Author Topic: MNDC250 Installation  (Read 199 times)

wandotales

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MNDC250 Installation
« on: August 04, 2018, 04:49:04 PM »
Hi everyone! I just recently purchased an MNDC250 disconnect panel and I am honestly confused. I am starting the solar installation for a van conversion. I have a 330W 36V single panel, a MC4 connector, a 30A MPPT controller, two 12V 150A lithium batteries, a 4/0 5' battery to inverter wire, and a 2000W inverter. For the box, I have a 15amp and 40amp breaker and 115V Surge protector.

Here's what I think I know:
- I connect the solar panel with MC4 connector and run the positive wire into the MNDC to the 15amp breaker, and then both wires into the MPPT controller. The positive wire on the battery-out side of the MPPT goes to the 40amp breaker and into the positive side of the battery, while the negative wire goes to the negative side of the opposite battery.
- Next, the battery negative 4/0 wire runs to the shunt and the positive 4/0 wire runs through the 250amp breaker in the MNDC to the inverter. The inverter positive 4/0 wire is run to AC outlets, and the negative 4/0 wire to the shunt.
- Also from the battery, a positive wire runs to the fuse block and from the opposite battery a negative wire runs to the fuse block. 
- For my DC appliances I will use AWG 18 wiring and for the AC outlets I will use AWG 12 wiring (I checked on Blue Sea Circuit Wizard). 

I'm not sure how the GFP 63amp comes into play, if my breakers are in the right spot, what to do with the surge protector, or where the display for the inverter and charge controller are connected.
Also are the breakers my on/off switch for the system or do I need to purchase that separately?

Someone please help! haha
« Last Edit: August 04, 2018, 05:22:35 PM by wandotales »

Westbranch

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Re: MNDC250 Installation
« Reply #1 on: August 04, 2018, 05:46:02 PM »
go to page 4 here   http://www.midnitesolar.com/pdfs/mndc125_250_manual.pdf... it is quite simple with the wiring diagram.  ;)
Come back with the next question..
KID FW1811 560W >C&D 24V 900Ah AGM
CL150 29032 FW V.2126-NW2097-GP2133 175A E-Panel WBjr, 3Px4s 140W > 24V 900Ah AGM,
2 Cisco WRT54GL i/c DD-WRT Rtr, NetGr DS104Hub
Cotek ST1500 Inv  want a 24V  ROSIE Inverter
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ClassicCrazy

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Re: MNDC250 Installation
« Reply #2 on: August 04, 2018, 06:26:33 PM »
Yes I was going to say same thing as Westbranch with that schematic - which should also be in the Mini DC disconnect box too. Skip the part 63/5amp breakers which are together and are the ground fault breakers if you don't have those and aren't going to use them.
There is a photo of simple wiring on Page 8 .
Ask again if you have any more questions after studying that schematic . It really cuts down on the wiring you need and is easy to do .

Larry
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

wandotales

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Re: MNDC250 Installation
« Reply #3 on: August 04, 2018, 06:52:42 PM »
Okay, I don't know if I'm that dense, but that's the diagram I've been staring at and have no idea how to figure out.

Westbranch

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Re: MNDC250 Installation
« Reply #4 on: August 04, 2018, 08:12:31 PM »
start with one wire so we can understand what is needed. and reference the schematic...
KID FW1811 560W >C&D 24V 900Ah AGM
CL150 29032 FW V.2126-NW2097-GP2133 175A E-Panel WBjr, 3Px4s 140W > 24V 900Ah AGM,
2 Cisco WRT54GL i/c DD-WRT Rtr, NetGr DS104Hub
Cotek ST1500 Inv  want a 24V  ROSIE Inverter
OmniCharge3024  Eu1/2/3000iGens
West Chilcotin 1680+W to come

ClassicCrazy

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Re: MNDC250 Installation
« Reply #5 on: August 04, 2018, 10:16:41 PM »
Look at the schematic
Where it says battery positive at the bottom left - that is where the positive wire from battery goes to the bottom of the big 250 amp breaker.  The top of that 250 amp breaker is the positive wire that goes to the positive inverter.

Going back to the bottom of the big 250 amp breaker where the positive wire from the battery goes - there is another wire that will go to the bottom of the 60 amp small breaker  labeled PV output disconnect ( I call it battery )  and the top of the breaker goes to the positive terminal of the output of the charge controller ( should be labeled  Bat + output  on the controller) . 

So you should get the idea - just follow all the wires out like that .

Larry

system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

wandotales

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Re: MNDC250 Installation
« Reply #6 on: August 04, 2018, 10:19:39 PM »
This is the diagram I made. I'm still not sure how the things on the bottom right should connect. How do I know that I don't need the ground fault breakers?
« Last Edit: August 05, 2018, 09:59:12 AM by wandotales »

ClassicCrazy

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Re: MNDC250 Installation
« Reply #7 on: August 05, 2018, 10:37:01 AM »
You shouldn't have all those wires going to the battery. There should only be two wires to battery. All the other connections are inside the MNDC box.

Basically you are moving the battery positive to the bottom of the 250 amp breaker and the battery negative to the shunt ( the opposite side of where the battery connects. )

So for example the red wire you show going from 40 amp breaker to battery positive would just go to the bottom connection of the 250 amp breaker( where the battery positive connects) .

Not sure what those two devices are on the right - but those wires should not be coming directly from the battery . If they are fuse boxes for loads then the positive connects to a DC breaker which is sized for the amp rating of the wire you use to go to those fuse boxes. The negatives would go to the DC shunt ( opposite side of the battery negative connection).

Larry
« Last Edit: August 05, 2018, 10:48:37 AM by ClassicCrazy »
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

Westbranch

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Re: MNDC250 Installation
« Reply #8 on: August 05, 2018, 11:12:59 AM »
Here a link showing the end result of assembling and mounting an E Panel.. You should be able to see most  of the wiring needed..
http://www.midnitesolar.com/pdfs/epanelManual.pdf
KID FW1811 560W >C&D 24V 900Ah AGM
CL150 29032 FW V.2126-NW2097-GP2133 175A E-Panel WBjr, 3Px4s 140W > 24V 900Ah AGM,
2 Cisco WRT54GL i/c DD-WRT Rtr, NetGr DS104Hub
Cotek ST1500 Inv  want a 24V  ROSIE Inverter
OmniCharge3024  Eu1/2/3000iGens
West Chilcotin 1680+W to come

wandotales

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Re: MNDC250 Installation
« Reply #9 on: August 05, 2018, 01:10:25 PM »
So helpful, I really appreciate you!

Okay let me gather my thoughts:
 - Batteries connected in parallel (positive to positive, negative to negative) with 4/0 wire
 - Positive wire from the PV runs into the 15amp breaker and then the MPPT PV+ side
 - Negative wire from the PV runs into the MPPT PV- side
 - Positive wire from the battery runs into the 250amp breaker
 - Negative battery wire runs to the 500amp shunt
 - Positive wire from the MPPT battery+ side runs into the 40amp breaker and then into the 250 amp breaker
 - Negative wire from the MPPT battery- side connects to the 500amp shunt
 - Positive wire from the inverter connects to the 250amp breaker
 - Negative wire from the inverter connects to the 500amp shunt (opposite side of battery)
 - Positive loads connected to the 40amp breaker
 - Negative loads connected to the 500amp shunt (opposite side of battery with inverter)
« Last Edit: August 05, 2018, 01:49:44 PM by wandotales »

ClassicCrazy

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Re: MNDC250 Installation
« Reply #10 on: August 06, 2018, 11:38:46 AM »
Hard to tell from your pictorial which terminals you  have the connections on.
It looks like you are missing one or two DC breakers in the MNDC box. 
Big one 250 amp is for your inverter
One the PV goes through to controller. ( yours is 15 amp on drawing )
One the output of the controller goes through on way to battery ( 40 amp on your drawing ?)
One is for your DC loads. It looks like you are missing this breaker in your drawing which means that the wire between your MNDC box and that DC distribution fuse box ( if that is what it is )  would be unprotected.  From your drawing it looks like you would need two DC breakers to feed separate DC distribution boxes. The MNDC has room for 5 DC din rail breakers so there would be room to add them.

You size the amps of the DC breakers for the size wire that you are using.
So for example  you have to use at least 14 gauge wire for your 15 amp breaker. You can use bigger wire if it will fit in. But lets say you use 10 gauge wire - you could still use the 15 amp breaker but you could also go up to a 30 amp breaker. The reason you would want to use larger wire is so you have less voltage drop. there are calculators to determine how much voltage drop you will have for the length of wire you are using.

Larry

« Last Edit: August 06, 2018, 11:49:55 AM by ClassicCrazy »
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

wandotales

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Re: MNDC250 Installation
« Reply #11 on: August 06, 2018, 08:26:22 PM »
Okay this is making sense. Also I spoke with a rep that said my MPPT to battery breaker should be 30amps like the MPPT. Do you know why I would have been sold 40amp instead?

This is the dc fuse block: https://www.amazon.com/gp/product/B01BXTXV1Q/ref=s9_dcacsd_dcoop_bw_c_x_2_w
It looks to me that the breakers are already in the fuse block or am I misunderstanding what the multicolored numbers are….
« Last Edit: August 07, 2018, 01:21:15 AM by wandotales »

ClassicCrazy

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Re: MNDC250 Installation
« Reply #12 on: August 06, 2018, 10:56:54 PM »
It does not matter what size breaker you have  for the MPPT controller - what matters is that you have the correct size breaker for the wire .  You cant put smaller wire on a larger breaker because it could be overloaded. But you can put larger wire on a smaller breaker . Part of your design has to take into consideration voltage drop for the length of your wire run.  That is why you might have to go larger wire. Also if you were running 30 amps on a 30 amp breaker you are right up on it's limit .

you have to design your system for cost ( smaller wire) and performance ( keeping voltage drop low )  and safety ( having the right size breaker or fuse for the wire you use )

If you have a short distance why not keep the 40 amp breaker and use 8 gauge wire  ? If you have a long distance you probably want to go with the larger wire gauge size wire too.

Yes you need a DC breaker at the MNDC box for the wire that goes to your DC fuse box.  You just have to imagine shorting a wire somewhere and what would open up to protect it. So if you shorted the wire between the DC fusebox and the MNDC box  - unless you had a breaker in the MNDC box there would be nothing to open up and protect it . The wires from your DC distribution box have fuses for each of the wires going to the loads so those wires are protected by those fuses.

Remember the breakers and fuses are not for the device rating  - they are for the rating of the wire connecting the device.

In your drawing above your 40 amp breaker to DC distribution fuse blocks do not look right.  You have two  wires of unknown size  coming from one 40 amp breaker.  If I had those breakers I would move the 40 amp breaker to the output of the controller and change that wire size to 8 gauge.  I would move the 30 amp breaker to be DC loads and use 10 gauge from that to one of your DC distribution panels.  Then I would get another 20 or 30 amp DC  breaker and wire that to the other DC distribution  using either 12 gauge for the 20 amp or 10 gauge for the 30 amp  As mentioned before some of that depends on what you need to do for voltage drop and the amount of amps you need for loads.

Larry

« Last Edit: August 07, 2018, 12:05:25 AM by ClassicCrazy »
system one
Classic 150 , 5s4p  Kyocera 135watt , 12s Soneil 2v 540amp lead crystal for 24v pack , Outback 3524 inverter
system two
Classic 150 ,5s 135 watt Kyocero , 16s Calb 100AH LiFePO4 , Outback VFX 3648 inverter
system three
Midnite KID MPPT 24 DC in to  12 volt AGM batterie

bee88man

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Re: MNDC250 Installation
« Reply #13 on: August 07, 2018, 10:15:58 AM »
Okay this is making sense. Also I spoke with a rep that said my MPPT to battery breaker should be 30amps like the MPPT. Do you know why I would have been sold 40amp instead?

This is the dc fuse block: https://www.amazon.com/gp/product/B01BXTXV1Q/ref=s9_dcacsd_dcoop_bw_c_x_2_w
It looks to me that the breakers are already in the fuse block or am I misunderstanding what the multicolored numbers are….

Multi-color numbers are fuses to protect down stream individule loads only.
What protects the upstream coming in?