rrTV-PHOTO   New HD TV
HOME   rrTV-PHOTO   GALLERIES   MY GALLERY   HELP-FAQ
myHOME PM pmRR MEMBERS 784 ONLINE 19 EVENTS SEARCH REGISTER  START HERE
 
2 pages [ <<    <    ( 1 )     2     NEXT    >> ]1645 viewsPOST REPLY
Esprit Model . Thunder Power RC . Mikado Modellhubschrauber

.
.
Radio - Servo - Gyro - Gov - Batt > NiMH Batteries
 
 
Hooked
Senior Heliman
Location: Trenton OH

I bought my first NiMH battery. I was told when not in use they had a self discharge rate faster than NiCD. But when I got it home and went to charge it, my charger ran for about 5 mins. then it said fully charged.So I thought something was wrong, so I hit discharge, I let it go down and it said 2600mah I figured that was good so I hit charge. And it seems to be doing good 7 flights and still shows fully charged on my tester. The only reason I bought this battery was for the extra capacity, but it seems that there is more benefit to the NiMN than the NiCD. I just wish someone would tell me what all the benefits are to the NiMH, it seems to me they have a much better dicharge rate. I beleive I was misinformed , that they lose power faster. Anyone who could shed some light on this battery, would be greatly appreciated. Thanks Steve
04-15-2002 Over year old.
 
 
rickc
Elite Veteran
Location: Creve Coeur IL. (Peoria Area)

My favorite is still my Duralites.

Rick
04-15-2002 Over year old.
HOMEPAGE  
 
 
Taipan
Key Veteran
Location: Sydney, Australia

The same thing happened with mine, then I remembered reading that they're purchased fully charged.

I thought NiCd self-discharged faster. Also isn't there no point in discharging NiMH as they're meant to have no memory effects?

This is confusing as I just read that with NiMH cellphone batteries they have memory effects & have to be discharged in order to charge fully.

My charger can cycle up to 99 times. Won't excesssive cycling reduce battery lives? There is a limit how many times they can be charged in their lifetime. 1000 is a number thrown around a bit.
04-15-2002 Over year old.
 
 
Furyextremester
Senior Heliman
Location: Va beach

Hey hooked,
heres the deal Nicad have a higher discharge rate then Nimh, and nicad build up memory, but nimh do not build memory and they can hold more milli amps than nicad, the problem is they cant discharge like the nicads can and thats why after 7 flights you havent used much current! got me so far. Really theres no real benefit to Nimh but the no memory and higher capacity, but in some ways nicad have nimh beat in my opinion, but in ways nimh have a huge advantage over nicads. Its all in the person and what applications the batteries are being used for, like i use a 6 volt 2700 mah NIMH pack that i can fly 6 or 7 flights on ccpm and not have to worry about charging until the 7 flight but you can see a performance change after that many flights. i also am using a 1200 nicad 6volt pack that i have to recharge about ever 3 flights but see a better performance on servos cause the nicads can push out more current or amps to the servos when needed...ie. inverted or high speed 3D. as far as shelf life nicads do drain a little faster cause thats the nature of the cell. Thats were the memory thing comes into affect because its the elements in the cell that are decaying and thats the disadvantage over nicads, Nimh do not drain as fast but still drain, BUT
they dont build the memory, and thats the issue at hand they last longer and hold the charge alot better. Oh and some batteries comes half charged or completely discharge, by law they are supposed to come discharge or a very low voltage, unlike car batteries which come charged thats the only expection. Hope the info is helpful and good luck
John
04-15-2002 Over year old.
 
 
JCadwell
Key Veteran
Location: Richland WA/ Morro Bay, CA

Nimh offer higher capacity in the same respective size, often at a reduced weight for the same size as well. The bonus of this is that you can use a larger capacity pack of about the same size and weight as a smaller nicad. Nimh do need to be charged with a charger that can peak detect them. Overcharging a Nimh can mean death to the pack, and they are more sensitive to overcharging damage than nicad. I run Nimh in all my helis, (both) and have no problems. I charge them with a sirius pro charger, and plug them in every couple of flights. If I'm not flying, a heli is usually on the pro. The pro is basically foolproof, and I never have to worry about it, maintain the packs, or do anything but fly.

Thanks, John Cadwell
04-15-2002 Over year old.
 
 
irq
Key Veteran
Location: San Diego, CA

There was a really good article in QST a few months ago, comparing all the different kinds of battery packs, NiCd, NiMH, lead acid, gell cells, etc. The article said that NiMH batteries will loose their power faster than NiCds will, from just sitting around. It also said that NiMH batteries do have a small amount of memory, but not as much as NiCd's. Also, NiCd batteries can usually handle more charge/discharge cycles than NiMH's do.

So it gets down to two advantages of NiMH over NiCd: less memory and more capacity in the same space. For example, I have a 4500mah 4.8v NiMH pack that weighs less than my older 1800mah NiCd pack. Its a little bit bigger, but actually weighs a tiny bit less. To me, the higher capacity available makes it all worth it.
04-15-2002 Over year old.
 
 
Pleskini
Senior Heliman
Location: Houston, TX

Lithium Ion

Anyone know of any applications of Litium Ion Batteries, or reaason for lack there of?

From what I hear NiMH and NiCd both do develop memories. Even worse NiMH cells if they fail, fail open. This will result in no power where NiCd will still atleast just drop voltage possibly giving you the ability to get your bird down safely. Just some things I have heard, not sure if that is fact or fiction.

Anyone with info on Lithium Ion batteries? I would be interrested.

Jeff
04-15-2002 Over year old.
HOMEPAGE  
 
 
irq
Key Veteran
Location: San Diego, CA

It is true that once NiMH batteries get towards the bottom of their capacity that they will drop off faster than NiCd's, but I personally don't see this as much of a problem because I never fly with my batteries down that low If you find yourself doing that a lot, do yourself (and your helicopter) a favor and buy a larger-capacity battery; they certainly can be had cheap enough at places like superbatterypacks.com. As for lithium ion batteries, I understand that they are quite fragile as far as charging goes (they require specialized circuitry, beyond the stuff even for NiMH), and I think I've also heard that they really don't like vibration much, or at least not as much as nicd/nimh, and obviously that is a concern for aircraft.
04-15-2002 Over year old.
 
 
Hooked
Senior Heliman
Location: Trenton OH

Appreciate all the info. Made 10 flight's on it checking ever flight and still showed 5.12 on my meter so I am very happy with it
04-16-2002 Over year old.
 
 
Furyextremester
Senior Heliman
Location: Va beach

Li Ion batteries are the best cell out yet, but they can not take shocks very well, there so sensitive to vibration they will burst, the amount of vibration we put off from our engines will explode a pack in a heart beat, but later on down the road when they improve them it will the choice of all batteries.
John
04-16-2002 Over year old.
 
 
SemiArticulate
Veteran
Location: On Location

Check this link out:

http://www.runryder.com/showtopic.h...&highlight=NiCd
04-16-2002 Over year old.
 
 
Hooked
Senior Heliman
Location: Trenton OH

SemiArticulate. Thank's I guess that it would be best if I did a search before posting a question.
Thank's
Steve
04-17-2002 Over year old.
 
 
SemiArticulate
Veteran
Location: On Location

I didn't mean that exactly. It is always good to post the question. You may get new people involved in the subject and find out something that was not covered in the old thread. But the thread I posted seemed to battle it out pretty well. I am not sure who won but I am sticking with NiCds for now. Only because they work fine for my application.
04-18-2002 Over year old.
 
 
Hotwings
Key Veteran
Location: Florida, Port Charlotte and West Palm Bch.

the nimh packs are great, used them in cars for a long time , fast charge, long batt life, flew my raven 50 5 times today and used 313mah out of 1650 AA pack, figure 25 safe flights at that rate, awesome. this is with digital servos and gy401 gyro. fut 9zhps, fun !! c-ya

Please cancel my clearance, I have the field in sight.
04-18-2002 Over year old.
 
 
Safe_Cracker
Key Veteran
Location: Chicago, IL

Li-ion.

Li-ion batteries have a huge memory problem and you have to FULLY discharge them before you can recharge.Nimh aren't supposed to hold a memory but we all know that every molecule holds some kind of a memory.Ni-cads are good for high discharge like electric flight packs and cars but hold a pretty hefty memory.Li-ion is like a cross from a Ni-cad and a Nimh but stack double the memory.When a Li-ion goes bad it just falls, no warning, usually.For longetivity, Nimh is the way to go.Anyone ever see what happens when there Li-ion battery from there cell phone or laptop goes bad?I use to only charge my cell phone from half way every day until I really needed it and when it hit the half way mark, it died, FAST!Hate to have had them in a chopper!
04-21-2002 Over year old.
 
 
SemiArticulate
Veteran
Location: On Location

Here is a repost of something I said on another thread:

NiCd's really don't have a memory effect. The only way to show "memory" in a NiCd is to discharge it to the exact same spot several times in lab quality conditions. As a practical matter, it is nonsense. But you say you have seen it! Well they, like anything else, will wear out. When they do, most people say "oh my god MEMORY!" Its been my experience that the more you screw with them, the sooner you get to replace them. Its not memory, they just degrade. The batteries I don't pester last longer than those I try to cycle and pay special attention to. But why do these guys who make batteries and chargers say all this stuff about "memory"? Because it benefits them. Are you going to buy a charger that doesn't claim to "prevent memory"? I think the myth started when rechargeables were first introduced. One company was late getting to the market and needed to break the hold that the others had on the market. So they sold theirs by claiming to not suffer from "memory" like the other guys. The myth was born. It has become so ingrained in peoples minds that now every battery problem must be "memory". Its practically created an industry and spawned all kinds of charging rituals and recipes. Its Hype. There is just enough truth in it to ensure it gets blown out of proportion.

http://www.runryder.com/showtopic.h...&highlight=NiCd
04-21-2002 Over year old.
 
 
Safe_Cracker
Key Veteran
Location: Chicago, IL

Not too much for ni-cad.

Ni-cads have a memory but not as bad as Li-ion! Li-ion has a huge memory affect for the average person who only wants to be lazy and NOT discharge there cells.I'm the same way,I would like to get away with not having to cycle my batteries and charge it at ANY point over and over again.Ni-cads will deal with this for a while,but it will take it's toll on them and Li-ion, FORGET IT!!! If you are this type of person, then Nimh is for you, that's all I'm trying to say.
04-21-2002 Over year old.
 
 
SemiArticulate
Veteran
Location: On Location

I don't know where you got this info but you don't need to cycle NiCds to prevent "memory". As I said, for all practical purposes, it is a myth. Li-ion I don't know much about and don't pretend to. Nimh and Li-ion require a little more work from the charger and I suspect "memory" problems in these are a result of poor charging.
04-21-2002 Over year old.
 
 
rsilvers
Senior Heliman
Location: Marshfield, MA

"It also said that NiMH batteries do have a small amount of memory, but not as much as NiCads"

NiCads have a tiny amount of memory. So tiny, that there is no reason to mention it at all as a downside. I prefer NiMh because they weigh less per energy density, not because they have less of an impossible to document without fancy test equipment and -precise repeating discharge patterns- problem incorrectly called "memory" by people who just have abused cells. Memory only occurs if you discharge to within 2% of the same spot time and time again. No one ever does this in practice. It is a non-issue but refuses to die.
04-21-2002 Over year old.
HOMEPAGE  
 
 
Safe_Cracker
Key Veteran
Location: Chicago, IL

Really.....

So you are saying that you have NEVER heard of a Ni-cad pack failing due to poor cycling?You mean manufacturers create cyclers and peak detecters just to keep people who can't let Ni-cads go, spending more money?I understand people get old enough to where they are tired of trying to keep up with technology, but it is time to move on and let go of Ni-cads.Everyone has there own oppinions and others actually have experience dealing with the actual product.There is a reason why there are products to help extend the life of Ni-cad battery packs, because poor charging kills them and NOT Nimh!!!!!
04-21-2002 Over year old.
 
 
2 pages [ <<    <    ( 1 )     2     NEXT    >> ]1645 viewsPOST REPLY
GrandRC . CanoMod . Futaba-RC

.
.
Radio - Servo - Gyro - Gov - Batt > NiMH Batteries
 PRINT TOPIC Advertisers 

Subscribe to This Topic

Monday, December 1 - 11:17 pm - Copyright Š 2000 - 2008 runryder.com | email | link to rr | runryder needs cookie