Advice on getting power 250ft to batteries

[J.P.M.]

I very much appreciate the impute, and hope for more. Some in the form of this is what I would do with the panels, would be great as well. Here is what I took into consideration for panel placement.

1) The storage shed for solar, and back up propane line is situated in between a 500 gallon propane tank, and the cabin, approximately 30' from each. I did consider putting the storage shed near the panels, however winter access would be more of a challenge, but not my biggest concern because I anticipate some winter snow removal from the panels. My issue with the shed near the panels was running and extra 250' +- underground propane line to the shed for a back up generator. As it sits everything fits nicely. I have a buried propane line to the cabin, and another to the shed spot for the generator. I also have the underground cable from the shed to the cabin in the ground. I also thought about just running the genset up close to the cabin, but I want to charge batteries as well, when needed.

2) The panel placement gives me a wide open field facing directly to the south. They will be out of the way, and I have plenty of room for expansion. With the right mounts I can tilt for snow drop off, and some reflection from snow, There are no trees, poles or anything else to cause shading from shortly after sun up, to shortly before sunset in the winter, just the clouds. Cloud shading is why I am interested in optimizers. I just don't know how much they will help with that.

I need to deal with the long DC run, and I am hoping the 6 awg will be ok. The tristar 60 mppt controller states an impute voltage of up to 600v, Could I not run 10 or 12 Of the mentioned KuDymond 38 volt panels all in series, or for expansion ability run 2 x 5 or 6 in series then parallel at the output 190 volts and 18 amps for 10 panels. On calculator.net using 250' of 6awg they indicate a a voltage drop of 1.87%. I think I'm missing something here. In "theory" with my very limited electrical mind, I thought 30 of these panels would be possible.

Gord

No significant shade on an array means things can get simpler - as in no need for optimizers or micros for shade considerations. Fewer electronics to fail as well. KISS applies.

As for array orientation, if you are after maximizing annual production per installed STC kW, run PVWatts for your location. For ground mount and max. annual production per installed STC kW, I'd suggest starting with an azimuth of maybe 190 - 200 deg. and a tilt at local latitude. Do a few runs and zero in on the optimum azimuth/tilt combination. If seasonal adjustment is planned, rerun at tilts of latitude +15 deg. for winter and latitude - 15 deg. for winter. Do 3 runs, one for winter, one for summer and one for spring and fall. Some finagling is necessary. Exact dead nuts max. orientation is not necessary. This ain't rocket science. +/- 5-10 deg. for both az. and tilt is probably close enough and may well make construction easier/better/cheaper/faster.

[Ampster]

......
As for bragging rights, this rather conventional house has achieved ZERO CARBON
FOOTPRINT with all electricity and heat coming from the sun, mini-split heat pumps
making a huge contribution. Bruce Roe

Thanks for the explanation. Congratulations on the zero carbon footprint. I have a friend in Southern California who accomplished the same thing. Much easier to do there. If I remember correctly, in 2020 new construction in California will be required to be zero carbon..Stay warm.

[In the Stix]

J.P.M Thanks for that advice. I will take the steps needed to get my direction, and various tilt angles as right as I can.

I hope to stay on the topic of the thread I started, and still hope for some direct answers to the questions I asked. I want to know opinions on the 6awg wire I have, and will it work? If so how should I wire the panels to work best thru the cable, and for the charge controller. I have to admit it is a bit frustrating to ask direct questions from those that know, then to read more side tracks then answers. I thought i would break down my questions into segments, starting at the source, the panel configuration, the long cable run, and the charge controllers ability to to get the batteries charged especially in winter. I will have other questions about, safety components, inverters, monitoring etc. I think I'm on the right track battery wise, but if not it would be great to know before I start this spring.

I am on a couple firearms/hunting related forums, and like to think I know my stuff pretty darn well. I purposely look for people who ask questions trying to gain knowledge, of various aspects, then try to answer their questions, and stay on the topic of the OP. I find it very interesting, and still learn a few things as I go. As you know, my knowledge in the topic of solar is very limited. I am the type of guy that likes to learn. If I had unlimited funds and could simply phone a couple companies, and tell them i want an expendable 15kw system, I still wouldn't without basic understanding. Please give me the benefit of your knowledge. I think with it I can achieve a good well designed system, at a price that I can afford.

Thanks Gord

[Ampster]

............

I hope to stay on the topic of the thread I started, and still hope for some direct answers to the questions I asked. I want to know opinions on the 6awg wire I have, and will it work? If so how should I wire the panels to work best thru the cable, and for the charge controller. I have to admit it is a bit frustrating to ask direct questions from those that know, then to read more side tracks then answers. I thought i would break down my questions into segments, starting at the source, the panel configuration, the long cable run, and the charge controllers ability to to get the batteries charged especially in winter. I will have other questions about,
.........

First, let me apologize for my part in the side tracks. It does take two to tango and the dance takes a while when you dance partner is long winded.. I did get a satisfactory answer from Bruce about how he chose the location he did. My takeaway is that it is worth the extra copper of you can accomplish your production goals. My guess is his production goal was "system" performance not just panel efficiency.

Specifically you asked about 6AWG and you.did a calculation showing less than 2% voltage drop on 600 volts. That looks to be fine. The trick is to keep the voltage high if you have a long run. It sound like your controller can handle the high voltage. I am not a big fan of direct burial cable because it limits your future options and plastic conduit is so cheap, especially compared to the labor involved in digging and filling a trench. Years ago when I was spending the money for trenching a new electrical service I also added a couple of 1" conduits for future TV cable, fiber optic or telephone or whatever the future held in store. It turned out to be worth the minor extra expense.

My suggestion would be if you are going to the trouble of digging a 250 foot trench put in at least 1 inch plastic conduit. You can always throw your direct burial cable in the trench. At least the conduit would give you an upgrade path if you wanted to add another string. My 2 cents

[J.P.M.]

J.P.M Thanks for that advice. I will take the steps needed to get my direction, and various tilt angles as right as I can.

I hope to stay on the topic of the thread I started, and still hope for some direct answers to the questions I asked. I want to know opinions on the 6awg wire I have, and will it work? If so how should I wire the panels to work best thru the cable, and for the charge controller. I have to admit it is a bit frustrating to ask direct questions from those that know, then to read more side tracks then answers. I thought i would break down my questions into segments, starting at the source, the panel configuration, the long cable run, and the charge controllers ability to to get the batteries charged especially in winter. I will have other questions about, safety components, inverters, monitoring etc. I think I'm on the right track battery wise, but if not it would be great to know before I start this spring.

I am on a couple firearms/hunting related forums, and like to think I know my stuff pretty darn well. I purposely look for people who ask questions trying to gain knowledge, of various aspects, then try to answer their questions, and stay on the topic of the OP. I find it very interesting, and still learn a few things as I go. As you know, my knowledge in the topic of solar is very limited. I am the type of guy that likes to learn. If I had unlimited funds and could simply phone a couple companies, and tell them i want an expendable 15kw system, I still wouldn't without basic understanding. Please give me the benefit of your knowledge. I think with it I can achieve a good well designed system, at a price that I can afford.

Thanks Gord

I agree with your comments and appreciate what you're writing. Some of what I contributed to this thread was way off track. As a way of atonement, after this thread, I'll not be wasting any more of your time by my spreading my spoor over this or any of your future threads.

As for education, and no more than my opinion, this forum is a good place to fill in the cracks created by real self education. Better questions get asked that way and they tend to be fewer in number. That's also considerate to other posters who won't be as frustrated answering questions a poster could answer for themselves. IMO only, that's a matter of consideration and respect not only for others but for questioner as well. The informed questions then act similar to mortar to fill in the cracks created by the self education, but the uninformed questions do not necessarily produce a good foundation or a first source of knowledge.

To that end is why I suggested you get informed about PVWatts. It's a good start on what you might need and one way to get information on things you mentioned in the first paragraph of your first post to this thread. Take it for what it's worth. There are also many good books dealing with residential solar PV design for both on and off grid. Google is your friend.

As for your frustration, I feel your pain , but maybe as one who sees the uninformed stumbling around in ignorance and unwilling to do a little reading on their own and then I wind up as cannon fodder when an attempt is made to help out with some things that may be useful but that the ignorant in their lack of knowledge find intrusive and off topic. In such cases I've learned to pick and choose which posts I read and ignore the ones where I'm ignorant of the subject matter and so possibly dangerous.

Since I'm not in the business of knowingly pissing people off, I'm afraid I'll need to decline your request for any further information. Sorry I wasted your time.

Good luck in your future endeavors.

[In the Stix]

My time was not wasted, and I wasn't t pissed off. I do apologize if I offended anyone. It was not my intent. I realize that people have varying opinions, about virtually every subject there is. The term "more then one way to skin a cat" applies to everything. If I can make this cable work, I would like to. 6-4-2 cable is not cheap up here.I can put the money saved elsewhere in the system. I'm working on that premise with the panels, and the Battery as well. These 3 areas are where I know I can save money. Possibly pole mounts as well. As I mentioned I am looking for good 3 season power supply, with some propane back up, for the next 6-7 years.

I am learning this morning.
Ampster your comment about a second string in the future got me thinking. My trenching costs me fuel, a few beers, and some food. My nephew has the equipment. I'm not concerned about possibly digging another trench in 6 years. I'm sure my buddy would be happy to keep an eye out for more new cable scrap. I think in 6 years he will find something. if he does I will buy it and store it. If I don't use it I will pass it along to someone else. If by chance he finds a suitable length of bigger cable before spring i will use that, but 6 awg is where I'm at right now..

The money that I could save by not buying another cable, could buy 6-8 more panels, could buy me more battery capacity, could buy more inverter, or other related components. I prefer to keep the costs down while buying and installing enough to do the job.

Let me ask more specific about panel wiring configuration, with the premise that the long run 6 awg wire is my only option. 6 to 7 years for batteries, and inverters, etc is my consideration.
5kw would be more then enough with everything turned on and running.

I can buy a 1 or 2 pole mount that will handle up to 20- KuDymond 144 cell, 340 watt, 38 volt 9 amp panels. Does it make more sense to buy a 20 panel system right now, at 50 cents per watt due to panel longevity? I prefer to keep my upfront costs down to start with less. then add in 6 years. What would you do?

If you were going to wire how would you do it?

10 to 12 of these panels 38 volt x 12 = 456 v @ 9 amps 1 string in series, or 2 strings 228 v @18 amps. not exact but close?

15-16 panels 1 string 570 volts @9 amps or 2 strings in series then parallel?

16 - 20 panels same question,

[In the Stix]

I agree with your comments and appreciate what you're writing. Some of what I contributed to this thread was way off track. As a way of atonement, after this thread, I'll not be wasting any more of your time by my spreading my spoor over this or any of your future threads.

As for education, and no more than my opinion, this forum is a good place to fill in the cracks created by real self education. Better questions get asked that way and they tend to be fewer in number. That's also considerate to other posters who won't be as frustrated answering questions a poster could answer for themselves. IMO only, that's a matter of consideration and respect not only for others but for questioner as well. The informed questions then act similar to mortar to fill in the cracks created by the self education, but the uninformed questions do not necessarily produce a good foundation or a first source of knowledge.

To that end is why I suggested you get informed about PVWatts. It's a good start on what you might need and one way to get information on things you mentioned in the first paragraph of your first post to this thread. Take it for what it's worth. There are also many good books dealing with residential solar PV design for both on and off grid. Google is your friend.

As for your frustration, I feel your pain , but maybe as one who sees the uninformed stumbling around in ignorance and unwilling to do a little reading on their own and then I wind up as cannon fodder when an attempt is made to help out with some things that may be useful but that the ignorant in their lack of knowledge find intrusive and off topic. In such cases I've learned to pick and choose which posts I read and ignore the ones where I'm ignorant of the subject matter and so possibly dangerous.

Since I'm not in the business of knowingly pissing people off, I'm afraid I'll need to decline your request for any further information. Sorry I wasted your time.

Good luck in your future endeavors.

JPM just for your information i have been reading and learning, " getting dat thar, real self education" Not only do you think you know the best way, and the amount of research needed in order to ask a question, you obviously did not like the fact that I asked questions. In your own superior, electrical mind you decided that I was to incompetent deserve your opinion. I am sure this is why you proceeded to do what I am sure you have done many times. Which was to change the subject, hijack the thread, and especially to take a few jabs at others including me, and my less then mediocre electrical mind. I am sorry that my inferior electrical intelligence was not worthy of your advice, or meaningful impute.
You could have advised 10 or 12 panels wired this way, or that way would work with the wire, and run length, or in contrast,,,, it will not work.

FYI I have a file folder over an inch thick. The first thing I did, which was quite some time ago, was to determine my worst case month, December, as you advised above. I can achieve this with limited panel production, and back up generation.

I also went to calculator.net to get an idea of the wire I bought, for this application, using a 600v charge controller.

I was hoping for some real world verification, and advice on how best to wire the panels.

I am sure you don't think about or care about wasting my time with your spoor, but rather you do not want to waste your time by answering questions of the unworthy, like me.

[Ampster]

I can buy a 1 or 2 pole mount that will handle up to 20- KuDymond 144 cell, 340 watt, 38 volt 9 amp panels. Does it make more sense to buy a 20 panel system right now, at 50 cents per watt due to panel longevity? I prefer to keep my upfront costs down to start with less. then add in 6 years. What would you do?

I need more information to advise on that. Generally pole mounts can be very productive but I know little about cost comparison.

If you were going to wire how would you do it?

10 to 12 of these panels 38 volt x 12 = 456 v @ 9 amps 1 string in series, or 2 strings 228 v @18 amps. not exact but close?

15-16 panels 1 string 570 volts @9 amps or 2 strings in series then parallel?

16 - 20 panels same question,

Based on your commitment to 6 AWG and the distance I would go with the highest voltage that your controller would handle. I would still throw in a piece of conduit but that is based on my assumptions about the price of conduit versus the time and effort to trench vs pulling a pair of wires.

[littleharbor]

15-16 panels 1 string 570 volts @9 amps or 2 strings in series then parallel?

16 - 20 panels same question,




Look up the string calculator for your controller and try different configurations. Your 15 - 16 panel string and higher count strings will likely be too many panels. The panels Voc. voltage is used for these calculations factored with the lowest expected temperatures for your area.

[In the Stix]

Thanks Ampster. After your suggestion, I checked on and decided that conduit will go in the ground. My commitment to 6 awg, is quite simple the 6 became available for $100, many times more $ to buy even at wholesale, the difference pays for the charge controller. and if 4, awg becomes available it will go in the ground. Maybe they will both go in the ground whether it is 4 or 6, if it makes sense, and more becomes available. The panels are frame-less. the best price I can find per watt, and are of good quality, I think.

I'm just trying to save money wherever I can, and learn whatever I can in order to make buying, and installation decisions, and at least have some basic knowledge, as I know solar is not just a plug it in and forget it proposition. We have a pretty ambitious year in front of us, that includes the solar/genset, finishing the cabin, building a self watering garden that's protected from the critters, and burying a sea-can underground, for canning, potatoes, and other food preservation. The sea-can will also provide weather protection should we ever need it. My wife and I have both lived thru a big tornado up here, and the cabin is on screw piles.There is a little more to our goals this year, but I don't want to be be too boring.

[neweclipse]

Not doubting your word, but, you built 6-7 homes and yet agonize over a piece of discounted copper...and, oh, wordy, yes.

[In the Stix]

Not doubting your word, but, you built 6-7 homes and yet agonize over a piece of discounted copper...and, oh, wordy, yes.

Although you are doubting, yes my wife and I did build houses. We did not do any electrical ourselves. We were the general contractors, and I did what you might consider to be the mundane trades myself. Paint, base boards, decks landscaping, and fences. Things like that.

I wouldn't call it agonizing, but did and do have some concern about the copper. I don't want to waste it if I can use it.

We have weather variations form -40 to +90 f Rarely over +80, and a few days each year below -40 daytime.

I will watch the "wordy" Very valid point. I've been told before.

You can criticize, or give me words of wisdom, "Your choice" I'm a big boy, I can take it. The latter would be much appreciated.

My average panel production will be approx 1240KWH? per year for 1kw of panels with December being the low of 720kwh/yr

We will be using a 600v charge controller.

Our plan is 6-7 years part time power, then up grade battery, inverter, etc. .Add to these panels our add another string.

[neweclipse]

There is your answer..."We will be using a 600v charge controller."

Higher the voltage, the lower the current.

[pellets4fuel]

Gord,
Midnight solar has a nice online calculator to see what size CC to use given different panel configurations. They take into account the temp coefficients that come into play for when your kicking out more power in colder weather. It's not just about the panel tag says under standard test conditions. Keep your volts up, and amps down to keep line size smaller and efficient. That 600v Mppt is a little more costly than Midnight 250 if it would work after checking the sizing tool. I am far from being smart enough to give advice. I am still learning myself and am finally going to build an experimental system in my shop this spring. About 1500w of panels with a 1200w wind generator. I too have the issue of almost the same exact distance as you that's why I was reading your thread, to help with my answers, and see what advice you got. I still need to read and educate myself more on the relation ship of size of batteries to input available as to have enough to keep X amount of amp hours charged. Good luck with it all!
David

[Mike90250]

Morningstar and Schneider also make 600V charge controllers.