Battery of Confusion

I hear a lot of people making comments about batteries that tells me they are confused over how batteries fit into their electric airplane power system.  I decided to do this blog entry to try to clear up some of this confusion without adding any more to the subject.

I hope to clear things up by relating an electrical system to an internal combustion system.

In a simplified internal combustion system the gas tank stores energy (in the form of gasoline), a carburetor controls the flow of energy to the motor, and the motor converts the energy into mechanical motion.

In our electric airplane power systems, the battery stores the energy (electricity), a speed controller feeds that energy to the electric motor, and the motor converts the energy into mechanical motion.

The battery as two parameters that it is rated by, the voltage and milliamp hours.  The milliamp hours is a rating of its capacity, just like a gas tank capacity might be rated in gallons.  A higher number of gallons does not make a car go any faster, it only allows the car to run longer.  The same is true for batteries.  A larger milliamp hour rating will not make your plane fly any faster, only run longer.  There is another little mix to this in that the milliamp rating (multiplied with the "C" rating) is related to the flow rate.  This is similar to a gas tank with either a low or high capacity fuel pump and line.  If an internal combustion engine requires more fuel than than the fuel pump and line can supply, its power and performance will suffer.  So too, if an electric motor demands more current (milliamps) than the battery can supply, the battery voltage will drop along with the electric motor power and performance.

The voltage rating is a little different and is more closely related to the octane rating of gas.  If I have a high performance car motor and run regular gas in it, I can only expect so much performance.  The fuel mixture is only capable of creating an explosion of so much to push the pistons down.  Now if I put high octane racing fuel in the tank, I can expect much more performance.  This fuel mixture is capable of a much greater explosion to push the pistons down.  A low voltage battery can only give its rated voltage to the electro-magnets that repel the permanent magnets.  A higher voltage rated battery will allow for a larger repelling force.

Now, keep in mind, just as the internal combustion race motor is built to take greater stresses, if a batteries voltage is increased, the speed controller and electric motor must be built to take on the extra stress.

I hope this analogy will help those out there that have been confused about batteries and their voltage and milliamp ratings.

Thanks for stopping by my blog.  Please feel free to post comments, good or bad, and be sure to come back and check for future posts.

Happy Birthday To Me!

So not enough candles.

So, it's my birthday (well a few days ago) and it was a big one, and my wife, the understanding and sweet wife she is, said that I should order the RC airplane I've been wanting for some time!  Now I've been pining for one of these since I first saw one over a year ago.  The plane I saw was a T28 Trojan (Parkzone).  I just loved the look and size of that plane.  And now, my wife was telling me to go buy one! Woo whoo!

On Sunday, I started reviewing all of my options for a T28.  First off I have to say that I was not interested in the small versions (800mm).  I wanted a big one!  After reviewing the Durafly (1100mm and retracts), Parkzone (1120mm), Dynam (1270mm and retracts), and Airfield (1400mm and retracts) models, I chose the big one, the Airfield, from Nitro planes.  Now it was by far the most expensive (about $280 including shipping), but aside from being the biggest, it had the coolest features.  These include lights, sequenced landing gear and doors, flaps, cowl flaps, and a 2.4GHz 6 channel transmitter!

Now I'm really excitted!

Was hoping there would be a big
picture of it on the box.  Oh well.

On Monday, I signed up for an account and ordered my birthday present.  By the end of the day, my order was processed and ready for shipping.  By Wednesday, it was on my doorstep!  Granted it only had to go from LA to Sacramento (both in California), but still, I only selected the base UPS ground shipping.

With the top off

All of the big parts laid out

Nice battery even if the charge cable
is a little short.

Now I did order the RTF version (mostly because they were back ordered on the ARF), but it is anything but RTF.  After about 2 hours I had it together with the glue drying (rudder and elevator need to be glued together) and all of the servo connection hooked up.  I guess the RTF part is that I had everything to fly, including the battery and radio.  I only needed to assemble it and charge the battery.  This thing is a monster!

The beast, all put together.

Now I'm all ready to fly and waiting for good weather.

Soon I'll have an update on how it flies and hopefully not one on how it crashes.

Thanks for stopping by my blog.  Please feel free to post comments, good or bad, and be sure to come back and check for future posts.

Battery Scare

My new LiPo

Hello all,


So this morning I'm laying in bed thinking about modding my transmitter battery when I realized that I had left my brand new Turnigy 2200 Lipid battery on my Tenergy charger all night! I had flown the previous day and wanted to make sure it was charged up if I had an opportunity to fly the next day. Well I had put it on the charger later that evening and forgot about it! Since none of our smoke alarms were going off I knew it had not overheated and burst into flames. Even so, I was glad that I had placed the charger and battery in a metal pan on the tile counter top in our kitchen so that if it had "burst into flames", the damage would be minimal. Now that I was pretty sure there was no fire (no alarm, remember), I was wondering what would be the state of the battery. I had visions of a puffed up, bloated, and worthless battery pack.

Team Tenergy charger and wall adapter

I rushed down stairs and into the kitchen. No scorched pan. No burnt smell. And, best of all, no puffed or bloated battery pack, and the charger light was still green! I quickly unplugged everything and checked it all out. The battery was not puffed at all or even warm. The charger was not warm and neither was the power adapter.

A closer look at the Team Tenergy charger

Wow, was I happy. This inexpensive Team Tenergy charger did exactly what I would want a charger to do, charge the battery appropriately and then turn off the charging. This has been a great little charger. I know it only charges at one amp (which means long charge times for large packs) and can only charge up to 4 cells, but right now that's all I need and it can charge from a wall power adapter or car battery. This little charger is easy to use as well as it has a red light to show that it is charging and a green light to show when it's done, and it does balancing too. Needles to say, I am very happy with this charger.


Thanks for stopping by my blog.  Please feel free to post comments, good or bad, and be sure to come back and check for future posts.