Is it more cost efficient to install multiple small systems or one large system

[TGinTX]

I'm still in planning stages. If I look at costs of replacement of parts, unavailability or parts, incompatibility as time goes by, does multiple smaller solar systems make more sense than one large system? I'm looking at costs over 15 years or so. For example, if I know I want to run a freezer, a tv, a coffee maker, a toaster. I feel like it might be easier to manage having the freezer on its own setup and the other appliances on a separate setup where I know I won't run any of them at the same time and where I can run the coffee maker & toaster only during daytime hours. I don't get a good indicator how long the different parts are actually lasting and having a really large battery failure seems like a very possible reality that makes many smaller batteries sound better. Thoughts?

 

[Mattb4]

I think you will find that you are better off with a comprehensive system designed to handle your loads. There is the exception of if you need to power a Well or possibly a large A/C unit. These might be better to have dedicated setups if you are totally off grid.

Batteries are expensive to buy and you really are better with a larger battery bank than multiple small ones that struggle to power a load. Batteries are consumables. Most failures however come about due to improper charging and usage. There can also manufacturing defects.

The thing with loads such as you list is they are cyclic. They do not have to be drawing from a system all at the same time. One PV/battery system can be used for all of them if you load manage.

 

[OffGridInTheCity]

Agree with @Mattb4 I have 'one' larger system made up of individual components....

3 x PV arrays -> 3 x Midnite Classic Controllers -> Battery Bank (of 9 x parallel batteries) -> 2 x 12,000w inverters -> many home circuits.

I operate as one large system but it is made up of individual components. For example, I can turn off one of the PV arrays to work on it but the system will operate with the other 2. I could unhook one of the 9 parallel batteries and work on it or replace it while the other 8 continue. I can disconnect one of the inverters and the other will continue to work.

To the overall question - I would suggest one larger system with multiple sub-components rather than multiple (independent) small systems in terms of home powerwalls.

There is a youtube guy that has a larger powerwall system but also 3 x rain-harvest tanks / pump houses that are indpenedent. He did individual battery/solar-panel/victron-equipment for each one but tracks them 'overall' thru victron monitoring. I would have just run wire out to the pumps rather than create individual systems but for small systems like this and comprehensive monitoring such as victron I can see it.

 

[Vigo]

One semi-relevant thing i would bring up is the 'minimum operating voltage' of high-voltage mppts. I.e. if you get a single large mppt which can accept a high voltage so that you can put all your panels in series, but you aren't way way above the minimum operating voltage, you may have been better off doing multiple strings into multiple smaller mppts just because they wouldn't be as prone to 'dropping out' and going from something to nothing. Just a thought.

 

[Leeds]

Efficiency?

I prefer a single battery bank to maintain.

But I'm all about a charge controller per string and I'm all about an inverter per load. Toggling inverters on as needed leaves you with no losses when the load is off, that's true efficiency.

I'm just wrapping up this project:

 

[Whats-n-Watts]

Efficiency?

I prefer a single battery bank to maintain.

But I'm all about a charge controller per string and I'm all about an inverter per load. Toggling inverters on as needed leaves you with no losses when the load is off, that's true efficiency.

I'm just wrapping up this project:

That's what I'm talking about! ?

 

[Skid]

I will probably have to set up a small system for a family in Nicaragua. They have a small 100 sq ft store with a chest freezer and fridge connected to the house and in the house, a flat screen TV and a few LED lights. To keep it as simple and trouble free as possible I think a Phoenix 24/1200 will have no trouble powering the small 100 sq ft store and a 24/500 to run the house, two 450w panels and a 24v 100ah battery to run it all.

 

[JRH]

I'm still in planning stages. If I look at costs of replacement of parts, unavailability or parts, incompatibility as time goes by, does multiple smaller solar systems make more sense than one large system? I'm looking at costs over 15 years or so. For example, if I know I want to run a freezer, a tv, a coffee maker, a toaster. I feel like it might be easier to manage having the freezer on its own setup and the other appliances on a separate setup where I know I won't run any of them at the same time and where I can run the coffee maker & toaster only during daytime hours. I don't get a good indicator how long the different parts are actually lasting and having a really large battery failure seems like a very possible reality that makes many smaller batteries sound better. Thoughts?

Thats a good question…I think there’s good points for both sides depending on your needs and goals. I am considering adding a couple more seperate inverters… plus fuses , switches and a SCC’s for each string all feeding from my main battery bank so that “ some stuff “ can be run while other stuff is down , off , under service or broken….…

not sure about the exact efficiency as I’m thinking more redundancy and versatility….I’m not positive yet how I will proceed , but I do know that a 25 hp spare outboard hung to a swivel bracket on the stern can slowly keep you moving if the inboard engine goes Ka- Poo…

J.