|Topic Review (Newest First)|
|07-30-2016 07:05 AM|
For the mounting: it was a fairly compact case and fit nicely, with some zip ties and sticky back cable mounts, to the underside of the dash right in front and above the passenger heater outlets. Under dash picture included as well as quick sketch of wiring.
I don't have any 'noise' in the sense of static or interference. I do have some "whine" at the low to middle speeds, but I believe this is a grounding issue of some sort because I had some alternator whine through the speakers even before I installed this. I ran my ground straight from the battery - and never really figured that one out, but it is faint so I don't really bother with it. At some point I may try an isolator or something.
|07-30-2016 03:58 AM|
Where did you hide it?
maybe a quick schematic sketch of how you wired it into the car?
Electronic noise? [tune to a not so strong FM station and see if it gets worse]
|07-28-2016 06:36 PM|
|07-28-2016 06:35 PM|
Well, I didn't give up and finally got it all worked out. I don't recommend this to anybody but in case someone is hell bent as I was to make this work I will provide some info. With this configuration I think I did get some modest improvements over stock: The fan speed is infinitely adjustable instead of just 3 positions. I don't know why anyone needs this, but its an outcome of using the PWM controller. 2. I wired with a push/pull potentiometer as suggested and can just flick it in/out to turn on/off the ac control and the blower and have it turn back on the ac and resume to whatever air speed I last had it to when pulled out. I see this as a minor convenience improvement. Lastly, I now have all my wiring and "resistors" inside the car where I can access without any disassembly of the front end/clam. Hopefully I won't ever need to touch this again.
The DC controller that worked for me and passed full voltage was this one: 12V 24V 48V 2000W MAX 10-50V 40A DC Motor Speed Control PWM HHO RC Controller
It was cheap, 7 bucks plus shipping, but worked as expected passing all the power at full turn. The issue with this is it has a built in potentiometer, so I had to a little surgery on it. I cut the potentiometer off with a wheel half way leaving just the base attached to the board. This avoided having to remove the existing solder points which is a pain on these and it left me some soldering points on the 'legs' to utilize. You can see in the pictures how I did it. Because it's so hard to work under the dash, I soldered the wires and quick disconnects at both ends so the hvac controls are still removable.
I used the same push/pull pot I used for the Tony Wa bypass. It needs minor alteration on the shaft to get the right size D to fit the original knob, but as you can see from the pics, everything looks very stock at first glance. The Pot I used is available from smc: SMC ELECTRONICS - Potentiometers (PT65).
You can ignore the red wire to the back of the controller. That was for the ac button power to turn on with the blower but apparently I don't understand DC electronics too well yet and that didn't work. Instead I wired the ac/recirc power direct from the push/pull power on the pot so it turns on/off with the switch.
Overall, its working great. Putting out a lot more air than before, probably because my wires were corroded.
|07-15-2016 07:30 AM|
Pity, had it worked out it would have been a fun mod.
Can just see the future post from some future owner......Hey is my fan switch broken?
thinking of pulling mine in and playing with the resistors today
|07-14-2016 08:53 AM|
|mavster||So here's where I landed on the DC controller. Since I couldn't get proper output on the controller, I went back to the original setup and OEM potentiometer with high setting running direct to the blower, and also ran a wire and redirected the low speed setting to the dc controller mounted under the dash and then pigtailed with the blower wire. This uses the oem pot to toggle between full blast and the DC controller acting like a large, adjustable resistor. Ultimately I am happy because I mostly use full speed but have the ability to turn it down for phone calls or during nice weather when I just want some airflow in the cockpit. All said and done, it wasn't worth the hassle and I would just stick with resistors as others have done but mounted in a more accessible location in case of any issues, similar to what exigegus has done.|
|07-13-2016 11:43 AM|
|mavster||Thanks for the tip. I very rarely listen to radio, but I did check this last night and it seemed ok although I got considerable noise when changing the speed of the controller with the radio on, probably because I shared the ground that I ran from the battery for the radio. Guess I'll need to find a new ground.|
|07-13-2016 10:52 AM|
that's what I was referring to, using it as bypass on high
if it needs a relay, couple bucks, NBD
one thing you might want to do is check out for radio interference. I am on the edge for some stations and turning the fan on will knock out reception. No audio noise, just less reception. You should check out your radio with the little PWM control running.
I built a little filter for the fan and am going to see if it helps, but I am also electronically a bit out of my depth.......
|07-13-2016 10:02 AM|
Just read through your other thread. Really good work and good info. I hadn't seen anyone convert the condenser. Had I known you made that work, I probably would have just went for that instead of trying to repair the OEM, although I am probably underestimating the effort to get all the brackets, hoses, lines etc. right and what the total cost and time investment is. But good to know there's an alternative should the welding approach not work out.
|07-13-2016 08:31 AM|
look carefully the widget I posted will both decrease and increase the voltage, so for a 14.5 volt input it will output .8 to 28 volts. Assuming you can get one that will handle over 12 amps, and you effectively limited its output so that it was not grossly over system voltage, say 18 volts or something it ought to do what you want
kinda complex tho
I was only speaking of the pot to run your speed control
|07-13-2016 08:09 AM|
Looks about the same as what I have except rated for less watts.
Found this one too:
New 10 50V 60A 3000W DC Motor Speed Control PWM HHO RC Controller with Case | eBay
As for the potentiometer with the switch, I like the idea but I would have no idea where to find a pot that I can put that kind of amperage through, sounds more like a rheostat? The one I bought for the Tony Wa bypass maxes at 1A. The fuse for the blower is rated at 20A.
|07-13-2016 04:45 AM|
buck boost converter
little bigger one of these
150W DC Converter 6 32V to 0 8 28V 5V 12V 24V Buck Boost Step Up Down Car Power | eBay
Bit of engineering required to not blow stuff up
|07-13-2016 03:07 AM|
Oh if you read my postings on reworking the Exige AC system you will see what I mean about switching the fittings. The condenser is factory installed upside down. I was really half kidding
|07-13-2016 03:04 AM|
I would say use the pot with the built in switch discussed earlier, worst case you need to run one wire and you will be happy with the results. The low and medium speeds are too high in my view.
Odd that it does so poorly.
I was curious and was looking through some things and there are some DC to DC converters that go both above and below the supply voltage, but finding one that both has a remote pot and high enough current capacity is difficult
|07-12-2016 07:16 PM|
I received my digital anemometer the other day and while I wait for the repair of my condenser I wired in the DC controller for airflow testing. The official results are in and they are not what I had hoped, but they are what I expected. Direct wired from the 12v source to the blower I get a reading of 3327 avg (ft/min) measured directly at the outlet of the HVAC/evaporator box. With the DC Controller wired in and full power at the pot, it's only putting out 1102 (ft/min). A huge difference in airflow. So as I originally suspected it is cutting voltage on the output although by all accounts it should not be. It's rated at 30a and 300watts so I don't really know why this is happening, other than the fact that its a cheap unit?
I am not going back to a resistor setup. So the options I see are:
a)Find a better DC controller that won't cut voltage on output, if this exists?
b) Create a hybrid solution and wire in a switch under the dash for full power and use the pot for variable low-med, not as elegant as I was shooting for
c) Go with the sure thing and go to single (high only) fan speed with the original switch wired direct to blower
Because its already loud in the cabin and I do occasionally have a need to talk on the phone, I would like to have some variable airflow, so not real fond of C.
I'm hoping someone here can suggest a good solution.
|07-12-2016 06:54 PM|
Originally Posted by exigeg2 View Post
|07-11-2016 11:01 AM|
you should have him cut the fittings off and reverse them so they are the right way around.....a few bucks in hoses and I think your ac will be the better for it.
pity bout the Alumiweld
|07-11-2016 10:49 AM|
I think the Alumiweld is a good product for certain applications, however, repairing a condenser may not be one of them. The repaired area began leaking as soon as I started pressure testing the system. I took it over to a professional welding shop today and he said that these are particularly difficult to repair because the gasses/oils in the condenser contaminate the alumiweld and you don't get a good bond. He was hesitant because of the prep work involved but is going to give it a go for me this week. Even with 2 hours of shop work, its considerably cheaper than buying even a used unit.
|07-06-2016 06:01 PM|
Preliminary results are good with the alumiweld. Thank you Roundabout for the suggestion. Probably not the prettiest job ever done but so far it is holding a vacuum with my hand pump at 20 in. Tomorrow I will test fit everything and put a full vacuum on it with the pump. If all goes well with that, hopefully it will hold under full pressure with the charge which is about 250-300psi with the current florida heat. The label claims a tensile strength of 47,000 psi, so I should be good if it bonded well.
Unfortunately, I did need to heat it and apply twice to get a good seal. I think this was just due to, my experience, and the very uneven twisted up surface but it didn't seem to be a problem. I guess we'll see.
|07-06-2016 12:02 PM|
Originally Posted by exigeg2 View Post
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