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diy solar

Inverter recommendations for 48V off-grid installation

I believe the power distribution panel line drawings may be attached to the distribution panels.

I've got the mini-pdp.
It provides breakers for AC in/out and bypass with a lock out (all included). There is a spare slot for one more AC breaker. I've got my AC coupled solar in that slot. Also neutral and ground bus bars.

On the DC side, it includes a 250amp battery breaker. With slots for 2 more DC breakers (intended for solar, but you could use them for anything DC)
 
I've got my AC coupled solar in that slot. Also neutral and ground bus bars.
@400bird what Grid Tie inverter(s) you using with the XW in AC Coupling? Does the frequency curtailment feature work good for you, in grid down situations? What Grid Code you running?
 
It's a Solar Edge 6kw. Circa 2018-19
Yes, it does frequency control. I'm in California, both are set to rule 21
It has worked fine in my grid down tests. But, in the months since install the grid has been uncharacteristicly reliable.

The frequency control is not as smooth as I expected. The PV sort of jumped down by 1/2 or 1/3, it didn't ramp down as smoothly as I had envisioned. But it did work. I'd blame the solar edge if I cared about the PV curtailment being smooth.
It worked, that's all I was looking for and the XW dumped everything (I wasn't using in the house) into the battery.
 
It's a Solar Edge 6kw. Circa 2018-19
Yes, it does frequency control. I'm in California, both are set to rule 21
It has worked fine in my grid down tests. But, in the months since install the grid has been uncharacteristicly reliable.

The frequency control is not as smooth as I expected. The PV sort of jumped down by 1/2 or 1/3, it didn't ramp down as smoothly as I had envisioned. But it did work. I'd blame the solar edge if I cared about the PV curtailment being smooth.
It worked, that's all I was looking for and the XW dumped everything (I wasn't using in the house) into the battery.
Cool. I have SMA Sunny Boy able to AC Couple thru mine. I did a lot of grid down testing and it works pretty good. The XW moves the frequency up slowly and sometimes lets the voltage on full batteries creep up before getting the Sunny Boy throttled down. I programmed the absorption charge a little lower in the XW "it uses that as a target voltage in AC Couple", so it has a little more buffer to get things shut down if a large house load drops with the batteries full.

I also loaded Cali Rule 21 codes "although I'm not in Cali", to gain the frequency/watt curtailment features.
 
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So.... Noob question: What is switchgear and what is it used for?
Midnight Solar makes some "pre-wired" breaker box setups for the XW's. I thought they was geared toward integrating with the Midnight charge controllers, buy maybe they work for any?

Anyway it's basically like the Schneider "wiring breaker boxes", but done by Midnight. '
 
Midnight Solar makes some "pre-wired" breaker box setups for the XW's. I thought they was geared toward integrating with the Midnight charge controllers, buy maybe they work for any?

Anyway it's basically like the Schneider "wiring breaker boxes", but done by Midnight. '
And I think the MN ePanel costs a little less? Maybe?

But the design seems better than the Schneider box. If I remember correctly, the Schneider box does not have a location for the XW system control panel (SCP) , and the Midnite solar box does. I know the ePanel designed for the SW has a knockout for the SCP, That alone is nice.

By switchgear (rightly or wrongly) I mean electrical boxes, combiners, etc and breakers. I really like Midnite Solar breakers. (well I really really like the classic SCC too, but that might not work for a hi voltage setup .... but if they could get the Hawkesbay or Barcelona released soon .... Mmmmmm)
 
You mentioned the Honda EU700is generator as a piece of the puzzle you already have. I've been looking at a new inverter generator myself and came across this DuroMax XP9000iH with remote electric start for $2600. I haven't pulled the trigger yet, so I can't do a review but it appears it will meet or exceed all my power quality requirements, without a high cost ...if I stand far enough away. It's also duel fuel which might be a plus? ;)

DuroMax XP9000iH 9000-Watt 459cc Dual Fuel Digital Inverter Hybrid Portable Generator​

 
DuroMax XP9000iH 9000-Watt 459cc Dual Fuel Digital Inverter Hybrid Portable Generator
I looked at alternatives to the Honda too because Hondas are so expensive. I bought mine two years ago and got a pretty good deal at $4300. At the time the DuroMax and others were going for under $2000. I have no firsthand knowledge of the DuroMax, but it seems like a good deal. The main things I think you're getting with the Honda are the extremely low noise level and ... well, it's a Honda. I also have had the Honda EU2000 for something like 15 years and it just runs without hassle. I think that was the main reason I went with the bigger Honda in spite of the cost.

Also for the larger Honda, it looks like there is an aftermarket automatic generator start module. It may also work with the DuroMax.
 
And I think the MN ePanel costs a little less? Maybe?

But the design seems better than the Schneider box. If I remember correctly, the Schneider box does not have a location for the XW system control panel (SCP) , and the Midnite solar box does. I know the ePanel designed for the SW has a knockout for the SCP, That alone is nice.

By switchgear (rightly or wrongly) I mean electrical boxes, combiners, etc and breakers. I really like Midnite Solar breakers. (well I really really like the classic SCC too, but that might not work for a hi voltage setup .... but if they could get the Hawkesbay or Barcelona released soon .... Mmmmmm)
I think the SCP mounts in the XW itself. It replaces the original display.

Also, I believe it is significantly more expensive.
Depending on options, the Midnite panel costs around $1300. While the mini PDP seems comparable at around $600 depending on where you shop. The biggest difference I see is that the midnight includes more bus bars. Those wouldn't be useful for my install.
 
I looked at alternatives to the Honda too because Hondas are so expensive. I bought mine two years ago and got a pretty good deal at $4300. At the time the DuroMax and others were going for under $2000. I have no firsthand knowledge of the DuroMax, but it seems like a good deal. The main things I think you're getting with the Honda are the extremely low noise level and ... well, it's a Honda. I also have had the Honda EU2000 for something like 15 years and it just runs without hassle. I think that was the main reason I went with the bigger Honda in spite of the cost.

Also for the larger Honda, it looks like there is an aftermarket automatic generator start module. It may also work with the DuroMax.
In my search for an inverter generator to fit my needs I never even came across the Honda, because my search term included "duel fuel" and apparently Honda doesn't offer it that way? Propane is a must in my application only because of the convenience it offers me. I really don't want to keep enough gasoline stored and maintained that it would take me to get through 2-3 day blackouts that come once or twice a year. When they do that almost always means I'm snow or ice bound and going out to get fuel isn't an option. I have a 1000gal propane tank to draw my gas out of into smaller portable bottles. The last 48 hour outage was 2 weeks ago and the 2nd one this winter looks like it could happen on Wednesday.
 
Anyone else think that might be a problem? ?
Looking for recommendations for off-grid inverters for a system with these characteristics:
  • 48V
  • un-inspected: off-grid, no building or electrical inspections required
  • ~6 KW solar panels expanding to 12-18 KW over time
  • PV array would probably settle in at around 400 V, 19 A initially, expanding to multiple arrays
  • battery storage (looking at the EG4 batteries at the moment)
  • 9100 ft elevation
  • many days below freezing, with many also below zero
  • ~5-6 KW of inverter capacity initially, expanding if required
  • 240 V required
  • The cabin will be uninhabited 3-5 days/week
  • generator backup, and I have a Honda EU700is generator, currently without autostart
If you have an inverter brand/model recommendation based on your experience, please indicate why you recommend, and pros/cons. I've seen a lot of discussion of issues with certain brands on this forum, but not anything collecting it into one place for my scenario.

Research so far:
  • Sol-Ark 12K: Perhaps not the best for off-grid use. Seems to include features that benefit grid-tie systems that I would not want to pay for. Seems touchy, as a lot of folks have struggled with it shutting down with slight imbalances on the AC legs. Needs an additional autotransformer to overcome this. Pricey.
  • Victron Quattro 5000 KVA: Seems straightforward. You buy two to get 240 V. Not UL listed, which does not matter for me. Less pricey than Sol-Ark for two. Reputable brand.
  • Growatt 5000W 48V: Price seems too good to be true. Needs an autotransformer to produce 240 V. Relatively high idle watt usage. Reputation of the brand? Reliability? Longevitiy?
Would appreciate any advice you guys can provide as I embark on my design.
I can't comment about inverters I'm learning too. I will comment about the freezing weather. We had temps as low as -47 here this winter. My components are going to go into a highly insulated 10x10 shed. I have propane from a large tank roughed in to it for a wall heater, and gen set. I was going to build heat pad back up in case the wall heater ever failed in winter. Instead of that I am going to use 2 low btu Rinnai wall heaters with real thermostats set to different temps. One for heat one for back up, and I will switch back and forth for primary each time we are out. Shed specs 2x8 floor and walls, with hardware cloth underneath to keep the critters out. I use 1/4" hardware cloth, but if you have mice and rats, or other bigger critters use a layer 0f 1/4' then a layer of 1/2 " Rats can bite through the thinner ga 1/4", and some mice can squeeze through the 1/2" We did this on all 3 of the cabins we built, instead of boxing in the bottom. If moisture ever does seep in, it will eventually dry out without rotting the joists, and it's better protection from critters. R-32 Rockwool insulation walls and floor, R64 attic. Walls, floor, and ceiling, sheeted with cement board, and a rubber mat on the floor. If anything goes wrong when we aren't there, any fire damage should be contained. I'm going to cage off a little area away from the components, with a small cat door for a couple feral cats for year around mice control. 2 cold weather problems solved.
 
I am also planning a heavily insulated room, minimally heated, for the equipment and batteries. Every other thing in the cabin will be cold-weather tolerant. In case the heating fails for some reason, I'm selecting good old lead acid batteries, which are fine in freezing temps, as long as they are charged.
 
Sounds like a sweet system. It's double what my system is and four times more batteries. I guess for a true off grid system you really need several days of extra batteries to cover bad weather. What brand of batteries did you buy?
Eve 280ah. 9 x 16s.
 
Been a while and a lot of water has passed under the bridge. After consulting with AltE and Schneider about the altitude issue, it was strongly recommended by both not to exceed the altitude limitation. The concern is arcing across circuit boards due to the air at altitude being less of an insulator than at lower elevations. So... all the Schneider stuff went back with accompanying expensive shipping.:(
After more research and shopping, I settled on Victron equipment, which is rated up to 5000 m. I am planning to haul it to the cabin and start installing as soon as the snow melts. The list so far:
  • 2X Quattro 3000 KVA inverters (which coordinate between themselves to provide split phase 120 V and 240 V AC and are stackable)
  • SmartSolar MPPT 250/85 SCC
  • BMV-712 Battery Monitor
  • Cerbo GX Comm Device
  • GX 50 Touch Screen
I've settled on Longi 355 W panels that I can get locally at a good price in a 5S3P arrangement, providing nominal 5325 W. Also I will probably go with an Iron Ridge ground mount with locally sourced pipe. For batteries, I am considering Crown lead acid batteries for about 10-15 KWH. I bought an inexpensive combiner box off Amazon. Basically all I have left is wire and switches. Now if the snow will melt...
 
Been a while and a lot of water has passed under the bridge. After consulting with AltE and Schneider about the altitude issue, it was strongly recommended by both not to exceed the altitude limitation. The concern is arcing across circuit boards due to the air at altitude being less of an insulator than at lower elevations. So... all the Schneider stuff went back with accompanying expensive shipping.:(

Alternate solution would have been to run it in an SF6 atmosphere. Much better dielectric performance than air.
(Converse, don't vent a helium balloon near the air inlets.)

Seriously though, potted board which I think Victron uses should be a plus. Maybe they also have larger spacing between high voltage terminals.

SMA Sunny Island says,

"Installation altitude The Sunny Island has been designed for use at altitudes of up to 9,840 ft (3,000 m) above MSL. Please contact SMA before using the device at altitudes above 9,840 ft (3,000 m). A performance loss of 0.5% per 330 ft (100 m) is to be expected starting at an altitude of 6,560 ft (2,000 m) above MSL."

It was of course originally designed for 220V, modified for 120V US operation, so might have more margin regarding arcing.
 
"Installation altitude The Sunny Island has been designed for use at altitudes of up to 9,840 ft (3,000 m) above MSL. Please contact SMA before using the device at altitudes above 9,840 ft (3,000 m). A performance loss of 0.5% per 330 ft (100 m) is to be expected starting at an altitude of 6,560 ft (2,000 m) above MSL."
Yes, SMA was a good option too. Heard good things about them. In the end, I've used Victron before and been very happy. Hope it lasts...
 
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