Archive for June, 2011


Hello!

I just received my parallel charging board from Hobbycity. They were super fast, I expected the package for the end of this week, it arrived on Monday. Great service!

According to reviews it can happen that polarity is wrong on the connectors. This causes risk of permanent failure on the batteries that you connect to it. So it is a good idea to check connections and polarities prior to using this board.

Mine looks like following after removing the isolation from the back.

From behind

And from above:

From above

I think that this looks okay. The red wire is connected to the plus side of the main XT60 connector. And all the charging XT60 connectors are on the same side, the side to which the red wire is soldered.

I checked if the balancing port ground wire is connected to the matching side of the balancing connectors. It looks like so.

I just double check this one more time and then will do a big charging of 6 batteries at once. Since I received my 3 new Zippy 3S 2200 mAh 20C batteries I can use 6 packs. I just made sure that they are all okay, checked the voltages.

One came with 2.2V on one cell, this I corrected to 3.8V with the storage charge option on the iCharger unit.

Later I will try to make a short resume of how you can do such a parallel charge and what do you need to look at to be on the safe side. I will update this very post to give you more details. Stay tuned.

Best regards,

Sir Crash a Lot

 

 

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My charger arrived

Hello!

I was in a dilemma about chargers and PSU’s for some time, could not really decide. Now I made decision and ordered them.

I went for the iCharger 106B+ charger and a Lindinger 20A power supply unit.

I went for the iCharger since it is the best and this small model has just right performance for my needs. I plan to charge my batteries to storage charge on the long run and have a full charge prior to flying. This enables long life for them.

The 20A PSU seems to be too large for the 10A charger but the more power you have in the PSU the more stable voltage it can deliver during load condition. And the less it will use the fan for cooling itself. This seemed to be a good compromise in cost and performance.

I had my first charge recorded to show some interesting details.

The charger is quite heavy, you can feel that there is material in it. Good quality feel on the house, the connectors and the buttons. I have some plastic screen protection on the display, haven’t removed it yet. Like on mobile phones, you remove this on first use. This is no quality issue, I thought I might have it on for a while.

The PSU is cooled by a fan, the fan runs very smooth and quiet. I charged one battery so far at a time, we will see how it will run on more load. I plan to parallel charge several batteries at once.

The charger enables all sort of protection features. You can have time based protection, capacity based boundary condition. You can have temperature sensor readings and stop charging on some defined value. And you have the intelligent control of charge that checks all cells during the process.

When I charged the interior temperature of the charger went up to 41 degrees centigrade, this is not much I think. The fan ran quite seldom, noise level was not disturbing in a quiet living room. My wife was reading on the couch, no comments on her side.

What is annoying is the beeping, that you can disable. On default it beeps on every press of a button. That was commented on the side of my wife, she welcomes that muted beeps 🙂

I even did a storage charge, please see noise levels at that operation in following clip.

What next?

I will read the manual, that never hurts. And I will use parallel charge soon. Ordered a charging board from Hobbycity along with 3 extra batteries.

What I read is that you should check polarity on this board. Some of them are wrong polarity, you can damage your battery if you have a wrong polarity connection. I will check mine when it arrives.

I have 10A limit on the charger, this means that I can charge all 6 batteries together with 1.66A each. This is 0,75C charging, so it will take approximately 1.3 hours to charge all of them at once. Since I don’t discharge them fully I assume that maybe less time will be enough even.

With a 20A charger this would be even less time. But I am not in a hurry. Compared to the charger I used so far this is magic speed. The other charger took 6.5 hours per battery. That is slow.

I even have a battery monitor being shipped.

This small unit can display the voltage in all cells, you can check the status on the field. Can have it in the shirt pocket, a must-have almost. Costs 1.86 USD, that is almost like a box of milk that I drink every day. 3% and 1.5 liters costs approximately 12 SEK.

I can recommend:

– the charger,

– the PSU

– the milk even 🙂

Excellent news. My cell checker arrived even.

 

 

Best regards,

Sir Crash a Lot

Hello!

As you could read I fixed the electrical problem that arose on 3rd flight. Since weather was promising I took my plane to the office and we went flying after office hours on Thursday.

I had my 2 keychain cameras along with 2 wide angle converters. No hat cam this time, I am working on my updated design.

We had a guest pilot from the office, he is flying a nice DG1000 glider. Something like this:

And we had a moderately tuned (according to the owner, he plans to tune it further) Funjet on 4S battery and some insane motor and prop. Like a missile it flew.

I had some incident again. One of the wide angle converters unscrewed itself, and the bigger half with the lens in front fell off. During flight. Into the propeller and away it flew. I have mathematical chance to find it, I will look next time though.

I made a slow-motion replay of it happening, you can see that it falls off and then blurry image. Since the other half with the macro lens stayed on (has magnetic lock) the image lost focus totally.

I decided to use thread-lock on the remaining converter, CA might create some white fog on the lens itself.

Then I started my plane twice (yes, 2x) into the vegetation. Very embarassing. And once I tried to hand start and failed badly. So my self confidence was quite low in the first part of flying. Anyhow with some careful flying this came to a reasonable level, I had some great fun in the sky.

Our colleague Fredrik was kind enough to record some of my flying with his mobile phone, you can see me from his point-of-view during the second half of the clip. Great recording he made. I just had to align my onboard camera footage and then you can benefit of 3 cameras at once picture-in-picture. I wish I had more cameras, 3 is just enough 🙂

This time I could fly much farther away, as I gain experience I manage more and more. This gives much nicer footage from the air, the area in which we are flying is really beautiful this time. A lot of green and vegetation everywhere, great variation in height as well.

When I flew out the juice from my batteries I started to record others flying. Fredrik made some nice flying with the DG1000, very fine landing and turns.

We had great time again, a nice day it was indeed.

Best regards,

Sir Crash a Lot

Hello!

My 3rd flight was not without problem. I enjoyed some nice flying during the first 2 batteries, then all of a sudden on the 3rd battery the power just cut out. Had to do emergency landing even.

The problem and its solution is described here, please see my other post.

It feels so that with every flight I learn something new, gather a lot of experience. I would not consider myself experienced yet, just my level is increasing from something very low to something less low maybe 🙂

Flying is great fun. If you just read this and don’t fly yet, do not hesitate. Just start flying, it is certainly something wonderful.

Best regards,

Sir Crash a Lot

 

Hello,

I had to do emergency landing last time (on my 3rd flight), lost power totally. I tried to find the problem, I got huge help from my colleague who remembered a similar issue from the past. It was a cable connection that failed.

The symptoms were quite alarming, the ESC booted up normally, I could even steer the plane. But for any power input the propeller just stuttered. When it happened and I was in the air I did not notice the stuttering since air passing by rotates the propeller even at no power. Just upon the very last moment when I wanted to adjust my gliding angle became it appearent. Quite scary it was.

I checked first if the problem persists. It did persist. Then I replaced my 25A ESC to my helicopter ESC that is 40A. Same problem. This helped to rule out quite a lot of items. The only one remaining was the electric motor. This gave me a bit of headache. I just glued it back to its place since it became loose.

Maybe I broke the connection there, where it is in the fuselage? Hope not. I started to peel away isolation from the contacts that are easy to access. The first one was okay, the second one actually was so broke that when I removed the isolation the connector just falled away. The cable just broke.

I decided to resolder all 3 of them. This item was not done by me, the connectors were on from the factory. Maybe they used some wrong parameters upon soldering, I don’t know. Anyhow during last time when I disconnected the motor and glued it back the cable broke and only that stiff black isolation held it together. At low power there was some current flow there, but after 2 flights and higher current draw the electrical connection got severed and the motor just quit on me. That explains the steering also, since it happens on a different circuit it was unaffected.

Now it is fixed, I tested the motor on the balcony. There was much rejoicing on part of my wife who tried to watch TV 🙂

I put some decals on the plane, now it is easier to see it in the air. I shall test this next time when I fly.

Best regards,

Sir Crash a Lot

Hello!

I purchased some items of true magnificence lately. On DealExtreme you can find all sort of items, but I happened to find something that enhances my recordings at an amazing extent. A wide-angle converter it is, that can be applied onto my keychain (keyfob) cameras.

It is called:

“Universal 13mm Wide-Angle/0.67X Macro Lens Attachment for Digital Cameras and Cell Phones”

and costs 10.37 USD at this time when I write this post. Why is it so expensive compared to some similar converters?

– It has a metal body

– It has a magnetic/adhesive ring (with extra ring if you might need it)

– It has a lens cover even

So I was keen on checking out the quality. Let’s state that the keyfob cameras are not so good quality, I happen to have the worst variant of them.

But I was curious how much worse it can be with an adapter. Well, surprisingly little decrease of quality, it is perfectly okay for my amateur use. A thousand words tell less than an image, so they say, so please find some images here.

And please find here a video of how it does perform. In the video you can see a comparison of both still images and video clips.

I have a clip the magnetic effect even.

I will need to test it further in the air. Next time I will have both my cameras fitted with these converters.

Update of 2011-07-07:

I purchased a 180 degrees fisheye converter even. Same good quality, same magnetic effect. But heavier and bigger. And a lot wider in its view angle. Please check out my comparison video.

Best regards,

Sir Crash a Lot

 

Hello!

The curse is lifted as it seems, spring came to Sweden at last. Now we had 20 degrees centigrade and no rain, a fine weekend for RC flight.

I am joining a model club, the process is ongoing. So I could participate at their field in a semi-approved way, very kind of the club that they allowed. The club is Mölndals Modellflyg, where one of my colleagues is flying.

I took my cameras, all my 3 batteries and went for my second flight ever with Easystar.

Weather was kind to us, gentle wind of 3-4 m/s and no rain whatsoever. Wind was mostly still, some gusts occasionally.

In the beginning there was not a lot of people, so I could fly without spectators. That helps, since when people watch I get nervous. So my first round I could take in a calm way. The second round was a bit more exciting, people arrived and started to watch how I fly. Without intention I managed to provide some piece of flying that raised their interest without doubt. I almost ditched my plane in the grass actually.

What I did wrong was that I flew over my head, too close to judge the vector of my plane. You should not fly directly above head as then you have difficulties judging what vector you fly. I drifted too close and lost orientation briefly. Wanted to turn away and lower a bit but got into a steep dive instead. Almost like a Stuka bomber, well slightly only. Anyhow I got awfully close to the ground, maybe 0,5 meters left. I managed to pull up, but it was close.

I got so embarassed that I lost the language even, wanted to comment my manoeuvre and tell that some wind gust pushed me into the depo but told “I made a joke” instead. Well, it was certainly adequate, since some amusement I caused in the depo anyhow 🙂

What lesson I learned? Do not fly overhead. Fly a bit away so that you can orientate yourself.

I could fly out the juice from all of my 3 batteries, it was great fun. Air traffic increased with time, after a while a lot of planes were in the air. I am not so good at keeping track of them yet, I tried to not fly too close to any of them. I spent almost 3 hours at the field in total, flying time was something 15-20 minutes maybe. At half throttle my plane can fly quite long, my last stretch was a bit over 7 minutes on a battery.

I will need to purchase some battery metering device, so that I can see what voltage I am at. Also I need to purchase a proper charger, charging my batteries takes 6.5 hours with my small charger that came along with my Lama3 helicopter. It can handle 0,8 A current and does not give any feedback on the process. Just an LED flashing.

I hope you like the video, I tried to film some other aircrafts, not only me doing boring ovals.

I think more simulator practice cannot hurt, I need to get more secure in my piloting skills.

Best regards,

Sir Crash a Lot