Conext XW+ Grid Support Voltage Questions
In the XW+, the Grid Support and Grid Support Voltage (GSV) settings seem to serve several purposes. One of those is to enable the use of excess power from an external DC charger to help power locally connected loads on ACout or even to sell back to the grid (if enabled).
I am mostly interested in the situation where the charger is a Conext
MPPT-80-600 or 60-150 and Enhanced Grid Support is enabled by setting
GSV to a high value above the charge controllers equalization voltage
(eg: 64 volts), and grid selling is disabled.
Question 1: Does this function work if the grid is down (eg: AC1 is not qualified)?
Question 2: If so, does it also work if a generator is running and qualified on AC2 (possibly with generator support enabled)?
Question 3: In these cases does a charge controller (eg: MPPT-80-600) modulate the PV power to match demand changes on ACout since it cannot sell excess power? Is that mediated by the DC bus voltage or by Xanbus commands?
Question 4: If Grid support is not enabled, would an MPPT-80-600 likewise modulate the DC power to maintain the absorption voltage or the float voltage (eliminating excess power)?
I have not been able to find answers to these questions in the manuals or online. My apologies if this has been addressed before. I do not own any Schneider equipment, but am considering installing an XW+ and an MPPT 80-600 and just want to understand how they work.
42 300W Solarworld. SB6.0, SB3.8, SB3.0 Owner installed. Mitsu. Hyperheat, State HPX-80. All electric, net+, climate zone 6.
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Comments
First why do you want to set the Grid Support voltage above the controllers 64V? Just disable grid selling, enable grid support, and set the grid support voltage somewhere around 48.5v to allow the grid to add some power only when your batteries get below the set voltage.
I set my grid support voltage at 49.0v and if my batteries drop below about 73% the grid automatically steps in and covers most of my loads protecting my batteries.
When using grid support the 6848 will always draw about 80 watts of energy from the grid. It does this so it can sync it's AC cycle to the Grid AC which is required if the grid suddenly needs to supply a lot of power to your system. So you're probably going to be buying about 25 cents worth of electricity per day on most days. But that allows you to automatically use grid power when you have a few no sun days and the batteries get low.
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1. Assuming no AC2 input when the grid is down the inverter simply keeps drawing on the batteries until the battery voltage drops below the Low Battery Cut Out setting which I set at 47.3v (about 30% SOC). When we lose the grid we usually don't notice unless I look at the meters. It's a very smooth transition between battery and grid power.
2. If I understand your question correctly the answer is yes.
3 and 4. Your charge controller is always adjusting it's output voltage/amperage in conjunction with the DC voltage and where it is in the charge cycle. When the panels are making more power than the charge controller needs the controller doesn't accept the extra power and the panels burn off the extra power as heat.
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
http://members.sti.net/offgridsolar/
E-mail [email protected]
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
The XW has 2 interlocking transfer switches, the generator cannot sell to the grid.
The XW can assist a small generator with a large load, by using the batteries. If you have sunlight at the time, your load is running off the sun, not the stored battery power, unless some local floor contractor alligator clips his 3HP floor sander into the main panel and you wonder why your batteries are going down !!
I am off grid and cannot help with selling to grid issues.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Is there any use case for enabling grid support without enabling sell?
Yes. I use grid support to protect my batteries but because of changes in what the utility is willing me to pay combined with higher meter fees I do not sell back to the grid.
So, I am simply asking how this equipment works before I buy it (or something else). I'm not real satisfied with someone saying basically "yes, it works." Any bozo marketer can say that. I want to know *how* it works and of course what doesn't work mostly to get past the marketing hype.
After 4 years I am happy with my Schneider equipment. Like anything it takes a little hands on learning to figure it all out.
Having 12,000 watts in panels gives you all sorts of options. We have 6000 watts in panels and the 6848 pulls from the grid about 1 day a month to supplement the battery power. Before we added 2 small wall mount propane heaters the 6848 was pulling from the grid more often in the winter because we use a 2 head mini-split occasionally for heat. Normally we use wood heat but those propane heaters are so easy we're doing less burning now days.
a thought...
When people see my panels they often ask about emergency power for when the grid goes down. For occasional emergency power I suggest that they consider a whole house generator; something you may also want to consider. For the $3000 that inverter is going to cost you can buy the generator. Wiring costs are probably less with the generator. Rent a 250 gallon propane tank ($48/year) and you'll have a lot more stored energy than the expensive battery bank will hold.
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
Yep, I run loads, and charge batteries on the dark days. I hear the generator lug down, and see the charger has backed off. When I was using a eu2000, I often had gen support activate, but with my main 3Kw generator. it never does.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
Conext XW6848 with PDP, SCP, 80/600 controller, 60/150 controller and Conext battery monitor
21 SW280 panels on Schletter ground mount
48v Rolls 6CS 27P
generator [default AC2] input) when the AC load current drawn from the generator
AGM batteries normally have an internal catalyst that fails after recombing "a lot" of Hydrogen and Oxygen back into water...
Hydro Caps are an aftermarket catalyst cap, and here is their FAQ that explains about their operation (should be similar to AGM operation):
http://hydrocapcorp.com/contact-us/faq/
And avoid high current "gassing" when charging... The catalysts do get hot (recombining hydrogen and oxygen generates heat)--And can damage/ruin the catalyst.
-Bill
Float duty has lower voltages for Bulk/Absorb + Float
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
https://en.wikipedia.org/wiki/VRLA_battery
-Bill