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04-30-2016, 08:19 AM
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#1
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Senior Member
Fleetwood Owners Club
Join Date: May 2012
Posts: 181
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Power switch on input side of controller?
Hello
I have two Kyocera 140 watt panels wired in parallel up on the roof of my rig. This panel array produces about 21 volts nominal and is wired into a Morningstar "Sun Saver" MPPT charge controller which is mounted inside the coach. The output of the controller is wired into my 4 x 6V battery series / parallel bank and the charge cable servicing the bank is fused with a 25 amp fuse. The system has worked well for the past two years.
The question I have is if it is necessary to install a fuse or some sort of switch on the input side of the controller (between the panels and the controller)? When I want to service the system now, I generally wait until the sun is not out, then disconnect one of the input lines to the controller. Has worked but is not the most elegant solution. Looking for ideas and guidance.
Thanks in advance
Jim
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Jim Brinsfield
07 Fleetwood Excursion
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04-30-2016, 08:32 AM
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#2
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Senior Member
Fleetwood Owners Club Ford Super Duty Owner
Join Date: Jun 2012
Location: SoCal
Posts: 15,749
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You are correct. A DC circuit breaker on the input and output of the solar controller allows for isolation and servicing. My system is this way. Recommended.
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Vince and Susan
2011 Tiffin Phaeton 40QTH (Cummins ISC/Freightliner)
Flat towing a modified 2005 Jeep (Rubicon Wrangler)
Previously a 2002 Fleetwood Pace Arrow 37A and a 1995 Safari Trek 2830.
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04-30-2016, 01:18 PM
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#3
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Senior Member
Fleetwood Owners Club
Join Date: May 2012
Posts: 181
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Thanks Vince for your response to my questions. I suppose a fuse or in your case apparently, a re-settable breaker used on the input side to the charge controller, is only really being used as a switch isolator to conviently remove power from the charge controller. I don't really see how these devices would enhance safety in the installation in any way. A short or current overload between the fuse or breaker and the solar array is not going to be protected by this design and since these devices would be located near to the charge controller, there is not much there to protect. So I would think a simple DC switch would provide the same function as a fuse or breaker.
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Jim Brinsfield
07 Fleetwood Excursion
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04-30-2016, 01:49 PM
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#4
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Senior Member
Join Date: Jul 2014
Posts: 35,349
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You are correct that a breaker or fuse rated above the output would never blow.
Breakers become nessessary at the junction box, when multiple panels can backfeed 1 shorted panel above the amp capacity of its wire.
A simple switch is all that's needed.
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04-30-2016, 04:19 PM
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#5
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Senior Member
Join Date: Aug 2015
Posts: 6,911
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An option, from handybob's site:
Quote:
I use the 250V cartridge type commercial fuses & holders. One of the folks I sent this to came up with a brilliant suggestion for fusing the solar leads; a two pole fused air conditioner electrical box with a pull-out disconnect. They are available 30 & 60 amp and have #4 lugs for the big wires we need to use. Connect the input from the panels to the controller on one side & the output from the controller to the batteries on the other. Disconnecting the entire solar system is then one simple motion. They are dependable and cheap, however the cheap one available at the box stores will not hold up to a constant DC load over about 25 amps, so look for a Midwest or GE.
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Mark
2008 Holiday Rambler Admiral 30PDD (Ford F-53 chassis)
2009 Honda Fit Sport
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05-01-2016, 07:48 AM
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#6
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Senior Member
Fleetwood Owners Club
Join Date: May 2012
Posts: 181
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I have purchased a marine grade battery isolation switch which I will use at the input to the charge control. Its a bit more elegant than just disconnecting the lead from the array to the controller when I need to service the system but it serves the same function. Thanks for your responses and suggestions
Jim
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Jim Brinsfield
07 Fleetwood Excursion
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05-08-2016, 06:22 AM
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#7
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Member
Join Date: Nov 2014
Location: Clearwater, FL
Posts: 40
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When I set up my system I installed a breaker between the SOLAR and the Morningstar MPPT 60 SOLAR charge controller and one between the SOLAR charge controller and the batteries. More so for the convenience of isolating each of them when I need to trouble shoot a problem.
One point to remember is that Morningstar's documentation stresses that you disconnect the MPPT controller from the batteries before disconnecting the SOLAR panels, to avoid possible electrical damage to the MPPT controller.
I may eventually remove the breaker between the MPPT controller and replace it with a disconnect switch..
Don
__________________
2013 Jayco Eagle 284BHS,2012 Ford F150XLT, EcoBoost w/3.73, 250Watt Grape Solar Panel, MorningStar MPPT 60 Charge Controller, Trojan T145 Batteries (260Ah), 1500 Watt Ramsond PSI, EnGenius WI-FI extender
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05-09-2016, 06:30 AM
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#8
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Senior Member
Fleetwood Owners Club
Join Date: May 2012
Posts: 181
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Quote:
Originally Posted by Mustang65
When I set up my system I installed a breaker between the SOLAR and the Morningstar MPPT 60 SOLAR charge controller and one between the SOLAR charge controller and the batteries. More so for the convenience of isolating each of them when I need to trouble shoot a problem.
One point to remember is that Morningstar's documentation stresses that you disconnect the MPPT controller from the batteries before disconnecting the SOLAR panels, to avoid possible electrical damage to the MPPT controller.
I may eventually remove the breaker between the MPPT controller and replace it with a disconnect switch..
Don
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With the SunSaver MPT 15 controller, there is no such limitation regarding the order of disconnect. In fact on page 21 of the operators manual there is a specific note that states "The controller will not be damaged regardless of the sequence of connections". The recommended connection order suggests that you first install the load fuse (I do not use the "load" feature on my unit so no fuse there), then install the battery bank fuse to power up the controller, then connect the solar array input power. I believe this is more of a safety issue and a best practice sort of thing. In any event, I appreciate your note.
Jim
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Jim Brinsfield
07 Fleetwood Excursion
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05-11-2016, 08:08 PM
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#9
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Community Moderator
Join Date: Sep 2011
Location: Between the Oceans
Posts: 8,026
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interesting topic on connect/disconnect sequences... for my midnite controller, i always connect the battery to it first; when disconnect, i disconnect the solar to it first. that is based on the manual and verbal verification with their tech support.
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Steven & Polly
2000 Country Coach Intrigue 40' ISC 350
2018 Ford Explorer 4WD
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05-12-2016, 06:36 AM
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#10
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Senior Member
Fleetwood Owners Club
Join Date: May 2012
Posts: 181
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Quote:
Originally Posted by CountryFit
interesting topic on connect/disconnect sequences... for my midnite controller, i always connect the battery to it first; when disconnect, i disconnect the solar to it first. that is based on the manual and verbal verification with their tech support.
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i think the sequence you outlined above is probably the best practice and is how I usually would operate my system.... battery is last off, first on.
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Jim Brinsfield
07 Fleetwood Excursion
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05-22-2016, 10:42 AM
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#11
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Member
Join Date: Nov 2014
Location: Clearwater, FL
Posts: 40
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Quote:
Originally Posted by Mustang65
When I set up my system I installed a breaker between the SOLAR and the Morningstar MPPT 60 SOLAR charge controller and one between the SOLAR charge controller and the batteries. More so for the convenience of isolating each of them when I need to trouble shoot a problem.
One point to remember is that Morningstar's documentation stresses that you disconnect the MPPT controller from the batteries before disconnecting the SOLAR panels, to avoid possible electrical damage to the MPPT controller.
I may eventually remove the breaker between the MPPT controller and replace it with a disconnect switch..
Don
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I apologize for this... I can not believe that I said to disconnect the battery(s) first. The MPPT is powered by the batteries, and the SOLAR panels should always get disconnected first... I must have been having a real bad day when I wrote that... I normally read everything over and over and over again before hitting submit. Again I apologize for it
Don
__________________
2013 Jayco Eagle 284BHS,2012 Ford F150XLT, EcoBoost w/3.73, 250Watt Grape Solar Panel, MorningStar MPPT 60 Charge Controller, Trojan T145 Batteries (260Ah), 1500 Watt Ramsond PSI, EnGenius WI-FI extender
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