42 kw Solar in place, looking for battery backup, system sized equal to light commercial

[JoeDirt]

We had a vendor bid Solar and battery back up. Solar has been installed. We have two meters, each with 100 kw generators for back up. Our arrays are 21 kw. When the vendor showed up to install the battery back up the wheels came off the bus. It was clear they had under bid they system due to there lack of knowledge of our on-site electrical needs.

We now need to start over on the battery portion of the build. We are grid tied currently, we are in a remote area with single phase power provided by a small power cooperative in North Central Idaho. We had been sold two 30 kw battery systems one for each solar array located at each meter. The vendor stated that our potential load would require a much larger system after arriving to install his product.

 

[OzSolar]

When the vendor showed up to install the battery back up the wheels came off the bus

Wow that's a wild deal. At least they knew enough to walk away before they really screwed things up. May I ask why you want to add batteries to a place that already has a substantial generator back up?

 

[JoeDirt]

We lost power for 6 days last winter, generators fuel cost at the time cost $1,500.00. With diesel cost rising, about 8 to 10 days of fuel on site. We live on a mountain with a 6 mile hill climb on a gravel road. )Some slopes are 11%) We can not depend on propane or diesel delivery’s. We hope to reduce generator run time, and balance batteries with generator for more self reliance.

 

[JoeDirt]

 

[JoeDirt]

These images are Septembers solar production, you can also see our power consumption. This might help understanding our battery needs.

 

[Danke]

You have an Enphase system? Do you sell back to utility? Do they give you credits?


Maybe some pictures of your system will help.

 

[fromport]

You have an Enphase system?

[not op, but based on info op posted]
yes

Do you sell back to utility?

yes

Do they give you credits?

i have to assume: yes

Maybe some pictures of your system will help.

Why would that help ?

He is more interested in helping size calculations of his storage system.
We need info like peak power, amount of rainy days he want to bridge.
No pictures will help with that ;-)

 

[JoeDirt]

Yes we sell back, at 0.036 cents a kw we pay 0.096 a kw, they do give credits. Here is a photo of one of our meters. This one is feed by 60 panels. We are grid tied and ac coupled.

 

[JoeDirt]

Here is a few years of power usage,

 

[JoeDirt]

Photos of second building

 

[OzSolar]

Sorry if you've got this all worked out already but I assume you don't so I'll offer some "high level" comments of my own.

In your situation, grid is up 98% of the time and you've already got a large generator, typically one designs for the inverter/battery system only for critical loads. Well pump, lighting, fridges. freezers, wifi/internet and the blower for a gas furnace or pumps for a gas boiler, etc. Heat pumps and heat strips generally should be avoided. Mini Splits are pretty doable. You haven't mentioned a budget but FWIW we design systems backwards from the budget rather than ask the customer what they want to do then return with a number that blows them away. Lessons learned...

I ~think~ you can AC couple Enphase with SolArk but I'm not sure.

If it was me I would install a critical load panel and back it up with an inverter large enough that runs your well pump. Since you already have the big generator you can do just fine with a battery on the smaller side. EG: a battery for 3 days costs 3x's what a battery that can support you for one day so just plan on a few hours of generator run time per day as needed during a power outage rather than spend extra for more battery that will sit unused 98% of the time.

You aren't that far from a company that I would recommend in case you haven't already bumped into them. Backwoods Solar

 

[JoeDirt]

Thanks for your input, we had a budget based on the bid we received of $35,000.00 for the back up battery portion of the system. The bid included 2x 30 kw battery system one on each system, and the inverter to run it. The company that bid the system told us that it would be our solution for all our power needs. Unfortunately that was not true.

I have looked into SolArk, product looks great but our load potential is to large for their product. We are looking for a product that may be more in the commercial size. I also realize that the budget will need to grow to suit such a system. Each of our 2 meters meters has 2 400 amp panels and an additional 100 amp panel serving 4 buildings.

We lose power, or drop power and comes back up a few times a month. We hope to be able to be as self sufficient as possible. We realize our generators will be a critical part of the system, but hope to relive the number of times a year it comes on for several hours. Also in the event of prolonged power outages reduce its overall run time.

We also have remote workers on site.

 

[OzSolar]

I think you can parallel up to 12 SolArk 15k so they likely can run your entire facility without breaking a sweat. That would break your budget pretty quickly though.

Wowsa.... something seems terribly amiss with the quote you got. Are you saying two systems with 30 kWH of batteries and a inverter installed for $35k total? I feel that a DIYer would have a hard time putting together 60KWH of batteries and two inverters of any usable size for less than $25K. And probably none of them would have UL listings, a meaningful warranty or pass any sort of inspections. How a company could drive many hours to your remote location and do that with equipment that wouldn't cause the customer a ton of grief seems unlikely to me.

Regardless....
I suggest that you first need to figure out what you want back up and how much KW and KWH each load needs. About the best way I know to do that is install something like an Emporia Energy Meter and keep an eye on things for a few months.

 

[OzSolar]

I keep forgetting to ask.... if I may be so bold... why aren't you dealing with the company that installed the 42kW of solar initially?

 

[JoeDirt]

Ozsolar

The company that installed our solar was affiliated with the battery company. Our solar install process was not a great experience. The solar part cost over $119,000.00 the battery components were $35,000.00.

We felt we did not want reward poor performance with further patronage.

 

[400bird]

You have two 400 amp panels per meter? And you want to keep it all running when the power goes out?

Are your generators already on automatic transfer switches and starters?

I haven't heard of any commercial grade battery inverters. I assume you have motors to start, so a high frequency inverter would be less than ideal.

I'm not sure you have much for options short of calling Tesla for some megapacks.
You could parallel many many high end consumer inverters, but ouch.

 

[OzSolar]

Ozsolar

The company that installed our solar was affiliated with the battery company. Our solar install process was not a great experience. The solar part cost over $119,000.00 the battery components were $35,000.00.

We felt we did not want reward poor performance with further patronage.

Sorry about that. Believe or not I knew that was the reason as soon I read your first post, thank you for confirming my suspicions.

 

[JoeDirt]

I checked on the Mega Pack, not in our budget lol.

 

[houseofancients]

You have two 400 amp panels per meter? And you want to keep it all running when the power goes out?

Are your generators already on automatic transfer switches and starters?

I haven't heard of any commercial grade battery inverters. I assume you have motors to start, so a high frequency inverter would be less than ideal.

I'm not sure you have much for options short of calling Tesla for some megapacks.
You could parallel many many high end consumer inverters, but ouch.

synsynk ( deye / sol-ark) doe make a 60 Kw single phase unit...
but man that is one big system..
also AWPS has build a system using solax equipment in nigeria using 12 15kw inverters and batteries to power a shopping mall

 

[Quattrohead]

Can we have a clue as to what you are doing with all that power ?
Also does the battery/inverter system need to be inspected/UL approved ?
Yes you can stack a load of Solark or indeed the LV6548 type inverters. There are industrial systems that can do this for you too but we don't know much about them here.