Community Forums

tednruthy · 11-26-2011, 10:49 AM

I am installing solar on my 38 ft 2001 DSDP. I want to put my Solar controller and inverter in a compartment immediately in front of my batteries to keep them very close together. This compartment is roughly 2X2X2 feet cube with no ventilation. I am thinking that two 12 volt chassis fans with bi-metal thermal switches that turn the fans on at say 95 degrees and off at 75 degrees would provide adequate ventilation. I would cut openings in the back that would vent into the open engine compartment. I would shield the openings on the outside to minimize possible outside road moisture and dirt. I am thinking that redundant fans and thermal switches is wise. I may also look for and install a remote thermal alarm. I will need to provide a means for air to enter the compartment also to balance with the exhaust air.

Have any of you got any suggestions or experience in venting a compartment like this. I want to use minimal power and it must be 12 volts assuming that the solar controller may need this ventilation even when the inverter is not being used.

How much heat will a Morningstar TriStar 60 amp mppt solar controller put out while processing say 500 watts of solar panel? Can anyone verify that this controller does not have a cooling fan? I could maybe tie an external fan into the internal fan if it had one. This compartment is in an ideal location but needs reliable venting. I think other models of Newmars have their converter/charger/inverter mounted in this compartment. If this is so please provide details of if/how this compartment is vented with fans. All your expert ideas will be welcomed. THANKS, TED

"007" · 11-28-2011, 07:31 PM

Sorry Ted didn't get to you sooner, welcome to the forum & irv2.
I have a small 600 inverter in that compartment and they have no ventilation that I can see.
The specs for your inverter should tell you how much heat it will generate and what you may need for ventilation.
I think any heat would dissipate out of compartment because there only metal side walls.
This thread will move to top of forum maybe someone else will have a answer for you.
You sound to be you have a good understanding of what you need to do.

Spikester · 11-29-2011, 08:38 PM

My 2000W inverter/batt charger is in the compartment you are talking about without it being ventilated. I have 400 Watts of solar panels, but my MPPT solar controller is in the tank compartment, peg board side, it does not generate that much heat so I would think that intallating it in the compartment you are talking about would be fine. Getting your solar input to that compartment could be the challenge do not use the Newmar solar pre-wire because the wire is to small of a guage, solar wire to your controller should be 8AWG or larger (the larger the better) to prevent excessive line loss from your panels therefore making your solar system more efficient.

Spike

bigskymt · 11-29-2011, 09:05 PM

We have about 500 watts of solar input to our controller which we installed in the electrical bay. No forced air ventilation and the bay is reasonably air tight.
We charge four 6v and two 12v deep cycle batts at a max of about 30 amps. The controller is warm to the touch only.
If you plan on using Newmars preinstalled wiring be advised (according to Newmar) the access panel on the roof may or may not provide access to the solar wiring (or it may be nearby) ...................in my case it wasn't.

tednruthy · 11-30-2011, 06:22 AM

Spike, Thanks for the input. My coach has no pre-wire for solar. I am coming straight down through the roof and into a bedroom cabinet to the floor and over a couple feet and straight fown into the cabinet location of the solar controller. About 12 feet I estimate. I am using #1 AWG welding cable. Then 00 AWG for the short runs controller to batteries and inverter to batteries. each about 4-5 feet. Less than 1% total loss from panels to batteries. TED

Quote:

Originally Posted by Spikester

My 2000W inverter/batt charger is in the compartment you are talking about without it being ventilated. I have 400 Watts of solar panels, but my MPPT solar controller is in the tank compartment, peg board side, it does not generate that much heat so I would think that intallating it in the compartment you are talking about would be fine. Getting your solar input to that compartment could be the challenge do not use the Newmar solar pre-wire because the wire is to small of a guage, solar wire to your controller should be 8AWG or larger (the larger the better) to prevent excessive line loss from your panels therefore making your solar system more efficient.

Spike

wa8yxm · 11-30-2011, 10:07 AM

I would recommend putting the inverter one compartment over from the batteries.

You really don't want battery vapors messing with the electronics inside the inverter.

One improvement you could make would be to build a wood box around the battery box (And/or use a vented battery box) use the fans to pull from the wood box to the OUTSIDE... If the batteries out gas acidic vapor (Which they do) hopefully the wood will sacrifice itself to save the inverter, epically since it's under negative pressure (The fan sucking air to the outside) so the fumes are pulled out and air from around the inverter pulled INTO the box.. You do need an air inlet.

In my case that is exactly what I did, both inlet and outlet are protected with air filters.. I took a small "Round" air filter of the automotive type and drilling a set of 4 holes around a 4" hole in the back of the compartment behind the inverter (in line with it's fan in fact) I ran 4 long threaded screws through the holes and locked them with nuts, washers and locktite.

I then slipped the filter over the screws

Then a piece of plywood, drilled in the same pattern, and some more washers and nuts. This keeps dirt and insects out of the compartment rather well but lets air in.

tednruthy · 11-30-2011, 03:38 PM

wa8yxm, I have no intention of putting any electronics in the battery compartment. I am using the compartment in front of the battery compartment which I likely will vent using a chassis fan with a filter into the battery compartment which is not really a compartment but open to the outside as it has no bottom. Thanks, Ted

Quote:

Originally Posted by wa8yxm

I would recommend putting the inverter one compartment over from the batteries.

You really don't want battery vapors messing with the electronics inside the inverter.

One improvement you could make would be to build a wood box around the battery box (And/or use a vented battery box) use the fans to pull from the wood box to the OUTSIDE... If the batteries out gas acidic vapor (Which they do) hopefully the wood will sacrifice itself to save the inverter, epically since it's under negative pressure (The fan sucking air to the outside) so the fumes are pulled out and air from around the inverter pulled INTO the box.. You do need an air inlet.

In my case that is exactly what I did, both inlet and outlet are protected with air filters.. I took a small "Round" air filter of the automotive type and drilling a set of 4 holes around a 4" hole in the back of the compartment behind the inverter (in line with it's fan in fact) I ran 4 long threaded screws through the holes and locked them with nuts, washers and locktite.

I then slipped the filter over the screws

Then a piece of plywood, drilled in the same pattern, and some more washers and nuts. This keeps dirt and insects out of the compartment rather well but lets air in.

Luv2go · 12-01-2011, 12:13 PM

Ted:

Sorry for my late response, I went camping for Thanksgiving Day weekend and am just now wading through my e-mails.

I have a 50A Blue Sky MPPT controller, a second 30A Blue Sky MPPT controller and a Trace SW series 2500W inverter in my inverter compartment. The compartment is much bigger than yours plus it is open to another compartment, giving about 2x2x8 ft of volume.

I have one ~70CFM 12V 4" computer fan as an exhaust fan connected to an attic fan switch and one 4" dryer duct type air intake. The fan is set to start at 90 degrees (was 100 when I lived in NC but I have lowered it now that I live in MA).

The fan never turns on with just the charge controllers operating, it does run when the inverter is charging from genny or shore power, also when the temperature is high as you would expect.

Temps in the compartment never get more than 5 degrees above ambient with this cooling setup. I monitor the compartment temp with a wireless thermometer with overtemp alarm set to 103 degrees F in NC, have not set it in MA.

The intake is on the bottom of the compartment, it uses a dryer exhaust vent pointed to the front of the coach so air is forced in while driving. A 90 degree ell (for a dryer) inside the compartment mounted to the exhaust vent minimizes water intrusion very well, even while driving in rain, etc. The exhaust is on the side wall towards the top of the compartment so I do get some natural convection cooling.

The Morningstar controller is very efficient, they claim 99% peak, real world should be 95%, so if you are processing 500W you'd have less than 25W of heat to dissipate. As I mentioned, just running my two controllers (real world output is about 700W in peak sun in FL in winter) I have never had the fan turn on.

I agree with your idea of redundant fans and controllers for your install, that and the alarm will give you some peace of mind.

BTW, great choice for wire size for panel run and the charge controller to battery run, the 00 is good for most inverters however mine required 4/0 for the 3' run from inverter to the batteries.

tednruthy · 12-02-2011, 10:02 AM

Stewart, Thanks for your experiences and insights. I have changed my cable size for all the high current long lengths (over 2 ft) to 3/0 (000). I got a call from where I ordered the welding cable stating they were out of stock on 00 so they are sending 000 AWG for the same price.. TED