This has bothered me for a while now!!! Attn. SteveP

[CK9887]

I finnaly recieved my August issue of RCCA.
Well, I was reading the Nitro Do's and Dont's and once again it says don't use rechargable AA's for your reciever pack becuase they are only 1.2v's each.

NOT TRUE!!!
That is only rechargable Nimh's.
Rechargable Nicd AA's are each 1.5v's.
I have a set of rechargable Nicd AA's and it says right on the battery, 1.5v's.
Where as my Nimh AA's say 1.2v.

I just wanted to set some of you guys straight on this. I have read numerous times in RCCA not to use rechargable AA's because they are only 1.2v's and I finnaly decided to speak up.


RCCA: you may want to set this straight in the next mag for some of the people that havent realized this??? Maybe put this in the readers writes?

[ncrego]

I'm looking at a set of Nicad AAs right now, and they are 1.2v, I've never seen a set that were 1.5

[CK9887]

Maybe i mixed up, i dont have rechargable Nicd's, I have Rechargable AA Alkalines which are 1.5v's each. I believe they are the rayovak and i got them at walmart , 4 for 5$.

Sorry i goofed up in the first post.

But they do make rechargable AA alkalines that are 1.5v's each.

They may be a little harder to find but i know walmart has them.

[CK9887]

Heres a set of rechargable Alkalines, each 1.5v's. Not as cheap as walmart but it shows you that they do exist:) ;) :D :p :)

http://www.batteryplanet.com/merchant2/merchant.mv?Screen=PROD&Product_Code=CA64

[Railman]

The voltage rating of a battery has to do with the average voltage over the usefull disaharge period. Alkalines are well over 1.6v when new. Nicad, & nmh are, for all practical purposes, the same, at about 1.4 v when fully charged. If you take a typical 6 cell sub- c pack, it will peak out at about 8.5v. So 8.5v/6cells=1.42v per cell. However the voltage drops rather quickly under discharge, until it gets down to about 1.3 volts, & then holds pretty steady till it reaches .9v. After that, there's not enough power (mah) left to be of use. Just look at a subc battery discharge curve, & you'll see what I mean.

The 1.2v rating is the average voltage over the discharge time period. The same is true for alkaline batts at a 1.5v rating. Once alkalines get to about 1.3v, they are useless.
Joe

[rccardude04]

The problem with the Alkaline batteries is that after like 3 charges they lose half of everything as far as voltage and capacity etc.
Example... After having some for probably 5-6 charges worth my magnum junior would not last near as long on a charge as it seemed like it should. When i got my RC10GT, I had an airtronics 3PS. the alkaline rechargables (same set from my magnum junior) would not light the lcd screen to even do display switch programming. it would sit there and beep the batteries dead alarm.
So they're probably good for a charge or 3, but be careful after then. And remember that alkaline cells will never deliver the current that a nimh or nicd pack will for faster/stronger servos.
-Eric

[Pro3/nmt105]

Whats wrong with running 1.2v nimh rechargeables. So you lose a little torque and speed its barley noticeable and saves you alot of money compared to buying alkalines or a reciever pack. Ive always run 4.8v in my reciever packs and havent had a problem yet.

[CK9887]

hmm,

i havent had problems with mine

[TSR6]

Originally posted by Pro3/nmt105
Whats wrong with running 1.2v nimh rechargeables. So you lose a little torque and speed and a car when they go dead.

[Dino451]

When ever my batteries are about to die they do it slowly. Everything slows down. i have never had a runaway with a dead recevier pack. If you know they way your rc should handle normally then you know when to stop and pack up and discharge then recharge.

[StevePond]

Originally posted by CK9887
I finnaly recieved my August issue of RCCA.
Well, I was reading the Nitro Do's and Dont's and once again it says don't use rechargable AA's for your reciever pack becuase they are only 1.2v's each.

NOT TRUE!!!
That is only rechargable Nimh's.
Rechargable Nicd AA's are each 1.5v's.
I have a set of rechargable Nicd AA's and it says right on the battery, 1.5v's.
Where as my Nimh AA's say 1.2v.

I just wanted to set some of you guys straight on this. I have read numerous times in RCCA not to use rechargable AA's because they are only 1.2v's and I finnaly decided to speak up.

RCCA: you may want to set this straight in the next mag for some of the people that havent realized this??? Maybe put this in the readers writes?

Originally posted by Pro3/nmt105
Whats wrong with running 1.2v nimh rechargeables. So you lose a little torque and speed its barley noticeable and saves you alot of money compared to buying alkalines or a reciever pack. Ive always run 4.8v in my reciever packs and havent had a problem yet.

CK - it is you that is mistaken. I don't claim to get it right all the time, buy we spend a little time looking into these things before we make any claims about what you should and shouldn't do.

To the credit of Stephen Bess, who wrote that piece, the article is right one the money and I know that because I researched it all myself to be sure he was correct. I never gave it much thought before because I've always used 5-cell packs for performance, but never tried installing 4 Ni-Cd or Ni-MH cells in the dry cell holder. Here's what I found: ALL of the major radio manufacturers suggest their receivers operate with 4.8 to 6.0 volts, except for one. That means you risk losing control of your vehicle shortly after turning on if you use four rechargeable Ni-Cd or Ni-MH cells in your dry cell holder. Yes, the nominal voltage of the pack is generally higher than 4.8 volts, but once you put a load on those cells (turning the switch on and operating the radio system) the voltage will drop below 4.8 volts and you risk losing control of your vehicle. KO Propo is the only radio manufacturer that rates their receivers to operate below 4.8 volts - they rate them down to 3.5 volts.

The Novak XXL and XXtra are rated from 3.0 to 10 volts, and the Lrp Phaser is rated from 3.5 to 6.5 volts. In both cases, I would imagine if you're spending money on an aftermarket receiver, you're already using a 5-cell reciever pack.

So, in most cases when using the receiver that came with your radio, you're playing with fire if you use four rechargeable cells as a power source. If you want to press your luck, that's up to you.

[CK9887]

I still dont know what the problem is with rechargable Alkalines???

The problem with the Alkaline batteries is that after like 3 charges they lose half of everything as far as voltage and capacity etc.

I have actually seen a few rechargable akalines that are only made to be charged a few times, like that link in my earlier post, i belive it says on the package 7x longer than ordinary Alkalines. That really means they can only be charged about 7 times before they are dead.

The rechargable Alkalines i have from walmart can be recharged 100times.

I havent just used them for my reciever pack, i also use them for my portable CD player. They probably have 30 charges on them and they last just as long as a new set of Alkalines.

[rccardude04]

well... they may have actually upgraded the cells since then, but these were supposedly good for like 300 charges or something silly. They didnt last near that. I was just warning people in case they were still the same. Just watch out.
-Eric

[Pro3/nmt105]

Originally posted by TSR6
and a car when they go dead.
My 3pk has a regular failsafe and battery failsafe so I shouldnt have any problems with that, and Ive been using them a long time with futaba recievers and have never had problems. When the servos speed slows down I put in a new set anyway because the performance sucks. I have a reciever pack in my ntc3, I just havent had a chance to get one for my gt.

[MPALLTHEWAY]

Those little dry battery boxes are dangerous when it comes to using Nicad 0r Nimh. Not only are you not giving enough power to your reciever (more glitches, less radio range) but take a hard landing and watch one of those cells pop out and you have lost all control of the car, (and as luck would have it 99.9% of run aways happen at WOT with the wheels straight) You know when you got into the hobby that it wasn't cheap so spend the $30 and buy a 5 cell 1100mah Ni-MH pack and be done with it. How much were those lame alkaline regargables from walmart? $20 to $25.

just my $.02

[TSR6]

Originally posted by MPALLTHEWAY
Those little dry battery boxes are dangerous when it comes to using Nicad 0r Nimh. Not only are you not giving enough power to your reciever (more glitches, less radio range) but take a hard landing and watch one of those cells pop out and you have lost all control of the car

Which is why you tie-strap the cells in. If you don't, you should.

[ncrego]

Which is another example of people entirely missing the point. It's amazing to me when I see people who have upgraded their servos to faster/stronger ones and then still run them off of rechargeable cells in a battery box. Or those that don't have a failsafe, or a return spring. All are necessary.

If you were able to cough up $300+ for an RC, don't cheap out after. Do it right, get a failsafe, and a 5 cell rechargeable pack. A good receiver pack will make your car perform better, the servos will move faster, and have more torque. And then when that battery dies, or you get a glitch, the spring and the failsafe will stop the car. This is NOT a cheap hobby. If you try to cheap out, you will either not be happy with the performance of your equipment, or you will damage it. Or worse, your nitro will go out of control and hurt someone. I don't even want to think of what it would feel like to get hit by my Savage.

[AudiTT-Quattro]

Just to throw a few more things in. Most standard receivers today don't operate under 3.8 volts and as soon as you put a load on 1.2v NiMH/NiCD cells, the voltage sags (this of course assumes a NiMH 4 cell pack). Use a 5 cell pack if you plan to use 1.2v cells which will bump the voltage up to a nominal 6.0v.

[heckflosse]

I tend to use 2000ma (1.44v when charged) ni-mh for general bashing in a confined area (back garden, works yard etc.) and Duracell Plus AAs for at the track or in a public place. My local Asda/Walmart often does buy one get one free offers and the Duracells work out at £1.25 for 4.
I bought so extremely cheap 1.5v alkalines of a market stall (30 for a £1 :D ), needless to say after not even a minute the failsafes kept cutting in:rolleyes: .

[TSR6]

I do not beleive in fail safes, or return springs. I do beleive you should have a good, quality rechargable rx pack though.

[ncrego]

What part of return springs and failsafes don't you believe in? Are you incapable of believing that they exist, or just that someone shouldn't use them? Why would anyone think that they are a bad thing? That's like saying it's a bad idea to wear a seatbelt while driving a car, or a helmet while riding a motorcycle. You may choose not to do either, but every bit of data on the subject points to it being a stupid thing to do without.

[TSR6]

my deal with failsafes is that they are a false feeling of safety. They make you feel all warm and good inside, but at the same time, they aren't all that great.

Return springs put more strain on your servo, and often times the spring itself isn't adaquate to pull the servo back to idle. If you wonder why your servo is having troubles centering, or why it wears out faster, just remember that your return spring buddy might be a double edged sword. Also, often times, return springs aren't even setup properly, and would not bring the engine back to idle if you lost your linkage. Very rarely have I seen anyone actually connect it to the carb itself.

Failsafes are great too, until you pop your linkage, batteries fall out. They also aren't exactly cheap. They often don't catch interferance, so the only real protection you are garenteed is the low voltage protection. They don't actually moniter receiver signal strength, they monitor the signal going to the throttle servo. Interfierance and glitching aren't loss of signal, they are conflicting signals. If the failsafe kicks in, your lucky. :)

I know InspGadgt has been pretty good with this topic, so i even dug up one of his posts... :)

"A few thoughts about failsafe devices:

External fail-safe devices activate only in the event of a loss of signal to the throttle servo. Now exactly what causes a loss of signal? There are 3 causes for a loss of signal. 1) Transmitter stops transmitting (batteries die, transmitter gets turned off, etc. etc.). 2) Receiver stops receiving (this can only happen from a loss of power from the receiver battery pack) or goes out of range. And 3) Signal cancellation. Now the first 2 causes are rather self-explanatory, but the third can cause a great deal of confusion to those who have not studied waveforms such as radio waves. Basically in order for signal cancellation to occur 2 or more waves when intersecting must be exactly opposite of each other to bring the combined waves to zero. Now lets think this from the other end of the equation. Most of us have made the mistake of turning on our car before the radio on more than on occasion. Now, what happens when the car is on but the radio isn’t? Most people will say, “The car goes crazy”. But this is not entirely accurate. I have on many occasions had the car just sit there and not go crazy at all. What causes the car to go crazy is the multitude of RF signals in the atmosphere from various sources such as cell phones, microwaves, aircraft radio, power wires, etc. etc. If your car were turned on in a room that shields all such signals out it would just sit there and do nothing. So if signal loss doesn’t cause glitching what does? Glitching occurs when the receiver receives more than one command on the same frequency. Since there are so many other sources of RF out there it’s quite easy for the receiver to pick up on one of these and get, shall we say, confused. Because there is no loss of signal in this case then an external fail safe device would do nothing to prevent a runaway. However it would make for a good alternative to a throttle return spring, as it will activate under the same circumstances. Additionally it will not place added stress on the servo.

There is one type of fail-safe device that will activate to prevent glitching. That is the fail-safe built into a PCM radio system. PCM works by having a code within the signal that is transmitted. If the receiver does not get that code or receives fro multiple sources then it automatically goes into fail-safe mode. But will not go into fail safe in the event of a loss of power so you would still need a return spring.

Now just because you have a fail safe, throttle return spring, or even PCM, don’t think you’re entirely safe. Let’s say your in the middle of a race, leading the A main and screaming down the straight when someone keys on their radio on your channel. Luckily you have PCM and your car safely fail-safes and comes to a stop…in the middle of the straight. And right then, second, third, and forth place cars slam into yours at full speed."

So for low reciever batts...yeah the fail safe will work...but that's easy to make sure never happens...just repeak the pack between runs. Low/dead transmitter batts, broken crystals, ect ect...your still going to get a signal wether it be a weak signal or a false signal from another source.

Sorry you wasted your $20-$35. Being prepared, and having your car setup properly is the best prevention you really have. Almost all run-aways are from user error anyways.

1. Loss of power? You should have charged your TX/RX cells.
2. Loss of signal? You shouldnt have driven out of range. See also: #1.
3. Pop'ed linkage? Stop hitting things, and have your linkage setup properly.

You said a fail-safe is like a car's seat belt? Yeah, sure.. It's like a street car's seat belt at over 120mph. Sorry, but at those speeds, it's just there to make you feel all warm and good inside. :) If you survive the brick wall, your damn lucky.

-Troy ;)

[ncrego]

You re right in that a failsafe and spring won't keep you protected in every situation. Nothing will. But they will cover you in some very common scenarios. And one of the most common is low voltage. I have a person who's cars I work on who was constantly having run aways. Broken parts ensued, as expected. Threw a failsafe on the throttle, and it hasn't happened once since.

I personally don't use a spring, for the very reasons you listed. Plus, I have a high torque servo, and the spring won't pull it shut unless I have so much tension on it that it is constantly fighting the servo, and increasing battery drain. I use the best method, PCM. It protects in every circumstance, barring a total catastrophic loss of power to the servo (lead coming undone, battery being ejected, etc). However, most people don't want to invest that much money in a radio, and for those people, a failsafe will help them in a very similar fashion.

It's not about covering you 100% of the time, but rather protecting in as many ways as you can. Nothing is totally guarranteed, except that things will go wrong. And the only way to help that is to keep up with your maintanance and always do a good preflight. A nitro RC is a dangerous thing to have, and to not use every possible thing you can to prevent it from going out of control and possibly damaging persons or property is irresponsible. If you can't afford the $30 for a failsafe, then you should take up a cheaper hobby. Anyone who is in this hobby and says they don't throw away $30-$40 on a regular basis on hop-ups and other unnecessary things is a liar, or doesn't have an adequate budget and shouldn't be in it anyway.

[TSR6]

Originally posted by ncrego
You re right in that a failsafe and spring won't keep you protected in every situation. Nothing will. But they will cover you in some very common scenarios. And one of the most common is low voltage. I have a person who's cars I work on who was constantly having run aways. Broken parts ensued, as expected. Threw a failsafe on the throttle, and it hasn't happened once since.

I personally don't use a spring, for the very reasons you listed. Plus, I have a high torque servo, and the spring won't pull it shut unless I have so much tension on it that it is constantly fighting the servo, and increasing battery drain. I use the best method, PCM. It protects in every circumstance, barring a total catastrophic loss of power to the servo (lead coming undone, battery being ejected, etc). However, most people don't want to invest that much money in a radio, and for those people, a failsafe will help them in a very similar fashion.

It's not about covering you 100% of the time, but rather protecting in as many ways as you can. Nothing is totally guarranteed, except that things will go wrong. And the only way to help that is to keep up with your maintanance and always do a good preflight. A nitro RC is a dangerous thing to have, and to not use every possible thing you can to prevent it from going out of control and possibly damaging persons or property is irresponsible. If you can't afford the $30 for a failsafe, then you should take up a cheaper hobby. Anyone who is in this hobby and says they don't throw away $30-$40 on a regular basis on hop-ups and other unnecessary things is a liar, or doesn't have an adequate budget and shouldn't be in it anyway.

What causes the low voltage problem? The user. Plain and simple, if something happens to the car, it's almost always the person's fault. As stated, a failsafe really only works well for the low voltage problem. The only time that happens is when the person is irresponsible, and doesn't keep tabs on the battery level.

It's not irresponsible to not have a failsafe. That’s the guilt trip end of it, and I've seen it a million times. "Won't you feel bad when.... "

My response, That won't happen. If you have your car and radio setup properly, and your batteries fully charged ( or fresh alkaline should you choose to use them ) you won't have a problem. I mentioned the radio, because that is also a common problem that adds to high servo stress, which drains the battery.

So, now that we have the voltage problem taken care of by keeping tabs on our batteries, what is the reason to buy a fail safe? I'm waiting, I don't see one...

I'd also like to know what money I ''throw away." The only major purchases I've made in the past 2 months are foam tires, a couple spare parts, and 2 bodies. Tell me what is unnecessary?

I'm not a liar, and I still don't have a reason to waste $25-30 on a little do-nothing box.

-Troy

[Trinityracinnut]

What causes the low voltage problem? The user. Plain and simple, if something happens to the car, it's almost always the person's fault. As stated, a failsafe really only works well for the low voltage problem. The only time that happens is when the person is irresponsible, and doesn't keep tabs on the battery level.

I agree troy, its the users fault for not watching and tracking their battery levels.

[rocknbil]

Originally posted by TSR6
....Return springs put more strain on your servo,.....Failsafes.....only real protection you are garenteed is the low voltage protection.....

Well trucking said!!!

[ncrego]

The irresponsibility comes from experienced users passing down their practices to those less experienced. The vast majority of people out there doing RC are not checking things and charging/replacing batteries as closely as you or I are. A lot of these things are bought by kids, who run it until it breaks, and those guys are the ones who are going to have run aways. I can tell you that my failsafes haven't kicked in but twice in the 4 years or so I've been doing nitro. But both of those times, if the car HAD gone out of control, it would not have been a good thing. I don't need guilt to make my point, If you don't want to use a failsafe, fine, don't. It's your money. And the fact that you preflight your equipment thoroughly makes them significantly less necessary than if you didn't. But a lot of people don't. And won't, since they aren't willing to put that much time into a toy. And it is precisely that reason why failsafes should be considered mandatory.

[Jamedup]

I realise this is a battery thread but it seemed to turn into safety thread so here's my two cents. To those of you that think throttle return springs are nonsense then your fooling yourselves. I watch over my electronics pretty good but some things can't be seen or tested then it's to late. Like a broken battery wire inside the insulation or a broken battery bar in a shrink wrapped pack. I've had both of those happen to me and my throttle return spring has saved my RC and in one case, bodily injury.

My throttle return spring won't pull my Futaba 9404 back without the engine running unless I use 2 springs. But.... it will pull the throttle back while the engine is running.

Even if it only pulls the throttle back to half throttle, that still may save the engine and/or some parts.

[InspGadgt]

How is it irresponsable to pass down the practice of always pre-flighting your equpment? Cuz that's what we're passing down not the lack of running a failsafe. Anyone who's spending $400+++ (which everyone does eventually even if it's not the inital cost) to get a nitro car running they ought to be responsible enough to ensure their own equipment is running properly. Hell even before I got into racing and only had my old Tamiya Blackfoot I always checked things over. That was $300 of my hard earned dollars that I did not want anything to go wrong with. The main problems I have with fail safes is 1) With proper preparation they are not needed. and 2) Most people make the mistake of over relying on a fail safe and not doing any pre-flights because of that. They think the fail safe will protect them from anything when they don't.

[ncrego]

Because you can't pass down common sense and responsibility, it's something that has to be learned from experience. I've always taken very good care of my equipment, from the start (1986 I got my Tamiya SuperShot, for those counting, and yes, that is sad). Just because I'm **** about maintenance. The same goes with my cars, motorcycles, computers, etc. However, a lot of people aren't like that, so telling people that failsafes are worthless isn't doing anyone any good.

You can't give me a single example or scenario where a failsafe has caused harm to anyone, anywhere. You can only give examples of how they might not be necessary. But in the end, there is only one truth, if your Nitro RC goes out of control at full throttle (around 30+ MPH), it is going to do damage to itself, and anything it hits, assuming it doesn't hit a tree, curb, or something of similar. And that damage can be as minor as a couple of broken parts, which will most likely cost in the neighborhood of $30 to fix, or as much as a multi-million dollar lawsuit if it hits someone and injures them. $30 is nothing in this hobby. Heck, I dropped that much on a skid plate for my Savage, or tires for my XXX-T, neither of which was worth even a fraction of the cost of the peace of mind imparted by having every bit of safety equipment possible. A failsafe is one part of that equipment, and a good preflight is the other.

[InspGadgt]

Both common sense and responsibility can be taught rather then learned by experienc IF people listen and do what they are told. Which they don't always do.

Actually I can come up with a scenario...Joe Shmo reads all the advertisements and hype on fail safes and buys one because he thinks it will keep his crappy AM radio from glitching. As he goes tearing around his neighborhood with his nitro car he gets a bad glitch, hits a curb full speed and flies through someone's window...or worse yet hits some kid playing on the sidewalk.

I'm not saying fail safes are totally worthless...I'm saying they don't do half of what they say they do. And that what they do prevent can easily be compensated for by stuff people should allready be doing.

RC can be a dangerous hobby. If people don't have or exercise some common sence and responsibility then they are going to be dangerous with their vehicles reguardless of if they have a fail safe or not.