Small OffGrid Solar Setup (advice needed)

**organic farmer** · 12-10-2021, 10:34 PM

Originally posted by KevinAus

Well hello there

...List of questions

1. I'm considering buying some second-hand panels, I see quite cheap ones some of them less than 5 years old. But my question is are all panels equal? Because most likely those panels have been connected to the grid so i'm not sure if they are for higher voltage or whats really going on over there. If you guys could give me recommendations and basic ideas I will try to understand.

Nobody ever connects a photovoltaic panel to the power grid, ever. These are completely non-compatible technologies.

A used photovoltaic panel that you acquire may have been used as a component in a larger system, and that system may have been connected to the power grid, or not. There is no way to tell.

Any photovoltaic panel that you do acquire will need to be tested, both voltage and amperage before you will know if it is healthy.

... 2. How should everything be connected? Parallel or in-series?

That depends on many factors.

I will not attempt to give you an Electrical Engineering degree in this post.

.... 3. I bought two 175AH life-po4 batteries by atlas the are 12v, How should I connect them?

This depends on the design of the system that you intend to build.

In series they will give you a 24vdc / 175ah battery bank, in parallel they will give you a 12vdc / 350ah battery bank.

... 4. And fuses and stuff what would you recommend getting me

When you have completed your Electrical Engineering degree, then you can tell us ab out the design of the system you are proposing.

... 5. If you guys have full set-up recommendations, that would be very welcomed.

Yes, I am sure it would be welcomed.

**KevinAus** · 12-10-2021, 10:51 PM

Thanks for your advice Solar Farmer!

**Mike90250** · 12-11-2021, 12:35 AM

First - STOP buying stuff. You are likely to end up with lots of things that won't work together.

Second. Figure your daily usage in watts.. example i use about 8,000watts (daily) in winter, and 15,000w in summer. ( I pump a lot of water in summer, and the fridges work harder )
2B) figure your peak wattage your inverter will have to supply to start the well pump ( likely the largest load ) Motors can take up to 10x the running load, to start, your batteries, cables and inverter have to be able to supply that for about 3 seconds. You are likely to have other loads running when the pump starts, factor that overhead too.

Third. watch your local weather for how long cloudy weather can last. Here we get 5 - 12 days of solid clouds, and i
have to run generator too keep the batteries up.

You want to generally size your battery to provide 3 days of power before it declines to 50%.

**KevinAus** · 12-11-2021, 12:54 AM

Thanks for your advice good Mike90250,

I wouldn't have much more than fridge and charge few devices. I would happily grow it it slowly if I feel like I need more. I would be okay without electricity too for a while, so wouldn't be massive issue if running low sometimes.

I was thinking getting either 400watt kit from Renogy or 800 watt kit and connect that up to my battery, because they make it fairly easy how they set up the kit. I have two 175ah life-po4 12v batteries coming already, I think I would need to connect them in parallel to keep 12v because 1500W 12v inverter is way more accessible for me to get right now. Mike90250 if you got time let me know what you think about it.

And i also wonder if i could connect few different arrays (charge controllers) to one battery, i hope you know what im trying to say.

Thanks for your help guys!

**Mike90250** · 12-11-2021, 01:56 AM

if your pump needs 8Kw to start, a 12v system is not going to work well long term. Otherwise, you will buy stuff, it works for some months, then you have to buy bigger stuff, new batteries won't work with old batteries, new batteries need bigger panels. and what happens with all the old stuff that doesn't work.

**SunEagle** · 12-11-2021, 08:52 AM

Originally posted by KevinAus

Thanks for your advice good Mike90250,

I wouldn't have much more than fridge and charge few devices. I would happily grow it it slowly if I feel like I need more. I would be okay without electricity too for a while, so wouldn't be massive issue if running low sometimes.

I was thinking getting either 400watt kit from Renogy or 800 watt kit and connect that up to my battery, because they make it fairly easy how they set up the kit. I have two 175ah life-po4 12v batteries coming already, I think I would need to connect them in parallel to keep 12v because 1500W 12v inverter is way more accessible for me to get right now. Mike90250 if you got time let me know what you think about it.

And i also wonder if i could connect few different arrays (charge controllers) to one battery, i hope you know what im trying to say.

Thanks for your help guys!

As Mike has stated stop buying things. Also an off grid solar/battery system can't be grown without spending a lot of money. You can't add new batteries to old ones without hurting the new ones. You best bet is to first determine how many watt hours your loads will use in a day and build the system based on that. Also remember "kits" are designed to cost you and then fail to provide what you truly need to power your loads. Don't be fooled into getting something before you know if it will last as long as you hope.

**KevinAus** · 12-12-2021, 07:55 PM

Thanks SunEagle for your advice, How about I have few independent systems if I want to add up in future?

I have one question that I seem to get different answers to, I've seen a lot of people in Youtube say that you can connect many different charge controllers to battery. That it won't cause any problems and in some situations is recommended. In electronic shop one guy didn't recommend that, he said it would cause problems. I don't know if it meant that would cause problems to my lithium batteries or to all batteries. If somebody can shine some light on that would be great.

What have I been thinking about is getting 2, 12v AGM L-Acid deep-cycle batteries to connect them in series to create 24v system, So I could directly run from that battery-bank to 24v appliances, I might need some inverter between there I suppose. And also another connection from that to another inverter to lithium charge controller to charge lithium batteries that are parallel 12v to give power to all 12v power requiring devices.

If anybody doing consultation over here would be greatly appreciated so I can ask live questions. And you can help me put together system thats gonna be good. I would happily send you some crypto

**SunEagle** · 12-12-2021, 08:25 PM

Originally posted by KevinAus

Thanks SunEagle for your advice, How about I have few independent systems if I want to add up in future?

I have one question that I seem to get different answers to, I've seen a lot of people in Youtube say that you can connect many different charge controllers to battery. That it won't cause any problems and in some situations is recommended. In electronic shop one guy didn't recommend that, he said it would cause problems. I don't know if it meant that would cause problems to my lithium batteries or to all batteries. If somebody can shine some light on that would be great.

What have I been thinking about is getting 2, 12v AGM L-Acid deep-cycle batteries to connect them in series to create 24v system, So I could directly run from that battery-bank to 24v appliances, I might need some inverter between there I suppose. And also another connection from that to another inverter to lithium charge controller to charge lithium batteries that are parallel 12v to give power to all 12v power requiring devices.

If anybody doing consultation over here would be greatly appreciated so I can ask live questions. And you can help me put together system thats gonna be good. I would happily send you some crypto

Well first what is shown on Youtube may be misleading. Next if you want your battery system to last more than a year you really need to learn more about the equipment and what it can do for you as opposed to believing what someone else shows you in a video.

Having a 24v battery system will require a quality CC and enough panels to provide about 30 charging volts and a 24V inverter. You can try to use multiple CC's on the same battery system but you run the risk of over charging them.

And sorry I don't consult so I really can't help you design the system.

**KevinAus** · 12-12-2021, 08:38 PM

You see many people doing that on Youtube on their caravans and some people who say they are experts saying that its okay to do it. And then I get guys like you saying that it comes with risk, I am really confused at this stage, but I want to get some small system going as soon as I can something even small as 2 250W panels etc.

SunEagle thanks for your advice anyway its greatly appreciated. I was watching one guy on youtube, if you could watch that video and comment on that would be great (3minutes) . Because what I understand from that is showing me that multiple solar charge controllers can be used, but then people worry about it long-term safety issues.

Can You Connect Multiple Solar Charge Controllers To A Single Battery Bank? in youtube search by channel Phocos, there are some other ones too, but thats short video just interested to hear what you think he is saying.

Cheers! Kevin from down under

**J.P.M.** · 12-12-2021, 08:49 PM

Originally posted by KevinAus

You see many people doing that on Youtube on their caravans and some people who say they are experts saying that its okay to do it. And then I get guys like you saying that it comes with risk, I am really confused at this stage, but I want to get some small system going as soon as I can something even small as 2 250W panels etc.

SunEagle thanks for your advice anyway its greatly appreciated. I was watching one guy on youtube, if you could watch that video and comment on that would be great (3minutes) . Because what I understand from that is showing me that multiple solar charge controllers can be used, but then people worry about it long-term safety issues.

Can You Connect Multiple Solar Charge Controllers To A Single Battery Bank? in youtube search by channel Phocos, there are some other ones too, but thats short video just interested to hear what you think he is saying.

Cheers! Kevin from down under

Youtube is the new idiot's bible.

It's unvetted crap.

Use it at your own risk.

**SunEagle** · 12-12-2021, 10:15 PM

Originally posted by KevinAus

You see many people doing that on Youtube on their caravans and some people who say they are experts saying that its okay to do it. And then I get guys like you saying that it comes with risk, I am really confused at this stage, but I want to get some small system going as soon as I can something even small as 2 250W panels etc.

SunEagle thanks for your advice anyway its greatly appreciated. I was watching one guy on youtube, if you could watch that video and comment on that would be great (3minutes) . Because what I understand from that is showing me that multiple solar charge controllers can be used, but then people worry about it long-term safety issues.

Can You Connect Multiple Solar Charge Controllers To A Single Battery Bank? in youtube search by channel Phocos, there are some other ones too, but thats short video just interested to hear what you think he is saying.

Cheers! Kevin from down under

I did not find that particular video but I will say is that first off Phocos is a company trying to sell you a hybrid inverter so IMO any salesperson will say anything to make a sale. But to be honest the hardware seems to be a higher quality then some of the cheap Chinese stuff so maybe multiple chargers will work on a single battery bank but again IMO those chargers need to "talk" to each other and work together instead of being single minded and work for themselves.

I also have to support JPM when he says Youtube is the new idiot's bible because no one really vets them and a lot of people believe in anything they see on the internet.

**Mike90250** · 12-12-2021, 10:42 PM

I have 3 charging sources on my batteries. Each source needs to be set up properly, with the right voltage set points, timers and such.
I'm sure somewhere, Shadetree Sam set up his system, and managed to fry something. Yet his idiot brother did nearly the same thing and it came out fine !

**KevinAus** · 12-15-2021, 09:32 PM

Haha thanks guys for good advice, sorry for long response I went out to farm. Yeah I agree you find a lot of mixed information in YT so something must not be right. But there are some quite reputable one that have built big viewer base and have business around that and seem to be very informed about that on come to mind is WillProwse on YT.
But you are guys are right even I could make video about some solar solution over there

, that poor guy who follows my advice lol.

One guy in Jaycar electronics its Aussie shop, he was fully living off -grid life and he had electrical education oh this dude was hilarious as well. I think he was working in military before as electrician, he had this setup he drawed up for me. And he didn't recommend connecting many sources to my 12v lithium battery setup.

His setup.

500W wind turbine with charge controller + 3, I think 250W-300W panels both connected to 2 Deep Cycle Lead Marina Batteries connected in series to make 24v of that he pulled cable to his 24v devices, fridge/washing machine/air conditioning (special ones I think, 24v) from lead he connected to small 150W inverter to Lithium Charge Controller and that to two parallel lithium batteries 12v, and from that he got electricity to his TV, Laptop, Lights, Fan
Any comments guys? :P

I'm starting to think that I wouldn't want to buy Wind Turbine for 600aussies maybe 400 American dollars, because Wind on my location haven't been massive, I get some breezes. But I'm not sure how much would it bring in.

This solar off-grid life is complicated lol

, hopefully one day I have all setup ready and I can enjoy flicking on my light :P. Thanks fellas, I hope you have a good day!

**AmitBajpayee** · 12-21-2021, 04:40 AM

Setting a small off-grid solar setup for daily energy needs will require basic instruments and tools. Solar panels are one of the main parts of this system that you have to select as per your requirement. As you mentioned you are looking for an off-grid solar set up you no need to worry about the extra connections and plugins with the grid supply.

Before start installing this setup for your home you must be aware of your daily energy requirement based on that you should select the number of arrays in the solar panels.

By using a solar power system you become completely independent, for the energy supply you no need to depend on the grid power supply.

You can enjoy the endless benefits of this power system.

Small OffGrid Solar Setup (advice needed)

Small OffGrid Solar Setup (advice needed)

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