My 12v Solar Panel Plan.. I would like feedback..

Cariboocoot

Re: My 12v Solar Panel Plan.. I would like feedback..

Just my opinion but ... fuse protection for short-circuited panels is not the same as following NEC regs for standard circuit protection. Most of the time the panels will produce less that their Imp rating. Therefore you really only have to protect them against being fed over the Isc rating; the usual "fudge factor" isn't an issue. Or to put it another way; the next available size up from the Isc is fine. You could use 7.5 Amp on the Grape panels and 10 Amp on the Cynergy without trouble.

Everyone is free to disagree or agree with this; just don't try to argue with me about it.

ywhic

Re: My 12v Solar Panel Plan.. I would like feedback..

Re-did my proposed setup

Morning Star Pro 30 Controller

Xantrex Pro SW1000 Inverter

2- NAPA 8144 Battery (6v and 184 ah each)

3- Panels of 100 watt or 2 of the 140 watt.. (pending timing).. (or some combo to be at or close to 300 watts to start)

Midnight Solar NMPV3 Box with 4 breakers pre-installed in it.. (10 or 15 amps pending on the panels chosen)

10AWG MC4 from the panels to the above 3R rated box..
(4 separate 15' MC4 cables and cut in half to get length to get to the MS MNPV3 box which will be mounted NEAR the panels)

8AWG wire from the MNPV3 outdoor box to a cutoff switch near the controller inbound lugs (for shut-off and maitenance of controller, etc..).. should be about 15' or less.

6AWG wire from the controller down to the battery with a 40 amp breaker on the + line..

2AWG wire from the batteries back to the inverter with a 110-140 amp breaker on the + line..

I got it to $740 with the batteries, but without the solar panels or the mounts for them..

I'll be making a hinge/adjustable system.. so I can adjust to my locations 3 horizons spring/summer/winter..

Does this sound like a safer/better setup??

Cariboocoot

Re: My 12v Solar Panel Plan.. I would like feedback..

I don't see anything amiss about it. Looks like it should all work well and have a bit of expandability built-in.

ywhic

Re: My 12v Solar Panel Plan.. I would like feedback..

Thanks..

Do think I should spring for the PowerMax PMTS-30 (mentioned in another post in this sub-forum) for $60 now or wait for abit after I do the initial install of this 'mess'..

Attachment not found.

Then when I kick on a Generator the circuit will switch automatically from Solar to Generator and back??

Cariboocoot

Re: My 12v Solar Panel Plan.. I would like feedback..

Your system is small; save your money. You really don't need auto transfer switch at this stage, do you?
You may find you want a different inverter, and go for one with a built-in transfer switch and charger.

ywhic

Re: My 12v Solar Panel Plan.. I would like feedback..

Thanks to all..

I printed out my shopping page(s).. some stuff from NAWS some from other place pricing dependent (shipping also)..

Now to save my $$$ and start buying in pieces..

niel

Re: My 12v Solar Panel Plan.. I would like feedback..

unless you have a way to maintain the batteries properly wait to get then last.

solarvic

Re: My 12v Solar Panel Plan.. I would like feedback..

You might save money on shipping charges if you order the componets all at 1 time from each supplyer. :Dsolarvic:D

dhsola

Re: My 12v Solar Panel Plan.. I would like feedback..

I like the Kyocera panels you mentioned because they have a junction box - no MC4 connectors required.
http://www.solar-electric.com/kykd140wasom.html

Kyocera says #10 wire max but I've used #10 Tray Cable and wired both wires from the two conductor cable into the junction box for the inter-connects with no problem. ..Also ran two of the #10 tray cables from the junction box to the bus bar and breaker(s). Made a bigger hole in the wall too.

Cariboocoot

Re: My 12v Solar Panel Plan.. I would like feedback..

But those junction boxes can present their own problems - like keeping water out. You have to take care with the installation.

dhsola

Re: My 12v Solar Panel Plan.. I would like feedback..

Cariboocoot wrote: »

But those junction boxes can present their own problems - like keeping water out. You have to take care with the installation.

We don't worry about rain here in the desert but when it does rain, we all go outside and drop to our knees in awe.

The junction boxes include little rubber bushings that go over the wire, under the outside nut (and through the woods to grandma's house) that seem to seal well and an additional seal around the knock-out. The junction box has a gasket around the door too. Here, I'm more concerned about the bushing and seals deteriorating from the heat. But yes, you should 'take care with the installation', probably more so if your panels are at high enough angle to get rain water on the back side.

ywhic

Re: My 12v Solar Panel Plan.. I would like feedback..

@ niel... batteries will be last and local from NAPA out in TX.
@ vic.. my free shipper (whoevers pricing is cheaper to start also) don't carry it all..

NAWS is going to be for my 8AWG wire (28' as I want extra), Midnite Combiner, Bussbar, & 4 Breakers $182
My MS Pro 30 charge controller and 4 sets of Z brackets from SolarBlvd.. $177
4- 15' MC4 wires from another place.. (free shipping and cheaper) $205
The Xantrex Pro SW1000 is from a Marine store with free shipping and cheaper also.. $237
10' of 6AWG wire 6/2 marine 3R wire from a another marine shop on EBAY $20..
3' of Powerbright 2AWG wire set.. $27 from Amazon..

NAPA batteries (last.. will be from NAPA out in TX) $268 for 2.. (no core as I don't have any)
Panels (pending) Grape will be from Home Depot or 100-125w panels from ULSOLAR ($600-800 pending on panel #)

@dhsola.. I'm acutally going to mount the junction combiner on a POLE under a 3x sized mini-roof to protect it all.. & I love Permatex RED (in addition to the provided rubber bushings of course)..... I will take care on that..

The panels angles are 60 for Spring, 84 for Summer, & 36 for winter.. guess I can rig a small aluminum back stop to deflect water away and mount to the frame edge.. or rig up something to protect the factory junction box.. thanks for the tip on that..

Thanks for all the tips..

Now off to tackle the WATER pump and piping for the cabin...

solarvic

Re: My 12v Solar Panel Plan.. I would like feedback..

I think its good to shop around but think you are paying too much for panels. You could get a couple bigger panels and have more power than you will get out of 3 dinky sized panels for less money. Get your panels shipped to a trucking terminal near you. You save lots of money over having delivered to a residence. For me UPS Freight seems to be the cheapest and the terminal is only about 30 miles from me. Last time I got 4 185 watt kyocera panels 1200 and $200.00 shipping from our host to nw pennsylvania. I think they are sold out of the 185 watt panels but they have a little larger panels at not too much more. solarvic

ywhic

Re: My 12v Solar Panel Plan.. I would like feedback..

solarvic wrote: »

I think its good to shop around but think you are paying too much for panels. You could get a couple bigger panels and have more power than you will get out of 3 dinky sized panels for less money. Get your panels shipped to a trucking terminal near you. You save lots of money over having delivered to a residence. For me UPS Freight seems to be the cheapest and the terminal is only about 30 miles from me. Last time I got 4 185 watt kyocera panels 1200 and $200.00 shipping from our host to nw pennsylvania. I think they are sold out of the 185 watt panels but they have a little larger panels at not too much more. solarvic

I'm guessing your panels are 24v... mine are 12v..

I found some 12v 125 watt panels $1.99/watt on about 4 different websites with free shipping..

Home Depot has the Grape 100 watt for $1.99/watt also with free shipping.. (but I am learning they are positive ground panels)

vtmaps

Re: My 12v Solar Panel Plan.. I would like feedback..

solarvic wrote: »

I think its good to shop around but think you are paying too much for panels. You could get a couple bigger panels and have more power than you will get out of 3 dinky sized panels for less money.

ywhic wrote: »

I'm guessing your panels are 24v... mine are 12v..

Albert, I'm sure you're correct about the larger panels being higher voltage. You would need an MPPT controller. As mentioned earlier in this thread, the increased cost of an MPPT controller might be offset by the savings on higher voltage panels and the savings on not needing combiner box and fuses. Have you considered the Rogue controller? I have never seen or used one, but it gets a lot of respect on this forum and can be had for about $325.

By the way, nobody on this forum answered your question about modifying a Midnite MNPV3 to hold more breakers. I saw your post over at Midnite where you got the answer you hoped for. Tip of the hat to you for realizing that it could be done. I'll keep it in mind if/when I ever need to upgrade my MNPV3.
--vtMaps

ywhic

Re: My 12v Solar Panel Plan.. I would like feedback..

vtmaps wrote: »

By the way, nobody on this forum answered your question about modifying a Midnite MNPV3 to hold more breakers. I saw your post over at Midnite where you got the answer you hoped for. Tip of the hat to you for realizing that it could be done. I'll keep it in mind if/when I ever need to upgrade my MNPV3.
--vtMaps

I try to go direct with questions when I can.. didn't know the rep would respond on the weekend over at Midnite Solar..

I'll stick with 12v panels for now.. for me 30 amp 'cabin' service to start with should be enough.. LoL

Photowhit

Re: My 12v Solar Panel Plan.. I would like feedback..

ywhic wrote: »

...I'll stick with 12v panels for now.. for me 30 amp 'cabin' service to start with should be enough.. LoL

There is another somewhat sophisticated way of 'growing' your system. As your running a 12 volt system, likely you could recieve as much current per dollar (Amps or Isc) by buying what they are calling 24 volt panels (for the most part, they aren't but that's another thing entirtely) and be safely with in your charge controllers VOC limits (pretty sure this works for C series CC, not sure about others but think/guess it's fine) Not sure what the difference in price is between the 235 watt panels@$1 a watt verses the cost of the 140 watt cycnergy.

Likely this would give you near the same output now on PWM charge controller, and then you could increase your useful Amps by near 50% by changing to a MPPT CC later.

Likely the shipping would cost more, but worth checking. The other panles are UL rated something to consider if you everr switch to an ongrid system. And the have Tyco connectors legal, but different from MC4 connectors.

You were doing so well understanding things, I figured it was time to confuse you a bit...lol.

For expansion reason, I'd plan to buy either panels in pairs, make growing to a 24 volt system easier.

ywhic

Re: My 12v Solar Panel Plan.. I would like feedback..

Quick followup question.

I am buying 8AWG wire to go from the PV combiner box about 15' to the cabin..

Can I use the same 8AWG wire for a 4' span to handle the MAX 30 amp load going down from the charge controller to the battery array??

I was going to go with 6 AWG but I already have extra 8 AWG here..

Looking at wire charts is giving me grief/headache.. Says 0.82% loss with 6AWG and .155% loss with 8AWG for 4'..

Cariboocoot

Re: My 12v Solar Panel Plan.. I would like feedback..

8 AWG will have no trouble handling 30 Amps @ "12 Volts" over 4 feet. As you've seen, the Voltage drop is minimal and it is certainly able to carry the current.

ywhic

Re: My 12v Solar Panel Plan.. I would like feedback..

1 more question..

If I go with 2 panels (12v) to start in parallel can I use 1 fuse/breaker for that pair?? (ex 15 amp)
I know you had mentioned something about NOT needing to fuse 1 pair.. I would like to fuse/breaker though..

So a 2nd pair of panels (12v) down the line (again in parallel) would have another fuse/breaker on that pair..

Part/Phase #1

Attachment not found.

Part/Phase#2 (with a 30 AMP breaker after the 1st 2 breakers just before going into the charge controller)..

Attachment not found.

Cariboocoot

Re: My 12v Solar Panel Plan.. I would like feedback..

Albert;

Your first diagram is correct. You can and should put circuit protection on the combined output of the two panels, just to be safe. If it is a breaker you have the advantage of being able to switch the panels off if need be.

The second diagram is not right. Each panel needs its own fuse; you can't combine two on one. Think of it this way; the fuse/breaker in the first diagram is for the whole array. It is equivalent to the third one shown in your second diagram. As shown in your drawing, three of the panels can send their combined Isc to the fourth if it becomes shorted and none of the circuit protection will be carrying more than its rated current.

Say the first panel in that drawing becomes shorted. It can take the full Isc of the second panel that is connected directly to it. It can not take the additional current supplied by the other two panels which will come through both breakers and not exceed either one's rating.

ywhic

Re: My 12v Solar Panel Plan.. I would like feedback..

Thanks.. figured I'd ask..

I'll just buy the 70AMP Rated 2/4 circuit QO 3R outdoor junction/box I found for like $35.. and throw some tandem 15amp breakers in it.. ot get the 6/12 box and throwup to 6 single QO breakers in that.. (at 10amps each)

For like $70 I can cover all 4 panels separately..

Cariboocoot

Re: My 12v Solar Panel Plan.. I would like feedback..

You mean you'll put up the combiner box for all four panels now and save yourself the rewiring later. Very sensible.

On an individual basis, most any solar panel only needs a 10 Amp breaker. Very few produce current above 8 Amps.

vtmaps

Re: My 12v Solar Panel Plan.. I would like feedback..

Cariboocoot wrote: »

Your first diagram is correct. You can and should put circuit protection on the combined output of the two panels, just to be safe. If it is a breaker you have the advantage of being able to switch the panels off if need be.

This is something that has always confused and/or bothered me. That breaker, if polarized, cannot provide circuit protection and be a PV disconnect. Those are two separate purposes:

1) As an overcurrent protection device its purpose is to prevent current flow from controller to panel. It should be sized greater than the max current from the panels, and consequently should never see overcurrent unless there is a fault in the controller that allows battery current to the panels. If the breaker is polarized, the panels are the load.

2) As a PV disconnect the controller is the load, and if the breaker is polarized it must be installed with polarity opposite the overcurrent breaker.

I inquired about this some time ago on the midnite forum because (at the time) I didn't understand why my Epanel wiring diagram has two breakers in series. One is for overcurrent protection and one is a PV disconnect. They are of opposite polarity.

NOTE 1) the overcurrent breaker happens to be ganged to a 0.5 amp breaker as part of the GFP device. This GFP device is required by NEC, but is probably a bad idea. Bill (the moderator) has written much about why this is such a bad idea.

NOTE 2) The midnite classic controller has built in GFP, so the current Epanel wiring diagrams have a note to omit the external GFP if a classic is used.

--vtMaps

BB.

Re: My 12v Solar Panel Plan.. I would like feedback..

The Xantrex XW MPPT 60 amp charge controller also include DCGFI internally too (probably the 600 volt MPPT controller also includes DCGFI--you would need to check)...

Since is pretty much physically impossible for a solar array to generate enough current to trip a breaker going to the charge controller--You are pretty much left with the breakers/fuses protecting the (3 or more) parallel connected solar panel strings (one fuse/breaker per parallel connected string). So, technically polarized breakers would be OK to use in this setup. On the other hand, it is questionable if breaker could/should be used as an array disconnect in normal operation.

I just don't have any experience with polarized breakers to know (normal operation, you open a 8-10 amp current--Abnormal, breakers may be rated for 1,000 amps or more disconnect). The problem with DC arcs is that even smaller DC arcs sustain very nicely--so it may still be an issue turning off even "normal" current flow if the wrong polarity.

-Bill

ywhic

Re: My 12v Solar Panel Plan.. I would like feedback..

Does anyone have a list of controllers with DC GFP built-in??

I am looking at the Morningstar Pro 30 (30 amp controller)..

Heres what the booklet says..

7.3 PROTECTIONS
The ProStar is fully protected against system faults listed below. Recovery is automatic except
where noted below. Refer to sections 4.0 and 5.0 for fault indications.
• Solar short circuit and overload – fully automatic recovery
• Load short circuit and overload – after 3 automatic load reconnect attempts (10
seconds between each attempt), the fault must be cleared and the load must be
turned off or disconnected for 10 seconds or longer to restore power to the load
terminals.
• Reverse polarity – fully protected except per Caution below
• Battery disconnected – the load is protected from voltage spikes
• High temperature – first the solar is disconnected, then the load will be
disconnected; auto reconnects
• High battery voltage – first the solar is disconnected, then the load will be
disconnected; auto reconnects
• Very low battery voltage – brownout protection, auto recovery into LVD state
• Battery select error – defaults to gel battery setting, flashes LEDs
• Temperature sensor failure – a remote probe failure defaults to the internal
temperature sensor, which defaults to a fixed 25°C if it fails

CAUTION: One source of potential damage to the controller is a reversed
battery polarity (+/–) together with a polarized or short-circuited load.

And this is listed earlier in the booklet..

LUD LVD – low voltage load disconnect (load only)
HUD high voltage disconnect (both solar and load)
HOT high temperature disconnect (both solar and load)
OCP overcurrent and short circuit protection (load, solar overcurrent)
0.0 short circuit protection (solar only)

I'd like to know which controllers has is built-in to try an avoid the separate circuit/breaker thing..

I know the Xantrex SW Pro 1000 inverter has GFI outlet (going to be my choice).. but thats another matter altogether..

Cariboocoot

Re: My 12v Solar Panel Plan.. I would like feedback..

vtmaps wrote: »

1) As an overcurrent protection device its purpose is to prevent current flow from controller to panel. It should be sized greater than the max current from the panels, and consequently should never see overcurrent unless there is a fault in the controller that allows battery current to the panels. If the breaker is polarized, the panels are the load.

Nope. An over-current protection device is to prevent too high current flow in the circuit which would lead to over-heating and possible ignition of other components, chiefly wiring. It doesn't matter what kind of circuit it is used in. Panels can only put out their Isc, so there is no way they can trip circuit protection greater than that. The panels are never the load in respect to the charge controller as it blocks current flow from the batteries. If it should fail, circuit protection on the output side of the controller should trip preventing battery current from frying the (defective) controller and back-feeding the panels.

2) As a PV disconnect the controller is the load, and if the breaker is polarized it must be installed with polarity opposite the overcurrent breaker.

I inquired about this some time ago on the midnite forum because (at the time) I didn't understand why my Epanel wiring diagram has two breakers in series. One is for overcurrent protection and one is a PV disconnect. They are of opposite polarity.

NOTE 1) the overcurrent breaker happens to be ganged to a 0.5 amp breaker as part of the GFP device. This GFP device is required by NEC, but is probably a bad idea. Bill (the moderator) has written much about why this is such a bad idea.

NOTE 2) The midnite classic controller has built in GFP, so the current Epanel wiring diagrams have a note to omit the external GFP if a classic is used.

--vtMaps

And there is where it goes wahoonie shaped with NEC's ground-fault rules applied. This is one of the issues with it that some of us abhor. In a straight-forward non-GFCI circuit this dual polarized circuit protection is unnecessary. And since that method has always worked in the past ...

I think NEC is a bit confused about battery-based systems, frankly. Their desire for the DC ground-fault protection seems to be based on ordinary GT inverters where the DC power could only come from panels. MidNite has attempted to deal with this as best they can. It is still flawed.

Bill can explain this better than I.
But you won't find me recommending the NEC rules on this unless it is required to get the system approved.

BB.

Re: My 12v Solar Panel Plan.. I would like feedback..

I am not a big fan of DCGFI and I would, personally, bypass it with a solid earth ground instead. Otherwise, the Midnite Classic and the Xantrex XW MPPT 60 amp controllers are two that I am aware of that have internal DCGFI (the 600 volt Xantrex may too).

Regarding AC GFI... Having one on the inverter may not be the best idea... Say you have three circuits at your home/cabin/RV... You pop the GFI on the outside outlet (using a power drill)--Turns off the power to your fridge and lights inside the living area too.

If you have multiple circuits, I would use a separate GFI per circuit to prevent a system wide blackout. (note: there may be an issue with AC GFI and MSW type inverters--you MAY get false trips).

-Bill

ywhic

Re: My 12v Solar Panel Plan.. I would like feedback..

Cariboocoot wrote: »

But you won't find me recommending the NEC rules on this unless it is required to get the system approved.

I got no building codes in the county/town where I am at.. and the panels are not going on ANY roof..

I'll be mounting them on posts in tandems in a curve.. (following the HORIZON for my location)..

Combiner outside (3R box) with individual breaker/fuses for each panel.. and a single breaker/fuse just before the charge controller soley as a disconnect..

ywhic

Re: My 12v Solar Panel Plan.. I would like feedback..

BB. wrote: »

Regarding AC GFI... Having one on the inverter may not be the best idea...

Bill,

The inverter I like with the features I would like is the Xantrex SW Pro 1000 Watt with a SINGLE built-in GFI outlet on the front.. I don't have a choice on that.. I don't think you can unwire it and put in a regular one..

Attachment not found.

I plan on doing a single cable to JUMP into the cabin 110v wiring.. (like an RV connect type juntion box)..

I'll keep that GFI outlet issue in my head..

You have any other suggestions for a good SINE inverter under $250 that has more than one outlet??