Will I trust it...?
Discussion
I couldn't resist a little bit of a challenge...
I have 'new' cooling fans for the Tiv ('new' as in bought probably three years ago but still not fitted) but whereas the originals draw 9 amps each the new ones draw up to 25 amps each so I wanted to try to ease the sudden loadings on the alternator by having both fans controlled independently.
My ECU has only one temperature controlled output so I couldn't use that ... Spiyda have a dual channel fan controller but it's set using pots and just didn't 'feel' accurate so I decided to build my own!
Using an Arduino microcontroller, a little bit of basic external circuitry and some programming I've got a two channel fan controller with independently configurable switch on and switch off points for each fan.
It calculates the temperature from the sender using something called a Steinhart-Hart equation which calculates the non-linear characteristics of the temperature sender (This is why I worry a bit when people use a resistor on the rangie sender to 'match' the existing gauge to it, it is simply wrong!) and can be modified to handle *ANY* thermistor based sender - I originally programmed it to work with a spare Smiths sender but, just to check, I bought a cheap "universal" sender, took three resistance / temperature readings to plug into a thermistor characteristics calculator and then transferring those values into the Arduino code gives me something that's calculating temperature with an accuracy of about 0.5 degree at room temperature and 2 degrees C at the extremes of -20 degrees and +98 degrees.
The "1-Wire" reading is taken from a One-Wire temperature sensor that provides a pretty accurate direct temperature value output which I'm using as a "check" against the calculated thermistor value. "Delta" is the current difference between the absolute value read from the One-Wire sensor and the calculated value from the thermistor and "D(max)" is the maximum variation since it was last reset.
Now I've just got to design and get made a PCB to replicate this:
It's been fun!
Phil
I have 'new' cooling fans for the Tiv ('new' as in bought probably three years ago but still not fitted) but whereas the originals draw 9 amps each the new ones draw up to 25 amps each so I wanted to try to ease the sudden loadings on the alternator by having both fans controlled independently.
My ECU has only one temperature controlled output so I couldn't use that ... Spiyda have a dual channel fan controller but it's set using pots and just didn't 'feel' accurate so I decided to build my own!
Using an Arduino microcontroller, a little bit of basic external circuitry and some programming I've got a two channel fan controller with independently configurable switch on and switch off points for each fan.
It calculates the temperature from the sender using something called a Steinhart-Hart equation which calculates the non-linear characteristics of the temperature sender (This is why I worry a bit when people use a resistor on the rangie sender to 'match' the existing gauge to it, it is simply wrong!) and can be modified to handle *ANY* thermistor based sender - I originally programmed it to work with a spare Smiths sender but, just to check, I bought a cheap "universal" sender, took three resistance / temperature readings to plug into a thermistor characteristics calculator and then transferring those values into the Arduino code gives me something that's calculating temperature with an accuracy of about 0.5 degree at room temperature and 2 degrees C at the extremes of -20 degrees and +98 degrees.
The "1-Wire" reading is taken from a One-Wire temperature sensor that provides a pretty accurate direct temperature value output which I'm using as a "check" against the calculated thermistor value. "Delta" is the current difference between the absolute value read from the One-Wire sensor and the calculated value from the thermistor and "D(max)" is the maximum variation since it was last reset.
Now I've just got to design and get made a PCB to replicate this:
It's been fun!
Phil
Phil, that’s very interesting mate!
I myself have recently been researching theoretical physics, in particular quantum field theory (QFT). QFT is a theoretical framework for constructing quantum mechanical models of subatomic particles in particle physics and quasiparticles in condensed matter physics. A QFT treats particles as excited states of an underlying physical field, so these are called field quanta.
I’ve been constructing a quantum mechanical model over the last few months and I’m hoping to complete it and start testing this weekend! Should the tests be successful I shall expand my endeavours into quantization of the electromagnetic field, with a view to building a number of small but powerful anti gravity devices. Installed in the right places these devices should enable me to bring Beasties dry weight down to around 550kg, giving an end result of around 650bhp/tonne
Were I to fit one of these devices to my person I’d also be able to get in the car without having to open the door (although this would obviously require removing the roof first).
I love these little science projects, and I wish you every success with yours
Keep us updated on progress!
Cheers for now mate,
Chilli
I myself have recently been researching theoretical physics, in particular quantum field theory (QFT). QFT is a theoretical framework for constructing quantum mechanical models of subatomic particles in particle physics and quasiparticles in condensed matter physics. A QFT treats particles as excited states of an underlying physical field, so these are called field quanta.
I’ve been constructing a quantum mechanical model over the last few months and I’m hoping to complete it and start testing this weekend! Should the tests be successful I shall expand my endeavours into quantization of the electromagnetic field, with a view to building a number of small but powerful anti gravity devices. Installed in the right places these devices should enable me to bring Beasties dry weight down to around 550kg, giving an end result of around 650bhp/tonne
Were I to fit one of these devices to my person I’d also be able to get in the car without having to open the door (although this would obviously require removing the roof first).
I love these little science projects, and I wish you every success with yours
Keep us updated on progress!
Cheers for now mate,
Chilli
this is how far I got concocting an idea I had about 2 years ago but it was clearly inferior to yours 
Bassfiend229hp said:
What were you wanting to build Simon...?
It was a crude mock up for variable speed fans and cut the initial surge I never got round to sourcing the essential components I was going to try in a scaled down version 1st 
but then decided seeing as it hardly dented the idle speed I wouldn't bother it dont see much traffic action realistically anyway 
Nice work Phil.
I'm running staged fans, one fan is triggered from the Canems output and the other from the otter switch, these have been tuned to overlap but often fan one is sufficient to keep the coolant temps under control so heavy electrical load spikes are a thing of the past. I now have closed loop idle management too, so no more fan on related drops in RPM ever.
The system works really well, the second otter switch triggered fan is wired as a permanent live and shares its circuit with a Davis Craig electric booster pump (EBP). Assuming the coolant temperature is hot enough to trigger fan 2 & EBP, both pump & fan will continue to run even after the ignition is switched off, this ensures both a flow of circulating coolant around the block and through the rad wile fan 2 runs to remove the heat from the rad.
When you turn any hot engine off you get a big heat surge up to the heads, the mechanical water pump is not turning so all you've got is thermosyphon moving the water, and thermosyphon is a very weak circulation flow indeed. TVR then decided it knew better than every other car maker and wired the fans so they go dead too when you turn the ignition off, this was a bit short sighted to say the least
TBH with my setup I'm just copying modern automotive coolant systems where for years electric fans have been configured to run after switch off, more recently manufacturers have started using electric water pumps, either booster pumps that work in partnership with a mechanical pump (like my system) or rely solely on an electric water pump and completely do away with the mechanical pump altogether.
As soon as you fit an electric water pump (either booster or master) you gain total control over water flow, electric water pumps are the same step forward in technology as when we moved from an engine driven rad fan to electric fans about 30 years ago or more.
Combine electric rad fans with an electric water pump and in theory you've created the perfect controllable coolant system, personally I'm not ready to completely give up the security of a mechanical water pump hence my booster pump setup, but my booster pump and one fan on a permanent live seems to be a good compromise.
If your controller doesn't perform as you expect there are a range of simple to sophisticated options from Davis Craig...
Good luck with yours though, its an interesting electronics project mate. I guess in your line of work you've got the technical knowledge and in house experience to undertake such experiments, whereas I'd have to play it safe and just buy something off the shelf.
https://daviescraig.com.au/switches-controllers
Dave.
I'm running staged fans, one fan is triggered from the Canems output and the other from the otter switch, these have been tuned to overlap but often fan one is sufficient to keep the coolant temps under control so heavy electrical load spikes are a thing of the past. I now have closed loop idle management too, so no more fan on related drops in RPM ever.
The system works really well, the second otter switch triggered fan is wired as a permanent live and shares its circuit with a Davis Craig electric booster pump (EBP). Assuming the coolant temperature is hot enough to trigger fan 2 & EBP, both pump & fan will continue to run even after the ignition is switched off, this ensures both a flow of circulating coolant around the block and through the rad wile fan 2 runs to remove the heat from the rad.
When you turn any hot engine off you get a big heat surge up to the heads, the mechanical water pump is not turning so all you've got is thermosyphon moving the water, and thermosyphon is a very weak circulation flow indeed. TVR then decided it knew better than every other car maker and wired the fans so they go dead too when you turn the ignition off, this was a bit short sighted to say the least
TBH with my setup I'm just copying modern automotive coolant systems where for years electric fans have been configured to run after switch off, more recently manufacturers have started using electric water pumps, either booster pumps that work in partnership with a mechanical pump (like my system) or rely solely on an electric water pump and completely do away with the mechanical pump altogether.
As soon as you fit an electric water pump (either booster or master) you gain total control over water flow, electric water pumps are the same step forward in technology as when we moved from an engine driven rad fan to electric fans about 30 years ago or more.
Combine electric rad fans with an electric water pump and in theory you've created the perfect controllable coolant system, personally I'm not ready to completely give up the security of a mechanical water pump hence my booster pump setup, but my booster pump and one fan on a permanent live seems to be a good compromise.
If your controller doesn't perform as you expect there are a range of simple to sophisticated options from Davis Craig...
Good luck with yours though, its an interesting electronics project mate. I guess in your line of work you've got the technical knowledge and in house experience to undertake such experiments, whereas I'd have to play it safe and just buy something off the shelf.
https://daviescraig.com.au/switches-controllers
Dave.
Edited by ChimpOnGas on Thursday 10th March 10:20
Sardonicus said:
t was a crude mock up for variable speed fans and cut the initial surge I never got round to sourcing the essential components I was going to try in a scaled down version 1st but then decided seeing as it hardly dented the idle speed I wouldn't bother it dont see much traffic action realistically anyway
but then decided seeing as it hardly dented the idle speed I wouldn't bother it dont see much traffic action realistically anyway - chuckle* ... one of the guys here was trying to convince me that I should use PWM to drive the fans at variable speeds dependent upon temperature and to provide a "soft start" but the actual power transistors (and associated heatsinking) required to do it weren't practical.
Phil
Bassfiend229hp said:
- chuckle* ... one of the guys here was trying to convince me that I should use PWM to drive the fans at variable speeds dependent upon temperature and to provide a "soft start" but the actual power transistors (and associated heatsinking) required to do it weren't practical.
Phil
I also discovered the complexity of going PWM just like a PC controls its fans (as you know) so the idea basically stalled for me at the time, but like yours Sorry Chilli 
ChilliWhizz said:
I can't believe nobody's interested in my project
I think it's a great project however I was going to go one step further and simply move the Tiv to the moon so that gravity was less and therefore I wouldn't have to worry about bolting all that gravity inversion crap to it......of course the 250,000 mile long hose to carry combustion air from earth may dent overall acceleration.
Phil
Sardonicus said:
Bassfiend229hp said:
- chuckle* ... one of the guys here was trying to convince me that I should use PWM to drive the fans at variable speeds dependent upon temperature and to provide a "soft start" but the actual power transistors (and associated heatsinking) required to do it weren't practical.
Phil
I also discovered the complexity of going PWM just like a PC controls its fans (as you know) so the idea basically stalled for me at the time, but like yours Sorry Chilli Google "Naim Statement" and you'll get an idea of what happens here when they're allowed a little bit of free reign.
Phil
Spal offer a PWM fan controller with lots of features...
http://www.hotrodhotline.com/pr/2008/08spaloct/
https://www.a1electric.com/spal/specs/FAN-PWM-V3.p...
It's an interesting product but probably complete overkill when you think the standard basic setup on a Chimaera does the job well enough, honestly how much complexity do we really need just to run two fans?
The most critical element for me is not the fancy shmancy features but the controller's reliability, it doesn't matter how smart the controller is... if it fails to turn the fans on when it should you'll still run the very real risk of cooking your engine.
With this in mind there's little to beat a good old fashioned otter switch
http://www.hotrodhotline.com/pr/2008/08spaloct/
https://www.a1electric.com/spal/specs/FAN-PWM-V3.p...
It's an interesting product but probably complete overkill when you think the standard basic setup on a Chimaera does the job well enough, honestly how much complexity do we really need just to run two fans?
The most critical element for me is not the fancy shmancy features but the controller's reliability, it doesn't matter how smart the controller is... if it fails to turn the fans on when it should you'll still run the very real risk of cooking your engine.
With this in mind there's little to beat a good old fashioned otter switch
ChilliWhizz said:
Phil, that’s very interesting mate!
I myself have recently been researching theoretical physics, in particular quantum field theory (QFT). QFT is a theoretical framework for constructing quantum mechanical models of subatomic particles in particle physics and quasiparticles in condensed matter physics. A QFT treats particles as excited states of an underlying physical field, so these are called field quanta.
I’ve been constructing a quantum mechanical model over the last few months and I’m hoping to complete it and start testing this weekend! Should the tests be successful I shall expand my endeavours into quantization of the electromagnetic field, with a view to building a number of small but powerful anti gravity devices. Installed in the right places these devices should enable me to bring Beasties dry weight down to around 550kg, giving an end result of around 650bhp/tonne
Were I to fit one of these devices to my person I’d also be able to get in the car without having to open the door (although this would obviously require removing the roof first).
I love these little science projects, and I wish you every success with yours
Keep us updated on progress!
Cheers for now mate,
Chilli
I myself have recently been researching theoretical physics, in particular quantum field theory (QFT). QFT is a theoretical framework for constructing quantum mechanical models of subatomic particles in particle physics and quasiparticles in condensed matter physics. A QFT treats particles as excited states of an underlying physical field, so these are called field quanta.
I’ve been constructing a quantum mechanical model over the last few months and I’m hoping to complete it and start testing this weekend! Should the tests be successful I shall expand my endeavours into quantization of the electromagnetic field, with a view to building a number of small but powerful anti gravity devices. Installed in the right places these devices should enable me to bring Beasties dry weight down to around 550kg, giving an end result of around 650bhp/tonne
Were I to fit one of these devices to my person I’d also be able to get in the car without having to open the door (although this would obviously require removing the roof first).
I love these little science projects, and I wish you every success with yours
Keep us updated on progress!
Cheers for now mate,
Chilli
ChilliWhizz said:
I can't believe nobody's interested in my project
Quick question for you Professor:If your system were to work as you expect, would it also be able to enable people to get their unfeasibly large ego into the car as well?
If so, what would the unit be likely to cost as I can think of several people who could do with one as a gift.
As always, I am forever in awe of your awesomeness.
With much grovelling and kindest regards,
J400GED
J400GED said:
ChilliWhizz said:
I can't believe nobody's interested in my project
Quick question for you Professor:If your system were to work as you expect, would it also be able to enable people to get their unfeasibly large ego into the car as well?
If so, what would the unit be likely to cost as I can think of several people who could do with one as a gift.
As always, I am forever in awe of your awesomeness.
With much grovelling and kindest regards,
J400GED
Unless I'm missing the point, the objective is not to start both fans at the same time to avoid the initial surge?
Would it not be as simple to wire the first fan as it is now, and wire the second fan to a second relay with the trigger to the output of the first relay with a time delay relay to give the required delay?
http://www.12voltplanet.co.uk/adjustable-delay-tim...
(you will need a bigger amp one)
Would it not be as simple to wire the first fan as it is now, and wire the second fan to a second relay with the trigger to the output of the first relay with a time delay relay to give the required delay?
http://www.12voltplanet.co.uk/adjustable-delay-tim...
(you will need a bigger amp one)
gavgavgav said:
Unless I'm missing the point, the objective is not to start both fans at the same time to avoid the initial surge?
Would it not be as simple to wire the first fan as it is now, and wire the second fan to a second relay with the trigger to the output of the first relay with a time delay relay to give the required delay?
http://www.12voltplanet.co.uk/adjustable-delay-tim...
(you will need a bigger amp one)
The objective is to better manage the cooling on the Tiv but mainly a learning exercise in finding out how the different temperature senders work, how they all have different temperature curves and why you can't just pop a sender onto a gauge that it isn't designed for using a simple padding resistor and expect it to be in any way accurate. Would it not be as simple to wire the first fan as it is now, and wire the second fan to a second relay with the trigger to the output of the first relay with a time delay relay to give the required delay?
http://www.12voltplanet.co.uk/adjustable-delay-tim...
(you will need a bigger amp one)
Phil
Gassing Station | Chimaera | Top of Page | What's New | My Stuff