planning to install pv system myself... what can I do/not do?

I'm working on building a house in southern Colorado and planning on putting in an off grid system with no tie ins and a diesel backup unit

I know as far as installing hv electrical systems 110/220vac it has to be performed by a licensed electrician, can I install the lv wiring myself? or does that have to be done by a licensed electrician too? If I can do the low voltage wiring that would make things a lot easier on the budget as I am a truck body electrician and I work on 12/24v wiring all damn day. If I am able to wire in the 24v lights and the PV system myself, I could save some $$$ plus the satisfaction of doing it myself trumps everything as with the rest of my house build

any information on this would be helpful

Comments

  • jcheiljcheil Solar Expert Posts: 722 ✭✭✭
    Re: planning to install pv system myself... what can I do/not do?

    There have been many threads on this before, but in general why even mess around with LV DC wiring?
    It is a lot cheaper to just wire everything for 110v AC.

    Most of your 12v/24v DC devices cost more than their 110v AC counterparts and having to run larger size wire for the DC devices can sometimes cost more than the device itself.
    Off-Grid in Central Florida since 2005, Full-Time since June 2014 | 12 X Sovello 205w panels, 9 X ToPoint 220w panels, 36x ToPoint 225w panels (12,525 watts total) | Custom built single-axis ground mounts | Complete FP2 Outback System: 3 x FM80, 2 x VFX3648, X240 Transformer, FLEXnet-DC, Mate-3, Hub-10, FW500 AC/DC | 24 x Trojan L16RE-B Batteries 1110ah @ 48v | Honda EU7000is Generator and a pile of "other" Generators | Home-Made PVC solar hot water collector | Custom data logging software http://www.somewhatcrookedcamp.com/monitormate.html
  • Organic FarmerOrganic Farmer Solar Expert Posts: 128 ✭✭
    Re: planning to install pv system myself... what can I do/not do?

    In many rural areas of the nation there is little-to-no code enforcement. Nobody cares what you do on your land. But the next parcel over might be in a different jurisdiction where the code enforcement officer is very strict.

    I live in a region where enforcement is very relaxed.

    I can not predict how your region is.
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: planning to install pv system myself... what can I do/not do?
    I know as far as installing hv electrical systems 110/220vac it has to be performed by a licensed electrician, can I install the lv wiring myself? or does that have to be done by a licensed electrician too? If I can do the low voltage wiring that would make things a lot easier on the budget as I am a truck body electrician and I work on 12/24v wiring all damn day. If I am able to wire in the 24v lights and the PV system myself, I could save some $$$ plus the satisfaction of doing it myself trumps everything as with the rest of my house build
    Welcome to the forum,

    In addition to what has been said, you should realize that your DC voltages will be all over the map... for example, a 24 volt system may be anywhere from 22.5 volts to 31 volts. This can play havoc with some DC lights, appliances, fans, or whatever.

    Take the advice already given and skip the DC wiring.

    As far as low voltage wiring is concerned... let's talk about what you plan to power with this system. You may find that you need a 48 volt system, and 48 volt systems range up to 62 volts at the battery. That is NOT low voltage.

    Even if you go with a 24 volt system, you will likely have PV string voltages that are not low voltage.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • wrenchmonkeywrenchmonkey Registered Users Posts: 2
    Re: planning to install pv system myself... what can I do/not do?
    vtmaps wrote: »
    Welcome to the forum,

    In addition to what has been said, you should realize that your DC voltages will be all over the map... for example, a 24 volt system may be anywhere from 22.5 volts to 31 volts. This can play havoc with some DC lights, appliances, fans, or whatever.

    Take the advice already given and skip the DC wiring.

    As far as low voltage wiring is concerned... let's talk about what you plan to power with this system. You may find that you need a 48 volt system, and 48 volt systems range up to 62 volts at the battery. That is NOT low voltage.

    Even if you go with a 24 volt system, you will likely have PV string voltages that are not low voltage.

    --vtMaps

    thanks,

    I see what you are talking about with varying voltage, the main reason I was planning on running LV lights is to reduce the load I would have to put on an inverter and reduce some of the parasitic loss associated by inverting, but with LED lights I guess it won't make that much difference.

    I'm looking at powering a 2 bedroom house with wood heat and enough power to run a regular size fridge/freezer, lights, washer, gas dryer, tv, radio and laptop (not all at once) and a water pump. also I will have 3 lights out to the horse barn and a few porch lights.
  • vtmapsvtmaps Solar Expert Posts: 3,738 ✭✭✭✭
    Re: planning to install pv system myself... what can I do/not do?
    I'm looking at powering a 2 bedroom house with wood heat and enough power to run a regular size fridge/freezer, lights, washer, gas dryer, tv, radio and laptop (not all at once) and a water pump. also I will have 3 lights out to the horse barn and a few porch lights.

    You want to design a system that will meet your needs. It is critical to know what your needs are (needs = loads).

    Imagine that you are shopping for a truck... You must know your loads or you might buy the wrong truck. It is a very expensive mistake to buy a half ton truck when you need a one ton (and vice versa). You cannot convert a half ton into a one ton (and vice versa).

    So it is with solar power systems: surprising little of your system will be usable when you realize what system you should have built.

    To design a system:
    1) define your loads (your needs)
    2) choose a battery and system voltage (far and away the most difficult part of the design)
    3) choose enough panels, electronics, and generator to keep your batteries charged and happy

    You are at the design stage where you must take the first step: define your loads. The average load, the peak load, the time of day (or night) that the load occurs, and the duration of the load are all important considerations in the design of a system.

    If you have an occasional very large load, you may decide to power it with a generator, rather than double the size of your entire system.

    Your (adjusted) lifestyle will dictate your loads... For example, I have chosen to limit my investment in batteries, meaning that they can barely sustain their voltage for the 10 minutes that my washing machine is drawing 500 watts. This means I do laundry when the sun shines or when the generator is running.

    Another consideration is your water pumping... for many off-grid homes the water pump is a defining factor in the design of a system. If you need 240 volts for a 'hard starting' conventional pump, you will have a large solar power system. An advantage of conventional pumps is they are cheap and locally available. Many off grid folks spend a small fortune on more efficient pumps, to avoid spending a larger fortune on upsizing their solar power system.

    Buy a kill-a-watt meter and think carefully about the kilowatthours that you will need.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: planning to install pv system myself... what can I do/not do?
    thanks,

    I see what you are talking about with varying voltage, the main reason I was planning on running LV lights is to reduce the load I would have to put on an inverter and reduce some of the parasitic loss associated by inverting, but with LED lights I guess it won't make that much difference.

    I'm looking at powering a 2 bedroom house with wood heat and enough power to run a regular size fridge/freezer, lights, washer, gas dryer, tv, radio and laptop (not all at once) and a water pump. also I will have 3 lights out to the horse barn and a few porch lights.

    If you're going to be running a refrigerator + other AC-only items the inverter is going to be fairly large and on most of the time. After that the 'extra on time' for incidentals like lights is irrelevant and not worth trying to save on. I know because I have worked this out and found no appreciable saving to having the Outback go to standby when there's no load demand.

    Washing machine is a big power user. So is a gas dryer if it has one of those heating elements for ignition. You might want to not figure those in to the design and instead run the generator to power them when it's time to do laundry (rather than have that much extra capacity sitting around doing nothing most of the time).

    Water pump can be another big draw, and can be mitigated somewhat by careful choice of pump and a large pressure tank or two.

    Get a Kill-A-Watt and measure the power usage of everything you can under actual working conditions. That information is golden for calculating a proper system size.
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: planning to install pv system myself... what can I do/not do?

    Based on my analysis for our place you are looking in the 3Kwh to 5Kwh or more per day. Similar structure and appliances
     
    KID #51B  4s 140W to 24V 900Ah C&D AGM
    CL#29032 FW 2126/ 2073/ 2133 175A E-Panel WBjr, 3 x 4s 140W to 24V 900Ah C&D AGM 
    Cotek ST1500W 24V Inverter,OmniCharge 3024,
    2 x Cisco WRT54GL i/c DD-WRT Rtr & Bridge,
    Eu3/2/1000i Gens, 1680W & E-Panel/WBjr to come, CL #647 asleep
    West Chilcotin, BC, Canada
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