Electronics Explanations.

[Donziikid]

Howdy and welcome to the largest compilation of Micro RC electronics related information. This thread will be edited when new information is found for Xmods PCB/Electronics. My sources vary greatly from Xmods forums to RC Aircraft forums and can be found at the bottom of this first post. Many thanks to those forums and distributors!

1. Batteries and battery terms:

RC Battery types:
There are many different types of batteries out there that you can choose from. However, in the 1:28th scale racing world there are two major types: nickel metal-hydride and lithium-chemistry batteries. These two types of batteries vary in different ways in how they act, last and perform out on the track. Nickel metal-hydrides (NiMH) are beginning to fade and become outdated, all though they have great power and durability when it comes to clumsy people. The new technology is the Lithium-Chemistry batteries (Lithium-ions and Lithium-Polymers.) These Lithium batteries offer a greater power band, lighter weight but greater care is needed to take care of these lithium batteries.

NiMH
Typically the battery found in many Xmod enthusiasts battery drawer. These NiMH batteries offer more power than an alkaline battery, more run time than an alkaline battery and many more uses than an alkaline battery; since they can be recharged multiple times. NiMH batteries sit at a voltage of around 1.2V when under load, but come off the charger a little higher than that (typically around 1.3*V per cell.).

The most used and purchased cells are the following. These cells can be bought at a RadioShack, Wal-Mart, Target, or any place that sells batteries:

1000mAh Duracell Rechargeable
900mAh Energizer Rechargeable
700mAh RadioShack Rechargeable

Some of the best rechargeable NiMH cells are the following. These cells can be found at AtomicMods or Shop.TinyRC.com:

750mAh Intellect Rechargeable
950mAh GP Rechargeable


LiPo and Li-Ion
Lithium batteries offer great punch off the line and some fantastic run times because of the way they are manufactures and made. LiPo and LiIon cells are normally in the 3.6V range when under load, most come off the charger somewhere around 4.2V. Lithium Ion cells are typically wrapped in a metal casing, much like NiMH cells. Lithium Polymer cells on the other hand are wrapped in a heat shrink type solution. Both of these batteries are very dangerous and can pose great problems when not handled carefully. I recommend reading a lot about them before even thinking about purchasing them.

Review on LiPo by Mongo. I find that to be the best review I have ever seen about Lithium Polymer batteries. There’s a lot of information in there that will help anyone seeking Lithium Polymer batteries. Same rules apply for Lithium Ion cells. Other warnings/reviews can be found here on XMS as well.

One of the top sellers of Lithium cells is AtomicMods. Search there for their 2s2p packs and other packs that they sell. You may also build your own packs, just make sure the voltage does not exceed 7.4V!


Discharge/Capacity/"C"
Broadly speaking, the "C" rating is a guide to how much current it is safe to draw from your battery. This is expressed in terms of the capacity or "C". Be advised that constant discharging of your lipo pack at its maximum C rating will almost definitely shorten its expected life.

A 2200mAh 10C battery is rated to be discharge at up to 22A (10 x 2200mA/1000) and the same size (2200mAh) 12C battery would be good for 26.4A (12 x 2200mA/1000).

The internal resistance in higher C rated packs is lower, meaning that the voltage drop found in higher C packs is not as common giving higher voltage under load and slightly more power.

Milli-amps/mAh
mAh is an acronym for Milliamp Hour, which is how much current a battery will discharge over a period of one hour. Higher numbers here result in a longer battery runtime and higher storage capacity.

For example a 2000 mAh pack will sustain a 2000 milliamp (2 amp) draw for one hour before dropping to a voltage level that is considered discharged (DEAD). A 1700 will sustain a 1700 mAh (1.7 amp) draw for one hour. 1000 mAh is equal to a 1 Amp Hour (AH) rating.

Like the C rating, the mAh rating also determines the maximum current that can be drawn from a pack as can be seen in the calculation in the C Rating definition above.

For example if you have three 11.1 Volt 10C packs, one rated at 1000 mAh, one rated at 1700 mAh and the other at 2000 mAh, we can determine that it is safe to draw the following amperage from these packs.
(Multiply the C rating by the mAh rating and divide by 1000 to convert milliamps to Amps)

10 X 1000 mA/1000 = 10 Amps
10 X 1700 mA/1000 = 17 Amps
10 X 2000 mA/1000 = 20 Amps

Battery Upgrades:
A lot of people are afraid to upgrade to Lithium-Chemistry batteries, and I can see why. So there is a nice alternative! You could perform a five, six, or even seven cell upgrade to your Xmods! With rechargeable batteries you can go all the way up to seven cells, but do not exceed seven cells as this will blow your electronics package (PCB).

When doing this modification you want to make sure to have the correct amount of batteries and you have to make sure they’re all the same. Say you have a Sanyo 700mAh battery as your fifth cell, but your other four cells are Energizer 900mAh. Your Sanyo will lose power quicker than your Energizers would and this would cause the Energizers to in turn charge your Sanyo. This can pose many problems, such as heat and explosion. So make sure you have the correct batteries to do this modification.

Five cell upgrade on 1.2V: 6V – Safe.
Six cell upgrade on 1.2V: 7.2V – Safe.
Seven cell upgrade on 1.2V: 8.4V – Cutting it close to that too high edge. But possible.
Eight cell upgrade on 1.2V: Ka-Boom! 9.6V, way too high!

This is a good tutorial that you can follow to install your upgraded cells:
For the Evolution series Xmods.
For the Gen1 series Xmods.

And for those of you not afraid to switch to Lithium-Chemistry battery follow these tutorials. Please be warned, Lithium’s are way different and more powerful than the power that NiMH produce:

Gen1:
Lithium-ion

Evolution:
Lithium Polymer Pro

2. FETs

A metal–oxide–semiconductor field-effect transistor (MOSFET or FET) is an electronical device that controls the current between two points (your motor and your electronics). There is an N-Channel FET and a P-Channel FET, the most common being IRF7324 FET P-Channel and IRF9910 FET N-Channel. The N-Channel FET goes on the forward pads and the P-Channel goes on your reverse pads, controlling your forward and reverse functions of your motor/electronics. These 9910 and 7324 FETs are upgrade FETs that can be bought at many e-retailers like AtomicMods or Xmods International for your Xmods EVO.
(FET channels 8962 and 4562 are used on Gen1 Xmods and Mini Zs.)

A great schwab of information on FETs can be found in this thread from ZX9RBART. FET Explanation

3. External Turbos.

Everyone in the Xmodding community just loves speed and nothing but speed. And what a better way to gain that little extra advantage over you opponents that investing in an external turbo from one of our many e-retailers.

Nelly External Turbo:
The ‘Nelly’ is one of the most sought after aftermarket external turbos’. Although these have been out of production since about September of 2006, they still can be found on some e-retailers as well as some forums dedicated to Micro RC. Nellys’ were invented for one purpose, to save your MOSFETs (learn more about MOSFETs in the section above labeled FETs.)

Originally Posted by ”Ph2t”

Nelly came about because I was becoming sick and tired of frying my MOSFET stacks in my mini-z madforce truck and other racers. I also wanted to get the greatest performance possible from the electronics in the various vendor cars. The stock electronics just doesn't cut it in terms of performance….
…Also, and this is a major design point for the Woah Nelly Turbo. I wanted to make the turbo as efficient as possible so even with no motor change (ie: no hot motor installed) you would still see a performance increase and have this external unit actually act as a "turbo" so to speak....

Many Nelly external turbos were manufactured by Ph2t.

-Stacked EVO Nelly Turbo
-Nelly Evo
-Nelly Deluxe
-Woah Nelly V1.3
-Woah Nelly V1.2
-Woah Nelly V1.1

All of Ph2ts Nelly External Turbos were hand made and hand tested with a Plasmatomic motor.

Information found at: Woahnelly.com



AtomicMods V2.2

Originally Posted by ”Rob from AtomicMods.com”

The V2 is a 'simple to install' superior alternative to Stacked FETs. It is the only board that offers regulated voltage back to the EP allowing you to run any voltage your motor can handle, and eliminating servo jitter. The V2s logic circuit decodes the signal from the two EP motor output wires eliminating the need to remove the motor FETs and solder 4 input wires to the pads.

The AtomicMods V2.2 power regulated board is quite the piece of work. Although there have been some cases of them worked flawlessly, more often than not people are blowing these boards due to the mislead information about how they work. To get the 30V maximum there must be a modification done to your board, which many people over look because they don’t want to ruin their board before it is even installed.

AtomicMods V2.2. Power Regulated Board can be bought straight from AtomicMods, I have yet to see it be purchased anywhere else by an e-retailer.

Information is limited from AtomicMods. I will update this when more information is acquired..


Spider External Turbos
Another Australian wonder. Ph2t stops making the Nellys and some other
Aussie picks up the External Turbo crown with the Spiders. Spiders have also branched out into other external turbos such as the “The Bug”. All updated information can be found at Ausmicro.com

--Spider v4.0 “Black Widow”

Originally Posted by ”Aaron from Ausmicro.com”

This is the smallest we can make the traditional four MOSFET H-Bridge until small MOSFETs with similar high performance are released. The board has had millimeters shaved from the already small v3.0 design and incorporates a number of changes to improve durability and performance.

Will update when more information is found!

4. Motors.

Need to know knowledge:
Stock Gen 1 FETs can handle approximately 47 turns, Evolution FETs can handle approximately 33T (Note- these numbers are approximates and I am not responsible for blown FETs as a result!). Most aftermarket Xmod motors use between 22awg and about 30awg. Remember, the lower the number, the bigger the wire diameter. Fairly high end motors have winds in the thirties. Very hot motors have winds in the twenties. And a few crazy people are doing sub-20 wraps (lowest I’ve seen is 12T)!

One of the biggest determining factors in motors is the wire. How many winds and what gauge wire. In general, bigger gauge wire and fewer winds will make a faster/more powerful motor. The downside to this is current flow. The less resistance (less length, bigger gauge), the more current your motor will draw. There are limits to what the batteries and electronics can handle. Most motor winding wire is copper, but some use silver wire, which is more conductive and will increase the current and power.

The best motor information I have ever read was written by two people.
CreativeSN. He’s one of the leading motor gurus in the miniature scene and still (to my knowledge) winds custom armatures for you to use in your Xmods. Visit him at FreestyleXmods.
RedSXmodder. He's a starting guy in the motor scene but winds some very nice armatures. Check out his work here on the forum and other forums and contact him if you would like a motor done for yourself!

Also, there's our very own redSXmodder here on XMS that I believe is open for motor winding business. Drop him a line and hopefully he'll get you worked out.

Further information on where to purchase motors can be found here at the Where to purchase: Motors thread here on XMS.




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This post will be edited many times whilst new information is formed and found each and every day in the Micro-scale RC world. Thanks for reading. Please post any questions as a new thread.

[ak47eaz]

whats the step with the v2.2 that people dont do..? im thinking bout getting one...but im open to the nelly or spider ..when i see them on ebay..i dont see in the picture where the wires hook up to