summerwind

i never said i used NiMH in my systems, so i'm not sure that what you are trying to add to the original discussion other than to start your usual backbiting.
you seem to have some idea of what you are talking about, but throughout almost all of your past and present posts to topics you quote spec's that are already available to anyone on the net.

i do wonder however if you have used NiMH cells exclusively over the last 20 years, why you suddenly changed to LifePo?
didn't you run mostly RC Boats all of the time?
what Tx are you using Eneloops in?.........i thought you had a 14MZ............

Silent-AV8R

Speaking of back biting, whatever. My comment was meant to respond to your statements that NiMH are a poor choice due to a sharp drop at the end of the useful charge. Nowhere did I say that you used them, but you clearly have stated that you think they are not a good cell technology. In addition, the conversation started to discuss the Sanyo Enelooop cells, which I have used almost since the day they came out. As I statd, I have several packs and based on my technical understanding of their specifications and my own experience gained from actually using them I posted what I thought about them.

Please help me to understand how posting clear information and links for people is a bad thing?? I am basically trained as a scientist and have been taught that it is all well and good to have an opinion, but that you need to have data and outside sources which you can cite to support it. That is why I tend to post links to sources and information that I think others will find useful. Again, I am unclear as to how that is a bad thing.


I have changed to LiFePO4 for the reasons I have stated previously. They are a robust high energy density and safe cell technology that has essentially zero self-discharge and that can be fast charged at a high rate.

As far as what I do in RC, I have been flying since I was 11 years old, which is now 44 years in the hobby. I have flown almost everything except turbine including a wide variety of sport planes, pattern (electric and IC), IMAC (biggest plane was a 45% Extra), helicopters, and lots of gliders (thermal duration, hand launch, giant scale). I did play around with boats for about 2 years, but was still very actively flying during that time. But even boats need RX and TX packs. So I am not sure exactly what your point is.

To be clear, I think your dislike of NiMH is counter to the proven results of thousands of modelers over an extended time period.

Silent-AV8R

You were editing to add this while I was typing my last post. Allow me to answer.

I own 6 radios right now. A Futaba 3PM, Futaba 4PK, Futaba 6EX-FASST, Futaba 9ZAP, JR 9303, and the Futaba 14MZ you noted.

I use the Eneloops in the 3PM, 6EX, 9ZAP, and 9303. I have changed my 4PK over to the Hyperion LiFePO4 pack and it is working very well. In addition I have 6 5-cell Eneloop RX packs that I have used in both boats and aircraft.

As I noted, I now use the Hyperion LiFePO4 packs in all my planes. I no longer use conventional NiMH packs in any plane, boat, or transmitter. But that is only because of not liking the self discharge that is typical of them.

Silent-AV8R

Take a look at the discharge curve I posted a few posts back. LiFePO4/A123 do have a very flat discharge curve. This means that simple voltage monitoring is not a great way to monitor them. But truthfully I do not think it is a great way to monitor anything except Lipo.

Having said that, what I do is develop a discharge curve under a known or typical load. I then use a timer to keep track of the time that pack has been flown and stop well short of when they hit the drop off. I check voltage to make sure the packs are still working correctly. Always check voltage under a decent load, at least 500 mA or even 1 amp. Unloaded voltage is next to meaningless. I will not fly a LiFePO4 pack that is at or below 6.3 volts, and that is way out at the end of the discharge curve. Given how fast they can be charged I see no reason to run them down to their last useful moment. When in doubt, throw them on the charger.

BuschBarber

My Feedback: (2)

Thank you very much. That makes a great deal of sense. I always use a 1a or 2a load when checking the voltage of Lithium batteries.

summerwind

Bill,
i just take your info with a grain of salt as in this post you say one thing,
http://www.rcuniverse.com/forum/m_19...tm.htm#1971286

but as time passes and users and techonical info becomes available, you post,
http://www.rcuniverse.com/forum/m_36...tm.htm#3641761

and,
http://www.rcuniverse.com/forum/m_48...tm.htm#4854364

you change your user advice as time passes, so i honestly can't see how anyone can take any of your advice.

real world use of product is everything.

Silent-AV8R

Wow, that took some time. Going back to 2004?? I am impressed. However, I fail to see the issue. I change my opinion based on new data. But even given that I do not see an issue with what I wrote in those posts. When higher capacity NiMH came out only the 2700 A cells were available and that is what we used. Over a short time we found that they did not perform as well as some newer cells with lower internal impedance. Follow the dates and you will see the progression.

Now that the newer LiFePO4 packs are out I have once again revised my thinking. The very nature of what I was taught as a scientist. Your understanding evolves as new data is acquired.

But again, nice job going back 6 years looking for a way to denigrate my opinion. However, you failed since my opinions are entirely consistent with the changing state of technology. Yours on the other hand ignore the actual real world results of thousands and thousands of users and the availability of new technology and cell types.

Oh well, in the end people are free to ignore me if they wish, I have no issue with that. I am comfortable with what I know and how I apply it to the hobby. I also think that I am able to back it up with proven data and information.

summerwind

Bill,

didn't know i was your biggest fan eh?

on a more serious note, i am open to new technology, and will explore.
having gone thru many months of NiMH testing tho, i still believe NiMH users are running on luck. why else can you explain why all the Radio MFG's have not supplied NiMH power with their systems?

my intent on this thread though was to find out why Futaba just slams the door on their customers.
beyond that, i feel it's time to move on and will do so.

starting another thread in terms of finding the best possible solutions to our onboard battery use is of course an option, but is useless too as there are many threads available via search.

Silent-AV8R

Cost was the major reason. The other was that early on NiMH could not deliver voltage as well as NiCad. That is why Futaba had "Nicad" only on many servo. Concerns about voltage under load. But that went away fairly quickly. There are NiMH cells now that out perform Nicad in every important manner.

As you now know it is not "Futaba slamming the door". NiCads are just going away, period. It took Baxter a few days to get the official word for you and in the meantime you started this thread.

Agreed.

summerwind

[size=3]>"It took Baxter a few days to get the official word for you and in the meantime you started this thread.

Silent-AV8R

[quote]ORIGINAL: summerwind

[size=3]>''It took Baxter a few days to get the official word for you and in the meantime you started this thread.

summerwind

Kool on yer part Bill........thx

ChuckCLJ

My Feedback: (3)

I second that opinion. The best receiver packs i ever owned were NOBS.

TimBle

jeez'z bickering like 8 yr olds.Futaba uses NiMH in their newest transmitters, the T12FG and T8FG. I doubt they would use a dodgy technology in their radio's.NiCAD production the world over has ceased. There are still packs and cells floating about and as has already been stated, limited production for use in certain medical equipment. That is not Futaba's fault, thats a decision taken by global environment lobby groups. Its also information that has been around for a few years.Get over it, move on

summerwind

ummm, that's pretty much what we did already............you have any other reason for responding to a dead thread?