# Need Help with DIY Solar Panel Setup for Current Prep Situation



## jerryv (Mar 17, 2020)

TLDR: With current resources available, how can I setup these panels (parallel, series/string, and how many, etc)? And are my components ok for now (or should I add/exchange)?

I'm working on a solar panel setup for my families house that wont be grid tied in right now. Maybe later once situation with Covid19 clears up and it would be easier to get right supplies and permitting setup with city. I purchase the solar panels new locally (which I rather not return) and ordered other components from Amazon and Home Depot (which can be returned/exchanged). Let me list out what I have:

2 @ BestEquip 60A MPPT Solar Charge Controller Auto Battery Regulator PV 150V MAX Input MPPT Charge Controller Finger Touch Interface for Solar Panel and Lithium Battery 
https://amzn.to/2w4ZyuC

1 @ AIMS Power PWRINV500048W Power Inverter, 5000 Watt Max Continuous Power, 48V, 10000 Watts Peak Surge Power, Modified Sine Wave, Cooling Fan Thermally Controlled, AC Direct Connect Terminal
https://amzn.to/2x3QciA

4 @ EverStart Maxx Lead Acid Marine & RV Battery, Group Size 29DC
https://www.walmart.com/ip/EverStart-Maxx-Lead-Acid-Marine-RV-Battery-Group-Size-29DC/131118029

I was planning to have a 48v system with 5kw and 120/110v AC (ideally would like 240/220 but might be out current budget)

Here are my questions. I've been researching these like crazy and sites either point to spam, solar company sales sites, or pinterest for some reason.

- What configuration should I do my panels in, parallel, series/stringed, and how many?
- What sort of combiner box should I get for above setup?
- Would I need another charge controller for the setup (I know the ones I do have are not as robust but with logistics/resources slowing down trying to make something work)?
- Can I ground each panel to the rails (unistruts) and then ground the unistruts to system (combiner box, down other components then to ground) or do/should I run a continuous wire that connects to all panels, rails and then down?

Once I know this, I can research what gauge of wire I should need as it would give me an idea of W, V, A are going through, was thinking of 10AWG for the DC wires from panels to combiner box and then maybe something thicker from there to inverter. And of course even thicker for battery terminals.

Thanks in advance.


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## Bearfootfarm (Jul 13, 2006)

jerryv said:


> I've been researching these like crazy and sites either point to spam, solar company sales sites, or pinterest for some reason.


This site it pretty good:
https://www.solarpaneltalk.com/


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## ET1 SS (Oct 22, 2005)

Also you will need a 51vdc power source for equalize charging the battery-bank.

Equalize chargers can routinely run for 36 hours and you want to do an equalize charge on your batteries once a month.

For a year now I have been tilting at windmills trying to work out the best way to maintain my battery-bank. We all need to consider battery maintenance before we even begin building our systems.


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## jerryv (Mar 17, 2020)

Bearfootfarm said:


> This site it pretty good:
> https://www.solarpaneltalk.com/


Yup, did join the site but waiting to be approved.. Thank you


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## MichaelK! (Oct 22, 2010)

It's hard to give you advice, for a couple of reasons. First, you haven't given the specifications of your solar panels, so we really can't give advice on whether things should be wired in parallel or serial, and what voltage to select. Secondly, the equipment you do list are low-end products that might not actually do what you want it to do. Let's hope that the controller is really a MPPT, and not a fake PWM unit that's commonly coming out of China. Your inverter is modified sine wave, which means that it's not a good choice for running anything with an electric motor; things like power tools, the refrigerator, a well pump, ect. The motors will run hot. Your nice TV might not like it either. 

The batteries are not real off-grid batteries, but a compromise unit that won't handle as many charge cycles. The word "start" right on the battery is a clue that it really isn't made for off-grid. The fact that the battery specifications don't even list amphours is also a clue. In my opinion it's mostly money you've wasted. You'll probably get it to sort of work, but you'll have significant disappointments.

I can make a few suggestions. Wiring the battery in series for 48V is the first thing you should do. Then connect the controller, and let it boot up. Only after the controller has booted should you try connecting the solar panels. How many panels you put in series depends on their output. One hundred watt 12V panels usually output around 18VDC. Four of them in series would give you 72VDC, which might charge your bank under any conditions. For 60 cell grid-tie batteries (30VDC) three in series would give you 90VDC. One thing you should make sure of though is to add up the "open circuit" voltages (VOC) of all the panels in series and make sure they don't exceed about ~125VDC. You're in Texas, but a very cold, below freezing morning could potentially send the open circuit voltage above 150V. NEVER connect the panels to the controller before first connecting the batteries and properly booting the controller up.

Let's say the panels are wired to 90VDC. Check with a volt meter before connecting them. The open circuit reading might actually be around 110-115VDC. Once you connect it to the controller, it should transform the voltage given to the batteries to around 55-59V. If it's significantly higher, then you got one of the fakes.


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## Nimrod (Jun 8, 2010)

A modified sine wave inverter will not run many electronics, like computers and A/V equipment, and may damage them.


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## wy_white_wolf (Oct 14, 2004)

Sorry to see you just wasted $400 on batteries that can not support the 5kw inverter. Those are 75ah batteries so you have 3600 watthours of storage. If one could use 100% of the batteries that would be about 45 minutes. But you can never use 100% without turning them into boat anchors. Recommended is 20% daily and occasionally going to 50%. So you have less than 10 minutes of usage. 

Now as others have mentioned that most electronics don't like modified sinewave inverters. Neither do electric motors. It makes them run hot and prematurely wear out. So not tv, frig, washer, dryer, etc.

May I suggest you quit wasting money and have someone professionally design your system. With what you've wasted already you could have covered his bill.

WWW


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## Steve_S (Feb 25, 2015)

https://diysolarforum.com/
to get real time help from those of us doing it & living it on Solar and more.


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## MichaelK! (Oct 22, 2010)

I have to say that the only good decision you've made in regards to this is to go with a 48V system. I'll try to give you some advice based on how my own systems have run.

First, what panels do you have? What is their rated amperage and voltage? Also, what is their open circuit amps and volts? Based on the observation that the rest of what you bought is low-budget junk, I have to assume your panels are garbage too?

*- What configuration should I do my panels in, parallel, series/stringed, and how many?
*
That can be decided once you give us the barest information of what panels you have.

*- What sort of combiner box should I get for above setup?
*
Typically you need a combiner if you have more than two parallel strings of solar panels. However, since I like the ability to switch off a string for troubleshooting purposes, I'd recommend having a combiner even with just two strings. I like Midnite's product.
https://www.ebay.com/itm/NEW-MidNit...AOSw0h1dO3xK:sc:FedExHomeDelivery!92509!US!-1

*- Would I need another charge controller for the setup (I know the ones I do have are not as robust but with logistics/resources slowing down trying to make something work)?*
Yes, for sure get a new controller. The one you paid good money for is likely to be garbage. I can recommend Midnight's controller. That's what I myself use now. One like this...
https://www.ebay.com/itm/MidNite-So...AOSwJ5dcbh~X:sc:FedExHomeDelivery!92509!US!-1
*
- Can I ground each panel to the rails (unistruts) and then ground the unistruts to system (combiner box, down other components then to ground) or do/should I run a continuous wire that connects to all panels, rails and then down?*
No, the panels should not be directly touching unistruts. Unistruts are galvanized steel, and the aluminum frames touching them will corrode by galvanic current. I use unistruts myself, but they are painted so bare aluminum is not touching them.

https://en.wikipedia.org/wiki/Galvanic_corrosion

_*Once I know this, I can research what gauge of wire I should need as it would give me an idea of W, V, A are going through, was thinking of 10AWG for the DC wires from panels to combiner box and then maybe something thicker from there to inverter. And of course even thicker for battery terminals. 
*_
Use this table to determine the appropriate wire gauges. Ignore watts or volts! The important parameter for determining wire gauge is amperage. I'd recommend 10 gauge from the panels to the combiner, Six gauge from the combiner to the controller, and then 4 gauge from the controller to the batteries. Use 000 or 0000 gauge copper wire from the batteries to the inverter. Use the same gauge from battery to battery.

Lastly, try to get you money back for the inverter. For running a household you should be using sine-wave only. I could suggest three alternatives, going up in price. Remember, you get what you pay for!

https://ressupply.com/inverters/samlex-s600r-148-pure-sine-wave-inverter

https://ressupply.com/inverters/schneider-electric-conext-sw4048-120240-invertercharger

https://ressupply.com/inverters/schneider-electric-conext-xw5548-na-invertercharger

Try really hard to get your money back on the batteries. They're the wrong ones for the job. Here's some examples of what to replace them with.

https://www.trojanbattery.com/pdf/datasheets/SPRE_06_255_DS.pdf

https://www.trojanbattery.com/pdf/datasheets/SPRE_06_415_DS.pdf


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## Stormila (12 mo ago)

Not only the supplies should make you put the pannels after this whole pandemic thing ends, but also the work of some masters. I know it might sound stupid if I tell you that you must call specialized people to put your system if you know everything about it, but you will never be sure of the quality of the work if specialists do not do it. I have two friends who installed their systems at the same time, one with the help of Off Grid Systems | K2 Fixings | Solar Street Lights - Victron Energy Spares - Car Park Lighting and one by himself. After his mistake, the last one now has to change all the panels!


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