EnderWiggin
New Member
- Joined
- Oct 12, 2020
- Messages
- 26
<tl/dr: Asking for recommendations on a remote island install for a three-phase inverter system using grid initially to charge batteries but without grid pass-through>
Hello there, long time lurker, first time poster.
Watched a lot of Will's stuff and really like the camaraderie on these boards - mostly civil on most issues!
I'm planning out a villa in the Dutch territory of Sint Maarten in the Caribbean Sea. Power from the island/grid is 120V, 3-phase (120 degree offset, all 200+V appliances are spec'd to also work at 208V). Comes in using 4-wire (120V/60A/60Hz per leg plus neutral), so a house max of 21.6KW, though it will never come close to that (all AC are mini splits, all hot water from tankless). May not do solar "day one" so most of my questions center around the charger/inverter piece.
The issue we have already with a condo we have on the island is how dirty the grid is - generated, as it is, by diesel. It browns from time to time, and the waveform is not smooth (we lose at least one minute on our clocks a day due to poorly clocked power). We also have frequent power outages/surges, and the power cost on the island is a bit higher than we'd like (especially with AC going most of the time). So, we need a system that will "clean" the grid into a pure sine wave, and we figure if we're doing that, might as well use an off grid style solution with solar, which would also act as whole-house UPS for sensitive electronics.
Solar is an "eventual" - it IS the Caribbean, after all - we know a guy with a 3BR condo with 12KW on his roof who is pulling down 2MW/month on average, so eventually we would only need grid as an extreme backup. We will never sell back to the grid, as the power company is clueless on how to handle that possibility.
So, our two main design goals/constraints are: 1) Use grid to charge batteries, but NEVER pass through, and 2) since we're doing this in Sint Maarten, replacement parts will be insanely expensive to source (and local support is practically nonexistent), so reliability is huge.
I want to start out by having the grid supply a "mains" panel with most 208V loads(AC, tankless hot water heater, dryer, oven), then feed the three legs to a manual transfer switch, to a "critical" 3-phase load panel. The inverters will be on the other selector of the MTS. At the start, I only want to power 120V things, and a few 208V things (like the dedicated mini split I will use to cool the electrical room, and the elevator) from the critical panel. Ideally, the solution should be able to, if we want in the future, move all the other 208V loads to the critical panel (as we add more battery and solar). We will be doing 48V LiFePo (~20KWh to start), either server rack or a power wall option.
In looking at our options for inverters, I've seen that Victron is one of the leaders in reliability. However, in posting on their forums, I discovered that the Quattro does not provide an option to always power the AC Out with battery inversion; if grid power exists (which we would only ever want to use to charge batteries), it will relay it through (unless it's "really dirty" which I can't rely on it being THAT bad all the time). So I cannot tie the AC In of the Quattro to grid.
My options seem to be down to (at least in my mind - no offense to other companies y'all use, I am focused on these three):
Long term, I suppose this is a moot point, because with solar should come the lack of need to ever use grid as long as my battery/usage ratio is set properly; heck, I could put a smart outlet on each inverter's AC input and only engage it when the charge levels are too low, and just "suck it up" that power is dirty for that short time.
Any guidance would be appreciated; further details available upon request. I have time to spare in this (villa won't be done until late 2023 at a minimum, so I won't be ordering anything until this time next year at the earliest) and the baseline of what we're doing is already set (with regards to the two panels and MTS), it's just the choice of inverters, really.
Hello there, long time lurker, first time poster.
Watched a lot of Will's stuff and really like the camaraderie on these boards - mostly civil on most issues!I'm planning out a villa in the Dutch territory of Sint Maarten in the Caribbean Sea. Power from the island/grid is 120V, 3-phase (120 degree offset, all 200+V appliances are spec'd to also work at 208V). Comes in using 4-wire (120V/60A/60Hz per leg plus neutral), so a house max of 21.6KW, though it will never come close to that (all AC are mini splits, all hot water from tankless). May not do solar "day one" so most of my questions center around the charger/inverter piece.
The issue we have already with a condo we have on the island is how dirty the grid is - generated, as it is, by diesel. It browns from time to time, and the waveform is not smooth (we lose at least one minute on our clocks a day due to poorly clocked power). We also have frequent power outages/surges, and the power cost on the island is a bit higher than we'd like (especially with AC going most of the time). So, we need a system that will "clean" the grid into a pure sine wave, and we figure if we're doing that, might as well use an off grid style solution with solar, which would also act as whole-house UPS for sensitive electronics.
Solar is an "eventual" - it IS the Caribbean, after all - we know a guy with a 3BR condo with 12KW on his roof who is pulling down 2MW/month on average, so eventually we would only need grid as an extreme backup. We will never sell back to the grid, as the power company is clueless on how to handle that possibility.
So, our two main design goals/constraints are: 1) Use grid to charge batteries, but NEVER pass through, and 2) since we're doing this in Sint Maarten, replacement parts will be insanely expensive to source (and local support is practically nonexistent), so reliability is huge.
I want to start out by having the grid supply a "mains" panel with most 208V loads(AC, tankless hot water heater, dryer, oven), then feed the three legs to a manual transfer switch, to a "critical" 3-phase load panel. The inverters will be on the other selector of the MTS. At the start, I only want to power 120V things, and a few 208V things (like the dedicated mini split I will use to cool the electrical room, and the elevator) from the critical panel. Ideally, the solution should be able to, if we want in the future, move all the other 208V loads to the critical panel (as we add more battery and solar). We will be doing 48V LiFePo (~20KWh to start), either server rack or a power wall option.
In looking at our options for inverters, I've seen that Victron is one of the leaders in reliability. However, in posting on their forums, I discovered that the Quattro does not provide an option to always power the AC Out with battery inversion; if grid power exists (which we would only ever want to use to charge batteries), it will relay it through (unless it's "really dirty" which I can't rely on it being THAT bad all the time). So I cannot tie the AC In of the Quattro to grid.
My options seem to be down to (at least in my mind - no offense to other companies y'all use, I am focused on these three):
- Signature Solar EG 6500-EX x 3 - has a setting for "SbU" which appears to allow for non-passthrough of grid to loads (i.e. constant inversion from solar/battery, even when grid is present, so we can still charge batteries). Cheapest, at $1300 per unit, especially since it also has a huge MPPT in each. But with "inexpensive" comes the possibility of "not as reliable" - though, at this price point, I could order four to have a spare and still come in loads cheaper than the other solutions. Another downside is that remote monitoring capabilities are not as good as the other options (ideal for when we're off-island).
- Victron Quattro 5000/48/120V x 3 plus CerboGX, Lynx, and MPPT(s) - would have to add some kind of charger (nothing Victron makes, since their chargers are all either 230V AC in or don't work with 48VDC out) to isolate charging from grid from the Quattros. Mid-price solution (I figure around $12K all in), reliable, excellent remote monitoring, but sourcing parts could be an issue.
- Schneider Electric XW Pro 120/240 x 3 plus PDP and MPPT(s) - I don't see if there's an option to specifically "always invert" on Schneider (help please?). Excellent power (can handle full load if needed, as well as additional burst), excellent remote monitoring, professional-looking (few exposed wires) install. But most expensive (I figure around $16K all in) and I've read highly mixed reviews on Schneider, ranging from "awesomest ever" to "they only want pros not diyers" to "yunk" (which I assume is "junk"). Also, mixed reviews on how they handle battery management with lithium. Tough to source parts.
Long term, I suppose this is a moot point, because with solar should come the lack of need to ever use grid as long as my battery/usage ratio is set properly; heck, I could put a smart outlet on each inverter's AC input and only engage it when the charge levels are too low, and just "suck it up" that power is dirty for that short time.
Any guidance would be appreciated; further details available upon request. I have time to spare in this (villa won't be done until late 2023 at a minimum, so I won't be ordering anything until this time next year at the earliest) and the baseline of what we're doing is already set (with regards to the two panels and MTS), it's just the choice of inverters, really.
