Need someone who is very familiar with DC Solar trailers. We have 8 on an off grid vinyard Arizona. Want to connect multiple trailers

[Ventureup]

We have an off grid vinyard in AZ and yes 8 of the DC Solar trailers. I understand the 10 panels on each trailer are inadequate to constantly charge batteries efficiently. So no that we have a couple with failing batteries, we want to put a couple of trailers next to each other, connect panels, so that 20 total panels are charging just 2 batteries in one trailer only using the charge controller and 2SMA converters on the one main trailer. Anyone have experience splicing in more panels. We would like to hire a consultant is someone is available. Thanks David 602 909 5560

 

[G00SE]

Do you have any pictures of the labels of the panels? I believe most of them came with 235-265w talesun panels
You should have a midnite 250 charge controller in the frontal storage between the inverters. You will likely need to run these controllers to the system/battery you are desiring to charge as they are each only rated for 60a and 20-250w panels would be a waste on one charge controller. Are you wanting to maintain AC output of all 16 Sunny islands or just some of them?

 

[sunshine_eggo]

We have an off grid vinyard in AZ

Where in AZ?

and yes 8 of the DC Solar trailers.

Are these those solar trailers that pop up at auction regularly? SMA inverter and Midnite controller.

I understand the 10 panels on each trailer are inadequate to constantly charge batteries efficiently.

This is not true as a general statement. If they are lead acid, the panels must be capable of delivering 6-20% of the rated capacity.

So no that we have a couple with failing batteries, we want to put a couple of trailers next to each other, connect panels, so that 20 total panels are charging just 2 batteries in one trailer only using the charge controller and 2SMA converters on the one main trailer. Anyone have experience splicing in more panels. We would like to hire a consultant is someone is available. Thanks David 602 909 5560

This is probably not an option.

 

[Ventureup]

Do you have any pictures of the labels of the panels? I believe most of them came with 235-265w talesun panels
You should have a midnite 250 charge controller in the frontal storage between the inverters. You will likely need to run these to the system/battery you are desiring to charge as they are only rated for 60a and 20-250w panels would be a waste on one charge controller. Are you wanting to maintain AC output of all 16 Sunny islands or just some of them?

Thanks for the quick reply. Out of the 8 DC trailers, I know most have the 250w talesun panels (I think one or 2 trailers have 250w). Yes we have the 250 midnight controller along with the 2SMA converters. Maybe we we can only hook up a total of 18 panels to one trailer system. For our situation, we need one trailer at our well, one trailer at a smaller casita, 1 trailer at an underground process area, and one trailer at a workers trailer. So we need 4 separate trailers running on the ranch at 4 separate areas. We have a total of 8 DC Solar trailers. We have replaced the batteries on a couple of trailers (about $15k per trailer for the 2 batteries) and for a couple of trailers we are salvaging good cells from some batteries and swamping them out with bad cells to build a good but still old battery. So the idea now is to simply add panels from trailers that we are not using or had bad batteries, and in the 4 places we need power, to have the original trailer with another trailer of panels hooked to it. So I guess each place would have 18 panels running into A single trailer, with one charge controller and the 2 SmA converters.

Our question is how do we hook up the additional panels, and if we can only use 18 total, that’s fine. so that 18 panels are running a single unit and charging 2 batteries.
Thanks so much for your imput

 

[Ventureup]

Where in AZ?



Are these those solar trailers that pop up at auction regularly? SMA inverter and Midnite controller.



This is not true as a general statement. If they are lead acid, the panels must be capable of delivering 6-20% of the rated capacity.



This is probably not an option.

 

[Ventureup]

We are in Gold Cayon at the base of the Superstition Mountains. Yes they are all the DC Solar trailers that were auctioned. We pitched them in Phx, Vegas and Kentucky.

 

[Ventureup]

Thanks for the quick reply. Out of the 8 DC trailers, I know most have the 250w talesun panels (I think one or 2 trailers have 250w). Yes we have the 250 midnight controller along with the 2SMA converters. Maybe we we can only hook up a total of 18 panels to one trailer system. For our situation, we need one trailer at our well, one trailer at a smaller casita, 1 trailer at an underground process area, and one trailer at a workers trailer. So we need 4 separate trailers running on the ranch at 4 separate areas. We have a total of 8 DC Solar trailers. We have replaced the batteries on a couple of trailers (about $15k per trailer for the 2 batteries) and for a couple of trailers we are salvaging good cells from some batteries and swamping them out with bad cells to build a good but still old battery. So the idea now is to simply add panels from trailers that we are not using or had bad batteries, and in the 4 places we need power, to have the original trailer with another trailer of panels hooked to it. So I guess each place would have 18 panels running into A single trailer, with one charge controller and the 2 SmA converters.

Our question is how do we hook up the additional panels, and if we can only use 18 total, that’s fine. so that 18 panels are running a single unit and charging 2 batteries.
Thanks so much for your imput

 

[Ventureup]

I can post photos tomorrow if that helps.
Thank uou
D

 

[sunshine_eggo]

Hey neighbor. I'm in Mesa. Our off-grid place is up past Show Low towards Concho.

10X 250W = 2500W

The controllers can provide a max of 55A on a 48V system or about 3000W at peak battery voltage, so the MPPT is decently sized to the array.

If your batteries are about 25kWh (520Ah @ 48V), then the arrays are well-sized. They're 468Ah according to various web references, so again, the arrays are the right size for the batteries.

Working under incorrect understanding, you've concluded a certain solution to your problem. I don't think this is a fix for you.

Can you describe what the operational issue is, so we can get a better handle on what you need?

 

[G00SE]

In the manual for these trailers there is a section about daisy chaining them together using Anderson plugs in the back of the cabinets and then separate battery connections. It also I believe shows an option to run one trailer into the gen input of the other. I’m trying to find my downloaded manual of them but am struggling
In your case, since you’re not needing 4x Sunny island output capacity you could repurpose the 10 panels and midnite 250 from one trailer and connect it to the trailer that will be deemed the power cabinet for each site.
Some of these have the “carpoff” midnite charge controller and lack the “follow me” mode. Others have the full featured charge controller and if so, would allow you to connect multiple midnite 250 together with cat cables so that they will stay in the same mode. If you look under the cover and see 3-rj45 ports it is the full version. This would all require some redesign/rewriring and potentially disassembly of some boxes to access the charge controllers and combiner boxes and shunts

 

[Hedges]

You could certainly parallel the output of multiple Classic charge controllers onto battery of one trailer.
Either fat wires from output of classics to the battery, or better to relocate classics next to the battery being charged, and extend PV wires.

I think these systems use battery shunt so Sunny Island knows about current from Classic.
An alternative configuration, at least with older firmware and lead-acid batteries, has a data interface so SI tells Classic what to do.

Orientation option of panels as mounted probably isn't ideal for winter. You might want to lift one bank so both banks could tilt South without shading each other.

For summer, one bank tilted West and one tilted East may be good. Hopefully the two banks are two strings paralleled, so orientation can be different.

You can connect 4x Sunny Island 2p2s for double output. To do that, extend sync bus with RJ45 Ethernet cable, configure second trailer's SI as Slave2 and Slave3, configure first trailer's master SI for 4 inverters. Connect all inverters to same battery bank.

If you wanted more than 4 inverters, easiest to be separate systems.
There may be ways to make one system look like grid to other system.
Preferred way may be to buy a Multi-Cluster box, configure each system with 3x SI or 3-phase, and have something like 4 clusters for 12 SI system, 3 phase, 120/208Y 150A per phase.

 

[sunshine_eggo]

Just spoke with David. I almost picked up one of those trailers and had to fight off my hoarding demons to resist. He's 31 minutes from me, so I'll be heading over there in the next week or two.

 

[Hedges]

If the prospect of having to store something so large and heavy is what kept you from giving in, I might be able to help you.

Battery Inverter Solar Cabinet: (QTY 2) SMA Sunny Island SI-6048 w/ Warranty | eBay

These cabinets were designed and built by DC Solar. If you use the cabinet as-is there are only 2 connections required to have a functioning system (battery connection and solar panel connection). This setup will generate power even when there is no connection to the power grid.

www.ebay.com

The only thing keeping me from acquiring boxes like these (and improving their ventilation) is the dozens of factory sealed boxes of SMA battery and PV inverters I've already got on the shelf.