a Hydrimax 2000 mAh NiMH. Pros and cons? Any input would be greatly appreciated.

jester_s1

NiMh is lighter for its capacity, which isn't a worry most of the time with a transmitter. Since you're asking for advice, consider an Eneloop pack. That's a NiMh that's designed to be very low self-discharge. It lets you charge when you feel like it and not have to worry about it if you don't fly every week.

countilaw

The NiMH is a much better choice over Cads. The Eneloop are even a better choice. Of the two, go with what your pocket book can afford.

You will probably get someone on here recommend LiPo, with statements like, "I only charge my LiPo's once a year" or "Don't worry about 11.1 V in your TX, it will take it", and " Add a voltage regulator in line with your LiPos and you'll be ok"

Best to stay away from LiPo in your Tx. The worries, precautions and the maintenance just aren't worth it.

Frank

049flyer

My Feedback: (18)

Nicads have advantages that are worth considering.

1. Nicads ard very robust. Tolerant of abuse and last a very long time. Nimh batteries are often short lived and not as tolerant of abuse.
2. Nicads are much more tolerant of quick charging. Nimh batteries often don't quick charge reliably, they are prone to frequent false peaking.
3. Nicads typically have slightly higher voltage than Nimh.
4. You will need a high output charger to charge higher capacity Nimh batteries.
5. Modern Nicads have higher capacity. I just bought a pack for my transmitter, removed a 500 ma pack that lasted over 5 years and replaced it with an SR pack of the same physical size but rated at 1000 ma. BUT it cycles out at 1400 ma. Bottom line is I have a 1400 ma pack instead of a 500 ma pack and all of the advantages stated above.

I have rarely seen a Nimh battery cycle to even it's rated capacity much less 40% over it's rated capacity.

Batteries are one of those issues where there is no perfect answer. There are pros and cons for each type and everyone has their own preference. Plus there are vast difference within each type of battery that further clouds the issue.

Read the charge data carefully for whatever battery you are considering and be sure you treat it properly if you expect maximum life.

BarracudaHockey

My Feedback: (11)

For a transmitter just buy one that fits and go fly, bigger capacity means you can fly longer. NiMH or NiCad really don't make a real world difference.

j.duncker

My Feedback: (2)

One thing to be VERY aware of with a NiMH pack is that once the voltage starts to drop below 8.2 volts it drops FAST.

On mine it would go from 8.3 volts to shutdown in less than 5 mins.

Gray Beard

My Feedback: (-1)

I agree with both Andy and Jester. I like Eneloope's in my planes but I had a problem with them in my TX? It was a pack I had made up though so I think it was my own fault, another operator malfunction. I like Eneloope's because they don't self discharge like nicad and nimh. That's there big claim to fame.

acdii

Only use a Lipo if the radio is designed for it. The DX8 is designed to use either one using the same charger, the charging logic is built into the radio. As others said, just go with a bigger mah pack, regardless of type and enjoy.

rlipsett

eneloop cells are great. I went to radio shack and bought a standard 8 cell battery holder. I soldered on the reciever jack to the holder so that I could plug it into the transmitter. this way I could easily replace cells when they where out, they simply click in like a normal battery and the nimh eneloop batteries charge right up inside the transmitter and are very tolerant of mistakes like the nicad. you can find great bargains on eneloop aa cells if you look around especially on ebay

KW_Counter

NiCds are a better battery than NiMh for the many reasons stated.
The biggest disadvantage to NiCds is disposal, they are hazardous waste.
Cadmium is a heavy metal. Home Depot will take used batteries.
Also notice, NiCds seem more difficult to get these days.

I have switched to LiFe's in my Transmitters.
These are 3.3 volts per cell vs. 3.7 for a LiPo.
Therefore, I am replacing a 9.8 volt battery with a 9.9.
I got these from Hobby King.
The fit is a little tight in the radio.
I need to remove them to charge them.
The charge jack on the radio should not be used with these.
I charge once a month or so instead of every week.

Good Luck,
KW_Counter

jester_s1

I use an LiFe in my transmitter and won't ever use anything else. It cost half what an Eneloop pack would have cost, and has all the benefits. I only suggested Eneloops because the OP framed the question as NiCd vs Nimh.

rlipsett

jester what did your pack cost? the eneloop pack costs only $28 dollars total and that included the rad shack battery holder

k3 valley flyer

My Feedback: (18)

My own experience with NiMh was so bad I have discontinued using them, threw them away. Eneloops are much better but also be careful to charge them slowly. Nicads are fool proof, maybe that is why I like them!

kenh3497

DO NOT quote me on this, but I believe the NiMh have a lower cycle life also. EXAMPLE ONLY...If you get 1000 cylcles out of a NiCd you will only get 500 cycles out of a NiMh

Ken

BarracudaHockey

My Feedback: (11)

We won't quote you because that is wrong

Gray Beard

My Feedback: (-1)

There is something about the discharge between them from what I was told in the past. CH ignitions at one time stated to use nicads instead of nihm but I was never told the why of it, I have been told by guys at the field but that doesn't count for anything.

BarracudaHockey

My Feedback: (11)

What the story is, NiMH (mostly older generation cells) have a higher internal resistance than NiCad, so when they first came out there were lots of things like digital servos and ignitions that warned against using them because under load the voltage would drop off more than NiCad, not really an issue any more.

I renew what I said to the OP. At the discharge levels involved at running a transmitter, he will not be able to know the difference between NiMH and NiCad.

He didn't ask about Eneloop, A123 etc

I too use LiFe batteries in my transmitters.

opjose

Tideflyer:

Your charger is yet another based upon the Imax B6 electronics and software.

Download any of the iMax B6 manuals available for similiar: Hitec, E-Flite, Venom, Turnigy, etc. chargers.

You'll find that some vendors provide much better documentation than others.

jknox

I've used a 2000 mAh NiMH pack in my transmitter for about a year now and have been very happy with the performance. I can fly all day, which is anywhere from 12 -15 flights and still go home with over 9.6V in the pack. With the original 700 mAh NiCd pack I was below 9.6 by the 5thflight. I've probably cycled the pack over 75 times by now and am still able to draw over 1900 mAh in a discharge cycle. Iuse a good computer charger set at1/5 C rate. You do have to be more careful with charging rates as compared to NiCds. If you abuse the pack by fast charging to the point that you overheat it regularly then you won't be happy with NiMH. If you treat a NiMH pack right it will give you good service life and much longer run times than NiCds.

Mr Cox

On the contrary, the "regular" NiMH batteries discharge on their own very quickly so you'll always have to charge them right before you go flying, while Eneloop allows you to charge well in advance, as they keep their charge.

So to answer the original question, it is fine to change to NiMH but you'll want to get the Eneloop type of batteries (i.e. the modern low disharge ones, nothing else)

mike109

G'day

Another vote for Sanyo Eneloop cells and their newer XX version too.

I have now converted all my transmitters to Eneloop packs. We are lucky here in Australia as the importer of Sanyo cells makes packs for all sorts of applications including for RC transmitters and receivers so it is easy to convert to the newer cells as the packs come with the correct plugs for the different types of Tx and Rx which are common here..

My Hitec Aurora 9 was originally fitted with plain green Sanyo NiMh cells and while they worked OK they self discharged and were quite a low capacity set. Since I have put the Eneloops in it, it is a far more useful radio.

I have also converted my Spektrum DX7 and several older JR 2610 transmitters as well and almost all my receiver packs are not Eneloops. I have been very pleased with the results.

Mike in Oz

opjose

Define "very quickly"?

AFAIK NiMH cells discharge around 10% per MONTH.

The Eneloops seeom to discharge at a far slower rate.

KW_Counter

From Wikipedia:
I had read somewhere they discharged several percent a day.
My experience is I would have to charge my receiver packs weekly,
even if I didn't fly the previous week.

KW_Counter

opjose

Wow, I've NEVER seen a NiMH battery discharge at more than 1% a DAY and even that is pretty high.

10%-20% per month dependant upon the pack age is more in line with my experience.

I put Eneloops 2700mAh on my TX's and I'll go fly all weekend long a month after I last charged the battery ( If I didn't get out and fly during that time ).

freakingfast

My Feedback: (3)

Eneloop! Very happy for over a year now. I have an old JR 8103, and the Eneloop is superior than the 3 other high quality predecessors. Works fine with an old Double Vision charger. Batteries are slightly warm not hot.