Morningstar Tristar MPPT 60 charge controller mounting question.

ClydesdaleKevin · September 15, 2012, 08:14 AM

So according to the instructions, they say I'm supposed to mount the controller vertically, with 6 inches above the controller of clearance, and 6 inches below. Just not possible! My power center is under the dinette bench seat.

Is it going to be a problem to mount the controller horizontally? It would have over 6 inches of clearance all the way around it, and almost a foot above it and the heat sink. I would think this would be alright, especially if I mount it on a wood spacer to get airflow under it as well.

Any advice or suggestions?

I could add a vent under the dinette table to the side of the cabinet, maybe with a muffin fan...that would keep air flowing over it since the front door to the cabinet isn't air tight.

Do you think its going to cause an overheating problem?

Kev

gadgetman · September 15, 2012, 05:23 PM

I would add a pc fan so it could blow through the cooling fins. I would wire the fan to a solar panel output so when the sun is out and the controller is working the fan would be running. That should let you maout it any direction you want without overheating the controller. Use a pc fan under 50 cfm so you wont hear it. Fuse the fan with a 1 amp fuse.

ClydesdaleKevin · September 16, 2012, 06:56 AM

Thanks! That is pretty much the same thing I was thinking. I was even considering 2 muffin fans...one blowing from the bottom of the controller through the fins, and one at the top of the controller blowing the hot air away from the fins.

Kev

ClydesdaleKevin · September 17, 2012, 06:36 AM

So another question about the muffin fan, specifically their voltage tolerance. Most of the ones I looked at on eBay had a voltage range of 9-14 volts for a 12 volt system, with one heavy duty model having a voltage range of 9-15 volts. If that is the case, is the higher absorbsion stage voltage of 14.2 volts and the really high equalize voltage of 15.4 volts going to hurt and burn out the motor in the fan?

Thanks!

Kev

gadgetman · September 17, 2012, 06:45 PM

I use a 24v fan but I am hooked directally into the solar panel output of 18v.

Most of those 12v fans are pretty tolerant to higher voltages. I wouldnt worry about voltages up to 15.5. usually that will be a short term voltage anyway. I am not sure of the voltage from your panels but if above 30 volts you could just go direct to the solar panel so it only runs when the sun is out, fuse the fan as rated and use 2 24v fans in series. That will alow voltages up to 52 volts 48 being ideal.

ClydesdaleKevin · September 18, 2012, 07:22 AM

So I could get the project finished today, I went to Radio Shack and picked up a 12 volt muffin fan, tolerant up to 14 volts, and since it only draws .31 amps, I picked up a little 12 volt voltage regulator there as well for 3 bucks. Its tolerant up to 30 volts, but I'm still going to wire it in on the battery side with a switch, and a 1 amp inline fuse. I really like the idea of running it to the panels, but they put out way too much voltage, so a switch it is.

I'm going with a single fan mounted to blow right through the cooling fins of the controller...I'm sure that will be more than adequate, since its designed to keep cool enough without a fan convectionally just hanging on a wall....don't want to add more amp draws now that we have a great solar system.

Now I'm sort of regretting giving away our little Kyocera 65 watt panel we had on the roof. It was mounted on the air conditioner shroud with wires already run to a cheapo Sunforce charge controller, which I could have bypassed and run the wires to the fan directly, since that panel only put out 16 volts max. Ah well, hindsight is 20/20! Already removed it from the roof and gifted it and the Sunforce to our our friend Arlene.

I'll have to keep the switch in the power compartment though...don't want the pups bumping it and turning it off and on.

Thanks for the input though! I might in the future just go ahead and get a small little 12 volt panel that puts out just enough power to run the muffin fan. I wonder how many volts my little Coleman battery tender solar panel puts out, the one I used to use on the dash of the Jeep Cherokee when we towed it, but can't use in the Wrangler because of the flat windshield? Hmmmmm...gonna have to test it today with the volt meter...supposed to put out 1-2 trickle charging amps, enough to run the fan if it puts out 12 volts...I wonder if its waterproof? I'll have to check it out...could mount it right to the fridge vent.

Kev

ClydesdaleKevin · September 18, 2012, 07:35 AM

So I found the manual for the little Coleman solar panel...and its fully weatherproof!

Power rating is up to 1.25 watts, with a current of 83 mAmps @ 15 volts.

The muffin fan is rated at 12 volts DC, voltage range of 10.2 to 13.8 volts. Rated current 0.32 amps, rated power of 3.84W max.

Think the little panel will power the fan?

Kev

ClydesdaleKevin · September 18, 2012, 09:00 AM

I just had another thought...since the panels put out around 30 volts, what would prevent me from using an automotive external voltage regulator to step the voltage from the panels down to 12 volts for use with the fan?

I was thinking the external kind they used on very old VW Beetles...60s era...when they still used generators (DC output) instead of alternators. Cheap and should step the volts down.

Anyone here think it will work?

Kev

gadgetman · September 18, 2012, 11:00 AM

Its just something else to break and use up watts, just wire 24vs in series. The 30 to 35 volts will just make them slower.

Oz · September 18, 2012, 08:46 PM

Hey Moonlitcoyote.... see how "simple" all this solar stuff is? Bah-hahahahah! :)rotflmao

Yeah, right... If we're making it harder than it is, why are there sooooooo many questions about it, and answers that are so lengthy with all kinds of different numbers in them depending on what the other different numbers are? Hm?

I covered an umbrella with tin foil, put it on the roof, taped an extension cord to it and screwed it to my battery... there, I have "simple" solar!

ClydesdaleKevin · September 19, 2012, 06:48 AM

LOL Mark! It isn't all that simple, but with enough research and all the good advice on this forum, even I can do it!

I tried running the fan off a small 1 amp voltage regulator I got from Radio Shack that says it takes up to 30 volts in and puts out 12 volts, but by the time I tried to see if it worked, it was almost 6pm and raining like heck...I mean a real gullywasher...so I don't know if it works yet or not since the solar array was only putting out around 16 volts. When the volts dropped down to 13 as it got darker, I tried the fan directly at the solar array but it just hummed a little and wouldn't run. To make sure the fan was good, I tried it at the batteries and it fires right up, so I'm guessing the solar array wasn't putting out enough watts to run the fan when it was almost dark.

A test with my voltmeter did indeed show the 16+volts in to the regulator and 12 volts out, but either the cheap little regulator doesn't put out enough watts to run the fan (says 3 watts while the fan consumes 3.5), or there simply wasn't enough sunlight. I'll test it again today at lunch.

Another thought I had was to use a rheostat or potentiometer, but of course Radio Shack hardly has anything like that now, and nothing big enough to handle the 30 volts in.

I don't have time to wait for 2 24 volt fans to arrive from whereever they would get shipped, since we are leaving to North Carolina by the end of next week...gotta get these projects finished and all.

If this doesn't work, I'll try the voltage regulator off a 67 VW Beetle with a generator.

Kev

ClydesdaleKevin · September 19, 2012, 07:29 AM

Okay, belay my last. I just ordered a 120mm 48 volt fan that draws even less amps than the 12 volt fan I got at Radio Shack, which I can return since I didn't modify it yet. Brand new on eBay for 14 bucks with free expedited shipping and is supposed to be here on or before this coming Monday, so the timing is perfect.

The specs for the fan say it will run on 24-48 volts, .190 amps, and 93cfm at 48 volts, which means it will push out less at 24 volts and make less noise.

Not really enough room in the compartment for 2 24 volt fans, and this is the equivalent while drawing less amps than 2 fans wired in series.

No info on the watts the fan uses though, but the panels should put out more than sufficient wattage to run the fan.

Since its the same size as the 12 volt fan, it will mount on the brackets I already made for the fan, so I can install it Monday. If I can manage to find the time to finish wiring in the system before Monday, I still have the 12 volt fan to cool the controller while testing it.

I'm just hoping it really will run at lower voltage, but it should.

Kev

ClydesdaleKevin · September 19, 2012, 07:43 AM

Just checked out Mechatronic's website, the makers of the 48 volt fan, and apparently it is supposed to run on as little as 12 volts...just draws more amps the lower the voltage. Should work out well.

Kev

gadgetman · September 19, 2012, 10:08 AM

The specs for the fan say it will run on 24-48 volts, .190 amps, and 93cfm at 48 volts, which means it will push out less at 24 volts and make less noise.

No info on the watts the fan uses though, but the panels should put out more than sufficient wattage to run the fan.

.190 x 48 = 9.1 watts 93 cfm is a lot, the fan will be noisy at that rate. Those are high speed fans.

ClydesdaleKevin · September 20, 2012, 07:33 AM

Maximum voltage the solar array puts out is around 30 volts, so it won't run as fast and be quite so loud, and being installed under the dinette bench will muffle the sound. I'd rather put up with a little bit of white noise than make the solar controller less effective from overheating.

Morningstar's tech department wrote me back about the horizontal install, and they said it wouldn't hurt the controller, but could cost me efficiency since it has a built in safety feature that steps down the output if the controller gets too hot until it cools down...they said the muffin fan would work just fine to keep the controller cool and operating at peak efficiency.

And I even decided what I'm going to do with the 12 volt muffin fan...some time in Carolina before our winter vacation I'll take the loud rattletrap conventional 12 volt van out of the range hood over our stove, and replace it with the 12 volt muffin fan since they are about the same size. Way quieter, more CFM, and less amps...sounds like a good plan to me!

Now if they only made low amp draw fans to replace the blower fans in our furnaces....

Kev