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Your Reviewer

My Credentials
So who's doing this reviewing then?

Well I've been building and flying or driving radio controlled models for over 40 years and during that time I like to think I've built up a reasonable amount of knowledge.

I'm also a qualified electronics engineer who has worked in radio frequency, analog, digital systems and software for more than three decades. In fact I designed and built my first RC set back in 1969.

For the past nine years I've also been involved in the design and manufacture of some rather sophisticated engine technology and UAV flight control systems.

So, chances are I've been there, done that and have a huge pile of tee shirts to prove it.

Right now I'm heavily into 3D flying and enjoy all aspects of the RC hobby. I may be old but I don't feel it.

In the Pipeline

Here's just a little bit of what's to come on this site...

RC explained: Demystifying terms such as PCM, PPM dual conversion, single conversion, full-range etc., this feature will explain it all.

Cheap Chinese Engines: Just how good are those cheap Chinese glow and gas engines that sell for half the price of their "brand-name" equivalent? I put several to the test.

Build your own radio gear?: Back in the old days, building your own RC gear was not uncommon and now the arrival of 2.4GHz has made it practical again.


A DIY $8 Lithium Transmitter Battery


The FlySky 9X, also sold as the Turnigy 9X and iMax 9X (review), is a low-cost 2.4GHz RC system that is enjoying particular success right now.

Like many low-cost radio systems, it is supplied with an 8-cell AA battery holder instead of a rechargeable Nicad or NiMH pack.

Of course you could rush out and buy eight rechargeable AA batteries, or you could opt for one of the new 3-cell LiPo packs designed specifically for transmitter use. However, there is a far cheaper, safer, and better alternative.

Why not Nicad or NiMH?

The simplest way to power your 9X transmitter is to simply fit eight AA-sized Nicad or NiMH cells. Let's face it, these batteries have been powering transmitters for decades, so why would you want to use anything else?

Well one good reason, in the case of NiMH cells is their relatively high rate of self-discharge. Even if you fit the latest 2700mAH NiMH AA cells to your 9X and charge it today, chances are that if you have a few weekends of bad weather and then try to use it, much of the charge will be gone.

That's because NiMH batteries tend to discharge quite quickly, all by themselves.

The answer to this might be to buy some of those new Sanyo Enerloop batteries -- but have you seen the price???

Maybe the best option is to go lithium.

Lithium cells can not only store a lot of power in a small space but they also have a very low rate of self-discharge. In fact, with the right lithium battery installed, you could charge your transmitter in the fall and it'll still have enough charge for a full weekend's flying in the spring -- after sitting on the shelf for several months.

But, there are lithium batteries -- and there are lithium batteries.

Go Lithium With Safety!

One of the problems with the standard 3-cell lipo transmitter batteries is that they can be overcharged -- with a resultant risk of fire.

Another problem is that if you forget to turn your transmitter off, these packs can be over-discharged to the point where the cells are damaged and may no longer work.

And, in the case of a transmitter like the 9X using any of the widely available JR-compatible 2.4GHz modules on the market, there are also some risks associated with the very high (often over 12V) output of a freshly charged LiPo battery pack.

Heat Kills

One of the biggest factors in the reliability and life of electronic components is the heat at which they operate. Modern 2.4GHz radios like the 9X don't actually need the full 10V or so that an 8-cell AA pack delivers and they certainly don't need the 11V-12V a 3S LiPo supplies.

That's because, the circuitry inside is designed to run on a maximum of just 5 volts. Yes, up to 6 volts of the power coming from most transmitter batteries will be wasted.

What happens to all that energy?

It's converted to heat. Heat that makes critical components called voltage regulators run hotter than they need to.

It makes a lot of sense therefor, to use a battery that provides "just enough" voltage. Not too much, not too little.

That's where this low-cost lithium battery conversion comes in.

Not only is this an incredibly cheap transmitter battery option but it's also safer and will help your radio run cooler and longer.

The Batteries We'll Use

The key to this low-cost transmitter pack are the Lithium Ion batteries sold at DealExtreme for as little as $8.01 a pair, including airmail shipping.

Yes, that's quite a deal!

The cells I used are the TrustFire 2400mAH ones with the brilliant feature of built-in over-voltage and over-discharge protection. Yes, that's right... they're protected against overcharging and they won't be damaged, even if you accidentally leave your transmitter on all week.

If you're not a penny-pincher like me, you might prefer to go for more capacity with either the 2500mAH cells or even some 3000mAH cells.

If you're interested in using these batteries in your 9X then Let's get started...

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The Blog

Updated: 20 Sep 2012
Here's a blog that will keep you informed just what's going on behind the scenes at RC Model Reviews and also tells you a little more about myself.

How compatible are 2.4GHz RC systems?

23 Mar 2010
How come there's no compatibility between different brands of transmitters and receivers? Why can't you use a cheap Chinese receiver with your Futaba FASST radio?

How to get a product reviewed here

4 Mar 2010
Since this has become a very frequently asked question, I've posted this simple guide to getting your product, or a product you're thinking of buying reviewed here at RCModelReviews

How servos work

Useful information on what's inside your servos and how they work.

The Good Oil

Important facts you should know about the oils that are used in our model engine fuels.

Heads-Up: 2.4GHz RC systems tested

How well do five different 2.4GHz systems stack up when hit by interference? The answers are here, with more to come.

Review: Bushnell's $80 Speed Gun

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Review: TowerPro MG995 servo

These are possibly the world's worst servos, find out exactly why you should avoid these boat-anchors at any cost.

Review: SK90


It's cheap but can it really stack up against other glow engines in the .90 market? Find out in this review.

Review: iMax 9X 2.4GHz radio

How does this cheap 9-channel 2.4GHz radio system perform when compared to big-name systems that can cost two or three times as much? Have the Chinese finally developed a real contender with the iMax 9X?

2.4GHz Explained

Does all this 2.4GHz stuff have your head spinning? 2.4GHz

I've done my best to demystify the whole subject so if you feel like a bit of learning, this is the stuff for you!

Fix That Engine!

How can you tell when your engine needs new bearings? Who has the best prices and service on replacements? Just how do you change them? Get all that information and watch a great video tutorial anyone can follow.

Chinese Servos - How do they stack up?


The Chinese are now churning out a huge number of very reasonably priced no-name servos. But are they any good?

Baffled by batteries?

Batteries Nicad, NiMH, Li-Ion, LiPoly, LiFePO4, A123... the range of different battery types has never been greater. So how do they differ and what type should you be using?

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