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Discussion Starter · #1 · (Edited)
While messing about in the back I captured some data from the two IPU fan data lines.

1) is the 200hz 5ms period pwm sent by the MCM which controls the fan speed.
The lower the duty the higher the fan speed.

Low Speed = Low 1.15ms High 3.85ms
Med Speed = Low 1.95ms High 3.05ms
High Speed = Low 3.00ms High 2.00ms

2) is the fan speed feedback sent to the MCM which is a simple pulse that increases as the speed increases.

Using the Honda tool you can run the fan though an off, low, medium and high test sequence.
I captured the data whilst this test was executing.
You need the free Salea logic analyser software installed to view/manipulate the file.
http://www.saleae.com/downloads

A simple 12F683 pic chip could control the fan with it's pwm output.
The fan is quite a high current device so would need a decent psu as well as the pwm device.
 

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Discussion Starter · #2 ·
Fan Control

I've modified my IPU Interceptor code to now look at the IGBT temperature byte in the data passing through it and then set the pic 12F1822 hardware pwm accordingly based on my temp thresholds. Just need to add a wire from my interceptor pic to the fan pwm control wire.

As I mentioned earlier for those wanting manual control of their HCH1 IPU fan this may be a nice solution which can easily be transferred to a 12F683 pic for use with basic grid chargers.
 

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Are you going to provide any more (DIY?) details on this for the HCH1 fan control? That is, when you get time:). Dumb question, but I assume there is just one fan in the HCH1 that cools everything back there?
 

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Discussion Starter · #5 · (Edited)
I've knocked up some quick software to drive the IPU fan pwm with a little 12F683 pic.
Going to be needed for HCH1 grid chargers.
I'll try and test it next week, my civic is in the garage this week having a new clutch fitted.
 

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Discussion Starter · #6 ·
I should get my HCH1 back tomorrow after new clutch being fitted.

The auto Fan controller for when the car is being driven is an interesting challenge and is different to the controller reqd when then car is off and just grid charging.

For Grid charging use only we need a 12V fan power supply and then the little pic to provide the pwm on the fan drive wire. It simple to set that so fan runs at low speed all time grid charger is plugged in. As the MCM is not powered it doesn't know about any issues.

Changing the way the fan operates when the car is driven means we may have to tackle the way the fan speed is monitored in the MCM. Until I get my car back I can't test all the various scenarios for this. But if we force it to run when the MCM is not actually commanding it or we force it to run at a faster/slower speed than the MCM is commanding it may throw a fault code due to discrepancy between commanded speed and reported speed.

If we can solve that problem then forcing it to run at whatever speed we like is fine.

Would people like manual control of the fan speed when vehicle is driven or fan to run say at medium speed all the time. Manual control means 2 wires from the ipu compartment to an accessible button. Auto medium speed all the time does not. The gizmo can detect the igbt temp very easily so can disable the fan at any time the temp in the back is < 20C say. So it doesn't run when not reqd. The igbt temp is pretty much ambient temp when the car is first started.

I might be able to pick up the battery temp data in the back but i need to look at the MOTB data as it's probably in there ;)

Tomorrow I intend to check current drawn by the IPU fan at low speed for the grid charger version so we can size a suitable 12v constant voltage led psu. Probably around 3A 40w or so.
 

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I wonder if another viable approach be to spoof a higher temperature to whatever sensor is hooked to the fan control (adding a resistor in parallel or some such).

Or would the disagreement between sensor values cause a freak-out?
 

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Discussion Starter · #8 ·
Spoofing a higher temp would have to be done on all three battery sensors and would likely affect assist/regen and could disable or reduce them when temp got warm. Might even set codes. Non starter IMHO.
 

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Discussion Starter · #9 ·
Testing my pic 12F683 pwm fan driver today using another led power supply.

This one is constant voltage 12v 1.8A 18w max which allows the HCH1 fan to be driven at a reasonable rate.

LED Driver Transformer Power Supply 240V-DC12V | eBay

I settled on a pwm which gave a 1A load and nice airflow.

The thing I like about this psu is that it is same shape, size, mounting as the 60-90v led power supplies that form the basis of the grid charger. So one 12v driver and two 90v drivers gives you the basic dumb charger. And for the HCH1 the addition of the pwm driver means the fan is driven at a suitable rate.

I found that the Oem HCH1 pwm line interferes with my pics pwm even when off, so I will add a transistor driver stage to see if that works. With the pwm line to the car disconnected but swapped to my pic worked fine, but with the car off and the pwm line to the car still connected did not work correctly which is a bit odd. Might need a tiny switch over relay if transistor doesn't cure it.
 

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guinea pig

Peter, if you would like a guinea pig on the fan control testing I'm offering, I already have all the rear trims out as I have been looking into this myself and looking at the prospect of a grid charger in preparation of the cars warranty expiring

Dave
 

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Mike and I both used relay's to isolate the car's wiring from the grid charger. You will also need a diode to prevent the car's 12v from powering the relay and putting the fan in "charge" mode while driving
 

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Discussion Starter · #14 ·
You will also need a diode to prevent the car's 12v from powering the relay and putting the fan in "charge" mode while driving
Jeff I'm not sure we want to prevent the fan working all the time, and part of the project is a manually operated fan, so that the driver can run the fan earlier or faster than the car does, to help keep battery temp lower than the car wants when it starts to warm up. The power electronics also heats up quite a lot without the fan running which worries me a bit. I've been monitoring the igbt temp under heavy assist/regen and without the fan it gets pretty hot.

Might end up with two systems, but a grid charger fan driver which can also drive/overide the fan when the car is being driven might be useful.
 

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Came across this last night any thoughts on it as an option for controlling fan speed? I noticed it can work with a ptc thermistor.
I don't know how it would intergrate with the existing OEM system.
http://www.micrel.com/_PDF/mic502.pdf
 

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Jeff I'm not sure we want to prevent the fan working all the time, and part of the project is a manually operated fan, so that the driver can run the fan earlier or faster than the car does, to help keep battery temp lower than the car wants when it starts to warm up. The power electronics also heats up quite a lot without the fan running which worries me a bit. I've been monitoring the igbt temp under heavy assist/regen and without the fan it gets pretty hot.

Might end up with two systems, but a grid charger fan driver which can also drive/overide the fan when the car is being driven might be useful.
Interesting. You could put in the diode (as I do) for when you want the car in 'normal' mode then have a switchable bypass when you want to manually turn the fan on. Neat idea, I like it!

Edit: not sure if this would result in a DTC indication. Does the can provide feedback via the PWM and/or TACH signals? If so might be an issue
 

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Discussion Starter · #17 · (Edited)
Running the fan when not commanded by the car does not result in any DTC's via the speed feedback loop.
However not sure about when the car is trying to run the fan though at the same time and or different speeds. That might provoke a DTC.
I haven't had any fan related dtc's in my hch1 testing over the last few months though.

I have now finished the little 12F683 circuit to run the fan for my HCH1 chargers.
Now need to knock up a little pcb.

Attached is the simple base source and hex code fyi.
With the PWM values given the fan draws about 1A from a 12v supply.

I post the schematic in a few days.

I think I will include a jumper so the builder can run the fan whenever the car is turned on in hotter climates.
A secondary pwm setting could also give a higher fan speed in this scenario.

Monitoring the incoming pwm from the car would tell you when the car is starting to demand fan operation.
The pic could then mimic the car pwm and crank the fan up and down.

Quite a lot is possible with some clever pic programming.
 

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Discussion Starter · #18 ·
Schematic

Here is my IMA HCH1 Fan control schematic. Now laying out a little pcb.
The software I posted now needs updating to accomodate some new functions.

Hopefully it's pretty self explanatory.

Notes.

The HCH1 requires a 12V power supply of about 1.5A minimum capability.
The pcb has a fan speed adjustment pot.
The speed adjustment will have limits so you can't exceed the selected psu current capability.

The pcb can operate in a few different modes.

Jumper 1 open it only operates when the 12v power supply is active at all other times the car has control.
Jumper 1 closed it operates with the car on as well, and then functions are further defined by the setting of jumper 2.

Jumper 2 open means the fan will run constantly at your selected speed.
Jumper 2 closed means the fan will mimic the fan speed commanded by the car.

Lots more variations possible with program changes. But you get the idea.
Any obvious errors let me know asap. :)
 

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Schematic looks good to me Peter, Are you going to be supplying PCB's for for this project? or would the demand be too low.

Dave
 
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