How JustAnswer Works:

  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.

Ask Kevin Your Own Question

Kevin
Kevin, Licensed Electrician
Category: Electrical
Satisfied Customers: 1139
Experience:  27 years as a Licensed Electrical Contractor in Illinois, 5 year college Electrical Instructor, Former Electrical Inspector, Diploma in Digital Electronics, Former Illinois Licensed Home Inspector
71008832
Type Your Electrical Question Here...
Kevin is online now
A new question is answered every 9 seconds

I am seeking advise on the best component matching for a small

Resolved Question:

I am seeking advise on the best component matching for a small 12 Volt home solar powered system
Submitted: 10 months ago.
Category: Electrical
Expert:  Kevin replied 10 months ago.

Hello Joel.....my name is XXXXX XXXXX I will be happy to assist you with your electrical question. My goal is to exceed your expectations on Just Answer!

 

1) What loads do you wish to power using solar?

 

2) Will the loads be DC or AC? Also how many amps?

 

3) What equipment have you purchased so far? Panels, Charge Controller, Batteries, Inverter, etc? I will need quantities as well as the size of the component wattages, amp-hours, etc.

 

Let me know what you have Joel and we can take it from there........Thanks...........Kevin!

Customer: replied 10 months ago.

Hello Kevin Thank you below are the components I have purchased with their links to amazon if you need any further info. Will these components work together?


 


Solar Panel Cable 50 Ft - Mc4 Pv Extension- 10awg - 600vdc - Sunlight Resistant
Sold by Shop Akari
http://www.amazon.com/gp/product/B008JHXF4O/ref=oh_details_o06_s00_i00?ie=UTF8&psc=1



SunforceNNN-NN-NNNNWatt Pure Sine Wave Inverter
http://www.amazon.com/dp/B0010X5KPG/ref=pe_385040_30332190_TE_M3T1_ST1_dp_1


 


I bought 2 of these batteries


Schumacher SB 121000 '12V' 100Ah AGM Sealed Lead Acid Power Sport Battery
http://www.amazon.com/gp/product/B009II5R9E/ref=oh_details_o07_s00_i00?ie=UTF8&psc=1


 


TRACER MPPT 3215RN Solar Charge Controller 30A 12V 24V EP
http://www.amazon.com/gp/product/B008KWPGAE/ref=oh_details_o08_s00_i00?ie=UTF8&psc=1


 


Battery Tender(NNN) NNN-NNNNDL-WH 12-Volt 4-Bank Battery Management System
http://www.amazon.com/gp/product/B000CIPHUI/ref=oh_details_o08_s01_i01?ie=UTF8&psc=1


 


Instapark® NEW All Black 150w Mono-crystalline Solar Panel, 150 Watt
Maximum Power Voltage: 18.12V; Open Circuit Voltage: 22V; Maximum Power Current: 8.28A
http://www.amazon.com/gp/product/B00AR81SMY/ref=oh_details_o08_s02_i00?ie=UTF8&psc=1

Expert:  Kevin replied 10 months ago.
1) How many panels?
Customer: replied 10 months ago.

2 panels

Expert:  Kevin replied 10 months ago.

Thanks for the replies Joel

 

1) All of the components look good except the battery tender. I assume that you will be using the battery tender to keep the batteries at full charge during the evening hours? If so, you only want to use the tender during the evening hours and never during the daylight. If using the tender simultaneously with the PV panels, possible to over-charge the batteries. To play it safe on the tender, I would recommend to plug the tender charger into a timer and only have it top-off the batteries during evening hours.

 

2) You will also need a roof mount or a pole mount to mount the panels. The mounts are always made of metal and need to be grounded using an Inter-system bonding device at your existing ground rod near your electrical meter socket. The equipment grounding conductor needs to be sized as 10 AWG Copper.

 

3) Code also requires a safety disconnect switch located on the exterior of the home prior to the cables being routed into the house. Since each panel is rated @ 8.28 amps, you could purchase an air conditioning disconnect switch (non-fusible type) 30 amp rated, 2 pole and weatherproof type that would be able to cut power from the PV's for any maintenance and/or safety reasons.

 

4) The 2 batteries will be installed in parallel for a 12 VDC output. You also need 2 plastic battery cases to protect the batteries.

 

5) Depending upon the distance from the PV's to the battery bank, you may want to consider increasing the cable size from 10 AWG to 8 AWG due to any voltage drop. I would need to know the approximate distance in order to calculate the voltage drop.

 

6) You will also require a combiner box or weatherproof junction box (NEMA 3R rated) for combining the PV cables on the exterior.

 

7) If you will be grid tied to your main electrical panel, let me know.

 

 

 

Hope this helps.........If you have any additional questions, let me know and I'll be glad to answer them for you.

 

Otherwise, don't forget to rate me before you log Off.

 

The next time you have an electrical question, you can also request for me at:http://www.justanswer.com/home-improvement/expert-your-electrician
..........Thanks..............Kevin!




 

 



 

Customer: replied 10 months ago.

Thank you Kevin. The distance will be 25 ft from the panels to the charge controller. Also up to how many similar spec batteries can I add to this battery bank with the existing components I have for this system? And can I add different brand 12 V batteries? And if so do they also have to be exactly 100Ah or is it ok if they will be 12V 110Ah?

Expert:  Kevin replied 10 months ago.

1) One additional code requirement I forgot to mention. If the PV cables will be passing thru the home prior to landing @ the exterior disconnect switch, the cables need to be routed in their own separate conduit and not shared with any AC high voltage conductors.

 

2) As an optional component......I would also recommend a lightening protector.

 

3) It is always recommended that batteries be the identical amp-hours and manufacturer. If the amp hours are different, there is a tendency for the weaker battery to bring down the stronger battery.

 

4) 25 feet distance is fine and that is not a problem then for the cable size

 

5) The quantities of batteries in the battery bank depend upon your daily connected loads and the amount of reserve amp-hours that you will require. You have 200 AH using 2 batteries. General rule of thumb is to have a 50% AH reserve on the batteries for up to 3 days with no sun. Therefore a 50% reserve would result in having (1) one battery @ 100 AH readily available over a 3 day period without sun light. Let me know how many connected amps and the amount of daily hour usage you will have and I can calculate that for you.

 

6) Joel......I need to log off of here for a few hours. Post any other questions or replies here and I will get back to you later this afternoon............Thanks.............Kevin!

Kevin, Licensed Electrician
Category: Electrical
Satisfied Customers: 1139
Experience: 27 years as a Licensed Electrical Contractor in Illinois, 5 year college Electrical Instructor, Former Electrical Inspector, Diploma in Digital Electronics, Former Illinois Licensed Home Inspector
Kevin and other Electrical Specialists are ready to help you
Expert:  Kevin replied 10 months ago.

Hello Joel.............Thank you for the excellent service rating..........much appreciated!

 

If you have any other questions, just let me know.

 

Take care and have a great evening.............Thanks...............Kevin!

Customer: replied 7 months ago.

Hello Kevin just a quick question. You mentioned above that 10AWG wire will be fine for a 25 foot run. Is 10AWG still good for a 50 foot run from solar panels to charge controller?. And if not how long would it be good for, until I need to consider a 8AWG. Thank you again for all of your help, Joel

Expert:  Kevin replied 7 months ago.
Good morning Joel,

1) The National Electrical Code recommends a maximum voltage drop (VD) of 3%. Using 10 AWG Copper at 18 volts and 16.5 amps, the VD maxes out at a 33 foot run (3%).

Using 10 AWG copper at a 25 foot run, the VD = 2.28% which is < than the maximum recommendation of 3%, therefore OK.

This is calculated based on the panels being installed in parallel with each other. For a parallel circuit the panel voltage remains the same (18 VDC), but the amperage is additive (8.28A + 8.28A) = 16.5A

2) Using 8 AWG copper at 18 volts and 16.5 amps, the VD maxes out at a 52 foot run (3%)

Hope this helps...........reply back with any questions..........Thanks..........Kevin!
Customer: replied 7 months ago.

Thank you that is very useful. Is there a website that shows all this and more for future reference. Thank you, Joel

Expert:  Kevin replied 7 months ago.

No problem, glad to assist Joel

1) There are numerous web sites for a voltage drop (VD) calculator. I use the following for calculating DC voltage drops.

http://www.bulkwire.com/wireresistance.asp

2) I also have a variety of National Electrical Code (NEC) and electrical theory books that I often use as well. Some of the calculations require looking up information in tables and then performing a manual calculation for combination series/parallel circuits. Just kinda depends what source has the required information. A good example of this is that some websites recommend a maximum of a 4% VD, where as the NEC recommends a maximum of a 3% VD.

JustAnswer in the News:

 
 
 
Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.
 
 
 

What Customers are Saying:

 
 
 
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
< Last | Next >
  • You did one super job of explaining to me everything there is to know about this fridge. I'm looking forward to asking you questions in the future. Jimmy Bagley, IA
  • Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help. Mary C. Freshfield, Liverpool, UK
  • This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!! Alex Los Angeles, CA
  • Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult. GP Hesperia, CA
  • I couldn't be more satisfied! This is the site I will always come to when I need a second opinion. Justin Kernersville, NC
  • Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around. Esther Woodstock, NY
  • Thank you so much for taking your time and knowledge to support my concerns. Not only did you answer my questions, you even took it a step further with replying with more pertinent information I needed to know. Robin Elkton, Maryland
 
 
 

Meet The Experts:

 
 
 
  • Mike

    Master Electrician

    Satisfied Customers:

    1425
    Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer
< Last | Next >
  • http://ww2.justanswer.com/uploads/mikepettinato/2009-9-4_41145_DSC005132.jpg Mike's Avatar

    Mike

    Master Electrician

    Satisfied Customers:

    1425
    Licensed Master Electrician - OnQ Certified Data Voice Audio Video Installer
  • http://ww2.justanswer.com/uploads/WI/WireitUp/2012-6-17_18212_Photo00006.64x64.jpg Jason's Avatar

    Jason

    Service Technician

    Satisfied Customers:

    3278
    Over 15 years of experience in all types of installations, troubleshooting, and repairs.
  • http://ww2.justanswer.com/uploads/MI/MikeG2010/2012-6-7_192640_IMG01612.64x64.jpg Mike G.'s Avatar

    Mike G.

    Master Electrician

    Satisfied Customers:

    5318
    Proven Professional 45 years Experience
  • http://ww2.justanswer.com/uploads/AS/AssuredElectrical/2011-9-13_221243_me.64x64.gif AssuredElectrical's Avatar

    AssuredElectrical

    Master Electrician

    Satisfied Customers:

    2149
    Contractor-40 Years in the ElectricalTrade
  • http://ww2.justanswer.com/uploads/electrifier/2008-12-16_200429_headbob1.jpg electrifier's Avatar

    electrifier

    Master Electrician

    Satisfied Customers:

    1454
    Electrical contractor and electrical inspector for over 24 years with phone and networking expertise
  • http://ww2.justanswer.com/uploads/rich03dungo/2010-3-17_101556_tshirt2.jpg Rich's Avatar

    Rich

    Master Electrician

    Satisfied Customers:

    1115
    Over 35 years residential, commercial, industrial wiring, install, troubleshoot, service, maintain
  • http://ww2.justanswer.com/uploads/UR/urelectrician/2012-9-28_223652_JustAnswerPic.64x64.jpg Kevin's Avatar

    Kevin

    Licensed Electrician

    Satisfied Customers:

    993
    27 years as a Licensed Electrical Contractor in Illinois, 5 year college Electrical Instructor, Former Electrical Inspector, Diploma in Digital Electronics, Former Illinois Licensed Home Inspector