Possible fix for dimming
#1
Possible fix for dimming
I was thinking about adding an inductor in series with the AC pump in order to slow the current draw and give the alternator/ELD (i'm assuming our Fits have an ELD) a chance to slowly ramp up to the new current draw and thus keep the voltage stable. I think this would definitely be cheaper/easier to install than voltage stabilizers/upgraded wiring. Just wanted to run this past any electrical folks that might be here.
This is still in concept stage as I haven't really thought out the requirements for the inductor (how many amps/henries it would have to be rated for). and where to place the inductor, shielding from moving parts, etc...
This is still in concept stage as I haven't really thought out the requirements for the inductor (how many amps/henries it would have to be rated for). and where to place the inductor, shielding from moving parts, etc...
#2
Never mind, according to Falstad's circuit simulator I would need something along the range of 4.7mH of which the highest current inductor I could find only safely runs 4 amps... Maybe instead make a replacement ELD that delayed the turn on of the ac compressor until the alternator could ramp up to normal output.
#4
True, its not THAT bad... but it bugs me every time the ac pump kicks in.. which over the lifetime of my fit will drive me bonkers. Right now I'm thinking of setting up an ATTiny chip that will sit between the ELD, ECU and ac pump relay. When the relay would normally get power a pin on the IC would go high. This would cause the IC to disconnect the ELD from the alternator and send the alternator a replacement signal to switch into high output. Meanwhile a timer would start and when it overflows would kick the relay back on, starting the AC pump. After another short time delay 1-2 seconds, the IC would tristate its signal to the alternator and allow the ELD to take back control.
I'm thinking an ATTiny25, a few caps and diodes, a 4MHz crystal and possible a switching transistor for the relay should be able to do the trick. All in all parts cost will likely be less than $10.
I'm thinking an ATTiny25, a few caps and diodes, a 4MHz crystal and possible a switching transistor for the relay should be able to do the trick. All in all parts cost will likely be less than $10.
#5
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Even if you could slow down the actuation of the clutch on the AC pump, which I dont think you can as it is probably solenoid based, you would probably wear it out a lot faster. Probably not designed for a soft slip type engagement.
#6
I kind of gave up on slowing the ac pump activation. Does the ac pump have a clutch? I figured that since it was electric, it was just a motor that was kicked on and off by a relay. Although I suppose if that's true PWM might be able to slowly activate the AC pump followed by a full on through a relay. That of course assumes the ECU/ELD setup would recognize the average drop in voltage in the system and would have the alternator compensate.
#11
If its belt driven I guess then the only way is to build a more sophisticated ELD that has some preemptive capabilities... although going even that far might not fix the issue if the engine is slowing down during activation.
#12
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On a related note.
My RX7 TT had a device that when you accelerated it would turn off the AC clutch, as that would zap some power.
That is doable and needed on our fits because we need all the power we can get to accelerate.
Number of ways to do it, find the ecu signal for WOT (wide open throttle) or low vacuum, or add a vacuum switch spliced into a vacuum line and then to a relay.
That IMHO would be a good project.
back to your issue, unfortunately your location of US does not reveal your climate. You may know that in Defrost your AC compressor will cycle on and off. There is a how to thread to eliminate auto AC compressor cycling when in defrost. That could help you with some of your problem.
My RX7 TT had a device that when you accelerated it would turn off the AC clutch, as that would zap some power.
That is doable and needed on our fits because we need all the power we can get to accelerate.
Number of ways to do it, find the ecu signal for WOT (wide open throttle) or low vacuum, or add a vacuum switch spliced into a vacuum line and then to a relay.
That IMHO would be a good project.
back to your issue, unfortunately your location of US does not reveal your climate. You may know that in Defrost your AC compressor will cycle on and off. There is a how to thread to eliminate auto AC compressor cycling when in defrost. That could help you with some of your problem.
#13
On a related note.
My RX7 TT had a device that when you accelerated it would turn off the AC clutch, as that would zap some power.
That is doable and needed on our fits because we need all the power we can get to accelerate.
Number of ways to do it, find the ecu signal for WOT (wide open throttle) or low vacuum, or add a vacuum switch spliced into a vacuum line and then to a relay.
That IMHO would be a good project.
back to your issue, unfortunately your location of US does not reveal your climate. You may know that in Defrost your AC compressor will cycle on and off. There is a how to thread to eliminate auto AC compressor cycling when in defrost. That could help you with some of your problem.
My RX7 TT had a device that when you accelerated it would turn off the AC clutch, as that would zap some power.
That is doable and needed on our fits because we need all the power we can get to accelerate.
Number of ways to do it, find the ecu signal for WOT (wide open throttle) or low vacuum, or add a vacuum switch spliced into a vacuum line and then to a relay.
That IMHO would be a good project.
back to your issue, unfortunately your location of US does not reveal your climate. You may know that in Defrost your AC compressor will cycle on and off. There is a how to thread to eliminate auto AC compressor cycling when in defrost. That could help you with some of your problem.
#14
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The defrost deal is NOT an AC comp disable. Make it optional, you lose nothing and have the best of both worlds
With auto defrost AC comp on disable, you have the choice of AC on if you also depress the AC button. The 'how to' just makes it so it isnt mandatory.
Here is the thread, it is really a cool mod
https://www.fitfreak.net/forums/2nd-...c-defrost.html
Last edited by Tork; 01-30-2009 at 10:43 PM.
#15
well work on the WOT/AC disable, lots of the fit community could dig that.
The defrost deal is NOT an AC comp disable. Make it optional, you lose nothing and have the best of both worlds
With auto defrost AC comp on disable, you have the choice of AC on if you also depress the AC button. The 'how to' just makes it so it isnt mandatory.
Here is the thread, it is really a cool mod
https://www.fitfreak.net/forums/2nd-...c-defrost.html
The defrost deal is NOT an AC comp disable. Make it optional, you lose nothing and have the best of both worlds
With auto defrost AC comp on disable, you have the choice of AC on if you also depress the AC button. The 'how to' just makes it so it isnt mandatory.
Here is the thread, it is really a cool mod
https://www.fitfreak.net/forums/2nd-...c-defrost.html
https://www.fitfreak.net/forums/108654-post101.html
#18
this.
OP, is this your first car? your first interaction with a car? ummm... when you kick on the AC, your lights dim. happens with all cars.
OP, is this your first car? your first interaction with a car? ummm... when you kick on the AC, your lights dim. happens with all cars.