Non E-panel installation references?

[BlackwaterPark]

Greetings.  New to forum,  and solar in general.   So,  just purchased the classic 150,  and trying to hunt down instalation instructions that don't include an e-panel or the like,  and not finding too much. 

Basically,  what I have is 4 6v gc2s configured to 24v, the classic,  a pair of 250w Canadian solar panels (30.1 vmp), the midnite 6 string combiner box,  and a samlex 600wsa.  The eventual plan is to have between 6 and 8 of those panels.   Will be mounting interior components on plywood for now (plan on getting epanel and vfx3524 in a few months,  just making due for now).  Is there a wiring schematic somewhere that shows how to wire the classic without the use of the panel?  What i was thinking of doing was running 4awg thhn from the combiner box to the controller where it says pv + and -.... Should a breaker interrupt the circuit between the two (aside from the 15a one in the combiner box)?  And the a 100a breaker on the positive line from controller to bank using 4awg.  Is this right?  And running the ground wire from the ground nut in the classic to the service panel ground bar.   Is it that easy,  or am i missing something?  This is completely off grid,  btw.  Any and all input would be appreciated, gentlemen.

[boB]

Good morning and welcome !

Well, sounds like you have this about right.

Breakers on the output (the 100 amp you mentioned ?) is absolutely necessary.

If it were me, and I was in a similar situation, I would plop the Classic up on the board, add that battery side breaker and start making electricity.

So, i.e., you can do without an E-panel.  But you will also need to connect up your inverter and/or other DC loads to the battery which can be done without an E-Panel but don't forget the circuit breakers on your inverters too.

boB

[BlackwaterPark]

Alacrity,  thy name is boB! Thanks much for the confirmation sir.   I believe a single dcv breaker would be placed on the positive lead to the inverter,  but i was unsure of the sizing there.   Any ideas?  For now,  ie until the vfx upgrade,  the loads are only led lights and misc electronics.

[boB]

The sizing depends on the power rating and the voltage and of course the wire size, which is what breakers are there to protect.

Sounds like you are at 12 volts DC so that's taken care of.

So, 250 watts X 2 is 500W and 500 W / 12V  is around 42 amps for the battery side so you would use sizing of
around  50 amps.  I would use 50 or 60 amps.
On the PV side, 500 watts is around 500W/30V (Vmp), and if PVs are in parallel, that's around 17 amps.
So 15 amps is going to be on the small-ish side and at short circuit current, those panels may put out a bit
more current when they drag down to near the battery voltage, which happens some when the MPPT is sweeping.

So, for PV side, I would size to more like 20 amps...  But with the 125% rule, better make that more like 25 amps.
That is to take care of Edge of cloud effect.  There would also be another 125% on top of that making it 156% but
since you are (hopefully) using magnetic-hydraulic breakers (like all of our breakers are), you can stick with
sizing for 125% above max Isc (short circuit current).

boB

PS, it's early for me and this was a quick calculation but I think it's about right.

[BlackwaterPark]

If when you say 12v your talking about the nominal back voltage,  is actually 24. Not sure if that's what you meant.   And all the breakers i have are the midnite ones from Alt-e (an incredible company to do business with bte, on recommendation from raechal at midnite... so many thanks for that .

[Westbranch]

here are some conceptual diagrams you can reference, near the bottom of the page

http://www.midnitesolar.com/pages/kid/index.php

hth

[zoneblue]

Think of it as two main buses, positive and negative. Attach the battery directly to the buses, using conduit, as that section is unfused. Then attach both your charging sources and loads to the buses. All positives that connect to the positive bus need a properly rated DC rated breaker. The negatives connect to the negatve bus. The third bus is the ground bus. Normally the negative and ground buses are tied. If you dont do that you should fuse both the negatives and positives. Download the manual for the MNDC which has excellent wiring diagrams, which will help your understanding.

Sounds like you might be able to do with a Big Baby box, and the matching short bus bar and that should get you going. But just remember that these systems have the potential to be quite dangerous, and that just becasue its temporary doesnt mean you dont have to get the basics right.

[BlackwaterPark]

I think i need clarification on the whole 12v part of the conversation mostly... If bOB was talking about bank voltage then I'm guessing the breaker sizes change from what was recommended here as my nominal voltage is actually 24v.  And, for this system,  is it better to parallel the panels or will series work fine?

[boB]

I think i need clarification on the whole 12v part of the conversation mostly... If bOB was talking about bank voltage then I'm guessing the breaker sizes change from what was recommended here as my nominal voltage is actually 24v.  And, for this system,  is it better to parallel the panels or will series work fine?

Oooops !

Yes, I thought you were 12V for some reason so divide all my current values by 2, basically, especially if your PVs are in series
going into the Classic.

[BlackwaterPark]

Ah, thanks for the clarification bob. So 15a on pv side,  and 30a on the bank side.   And thanks to everyone else for the input... especially pointing out the big baby box...i didn't know that was a thing prior... very economical, and safer than what i had in mind.

[vtmaps]

especially if your PVs are in series going into the Classic.

With a Vmp of 30.1, those panels MUST be in series in order to charge a 24 volt battery.

--vtMaps

[ClassicCrazy]

I use the Mini DC Disconnect  box - the schematic on the box makes wiring quite simple and has all the mounting places for breakers -  input PV and output to the battery along with the breaker for inverter - if you are going to use an inverter.
This box made my usual wiring tangles manageable and done the correct safe way. So for a couple hundred bucks well worth it. You do need to order the input and output breakers separately. And if you ever want to add the shunt for Whizbang Jr it has a place for that too. Link below is for 175 amp inverter breaker but there are other sizes.

http://www.solar-electric.com/installation-parts-and-equipment/midnite/elenanddcdi/midcdipoce/mndc175.html

[ClassicCrazy]

Here is photo of my system with mini pv panel mounted on plywood.

http://midniteforum.com/index.php?topic=960.0

[BlackwaterPark]

Think i am going to try that big baby box... From the looks of it, it appears that all my connections can be facilitated in it's small footprint, which is also am added bonus as space is a valuable commodity in my house.

[ClassicCrazy]

Think i am going to try that big baby box... From the looks of it, it appears that all my connections can be facilitated in it's small footprint, which is also am added bonus as space is a valuable commodity in my house.

I used two din rail type 63 amp breakers for input and output , but I had to change the output to 100 amps and that is the other style breaker - forget what it is called but it has the 1/4 inch studs for wiring on them. The Mini PV will hold 5 din rail type breakers or three of the other type. So get another breaker besides the PV input and Controller output  to use for DC loads.