Cooling Fan for iPad

 

Use of fan-cooled iPad 

In a previous post we described a mount for the iPad that allowed for convective cooling from below. That system worked quite well for several years.

But now and then the iPad overheated and had to be shut down. This happened often toward the end of a long trip. 

In each such case, the forced shutdown was really annoying:  No longer could we see ADS-B information about nearby aircraft and couldn't navigate precisely under tight airspace conditions. Not good.

Due to these difficulties, we decided to create an active cooling system using a fan. This post has the details.

The earlier post described how the cover for the iPad was modified to open up two cutouts on the back. 

We won't repeat the details of that modification and only point out that we enlarged these cutouts to create a maximum area exposing the back of the iPad. The photo below shows the resulting backside, with the iPad inserted.

Never mind the rough appearance of the cutouts. The cover is quite worn after many years of use, and we will replace it with a new one with carefully worked-out cutouts.

Two cutouts of back of iPad cover

The backside of the iPad cover rests on a housing created from two rectangular, thin plywood pieces separated by small wood blocks. 

Slots allow air to leave on three sides of the housing

The top plywood piece has a large cutout that reduces the piece to a narrow rim. Velcro strips on two ends of that rim, as shown below, connect with the corresponding Velcro pieces on the iPad cover.

Top of housing

The bottom piece has a cutout for the fan outlet. The fan takes the air from below and pushes it up against the backside of the iPad. Here is the bottom of the housing with the fan:

Bottom of housing with mounted fan

The slots separating the plywood pieces allow the air to escape on both sides of the housing and in front. The fourth side is closed off by a wood strip since the air would blow against the body, an unpleasant effect.

The fan is very quiet at 46 dB(A) and cannot be heard in the cockpit with a running engine. We obtained the fan from DigiKey, part number 603-1178-ND.

DigiKey fan 603-1178-ND, photo of DigiKey catalog

The fan is of high quality, with lifetime of 70,000 hrs at 40 deg C. It moves 113 CFM while consuming only 0.5 A at 12V.

We have installed suitable fan grilles, also supplied by Digikey, that protect both sides of the fan as seen in the above photos.

Use of the System

The photo at the beginning of this post shows use of the system in flight. On the right-hand side the 12V power supply cable and the iPad charge cable are plugged in.

The housing and iPad rest on the pilot's legs. The space between the legs allows the fan to take in air and blow it against the bottom of the iPad, to exit via the three slots in front and on two sides of the housing.

Performance Tests

We have tested the system under extreme conditions. In one case, we had refueled the airplane and half an hour later entered a very hot cockpit.

Upon opening the cover of the iPad, the Garmin Pilot immediately posted the warning message that the iPad was too hot to be used.

We started the engine and powered up everything. We then clicked the Garmin Pilot warning message away and used the iPad despite the warning, to see if the fan could cool down the iPad.

It did so: During the remainder of the trip the warning message didn't come up again.

Indeed, while glaring sunlight hit the glass plate of the iPad during the entire flight, the plate always felt just a bit warm.

Another Indication of Effectiveness

The iPad reacts in at least two ways when it becomes too hot: It lowers the brightness of the screen and no longer recharges the battery.

On the trips we have taken so far, we never saw either reaction, which supports the conclusion that the iPad encountered only moderate temperatures.

Other Options

Aviation supply stores offer cooling systems for the iPad. You may want to check out the possibilities before considering our solution. 

The choices offered by the market are in our opinion too expensive. On top, they rely on small batteries and require that the iPad is directly inserted into the device. 

During trips, we don't like to take the iPad out of its protective cover, for the simple reason that damage to the iPad due to a slip of the hand would have horrible consequences for the planning and execution of flights. 

In our approach, we can remove the iPad with its cover from the housing, take it into an airport terminal or wherever, without exposing the iPad to possible damage.

Mind you, this is just a personal opinion. 

Cost and Construction Effort

The total cost of the housing, including fan, electrical connectors, Velcro strips, and so on, came to less than $70. 

Design of the housing, selection of the fan, and deciding on the electrical connections took some time. Our son Martin helped a lot during that phase, in particular with the selection of the fan.

Reading this post saves you from all that work, and you can focus just on the construction. Since it mainly requires working with wood, that step is rather easy.

Have any question or feedback about this cooling system for the iPad? Please share your thoughts in the comments.