Good afternoon and Merry Christmas!
First post here. By way of introduction, I have a cabin I’ve built in Texas with a big flat roof that would be ideal for solar. Grid is not sensible ($25,000).
The Enphase IQ8s are finally out. I’d like to have a large array of panels (about 10kw), micro inverters, a main panel, a battery charger/inverter, and an expandable 48v set of rack batteries.
Any help putting this together with Midnite components would be appreciated. I’m particularly interested in the B17 product line.
Thanks
Tom
I don't see why the B17 (for battery backup) and Enphase microinverters shouldn't be a great combination !
Will have to think about this a little more.... The battery voltage regulation part at least.
If these newer Enphase inverters can adjust power level by shifting AC frequency, it should be a piece of cake !
The Barcelona MPPT charge controller should work well to just charge the batteries too without having to shift frequency.
Thanks boB. I’m pretty serious about getting started on this system once I can pin down the components. Getting up on the roof to install the panels before the end of April would help beat the heat.
The IQ8s will help me minimize DC lines running from the roof panels to the basement.
I’m thinking of this battery or something similar:
https://shop.signaturesolar.us/products/48v-100ah-lifepower4-battery-by-eg4?ref=cPwLcVc0SW-BjN
Let me know if I can provide any additional info.
Thanks
Tom
Quote from: Bluedog225 on December 26, 2021, 11:11:08 AM
I’m thinking of this battery or something similar:
https://shop.signaturesolar.us/products/48v-100ah-lifepower4-battery-by-eg4?ref=cPwLcVc0SW-BjN
Tom
Very interesting battery. You would probably want a few of those in parallel but could start with one.
I see that it is a pre-order now. Any idea when they can deliver ?
I was thinking of getting 6 of the 48V batteries and build a rack mount. But it might be nice to ease into it
There has been a lot of interest in the EG4 and it got a great review from Will Prowse. Many orders from folks on the diy solar forum recently that are arriving now. I think the lead time would be 6-8 weeks. Hopefully the shipping delays will work themselves out.
The biggest issue with the batteries, I think, is the communication protocol. So that the system can regulate the micro inverters and charging. This is where I’m over my head.
I’m hoping the Midnite team can work this out.
Good morning,
I wanted to check in and see if you have had a chance to think this through? The batteries are in stock. Also looking at the Fortress E-vault.
But either way, I want to make sure I can use the midnite equipment to support the Enphase IQ8s.
I’d like to get this all installed before it gets hot (around May).
I’d be happy to chat with you or one of the sales team if you prefer.
Thanks!
Tom
The MidNite inverters will be able to frequency-shift to control charging but maybe not right out of the gate.
I will forward this onto others
boB
I just got an eVault Max and the Classic programming for it was trivial.
Classic will be running open loop, and eVault & Schneider XW6848 will be closed loop
Quote from: mike90045 on February 02, 2022, 07:06:17 PM
I just got an eVault Max and the Classic programming for it was trivial.
Classic will be running open loop, and eVault & Schneider XW6848 will be closed loop
Mike, this is interesting !
I am wondering what you had to do to make the XW and eVault to work together.
What does the closed loop system do ? Does the eVault tell the XW to stop charging or reduce and increase current ?
Change charge voltage ? Does the eVault tell the XW system what the SOC% is ? Is it CANBUS or RS485 with a Schneider Combox ?
Sorry for all the questions.
boB
Quote from: Bluedog225 on February 02, 2022, 11:37:31 AM
Good morning,
I wanted to check in and see if you have had a chance to think this through? The batteries are in stock. Also looking at the Fortress E-vault.
But either way, I want to make sure I can use the midnite equipment to support the Enphase IQ8s.
I’d like to get this all installed before it gets hot (around May).
I’d be happy to chat with you or one of the sales team if you prefer.
Thanks!
Tom
As this is off grid, in my humble opinion micro inverters do not make sense as they are strictly gird tied. You would then need to add a second expensive inverter to ac couple and the charging is clunky at best.
What I would recommend is a DC coupled system where the modules go into a MPPT charge controller like the classic and then you use an inverter like a Magnum, Schneider, etc to power your AC loads
Feel free to email me Ryan@midnitesolar.com or call in 360-403-7207 xt151
Thanks for all the detailed responses. I realize I’m out of the mainstream here.
My goal is to avoid the risk of a long, unregulated, DC wire run through the structure and the associated fire risk. I’m willing to pay extra to mitigate this risk.
I need some sort of rapid shutdown device on the panels to accomplish this. Micros seem 100 percent reliable. No chance of DC arc anywhere downstream. My DC risk is isolated at the panel, and isolated at the inverter charger in the (somewhat fireproof) basement. All the rest is plain vanilla AC with the associated safety devices and track record.
Micro inverters seemed to fit this requirement. What are my other options? Are optimizers or some type of panel level rapid shut down device less complicated? And more reliable that a micro like the IQ8?
My other option is to run the DC lines from the roof to the basement in metal conduit to avoid damage from animals (rats/squirrels) or weather exposure. I’m not sure what happens with a prolonged DC arc to that conduit. I think it could be bad depending on where it expressed itself. I‘d rather minimize the DC arc issue in my design.
I‘m open to other solutions. The is a lot of appeal to a roof mounted array in my situation. But I’d like it to be as safe as a traditional utility feed. Otherwise, I’ve got to build another structure, run lines underground, etc. with a fair amount of extra expense and risk of theft.
I really appreciate your input on this.
Is your PV on the roof or outside on a pole mount ?
DC is definitely more "traditional" in an off grid system. But I would hope that we would eventually be able to do either one, including AC coupled. AC coupling possibility will come after the regular inverters but would be in a software update. Can't say exactly how long that software might take ?
High voltage from the PV to the charge controller near the batteries is about the same or possibly even better than using micro-inverters with frequency shift but like you say, the rapid shutdown part of things becomes important in that case. BUT only if the panels are mounted on the roof.
boB
I’ve got a big, flat, unshaded, secure, metal roof that begs for solar.
And a big, concrete garage 30 feet down for the batteries, inverter, etc.
All the requirements for rapid shutdown, etc for DC seem clumsy compared to micros for a roof mount.
@BoB
The open loop programming is trivial. Just set the Bulk & Absorb to their published safe limits (54.4V) and Float is just a hair less 54.2v
Closed loop uses a butchered ethernet cable to connect the battery BMS to Schneider Gateway, and the gateway passes the charge/no charge along to the Schneider gear, allowing a higher charge voltage, with confidence the BMS can cut it when needed:
b. eVault-&eVault MAX specific instructions:
i. Identify if the RJ45 cable is the A or B format. Typically, the cables are B format.
Whichever format, the eVault uses wire 3+5 for RJ485A/B communication.
ii. Cut off one end of the ethernet cable and connect wire 3 (typically green-white)
to port 18 and wire 5 (typically blue-white) to port 20 on the Conext Gateway/
Insight Facility (Exhibit A).
The RJ485 cables wires into the 20+ pin connector of the gateway and uses a serial interface to identify itself as a BMS and then passes control data to the Schneider gear.
The eVault Max that I have, has a precharge relay to prevent the inverter bootup surge from tripping the BMS offline. It seems to work pretty well.
Good morning,
I appreciate the thoughts on this. I’ve been digging around and frankly, have spent way too much time trying to figure out a way to get an Enphase micro solution.
I found out this morning that the Enphase warranty is conditioned on continuous connection to the internet. I’m off grid and no internet. (and that’s dumb-chuckle). So I’m done with them.
Do you guys offer (or know of) any solution that incorporates panel level arc-fault shutdown?
Many thanks.
Tom
The Issue with AC coupled is the 5 minute reconnect timer. Unless Enphase has developed a throttle back system AND a battery based inverter has the same protocol to control it you have the clunky on and off every 5 minutes and the battery doesnt really charge elegently.
Personally I would use a DC coupled system with simple rapid shut down on the roof and let the charge controller handle Arc Fault this way you minimize the electronics on the roof
Agreed.
I’ve read through the Classic manuals. I understand the ground fault stuff. I’m a little less clear on the arc fault but I generally get how it works. But it all cuts off the load, not the source.
I’m trying to find info on whether Midnite (or Midnite combined with the SMA Sunny Island) is able to communicate with a panel level device for rapid shut down? Like the Tigo optimizer? Or a SMA Sunspec module level shutdown device? Or the Apsmart?
https://www.sma-america.com/products/sunspec-certified-rapid-shutdown-technology.html
Many thanks!
Quote from: Bluedog225 on February 04, 2022, 11:06:37 AM
Good morning,
I appreciate the thoughts on this. I’ve been digging around and frankly, have spent way too much time trying to figure out a way to get an Enphase micro solution.
I found out this morning that the Enphase warranty is conditioned on continuous connection to the internet. I’m off grid and no internet. (and that’s dumb-chuckle). So I’m done with them.
Do you guys offer (or know of) any solution that incorporates panel level arc-fault shutdown?
Many thanks.
Tom
WOW! I don't think I knew that Enphase equipment HAD to be connected to the internet ! Doesn't make sense but I guess that even the Tesla Power Wall had to be connected to the internet to be able to run off-grid for very long a few years ago. I don't think they still do that though.
AFAIK, Panel (modular) level arc-fault is not legally needed. String level fits the bill just fine.
And series arc faults have been the only type of arcs that had to be mitigated.
Parallel faults not yet at least so the one per array just has to turn the PV connection off.
boB
Agreed.
I’m wanting to get ahead of the legal requirements. Panels and panel level shutdown devices are getting cheaper. I’d like to go ahead and be done with it. Just need a system that can reliably signal the device.
Shutting off at the panel makes sense to me.
Quote from: Bluedog225 on February 08, 2022, 01:28:37 PM
Agreed.
I’m wanting to get ahead of the legal requirements. Panels and panel level shutdown devices are getting cheaper. I’d like to go ahead and be done with it. Just need a system that can reliably signal the device.
Shutting off at the panel makes sense to me.
Just curious as to what is cheap ?
I think the cheapest out there might be something like in the $20 USD range for a single module.
Which module level shutdown products are you seeing ?
boB
That’s about what I’m seeing though $20 would be even better.
The SMA JMS-F SunSpec Rapid Shutdown Device is about $38.
The APsmart RSD System is about $28.
The Tigo is about $32.
I guess the way it works with something like the APsmart is the already existing arc fault/ground fault detection system in the classic trips, then the APsmart system detects the absence of AC and signals the RSD.
Maybe I’ve answered my own question. No need for further integration?