Solar systems widely available but... questions get no "Real" answers.

[47Ronin]

So in my previous now deleted post I made the comment that my solar system wasn't as sophisticated as some are. I then asked if it was worth it and the majority of the people said yes.

However the cost of solar isn't cheap and making a mistake with the hardware can be costly.

So I saved up some money and want to get a bigger system. I am looking into a 3Kw system 24 volts with two 100amp batteries. My question I ask each solar shop is "can it run a refrigerator" as this is my main concern and for how long.

I got mixed answers and each say "it depends" Right on startup I measured 1kw power draw for a second or two then it normalize to 300 Watt running for about an hour. Now in total it starts up about 3 to 4 times a day.

so I concluded that 1kw draw is about 4.35 amps depending if i did my math right and I know that the inverter can handle about 13amps of power so it should be enough.

However according to a search a refrigerator can pull as much as 25amps on start up and that will kill this inverter.

Thus now instead of a 3kw system that i can afford i was told to look at a 7+Kw system that is almost triple the cost.

To cope for now i got a bigger generator so that it can give a bit more flexibility to my house hold.

The point is not all of us are electricians, we have to go on what the solar shop say because we don't know and I had 7 conversations and the stood out because he said for my home i need TWO 7KW systems!

In conclusion I don't blame people for being skeptic about solar. There are many sharks in these waters and the greater public is buying expensive stuff on a guess if that. I do feel mybroadband can do a information piece on this topic because it is really HARD to find out what the truth is and how things work. It really is.

For those of you that are kind enough to give some info thank you in advance.

 

[ADrunkTeddyBear]

@DuracellBunny

 

[Gielie01]

@AngryDog how old is the fridge? Might be worthwhile looking into a newer fridge with a better energy rating.
Mine isnt "New new" but ive never seen it draw 1Kw, 1Kw is the running average for my house when there are people home.

The problem with solar is, without some real data a solar shop cant answer your questions, yes there are "fixed size" systems for sale and that covers a wide range of people's needs. But you have taken the first step, you need to look into what your power usage is, over a large period of time to make an educated decision. I monitored my usage for months before "designing" my system.

 

[Mzezman]

Those spikes are when my fridge comes on (during the night) - its a 2017 Samsung and not the greatest in efficiency but you can see approx 150W on startup. The more data you can present to them the better they should be able t make a recommendation for you. But yes there ARE some sharks and you need to be wary - hence getting multiple solution designs and quotes is always prudent

 

[DuracellBunny]

@AngryDog get that question alot, what can this inverter run and for how long can this kit last me. I usually recommend not killing the inverter and maxing the load at 3Kw but try keep at least 25% free for small spike loads. A fridge does have a high current draw on start up as you mention but it only lasts a few seconds and every inverter has an over load function where it can exceed the rated inverter for a few seconds, which the inverter would be able to handle that in rush of power needed for the fridge but I wouldnt recommend using this function as a norm and more of a worse case that you might have a few extra things on and the fridge needs to start up.

Got a customer up in Zambia, nice Aunty. Running a 3Kva inverter with 2 X 100Ah batteries. Appliances that she has connected, TV,Decoder,Fridge,lights 5X20w, Flood light,router and the odd charger here and their for their phones and the system has been working strong for her for the past 3 years. Batteries have finally given up and this period has given her a chance to save up money to switch to lithium and add a few panels. Only headache with this is that her inverter is the old Axperts that came with the measly MPPT with an VOC of 75v.

So try to choose an inverter that does have a large enough MPPT if you looking to add panels at a later stage.

I do understand that a lot of people don't have the budget to fork out on a system but sometimes starting off small to just run whats needed for comfort then why not and when funds do come available look at upgrading.

You more than welcome to drop me a PM if you need more help or got some Q's

 

[Kawak]

Your fridge can draw 1kw on startup, that's normal, the inverter will handle that, the how long it will run part is more involved. 2x 100a at 24 or 12 volts? Even at 24v you have a theoretical energy storage of 4.8kw, if lead, you can use 50% if lithium, close to 90%, summer vs winter and where you install your panels matter, the pitch of your panel matters alot as well. It's very difficult to just say you have enough unless you go in and ask for a massively oversized system.

I am still using a Samsung side by side from 2007, best fridge ever, never had an issue from day one. That fridge and a few other items are on the 3kw inverter which is the first one i got for load shedding, definitely OK, your energy storage requirements are what you need to investigate.

 

[jvniekerk_it]

@AngryDog
Just a little information on how you can go about sizing your system.
Firstly I got a Kill-A-Watt meter to test what the consumption is of all my devices that I want to run on the inverter.
This device also gives you a peak power usage an average for the device plugged into it.
https://www.geewiz.co.za/gadgets/43656-digital-watt-meter-kill-a-watt-measure-your-electricity-usage.html

The second device you can use if you want to go off grid is Nano View this is connected to your db board and will keep track of the houses power consumption as well as show the max wattage pulled daily and at what time your highest usage is.

The reason they told you you need 2 7kw inverters is as this is the maximum you can pull from the grid normally with single phase power is 14kw.

 

[TheChamp]

Something to consider, the draw of 1000W results in the 4A current on the AC side, on the DC side it is 41A @24V that your batteries must supply.

That's why LA are useless when it comes to designing a proper system. Get lithium batteries.

 

[Mier]

I'm running a Bosch double door (~12years old) and a Bosch wine cooler (6 years old) on my 3kw Infinisolar inverter without any issue (even when running from battery). It has never given an overload warning because of the fridges.

I would suggest a 48v system though. Much less current on the DC side. Pure sine wave goes without saying.

 

[TheChamp]

I'm running a Bosch double door (~12years old) and a Bosch wine cooler (6 years old) on my 3kw Infinisolar inverter without any issue (even when running from battery). It has never given an overload warning because of the fridges.

I would suggest a 48v system though. Much less current on the DC side. Pure sine wave goes without saying.

48V stuff will be expensive for someone of limited means, the 24V is just a perfect middle ground.

 

[Mike Hoxbig]

However the cost of solar isn't cheap and making a mistake with the hardware can be costly.

So I saved up some money and want to get a bigger system.

You can always finance a proper system if cost is an issue, and use what you saved up as a deposit. Don't let the cost hold you back from doing it properly. Most people don't think twice about the cost of buying a new car, but let it become an issue when it comes to something that is actually necessary...

 

[Mike Hoxbig]

As for the fridges, they hardly use anything unless you have something ancient. I have 2 fridges (1 of them a double door) and a chest freezer running permanently, and 15 outside lights - and my overnight load is 400w...

 

[Arthur]

"Solar system" in general parlance is an astronomical term referring to a star + planets. What the OP means is a "solar photovoltaic system" or "solar pv system".

 

[Neuk_]

We run a small 3kVa inverter with two strings of 1.8kW PV panels and soon to be replaced LA batteries that have given up on being alive. We have everything except our bedroom AC, oven and two sets of kitchen plugs for the electric kettle, toaster, etc. connected and I am still surprised at how well it has worked.

 

[47Ronin]

There are no solutions in South Africa. Unfortunately our battery prices are excessive and local manufactures of witch there is maybe one is so big and scary I didn't bother contacting them because we all know they only communicate to suppliers and resellers.

Since everyone and their dog wants a early retirement I decided to say No... I started looking in building my own batteries. It is not a complicated concept and despite what everyone say, on paper it looks to be a lot cheaper so I will dig deep and research this myself. Somehow in some way a better way must exist. I cannot understand why a battery cost is so very high and why our access to information about these companies are so very limited. YES all of them have websites and info on the product but hardly any of them put down a price that is even remotely affordable.

So Unfortunately there is no alternative other then figuring out what raw materials will cost how much free time I will need to build these things. How to charge and maintain them. Where to get the raw components and simply build a "process" where I can truly just "assemble" a battery that can handle 100Ah and if it does fail that it do so safely. So I will be building a few and mess them up on purpose to see what type of failure one can expect.

I for one is up for the challenge and Is working on getting parts/ charging equipment to make it a reality. Once done I will accumulate a list of parts cost and time spend as well as instructions. Other people in other countries that is also facing the same problems as us have already started doing this with a ton of success. Some even have a massive refurbishing market for batteries.

 

[ADrunkTeddyBear]

There are no solutions in South Africa. Unfortunately our battery prices are excessive and local manufactures of witch there is maybe one is so big and scary I didn't bother contacting them because we all know they only communicate to suppliers and resellers.

Since everyone and their dog wants a early retirement I decided to say No... I started looking in building my own batteries. It is not a complicated concept and despite what everyone say, on paper it looks to be a lot cheaper so I will dig deep and research this myself. Somehow in some way a better way must exist. I cannot understand why a battery cost is so very high and why our access to information about these companies are so very limited. YES all of them have websites and info on the product but hardly any of them put down a price that is even remotely affordable.

So Unfortunately there is no alternative other then figuring out what raw materials will cost how much free time I will need to build these things. How to charge and maintain them. Where to get the raw components and simply build a "process" where I can truly just "assemble" a battery that can handle 100Ah and if it does fail that it do so safely. So I will be building a few and mess them up on purpose to see what type of failure one can expect.

I for one is up for the challenge and Is working on getting parts/ charging equipment to make it a reality. Once done I will accumulate a list of parts cost and time spend as well as instructions. Other people in other countries that is also facing the same problems as us have already started doing this with a ton of success. Some even have a massive refurbishing market for batteries.

It isnt hard to build a battery Lithium Battery SA used to sell kits to build your own batteries back in the day

 

[Lupus]

It isnt hard to build a battery Lithium Battery SA used to sell kits to build your own batteries back in the day

They still have them if you know where to look

 

[Lupus]

We run a small 3kVa inverter with two strings of 1.8kW PV panels and soon to be replaced LA batteries that have given up on being alive. We have everything except our bedroom AC, oven and two sets of kitchen plugs for the electric kettle, toaster, etc. connected and I am still surprised at how well it has worked.

This is what I was thinking all I need, not the LA batteries. Have you looked at hubbles?

 

[Neuk_]

This is what I was thinking all I need, not the LA batteries. Have you looked at hubbles?

I considered Hubbles but went for these...

 

[ADrunkTeddyBear]

They still have them if you know where to look

I dont believe he does the 48V 5kW packs anymore. The smaller ones are still offered