If you need to go to places where the sand is soft and deep you'll be spending a lot of time on your knees beside 6 wheels attending to tyre pressures - first squat beside each wheel in turn to deflate. It's definitely a young man's job, holding that deflator two-handed to each valve for long minutes while the sibilant hiss of escaping gradually diminishes and the flies relentlessly attack and your knees burn like hot coals while the sun smites you mercilessly from above.
Then it's time to re inflate. Screw the hose onto the valve, walk back to the pump to switch it on; wait and watch until the tyre seems the right shape, walk to the compressor and switch it off, walk back to the wheel and check the gauge. Some more air required - walk back to the pump and turn it on. again, wait a little more and try again, and again. Repeat for all four wheels plus the two on the trailer.
Of course there's also the irritating matter of the compressor, a good one that set you back a hefty amount, having chafed through it's flimsy little nylon carry-bag, the cheap spiral plastic pipe, which is too short to reach the trailer, and has straightened after being stretched and heated by compressed air, making it unwilling to return to its place in the carry-bag. Then there's the problem of the cheap battery clamps which have corroded since last use and no longer make effective contact with the battery terminals.
There must be a better way than this...........
The Solution - Part 1
At 220 kPa the deflator valve releases approximately 1 litre per second from the tyre while the compressor, depending on it's capacity and the strength of the power source, will inflate at a higher or lower rate than that. The mobile phone app has a slide control that allows you to compensate for differences in tyre size and in-out flow rates.
The Anderson connectors are rated for 50A max though the internal switchgear can handle 60A. Most compressors draw no more than 45A.
And there's a flashlight button provided in case you're doing this in the dark.
The Solution - Part 2
(You can do this at home)
We mount the compressor securely in 50L plastic utility box together with the remote control unit, couple the pair together and to a generous length of 8mm air hose which is coiled neatly on a former attached to the underside of the lid, which is hinged at the rear.
In the box are also all the other essentials for getting out of trouble - repair kit, tyre levers, universal inner tube, and backup devices for inflation and deflation.
PneuMatic Controller Only
PneuMatic Extended Assembly
(Download from Home -> Downloads -> TPC 2)
In Manual Mode there are no pressure or time limits. The compressor and deflator both stay active as long as commanded.
You can start the compressor by tapping the left-hand green button. The button turns red and you stop the compressor by tapping it.
You can open the deflator valve by tapping the right-hand green button. The button turns red and you can close the deflator by tapping it.
Tyre Pressure Indicator
The controller measures hose pressure very accurately, but hose pressure will not be the same as tyre pressure during either inflation or deflation. To measure tyre pressure accurately the both the compressor and deflator must be OFF for at least 5 seconds to allow the pressure in the tyre to equalise with the hose pressure.
Auto Mode and the Tyre Size Selector
Tapping the central green button starts an Auto Mode cycle. The controller reads the hose pressure and the Target Pressure and decides whether inflation or deflation is required..
The controller then reads the Tyre Size slider, estimates how many seconds of operation are needed to reach the Target Pressure and starts the cycle accordingly. The larger the Tyre Size the longer the estimated time will be.
The estimated time remaining is shown on the screen.
When the estimated time has elapsed the controller stops inflation/deflation for 5 seconds and then reads the hose pressure. If the hose pressure is within 5 kPa of the Target Pressure it terminates Auto Mode and beeps. If the difference between hose pressure and Target Pressure is greater than 5 kPa it recalculates and starts another cycle.
This repeats until hose pressure, and hence tyre pressure is within 5kPa of Target Pressure.
Setting the Tyre Size slider to too great a size will result in inflation or deflation overshooting Target Pressure and extra, unnecesssary cycles.
Tapping the central red button terminates Auto Mode.
If the App is terminated both the compressor and deflator are turned OFF.
Battery voltage is by the control unit and displayed on the screen. Low voltage (< 11.7V) is indicated by a RED background.
The flashlight button is provided for night-time work.
If you are using a compressor with some muscle - not one of those toys that plug into a cigarette lighter outlet and that get zipped into a little bag and kept under the seat, you'll be connecting directly onto the battery with at least a 50 Amp DC Anderson connector. Most people would want to keep the engine running at idle to prevent unnecessary discharge of the battery while operating the compressor. The control unit can switch a DC current of up to 60A though the the Anderson connectors employed are only rated for 50A, which is current the limit of compressors that we support. Few 160L compressors draw more than 45A Max.
Under these circumstances there should not be enough volt-drop to the compressor to affect the operation of the remote control unit. If Bluetooth communication should fail while the compressor is drawing power it points to a connection problem that undoubtedly also inhibits proper functioning of the compressor and requires urgent investigation.
The cable between battery and compressor should have a cross-section of 6sq/mm, which can carry a current of up to 56A and be limited to about 2 metres if possible. Spring-loaded clamps are not ideal for connecting to a battery - it's advisable to make a short tail of 6sq/mm wires connected securely and permanently to the battery at one end and a 50A Anderson plug at the other.
The controller monitors the battery voltage as it is found supplied to the controller and transmits this value to the mobile phone, where it is displayed on the screen. Because small changes in battery voltage can be very significant in indicating battery condition it is important to get an accurate value reported. Since component tolerances can vary from unit to unit there is a calibration facility built into the mobile phone app to equalise these variances..
To enter Calibration Mode hold the blue Bluetooth icon down and tap DactylTech logo. The Tyre Size slider now becomes the means to adjust the reported voltage. Move the slider in small increment and allow several seconds for the display to stabilise after each adjustment until it matches a trusted voltage reference such as a digital multimeter.. To Save and Exit tap the DactylTech logo again and the diplay will revert to normal.
As a benchmark value: we know that the voltage output of a healthy fully-charged battery after an hour at rest with no load will be 12,6V. As the battery ages this value will decrease through 12,5V 12,4V until at 12,3V the battery can be considered end-of-life since it's capacity is half of it's nominal value.
While discharging the output voltage of the battery will steadily decrease until, when about 90% of the available charge has been depleted, the voltage falls to the critical level of 11,7V. Most people do not want their battery voltage to drop below 11,7V because this is where the real damage occurs. Hard lead sulphate builds up on the surface of the plates and this permanently compromises battery capacity. Batteries can be ruined in a single deep-discharge event. To warn of excessive discharge the Voltage display will show a RED background when the measured voltage dips below 11,7V. Due to the internal resistance of the battery the output voltage does not accurately reflect it's stae of charge while it is being discharged (or charged). Therefore only measurements made while the battery is at rest are relevant.