Air conditioner fan control

[94nubble]

I have installed an after market dashboard Air Conditioning system in my RV. The fan does not quite put out enough air. I have been playing with the idea of using a 1500W boost amp to increase the input to the fan a few volts to increase fan speed. The input would be directly off the alternator feed to the battery. Any one have any advise?
Tks...T

 

[Diver300]

Have you got any more details of the device you have fitted. Is it just a fan?

Boost amplifiers aren't generally set up to output a dc voltage, so a boost converter that is designed for a fixed output voltage would be better.

 

[94nubble]

https://www.amazon.com/Boost-Module...dp/B07TJGZWJ1/ref=psdc_10967761_t1_B077Q852DJ Is what I am thinking of using. The fan is a 3 speed dash unit sold by Old Air Products . https://www.oldairproducts.com/product/hurricane-3100-inside-package. Attached is the wiring.

 

[Diver300]

The booster device isn't an amplifier. It's called a boost converter or boost regulator. I thought that you were talking about an audio amplifier.

The boost device is fine. It will give you a larger voltage.

However, without knowing what sort of motor drives the fan, you can't be sure whether it will go faster, or not be damaged, if the voltage is increased.

If it is a simple DC motor, a larger voltage will make it go faster, but it will increase the heating of the motor. Do you have details of the motor?

The circuit looks about right, but I'm not sure what the delay on the relay does. You might well be able to get away with leaving the output of the boost converter permanently connected to the fan, and a diode to stop current flowing back into the normal fan controller.

 

[94nubble]

Thank you for your reply. Yes I put some isolation diodes on the output of the converter. I was using the delay relay (all I had) to give the boost a chance to power up before a load was applied. When I first hooked up the booster to the fan it ran great at 17 volts. After turning it on and off a few times it shorted out the Mosfet on the boost regulator. Now it shorts out the Mosfet immediately when the boost regulator is applied to the fan. I attached the specs for the boost regulator and the Mosfet. Any ideas on what I can do to protect the boost regulator or what might be happening?

 

[Diver300]

I don't know what the problem is.

There are a lot of warnings in the boost converter specifications which makes me think that it's not very well protected.

You should set the undervoltage protection so that the boost converter does not try to run unless the voltage is at 12 V.

You could try adding capacitance to the output.