B-Kool Portable A/C

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diamondchad
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Re: B-Kool Portable A/C

Post by diamondchad »

Hello all, thanks for the help! Wow...impressive. Thanks for the offer Tucker, much appreciated! However, no need..read on, LOL.

OK here's the update: I went to Radio Shack and bought two ferrite filters. I installed one on the blower motor and one on the pump motor. I installed the filters as close to the motor housings as possible. I'd say less than 1/8 inches. So, really close. This did not help. :(

I will try the the electric razor (battery operated) test next. Lastly, I will get my hands on a capacitor and install that if the electric razor test proves null or inconclusive.
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rwtucker
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Re: B-Kool Portable A/C

Post by rwtucker »

The plot thickens . . . :scratch:

I did see this comment on another website:
On Friday, August 29, 2014 a customer asked:
Q: How many amps does the 24 Volt model draw? Have any avionics interference issues been reported?
A: The 24 volt model draws less than 2.5 amps. The only interference we know of was on an older plane with a rusty socket. Once the socket was fixed the noise went away. The B-Kool has all electrical components shielded.
So you might look at the socket and wiring in that area.

The other line of investigation would focus on avionics, where a faulty shield ground could cause what you are experiencing.
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Sandy
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Re: B-Kool Portable A/C

Post by Sandy »

I bought the IcyBreeze unit (http://www.icybreeze.com) at Airventure, along with their rechargeable NiMH battery pack and "smart" charger to keep it isolated from the plane's power supply, and I have no EMF problems. Of course the battery does need to be recharged. I made a sloped "stand" that fits on the rear seat, so the cooler is level in the plane despite the slope of the rear seats. The IcyBreeze unit has a vent that is right between the the two front seats when it's sitting on the stand. I'm in Atlanta where it was in the 90's when I took off on Sunday to go to Detroit, and it was comfortable in the cockpit. I also bought the remote cord, so the unit can be turned on and off from the front, as the switch is all the way back and out of reach.

I, personally, do not like the idea of running a high draw accessory, particularly one with both a fan motor and a pump motor, off the aircraft's power, but I only have an electrical engineering degree from MIT, so what do I know? Note that NFlight (NFlight.com GoPro accessories) specifically warns against powering the GoPro from the plane due to interference.

I just looked at the B-Kool web site, and I see that it is designed to be powered by the plane's system. If I had that unit, I would probably buy a small 12v NiMH or motorcycle battery, and power it from that instead of the plane. I think that the IcyBreeze appears to be a better design overall, as you can use either the vent or the tube, and it has the internal, rechargeable battery, eliminating the need to hook it into the plane's electrical system, which, as I recall, is placarded against use in flight.

Sandy
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Re: B-Kool Portable A/C

Post by rwtucker »

Sandy raises some good points that made me think of other questions.

- I just spoke with B-Kool's owner who told me that the 24 volt unit (DA40's are 24 volts) draws from 2.2 to 2.4 amps. I would not mind running that load through the aux socket, especially since the stock alternator has >100% excess capacity for daytime operations. However, it would be a good idea to check the wiring.

- Given the background on this problem, it seems just as likely that the EMF is being radiated at the source rather than traveling via the power line and then through the shielded and grounded power source. The company's website says that the motors are shielded. I do not see any extra shielding in the picture of the brushless DC cooling fan on the top of the cooler. On the other hand, these types of fans are almost always internally shielded because their most common use is to cool electronics equipment. It would help to see how the pump motor is mounted and shielded, and if it is brushless.

- Given the low current drain, an inboard NiMH power source would be convenient, whether or not it eliminated the interference. Those of us who already carry small explosive devices on-board in the form of our iPads might even consider a well-designed and fused Li-ion source. (If you have a Garmin handheld, crack the battery case and notice how well protected those batteries are from thermal runaway.)

My thinking is still 50% on the problem being with the G1000 grounding, etc. A quick diagnosis is a battery operated shaver or beard trimmer. Every one of these I have seen use brush-type motors to economically achieve the torque necessary for the task. I have confirmed that mine are not shielded and throw off quite a bit of EMF.
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Re: B-Kool Portable A/C

Post by Sandy »

First, I am assuming that the problem evidences itself whether or not the plane's engine is on, so something else that you may try would be to figure out whether the fact that you have it plugged into the plane's power socket is relevant to the issue or whether the EMF is being radiated independently from the power source.

If I am correct that you are getting the interference with the engine off, then it should be a simple matter to rig up a "cigarette lighter jack" to a 24v supply to run the B-Kool while you listen to the radio for interference. A relatively easy way to do this would be to get two 12v batteries and hook them in series with a power outlet (https://www.radioshack.com/products/ene ... 5717193093). You really only need one extra 12v battery, as you can connect it in series with your car battery. If you do not get interference, you can move the plug to the plane's power outlet and see if the interference occurs when you change the power source.

If the foregoing does not "move" the interference with the location that the B-Kool is plugged into, then you might try creating a "Faraday cage" (really just a metal "case" enclosing the B-Kool), as electric fields, i.e., RF, cannot pass through, so that might tell you that the EMF is coming from the B-Kool. A simple approach to creating a Faraday cage it to grab a roll of aluminum foil and "package" the entire B-Kool. If the problem goes away, then you know that it was coming from (at least) one of the motors in the B-Kool.
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Re: B-Kool Portable A/C

Post by Kyle »

This may be a little off-topic but I'm fairly sure the aux power outlet in my DA40 is 12VDC not 24VDC. I will put a meter on it next time I'm out there but I recall it being placarded "12VDC GROUND OPS ONLY". I assume there is a 24VDC-12VDC converter behind the panel or maybe built into the socket.

Was there a change made at some point from 24VDC to 12VDC?
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Re: B-Kool Portable A/C

Post by Rick »

Kyle wrote:This may be a little off-topic but I'm fairly sure the aux power outlet in my DA40 is 12VDC not 24VDC. I will put a meter on it next time I'm out there but I recall it being placarded "12VDC GROUND OPS ONLY". I assume there is a 24VDC-12VDC converter behind the panel or maybe built into the socket.

Was there a change made at some point from 24VDC to 12VDC?
It probably is 12v. Diamond started putting in a converter sometime around 2006, I believe. Both the 2004 and 2005 I used to fly had 24v outlets, but my 2007 has the 12v outlet.

By the way, there is a small inline fuse that sits just behind the 12v outlet. When your outlet stops working, this is the first place to look. It's easily accessible with the glare shield removed.
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Re: B-Kool Portable A/C

Post by rwtucker »

Rick wrote:Was there a change made at some point from 24VDC to 12VDC? It probably is 12v. Diamond started putting in a converter sometime around 2006, I believe. Both the 2004 and 2005 I used to fly had 24v outlets, but my 2007 has the 12v outlet. By the way, there is a small inline fuse that sits just behind the 12v outlet. When your outlet stops working, this is the first place to look. It's easily accessible with the glare shield removed.
If that is the case, the 12 volt B-Kool will be drawing close to 5 amps and it would be important to assess the capacity not only of the fuse but of the step-down device. Have you located it Rick? It might look something like this. https://www.amazon.com/DROK-Converter-T ... B00C9UUFHC
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Re: B-Kool Portable A/C

Post by Rick »

The inline fuse is a 3 amp. It's tiny, and it looks like a diode. I found the DC converter back when I replaced my fuse - it is a small black box that sits behind the instrument panel.

See this photo for the location of the converter and the fuse:
DC Converter and Fuse Location
DC Converter and Fuse Location
And here is the wiring for it, with the Diamond part number:
12v Outlet Wiring
12v Outlet Wiring
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Re: B-Kool Portable A/C

Post by rwtucker »

Great detail Rick. So, right away, we later DA40 drivers would not be able to run a 4.4 - 4.8 amp B-Kool through this DC/DC converter rated at 2 amps continuous and a 3 amp fuse. Chad's DA40 apparently didn't have the converter so his limitation would be the wiring, fuse, etc. This is good to know.
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