Some Good Deal on Amazon Batteries

Need some rechargables AA and AAA batteries?  These seem to be a good deal.  The Internet believes they're manufactured by Sanyo and are rebranded Enerloops.  Woo hoo!

AA 2000 mAh
AA 2400 mAh
AAA 850 mAh






And two chargers:

EBL 808 8 bay charger
EBL 807 4 bay charger



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Class Supplies

Here's some good things to get for your OPQ.

Batteries.  Both of these are good.  I will usually buy whichever one is (a) in stock at the USA warehouse and (b) cheaper at the time.

• Turnigy nano-tech 2200mah 3S 25~50C Lipo Pack (US Warehouse)
• ZIPPY Flightmax 2200mAh 3S1P 40C (USA Warehouse)

Battery Chargers.  These come in a couple of variations.

DC-only input.  You can make these work if you (a) buy a DC power supply or (b) have an old PC power supply sitting around and are willing to do a bit of connector soldering.  If that's the case, buy some 4mm banana connectors and I'll show you how to do it.

Both of these are similar.  The IMAX brand has a better brand reputation than the Turnigy  brand. I can't quite make out which cables come with the IMAX, but it may be that some extra cables will be necessary from the (tiny) picture.

• Turnigy Accucel-6 50W 6A Balancer/Charger w/ Accessories (US Warehouse)
• IMAX B6 50W 5A Charger/Discharger 1-6 Cells (GENUINE) (US Warehouse)

I've got one of these.  It's basically four of the Accucel-6 chargers in one case.  You need to buy extra power leads, I think it only comes with one set.

• HobbyKing™ Quattro 4x6S Lithium Polymer Multi Charger (US Warehouse)

AC/DC Input.  These will work with AC wall power as well.

Here's the IMAX with AC input:

• IMAX B6-AC Charger/Discharger 1-6 Cells (GENUINE)

Note for the above Hobby King links:

• these are all links to the USA warehouse.  If you order from the international warehouse shipping is a lot longer.  Make sure you're ordering "USA Warehouse" items if this is important to you.

APC Props

These are good props, but more expensive and only come in a single color. APC props are proudly made in California!  The "P" props are the reverse orientation prop.  The price is per prop, so be sure and order two (at least) of the "SF" ("slow fly") and "SFP" ("slow fly pusher") models.

• 8x3.8SF
• 8x3.8SFP
• I think the 9x4.7SF and 9x4.7SFP sizes will also work but haven't checked them out.

HobbyKing Props

These are similar to the GemFan props.  Lots of colors. 8038, 8045, and 9047 are good sizes.

• Multi-Rotors & Parts > Propellers > 8 to 10 inches

GemFan Props

Super-popular, these are sometimes hard to find.  A lot of people like them because they're lighter and (the theory goes) will break and protect the motor shaft.

• Heli Direct

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Taranis Battery Notes

Bruce has a great video on using different types of batteries in a Taranis. Here's a few notes that I've put together.

• The illustration is from the Taranis manual, which also notes that the operating voltage range is from 6 to 15 volts.  You should read the manual.
• Don't charge anything but the stock batteries with the internal charger.  Specifically, don't charge LiPo or LiFe with the internal charger.
• The Taranis originally came with 800 mAh battery pack.  Currently ships with 2000 mAh battery pack.  This battery pack is also available at FrSky dealers.
• On older models, charge light was solid.  On newer models (the ones that came with 2000 mAh battery), charge light blinks.
• Internal charger shuts off automatically when battery is full.
• If you change battery types, update the voltage range and warning values on menu 1 of the radio setup screen.

battery        high  low  warn  notes

NiMH 800 mAh    8.0  6.5   6.5  stock battery on older models

NiMH 2000 mAh   8.0  6.5   6.5  stock battery on newer models

2S lipo         8.4  6.6   6.9  can plug into balance plug

3S LiPo        12.6  9.9  10.2  need to make plug/adapter

3S LiFe        10.8  8.4   9.9  need to make plug/adapter

Are your 18650 Li-ion Batteries Fake?

 TaoBao has some hints here.  I've copied the pictures below and translated the Chinese text. ht: ahvttvsn.

Note the 2D Bar Code.  I think the white text identifies the manufacturer.

Looks good on the outside, but look more carefully.

The outside code is super-thin and elastic.

 Take off the covering and look on the inside.

 Quality of body and cap is matched perfectly.  It is not done by a counterfeiter.



Bare ("naked") cell diagram.

 Counterfeit vs. Genuine.

Counterfeit is only plated on top and has dull body.
Genuine is consistently shiny.



Note the reflection on fake and real.

There's more information on the vendor's page.  There's a chart showing the lousy power output of the fakes.

Small Scale Battery Soldering

 The battery died in my tiny DSO Oscilloscope.  Opening it up showed a 1S LiPo of undetermined amperage.  Pay close attention to the smallness of the battery wires!

I had a spare 1S battery.  It was fitted with a JST connector, so I snipped that off.  The wires were huge compared to the old battery.

I'm pleased to say I got it soldered with no problem.  It's the closest work I've ever done with a live battery and I'm happy to say nothing was shorted. I was really sweating it out though!

I'm putting this picture up partly as reference for battery orientation, and partly coz I'm pleased with being able to make this connection successfully.

New Battery Bunker

 Here's my new battery charging bunker.  It's a concrete block, with flats on top and bottom.  I chiseled out a slot for the wiring.  I'm going to try the "sand in bag" technique for the top.  The idea is that you put the sand in a plastic bag, and a fire will melt the plastic, smothering the battery.  I might keep the concrete flat on top of the bag, so it will totally seal.  There's a smoke detector on top.

Here's the reason for the new battery bunker.  It was a 3S 500, relatively small.  I'm pretty paranoid about watching over charging, so I was there when one of the cells popped.  I took it off the charger and examined it; within a couple of minutes smoke started coming out, so I tossed it out the door and it burst into flames a few seconds later.  I wasn't concerned with the leaves, because it was a rainy night and everything was soaked.  I've also got a fire extinguisher next to my bench; you should too!

Update: with the recent dry weather, I have a sand-filled bucket sitting outside the door.

blogodex = {"toc" : "Battery Safety", "idx" : ["Batteries", "Charging", "Safety", "Battery Bunker"]};

LiFe battery in a 4x2x2 battery compartment

 Somebody on RCGroups was asking about how LiFe batteries fit into receivers with a 4x2x2 battery compartment, similar to what's on a Turnigy 9x.  Here's some pictures of how it fits (summary: just right!).  There's no stress on the battery compartment cover when snapping it on, and just enough room for the wires.  Use the power connector that looks like a servo connector.


HobbyKing 1500mAH LiFe 3S 9.9v Transmitter pack

It fits nicely in this configuration, but the 9x power connector is blocked.  This may or may not affect you depending on your receiver's connector configuration.

Update: Night Vapor Batteries

 Here's an update on my lightweight Night Vapor batteries.  I tried ordering some 50mAh cells, but they were out of stock and I got tired of waiting.  So I went ahead to try making some more 70mAh batteries.

Here's the 1S lead soldered onto the cell.  Notice the lead is a lot shorter than previously.

 That's because I got some liquid tape, and didn't have to leave enough room on the wires to put shrink wrap.

 I used a piece of craft stick to daub the liquid tape onto the exposed tab and solder connection.

 Here's what the final unit looks like.  The liquid tape seems to cover pretty well.

The battery doesn't fit into the Celestra charger as is, because the leads are a bit too short and the cell is a bit too wide.  Using a 1S extension solves things nicely.

And it's certainly light enough... Flying the Night Vapor smoothly I was able to get 17 minutes on this battery, about 4mA per minute.  I was impressed!

Update:  this connector is a "Molex PicoBlade (grid: 1.25mm)"

By The Numbers: LiFe batteries

Lithium Iron Phosphate (aka LiFe, LiFePo, LiFePo4) batteries are most often used in RCLand for transmitters.  They're safer than LiPo, since they don't emit oxygen during rapid breakdown leading to combustion.  Lots of chemical detail on wikipedia.

Here's the model that fits into the Turnigy 9X transmitter.  Use the servo-style connector to plug it in.  Note that there are two ways to plug it in: only one of them works; the other doesn't do anything.

Charge Levels

 1S   3S

3.3   9.9  nominal voltage

2.8   8.4  minimal discharge

3.6  10.8  maximum voltage

Charging

You need to set your charge into LiFe mode.  Don't charge in LiPo mode. Bruce has a video here that explains how to do this on a standard 4-button charger. Here's the tldr for a typical 1500 mAh 3S:

Save Data / 01 / LiFe / 9.9 / 1500 / (hold start) / 1.0 / 9.9 / (hold start)
Save Data / pgm number / LiFe / voltage / mah / (hold start) / charge current / voltage / (hold start)

cheap lightweight battery for Night Vapor

 One of the things I love so much about my night vapor is how light and floaty it is.  Turn the throttle down, you can't hear the motor, and it just effortlessly glides across the room.

Of course, a lot of this is due to its light weight.  17g AUW with the supplied 70 mAh battery.  Unfortunately, extras of this battery are $5.50 + shipping, and when I originally ordered I think it was closer to $8.00!  So of course, everybody buys the cheaper, larger batteries.

 But, that adds another 2-3 grams to the AUW.  Still it's a fine flyer, but just a little bit more speed is necessary to keep it in the air, and just a bit of the floatiness is lost.  I can compare this out the Concord Model Engineer's indoor fun fly, where a couple of other guys have night vapors.

So, when I noticed that Hobby King had cheap single battery cells, I thought I would try to make my own.

 Here's exactly what I used:

• Zippy 70 mAh, 20C cell. I bought 3 units to experiment with.
• Mini plug extension wire. Cut in half to use the female plug.
• 2mm shrink tubing.  This is good cheap stuff to fill out the weight on any HK orders.

Total cost for 3 batteries: $5.50, $1.82 each.

I've never worked with raw battery cells before, so I was a bit nervous.  It turned out to be no problem... just keep in mind that you're working with a live circuit, don't touch wires together, don't short the tabs with a screwdriver etc.

The battery tabs take standard solder.  I snipped and tinned my wire, and then tinned the battery tab, leaving a proper sized blob to attach the wire.

I then put the cell flat on a piece of wood, and lined the wire up.  Touching the soldering iron to the wire allowed me to mash the wire down onto the tinned tab, making a very nice solder joint.

On two of the cells I make a straight solder joint, so I had the shrink tube on the wire as I soldered it.  Because of this, the wires were a bit longer than I liked... extra weight, and I was worried it might not fit in the plane very well.

 So for the third try, I flipped the wire around.  This is the top battery in the first picture.  This produced excellent results:  the wire was a lot shorter, it ran alongside the battery, and I was able to put the shrink tube on after the soldering, since I could just slip it over the tab and wire, heat it, and trim.

I think I'll resolder the other two cells in the same way.



[update: solved the charger problem using the 1S extension wires from Hobby King.]

 Mini Plug Extention for Micro Battery 10cm (5pcs/bag)

 When soldering, be sure and do one side completely (all the way up to shrink tubing), and you'll have a lot less chance of shorting the battery tabs together.

The completed battery is too fat to to fit nicely in the holder, but a bit of blue tape holds in on nicely.  I might a a tiny bit of velcro as well.  When I flew it for testing, there was a bit more tape than what I'm showing here.

The batteries fly perfectly; slow and floaty behavior restored due to the low weight, and the 20S discharge gives a lot more power.  The original 70mAh cells don't have a discharge rating, but the replacement eFlight 150s are rated at 12C.

I didn't test relative flight times, coz I was pushing the testing between a couple of other activities.  I'm guessing it will be comparable to the original battery, but I'll try it later and update this post.


I've misplaced my little subgram scale, but using my big scale show the following weights:

• Turnigy 138, 5g
• Parkzone 150, 4g
• Original Parkzone 70, 2g
• These replacements, 2g (I'm assuming the 3rd one was a bit less and would show it on the higher precision scale)

But, using my big scale, the the plane's AUW including the battery drops from 17g to 16g (with no battery, it's 14g).  So, it seems that these replacements are lighter than the original, and could get even a bit lighter if I were more aggressive about trimming the wire.

They fit on the charger nicely... line them up and poke them in with your fingernail,  pull them out by holding on to both wires (not the battery body) when finished.  Note that I have to tip up the third battery to get it to fit into the solder.  When I redo the others, I'll solder on the other side of the battery (if possible?) so that the batteries won't have to be tipped up; but it doesn't seem to be enough of a problem to resolder the one that's already made.

Update: Figured out how to eliminate the shrink wrap.
http://eastbay-rc.blogspot.com/2012/01/update-night-vapor-batteries.html

An Idea for a Safe Lipo Charger

I heard somebody describing this idea, but I can't remember who.  He had seen a much larger system like this while working on a military project.

• take two flowerpots.  flowerpot 1 is the base, flowerpot 2 is the top.
• cut a notch out out of the rim of flowerpot 1.  this is for lipo charging wires.
• fill flowerpot 2 with sand.
• cover flowerpot 2 with a sheet of thin plastic, something like grocery bags.
• secure the plastic around the rim.
• attach a piece of chickenwire to flowerpot 2.
• put the batteries in flowerpot 1.
• place flowerpot 2 upside down over flowerpot 1.
• if the batteries catch fire, the plastic will burn and the sand will flood the batteries in flowerpot 1.

This works best if you have nice long charging cables.  I intend to try this some day, but for now I'm just using a lipo sack since I usually am charging small batteries one or two at a time.

It would be nice to have this setup sitting on the porch and just run the charging cables outside.

e-Station charging software and driver

e-STATION Chargers for Electric R/C:

This is for all rebrands as well, including the THUNDER AC6.

To install:

• don't attach USB yet!
• download and unzip
• run setup/setup.exe
• click "install driver".  this will install a driver for "Silicon Laboratories CP210x VCP, CP2010x USB to UART bridge".
• click "install monitor"
• serial number is in SerialNumber.txt
• reboot 
• attach USB
• run all programs/estation/estation

If anybody knows of a mac version of this software please let me know!

I'm installing it in an XP vmware fusion session.

Replacing an ar.drone parrot battery

The specs for the ar.Drone battery are as follows:

• 3S 11.0v
• 1000mAh
• discharge plug: small Tamiya
• charge/balance plug: JST-XH

This can be upgraded with the following battery and adapter.  The battery is 2 grams lighter, and holds a charge of 1300 mAh.  No modifications to the batteries or parrot are necessary.

• Turnigy 1300mAh 3S 20C Lipo Pack
• Female Mini Tamiya <-> Male XT60

The battery can be charged at up to 2.6 amps.  This charger is cheap and will go up to 2.0 amps:

• HobbyKing Simplex 1~4S LiPo/LiFe 12,110~240v charger 
• Turnigy 2S 3S Balance Charger. Direct 110/240v Input

Piranha and Homemade 3S 240mAh lipo battery

Mike at Concord Model Engineers had a nifty little indoor combat flyer, christened the Piranha.  I stupidly didn't take a picture of the plane, but it's in the background.  I'll take some more pictures at the next CME indoor fly... I want to build one!

Stats as I recall them: 24'' wingspan, 3oz. (!) 6mm EPP, 2.5g servos, HK AP05 motor, 5x3 prop.

Mike builds his own small, lightweight 3S batteries out of ZIPPY 240mAh 20C single cells. He solders the three cells together, tab-to-tab and attaches a mini-JST connector.  It looks like lightweight medical tap holds everything together, and attaches velcro as necessary. Zoom in to see exactly where the tabs are being soldered.  He doesn't bother with balancing.  Battery weight: [[[???]]], contrast with Turnigy Nanotech 3S 370mAh at 39g.

,

Wiring multi-cell batteries

aasd

Diagrams posted by "byrum" at hobbyking in one of the battery reviews.

The power is in series.  Each pair of wires in the balance connector makes a circuit for one cell.

By The Numbers: Batteries

LiPo Batteries.

• Configuration: How many cells the battery has. (1S, 2S, 3S)
  
• Capacity : How much electricity the battery holds. (500 mAh, 1000 mAh, 2200 mAh)
• Constant discharge: How fast the electricity can flow from the battery. (15C, 25C, 35-45C)
• Burst rate: A peak value that the battery can discharge for a short period of time.  (37C ,15sec)
• Pack size: three dimensions, HxWxL
  
• Weight: in these modern times, always expressed in grams.
• Charge Rate: how high of a current at which the battery can be charged (1C, 5C)

Notes.

"C" rate: This is the amount of power that can be pushed out of the battery at any particular instant in time. It is a ratio of the Capacity.  a 500 mAh battery discharging at 15C will be discharging at 750 mA. (500 * 15 = 750)
Lots of details here.

Voltage:  A single lipo cell will have a voltage range of 3.0V - 4.2V. The "nominal" voltage (how it's typically referred to) is 3.7V. If the cell goes below 3.0V, it won't be able to be recharged.  Most people recommend not letting a cell go below 3.2 volts so that you'll have a bit of safety margin.

So, a 3S battery will have 3 cells, a nominal voltage of 11.1V, and a voltage range of 9V - 12.6V (the nominal values multiplied by 3.

Your discharge rate requirements will be defined by your motor and ESC combination.  Models with high instantaneous power demands (helis, stunt 3D flying) will have higher discharge requirements.  Models with low instantaneous power demands (gliders, trainers) will have lower requirements.  Higher discharge rates usually mean the batteries will be heavier and more expensive.

Example: http://hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=9312

• Configuration : 2S 7.4v
• Capacity : 2150mAh
• Constant discharge: 25C
• Burst rate: 37C (15sec)
• Pack size: 113x33x16mm
• Weight : 129g
• Charge rate not specified, so we assume 1C