Hey everyone (mostly the experts)

I am busy doing some research for a project that needs to be launched in the next few months.

What I am looking for is some advice on which inverters and chargers may be the best or recommended for Continuous High Loads 24/7

Cost is NOT an issue and yes, I know, I need a shit ton of batteries to run 24/7

Continuous AC load will be 10kw Daytime and about 8kw Night time.
I have space for approximately 100kw Solar panels, so should be plenty to keep the batteries charged for night time use?

Project lifespan will be 10 years max.

Any insights, suggestions, comments welcomed and appreciated.

Is this for a completely off-grid setup?

And is there backup generator if it is cloudy for a few days?

59 minutes ago, Luminous said:

Is this for a completely off-grid setup?

And is there backup generator if it is cloudy for a few days?

This will be 100% off-grid, battery backups will be enough for close to 2 days and there are 2x 2.5kva generators to supplement charging if the sun stays away for more than 2 days.

3 sunny islands with 3 tesla powerwalls for a money is no object option.

 I've even seen a post about a solar roof on the forum can't remember by who.

On 2021/06/15 at 11:14 AM, WannabeSolarSparky said:

Hey everyone (mostly the experts)

I am busy doing some research for a project that needs to be launched in the next few months.

What I am looking for is some advice on which inverters and chargers may be the best or recommended for Continuous High Loads 24/7

Cost is NOT an issue and yes, I know, I need a shit ton of batteries to run 24/7

Continuous AC load will be 10kw Daytime and about 8kw Night time.
I have space for approximately 100kw Solar panels, so should be plenty to keep the batteries charged for night time use?

Project lifespan will be 10 years max.

Any insights, suggestions, comments welcomed and appreciated.

 

Did you say 100kw of solar panels?

 

EDIT: If so, then you should look into some kind of  high voltage battery system. Cause 100kw at 48V would be over 2000 Amps and that's just insane.

Edited June 16, 20214 yr by tetrasection

hmm if i an reading this correctly ,you will be using more than 200kwh a day . meaning you will need about 300kwh of lifepo4, you say cost is not an issue but it may become an issue , this could be a R4 million job easy and thats just a rough guess , 10 years is a short time frame for a setup that is meant to last 25 years plus. You should probably be talking to a solar installer and not the forums . 

10 minutes ago, Nexuss said:

hmm if i an reading this correctly ,you will be using more than 200kwh a day . meaning you will need about 300kwh of lifepo4, you say cost is not an issue but it may become an issue , this could be a R4 million job easy and thats just a rough guess , 10 years is a short time frame for a setup that is meant to last 25 years plus. You should probably be talking to a solar installer and not the forums . 

 

Yeah this is powerplant level stuff lol

Maybe look into some kind of hydro storage or vanadium redox batteries.

Edited June 16, 20214 yr by tetrasection

5 minutes ago, Brani said:

May be a good idea to have some PV inverters also coupled with they system, like Fronius.

Yeah with 100kw of panels you're looking at something like this:

He wants to power 10kw times 24 hours?

Contact Mircocare, they build some awesome mini grid systems these days. Keep it local, easy to fix, easy to upgrade.

 

on the other hand, 10kw ain't that much, so, an good transformer based inverter with an AC coupled Grid tie inverter and some goooooood batteries!

 

o, did i say Batteries!

Batteries!

Batteries!

2 hours ago, 87 Dream said:

They way I understand this post is that 10kw & 8kw by day & night respectively. The total demand will never go above 10kw so choose your choice of inverter system.

You can upscale to 3 of these said systems in parallel so that you have the machines not working as hard for the given job so you have some longevity as well as redundancy. One unit working at close to peak on this job will be all your eggs in a single basket scenario which wouldn't be wise. Add solar panels PV to the amount of 15kw using multiple MPPTs so that you can feed the inverters to feed the loads directly during the day as well as charge the batteries with the excess power. 

By night the given storage will need some margin in capacity & also some margin for bad light days. Margin can be scaled for up to 4 days of reserves & then you have yourself the solution totally met. That equates to +-400kWh of battery storage. At this capacity level you can throw away the Generators. Your load is covered through PV & storage. Rent a Generator should you find it ever necessary. You will know after 2 days of poor weather & forecasts. Gives you time to plan a hired unit. Saves on costs. So you can scale any which way you like eg. 25 X 16kWh battery packs all connected in parallel via industrial grade busbars to your inverters. 

The type of battery storage capacity makes this mini grid status but totally scalable & possible. Such a battery storage centre would need a well designed system to keep the inverters halfway between the battery banks to balance the resistance within the storage units. Really not at all beyond the scope of what battery technology has readily available in the local market. The least complicated way would be a tailor made solution using the largest sized quality cells available & custom built enclosures.

Companies in the off-grid mining industry in Africa are setting up & carrying out these exact type of operations daily. Their scales of operations are even higher. Mainly making use of old shipping containers with AC units inside to keep the batteries/ Inverters safe, optimum & easy to transport & then laying out the PV as a fixed built structure. 

87

 

I would go a completely different route.

I would split up the loads into 4 equal sections and have 4x 5kw high voltage inverters, each with a separate PV string and battery bank. That way you don't need to go to extremes when it comes to cabling.

With that setup you're limited to around 25kw total PV power. If you wanna go higher, you'll need more MPPTs, or bigger inverters.

 

Edited June 17, 20214 yr by tetrasection

Sounds like you basically need a mini version of this setup: https://www.freedomwon.co.za/freedom-won-powering-the-future/

 

 

On 2021/06/16 at 8:20 PM, Nexuss said:

hmm if i an reading this correctly ,you will be using more than 200kwh a day . meaning you will need about 300kwh of lifepo4, you say cost is not an issue but it may become an issue , this could be a R4 million job easy and thats just a rough guess , 10 years is a short time frame for a setup that is meant to last 25 years plus. You should probably be talking to a solar installer and not the forums . 

Option A - The project only needs to run for 10 years, at the end of the 10 years all the hardware will be sold off.
Option B - After 10 years if Eskom and "guvament" get their act together then might be harnessed to feed back to the grid till the system dies a natural death.
 

On 2021/06/17 at 8:57 AM, 87 Dream said:

They way I understand this post is that 10kw & 8kw by day & night respectively. The total demand will never go above 10kw so choose your choice of inverter system.

You can upscale to 3 of these said systems in parallel so that you have the machines not working as hard for the given job so you have some longevity as well as redundancy. One unit working at close to peak on this job will be all your eggs in a single basket scenario which wouldn't be wise. Add solar panels PV to the amount of 15kw using multiple MPPTs so that you can feed the inverters to feed the loads directly during the day as well as charge the batteries with the excess power. 

By night the given storage will need some margin in capacity & also some margin for bad light days. Margin can be scaled for up to 4 days of reserves & then you have yourself the solution totally met. That equates to +-400kWh of battery storage. At this capacity level you can throw away the Generators. Your load is covered through PV & storage. Rent a Generator should you find it ever necessary. You will know after 2 days of poor weather & forecasts. Gives you time to plan a hired unit. Saves on costs. So you can scale any which way you like eg. 25 X 16kWh battery packs all connected in parallel via industrial grade busbars to your inverters. 

The type of battery storage capacity makes this mini grid status but totally scalable & possible. Such a battery storage centre would need a well designed system to keep the inverters halfway between the battery banks to balance the resistance within the storage units. Really not at all beyond the scope of what battery technology has readily available in the local market. The least complicated way would be a tailor made solution using the largest sized quality cells available & custom built enclosures.

Companies in the off-grid mining industry in Africa are setting up & carrying out these exact type of operations daily. Their scales of operations are even higher. Mainly making use of old shipping containers with AC units inside to keep the batteries/ Inverters safe, optimum & easy to transport & then laying out the PV as a fixed built structure. 

87

Thank you for the insight, added to our spec notes.

On 2021/06/16 at 10:17 PM, Buyeye said:

He wants to power 10kw times 24 hours?

Correct

The system will be divided into 6 separate units. Each running 4kw continuous.
As cost is no issue we are looking along the lines of Sunsynk 8kw which would allow each unit to only run at 50% capacity which should help with the longevity.

We also do not really want to go high voltage as all the hardware would need to be sold on after the 10 year period ends.

But this is all still exploratory and so far a few replies here have helped a lot with the thinking and planning.

On 2021/06/16 at 8:05 PM, tetrasection said:

 

Did you say 100kw of solar panels?

 

EDIT: If so, then you should look into some kind of  high voltage battery system. Cause 100kw at 48V would be over 2000 Amps and that's just insane.

lol yeah sorry, I should have given some more info/insight about the project.

It will be spit into 6 separate independant units, each doing 4kw continuous.

 

9 minutes ago, WannabeSolarSparky said:

lol yeah sorry, I should have given some more info/insight about the project.

It will be spit into 6 separate independant units, each doing 4kw continuous.

 

Yeah then go with 6 inverters each with their own panels and batteries. With 6x 8kw inverters you can use around 80kw of panels so you should be good.

Would you be running single phase or three phase?

 

On 2021/06/19 at 8:39 PM, WannabeSolarSparky said:

lol yeah sorry, I should have given some more info/insight about the project.

It will be spit into 6 separate independant units, each doing 4kw continuous.

Have you considered adding wind to supplement nighttime loads? Would be way more cost effective than adding almost half a megawatt of lithium batteries...

On 2021/06/26 at 4:07 AM, tetrasection said:

Have you considered adding wind to supplement nighttime loads? Would be way more cost effective than adding almost half a megawatt of lithium batteries...

That is already a consideration if we decide to scale up bigger than the current plan

Having read through this with some interest I would say that your best bet may actually be Victron Quattro units 6x10kW. Coupled with each would be 250/100 MPPTs and each with about 40kWh of storage. The reason for going even larger than the 8kW would be the fact that air-conditioners are particularly unpleasant loads at start-up. Additionally the Quattro gives you the option of connecting generating power as a secondary AC input and they have the option of running PV on both the AC and DC side which allows you to connect some of the panels (via a Fronius) on the AC side thus sparing you the need to couple all PV on the DC side. The Victron website has a few reference projects using Quattro units at roughly this scale. Disclaimer: I do not work for Victron and don't run them in my setup.

Edited July 13, 20214 yr by Nonlinear