A Forum run by Enthusiasts of MidNite Solar

Charge Controllers and Clippers => The "Classic" charge controller => Topic started by: unyalli on April 23, 2014, 07:59:40 PM

Title: Using aux 1 to cool classic 150 (best recomended settings)
Post by: unyalli on April 23, 2014, 07:59:40 PM
I've studied and studied the aux 1 settings and descriptions to no avail. My classic 150 is going in the forward compartment of my fifth wheel RV. I want to provide it with filtered forced air from beneath the RV. I know how I am going to duct this air and the fan I'm going to use draws 0.14 amps at 12 volts to produce 40 cfm airflow. Since I can't set aux 1 to turn on when a temp in the classic goes over a set point what setting should I use?.

-Jeff
Title: Re: Using aux 1 to cool classic 150 (best recomended settings)
Post by: dgd on April 23, 2014, 09:58:14 PM
What about just using a temp controlled switch in the compartment or on the Classic heat sink ?

dgd
Title: Re: Using aux 1 to cool classic 150 (best recomended settings)
Post by: vtmaps on April 24, 2014, 03:35:46 AM
Quote from: unyalli on April 23, 2014, 07:59:40 PM
I want to provide it with filtered forced air from beneath the RV. I know how I am going to duct this air and the fan I'm going to use draws 0.14 amps at 12 volts to produce 40 cfm airflow.

Have you tested the fan-duct-filter together?  A fan that produces 40 cfm and consumes only 1.7 watts will have very low static air pressure.  In other words, it may not be able to overcome the resistance of the duct and filter.

--vtMaps
Title: Re: Using aux 1 to cool classic 150 (best recomended settings)
Post by: unyalli on April 24, 2014, 06:27:33 AM
I could use a temp controlled switch but was trying to determine under what existing setting would the classic be creating the most heat and could use an assist for it's existing cooling fans.

I have not tested the ducting which will consist of two thin wall conduits coming from a plenum at the bottom of the bay to the two bottom holes in the classic. I figure the existing fans could use a boost of air from outside the compartment.
Title: Re: Using aux 1 to cool classic 150 (best recomended settings)
Post by: dgd on April 24, 2014, 06:47:03 AM
Quote from: unyalli on April 24, 2014, 06:27:33 AM
I could use a temp controlled switch but was trying to determine under what existing setting would the classic be creating the most heat and could use an assist for it's existing cooling fans.

I would guess that when the Classic uses the turbo fan then that is the time it needs to remove excess heat most.
Perhaps a small relay on the turbo fan power wires to switch power your larger ducted fan.

dgd
Title: Re: Using aux 1 to cool classic 150 (best recomended settings)
Post by: philb on April 24, 2014, 11:18:02 PM
The external fans on my classics are set via aux 1 to daylight.  They do run about an hour past dark.

Two classics and a kid are in a 2x2x4 foot ventilated square box and produce around 20 kWh on a typical day this time of the year. So far, I haven't seen the need to use filtered air. If the filters clog, they could overheat rather quickly. The boards have a very light dust on them but not enough to cause any problems.
My second system also has a classic without an external fan inside a 16x40 ft shop. It needs a spray from the air can at least every 3 months.

  I'm considering using a 120 vac photocell to turn fans on and off in the box. If a classic should reset for some reason the fan may not come back on. The kid has blown 2 30 amp fuses since its commissioning, so I certainly won't use the aux on it until I get the issue solved.

The waste not high aux function may also work for you.
Title: Re: Using aux 1 to cool classic 150 (best recomended settings)
Post by: Westbranch on April 24, 2014, 11:52:49 PM
Phil, why not use a small dedicated PV to run a DC fan? on/off sunrise/sunset...
Title: Re: Using aux 1 to cool classic 150 (best recomended settings)
Post by: philb on April 25, 2014, 01:39:27 AM
Westbranch,
That's probably the best way to do it. I had the wrong hat on that time! ::)
Harbor freight does have 1.5 watt panels for less that $15.

I was thinking at the time that I had all that 24 vdc and 120 vac power in front of me, why not use that? Just a few more wires this way and I'd had to drug my panel construction kit out to do the panel/fan assy.  ;D
Title: Re: Using aux 1 to cool classic 150 (best recomended settings)
Post by: Westbranch on April 25, 2014, 03:53:11 PM
Or a 24V muffin fan?