ImAnIdiotPleaseBePatient
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True but 396v diy batteries.
HELP : New Hybrid System Design
- Thread starter greeksolar
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PreppenWolf
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50kWh is a good battery storage starting point. I would try to expand it over time to above your target daily usage to give yourself more buffer.
Add as many panels over time as you can. Panels are cheap and only get cheaper. For instance I have 15kW of panels. On a full cloud day I make only 1.5kW. My best day in February was 45.3kWh.
Do you have a good south facing location? Any buildings/trees blocking sun or do you have full horizon? Is you property on the south side of your property's elevation change?
Add as many panels over time as you can. Panels are cheap and only get cheaper. For instance I have 15kW of panels. On a full cloud day I make only 1.5kW. My best day in February was 45.3kWh.
Do you have a good south facing location? Any buildings/trees blocking sun or do you have full horizon? Is you property on the south side of your property's elevation change?
timselectric
If I can do it, you can do it.
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They can be built for your choice of voltage.
I've seen a 240v one.
Hedges
I See Electromagnetic Fields!
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SMA has a 70 kW 3-phase inverter for 400V batteries. I'm not sure if it will accept AC input with missing phases.
They have 3-phase PV inverters in the 30 to 60 kW range.
Their Sunny Island is 6kW and uses 48V battery, three inverters for 3-phase makes 18kW, should manage 36kW of PV inverter.
That one should be able to take in 1 or 2 phases and make the missing phase. I'm doing that with the 120V US model.
Multi-Cluster lets multiple 3-phase clusters combine their power. I don't know if that configuration works with missing phases.
If one phase is from the grid and another from Sunny Island, frequency and phase track the grid but voltage does not. That makes asymmetric 3-phase, which may be an issue for some transformers and motors. I may have observed that feeding a 208 to 240V step-up transformer that is 3 windings on one "E" core. I do not see that when three separate transformers with their own cores are used.
To feed grid into an inverter island system, I would like to rectify the grid and feed it to the PV (or turbine) input, then AC couple to island system. (better precharge to avoid excessive inrush.)
REC BMS supports 128s.
I don't know what its communication is compatible with.
They have 3-phase PV inverters in the 30 to 60 kW range.
Their Sunny Island is 6kW and uses 48V battery, three inverters for 3-phase makes 18kW, should manage 36kW of PV inverter.
That one should be able to take in 1 or 2 phases and make the missing phase. I'm doing that with the 120V US model.
Multi-Cluster lets multiple 3-phase clusters combine their power. I don't know if that configuration works with missing phases.
If one phase is from the grid and another from Sunny Island, frequency and phase track the grid but voltage does not. That makes asymmetric 3-phase, which may be an issue for some transformers and motors. I may have observed that feeding a 208 to 240V step-up transformer that is 3 windings on one "E" core. I do not see that when three separate transformers with their own cores are used.
To feed grid into an inverter island system, I would like to rectify the grid and feed it to the PV (or turbine) input, then AC couple to island system. (better precharge to avoid excessive inrush.)
REC BMS supports 128s.
I don't know what its communication is compatible with.
ImAnIdiotPleaseBePatient
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Yeah now that you mention it I think they said that to me as well.
greeksolar
New Member
Here is over all weather.
Thessaloníki Climate, Weather By Month, Average Temperature (Greece) - Weather Spark
In Thessaloníki, the summers are hot, dry, and mostly clear and the winters are very cold and partly cloudy. Over the course of the year, the temperature typically varies from 34°F to 90°F and is rarely below 25°F or above 96°F.weatherspark.com
This is the most relevant part for estimating solar output.
View attachment 137368
Here is solar equivalent hours for 25degree from horizontal exactly south facing.
View attachment 137371
Here is solar equivalent hours for 50degree from horizontal exactly south facing.
View attachment 137372
Don't go more than 50deg as you won't gain more than 1% in December and you'll sacrifice in all other months. 25deg seems like a reasonable low number to not sacrifice more than 2-3% of July.
thank you! I don't want to go more than 25 degree for aesthetic reasons also, and potential increased wind exposure.
greeksolar
New Member
Hello, excuse my ignorance and thank you for the response.
Would it be easier if we designed it so the single phase from the grid was only used to charge the batteries, and not power the loads? possibly separate battery banks with separate chargers, and the grid charging one at a time. Excuse me if I'm totally off base here.
thank you
greeksolar
New Member
Hello, we are in the middle of wheat and sheep grazing fields, no shade at all. Full sun always.
Wow only 1.5kwh on cloudy day. I'm starting with a 20 KW PV system.
greeksolar
New Member
I saw Sandi, I was thinking it would be better to go with a "name brand" western inverter rather than Chinese owned/engineered brand. I've gotten lots of offers from Sandi and Deye, maybe not so bad after all?
timselectric
If I can do it, you can do it.
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It could simplify things.
But no need for multiple battery banks.
One bank can charge and discharge at the same time.
PreppenWolf
Solar Wizard
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That is why the cloud cover chart for your area is really the most important data. Clouds are the enemy!
Hedges
I See Electromagnetic Fields!
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PV/battery systems do fail, so it is good to have grid as backup to power loads directly. If you have 3-phase loads and 3-phase grid, you can do that with a transfer switch. I'm setting up 3-phase inverter for 3-phase shop tools, but will continue to have single phase service because price to get 3-phase was too high (even though available as high voltage on a pole only 200' away.)
I would have installed 3-phase HVAC, but will probably use single-phase so my inverters aren't needed to heat the house. VFD can also power 3-phase motors more cheaply and reliably than an inverter/battery system.
3-phase loads of course start better and have more torque. Battery inverter has to be able to deliver starting surge.
Good battery chargers are expensive (those that carefully regulate battery voltage, but inverter/chargers are common. You can charge battery with either single phase or three phase. If charging with 3-phase and powering 3-phase loads, ripple on battery should be eliminated because power delivery is constant. If powering single phase from battery, there is ripple on the battery (of full current, capacitors can't smooth that), and if charging at same time, single phase grid will not be in sync, so ripple still present. Not terrible, that is normal for battery/PV system, but if inverters can pass through the single or 3-phase grid to load, battery can be kept at float, probably last longer.
My systems are SMA Sunny Island, which pass through grid (or generator), and can add power from battery synchronized to grid (in the event current draw is higher than what input can deliver). They also have Sunny Boy or Sunny TriPower, which use PV and also deliver synchronized AC power.
48V battery
60kW up to 1000V battery.
I'm not completely sure this works off-grid but I think so.
If 18kW from battery, 33kW starting surge, 36kW from PV was sufficient, I would use Sunny Island.
Up to 500 kWh battery (per 3-phase cluster.)
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