Hello!
I live in a country where the political situation has in a way forced me to install an off-grid PV system. Energy costs have been going up and up and in the near future we'll have lots of power outages because of many factors, including no maintenance of generation equipment (which is run by the government). Just this year the KWh cost will go up at least 17% and last year the increase was around 10%.
Since a few months ago I started sourcing components, but the most difficult part were the batteries. I could only find sealed "mixed use" batteries sold as "deep cycle" batteries. That's what all solar stuff companies carry around here. They are not exactly cheap and offer very limited Ah. The best thing I could find were Outback 200NC, which are true deep cycle batteries, but have really low capacity and high price tag (178Ah@C/20 and $475 each, advertised as 200Ah, which is right, but @C/100!). Next best were Ritar DC-12-200C which on paper are better than the Outbacks at the same price, but found very few and mixed opinions on that brand.
I finally found someone that could get me Trojan SPRE 06 415 for $385 each delivered to my house, and that's what I'll go for. These are rated for 377Ah @ C/20.
I don't have a really big budget, so I compromised on some components.
So what I have is:
- 9xSG330P Peimar 330W Poly panels (2970Wp)
- Tristar TS-MPPT-60 charge controller (got it second hand off eBay, just 60 days use for $380 with meter)
- 8xTrojan SPRE 06 415 (on the way)
- Spartan Power SP-TS4500PLUS transfer switch.
- 2xAPC SMT2200 that I'll use as inverters (here's the compromise). These I already had. I got them some time ago at an auction for $90 each.
Additional stuff that I ordered, still not arrived:
- MC4 connectors, Multi-Contact brand
- Water Miser XL battery caps
- Hydrometer
Things I'll order soon:
- IotaWatt for logging and monitoring of energy usage.
So my monthly energy use varies by season. From March to April the consumption is a tad below 500KWh a month. Those are the hottest months. From November to January the energy usage is the lowest, around 350KWh a month. The rest of the year consumption varies between 350 and 420KWh.
There's a lot of sun here. During the longer days the sun goes up around 5:30am and goes down around 6:30pm. During the shortest days the sun goes up around 6:30am and down around 5:15pm.
From October to end of November there's a lot of rain, so there's little sun. At the same time, it's not hot and energy use is lower.
All in all I expect to get at least some energy on cloudy days.
During the day I have a minimum load of around 350VA. It can go to around 650VA constant. There'll be peaks for short periods of time (microwave oven, toaster, some tool, washing machine, etc.).
During the night the load for up to a minimum of around 700VA, it can go up to 1200-1300VA when using the A/C with a peak of around 1900VA.
As for the APC SMT2200 UPSs, they are pure sine 2200VA/1980W and have a 48V input. I tested one with the microvwave oven AND toaster simultaiously, and it can handle the load. I'll put one "Inverter" for high consumption loads, the other one for the rest of things. I know these are not meant to work continuously, but I already have a smaller SUA1000 unit working as a UPS, and it has no problem providing power for about 20hours at around 30% load. I tested this during power outages to power my critical computer stuff.
I'll modify the APC units to be ableto better handle extended battery use. First mod, cooling: temperature controlled fan controller with 3 fans blowing over the transformers and MOSFETS. The case already has a fan, I'll replace it with a better, more silent one to extract hot air. I'll also put heatsinks on the transformers. Second mod: Schottky diode on the positive cable to the batteries, so that it won't charge the batteries off the power grid at night. I will put a bypass switch so I can charge the batteries off the UPS when required.
The transfer switch will connect to the main panel, and it'll provide connection to the inverters. When the batteries go below a set voltage, the SMT2200s will get power from the grid and they'll act as voltage regulators. When battery voltage reaches a set voltage, the UPSs will act as inverters.
So far only the panels have been installed on the roof:
I still have not decided where tu put the batteries, I'll elaborate on that later along with some other doubts that I have.
So, I'm open to comments/suggestions.
I live in a country where the political situation has in a way forced me to install an off-grid PV system. Energy costs have been going up and up and in the near future we'll have lots of power outages because of many factors, including no maintenance of generation equipment (which is run by the government). Just this year the KWh cost will go up at least 17% and last year the increase was around 10%.
Since a few months ago I started sourcing components, but the most difficult part were the batteries. I could only find sealed "mixed use" batteries sold as "deep cycle" batteries. That's what all solar stuff companies carry around here. They are not exactly cheap and offer very limited Ah. The best thing I could find were Outback 200NC, which are true deep cycle batteries, but have really low capacity and high price tag (178Ah@C/20 and $475 each, advertised as 200Ah, which is right, but @C/100!). Next best were Ritar DC-12-200C which on paper are better than the Outbacks at the same price, but found very few and mixed opinions on that brand.
I finally found someone that could get me Trojan SPRE 06 415 for $385 each delivered to my house, and that's what I'll go for. These are rated for 377Ah @ C/20.
I don't have a really big budget, so I compromised on some components.
So what I have is:
- 9xSG330P Peimar 330W Poly panels (2970Wp)
- Tristar TS-MPPT-60 charge controller (got it second hand off eBay, just 60 days use for $380 with meter)
- 8xTrojan SPRE 06 415 (on the way)
- Spartan Power SP-TS4500PLUS transfer switch.
- 2xAPC SMT2200 that I'll use as inverters (here's the compromise). These I already had. I got them some time ago at an auction for $90 each.
Additional stuff that I ordered, still not arrived:
- MC4 connectors, Multi-Contact brand
- Water Miser XL battery caps
- Hydrometer
Things I'll order soon:
- IotaWatt for logging and monitoring of energy usage.
So my monthly energy use varies by season. From March to April the consumption is a tad below 500KWh a month. Those are the hottest months. From November to January the energy usage is the lowest, around 350KWh a month. The rest of the year consumption varies between 350 and 420KWh.
There's a lot of sun here. During the longer days the sun goes up around 5:30am and goes down around 6:30pm. During the shortest days the sun goes up around 6:30am and down around 5:15pm.
From October to end of November there's a lot of rain, so there's little sun. At the same time, it's not hot and energy use is lower.
All in all I expect to get at least some energy on cloudy days.
During the day I have a minimum load of around 350VA. It can go to around 650VA constant. There'll be peaks for short periods of time (microwave oven, toaster, some tool, washing machine, etc.).
During the night the load for up to a minimum of around 700VA, it can go up to 1200-1300VA when using the A/C with a peak of around 1900VA.
As for the APC SMT2200 UPSs, they are pure sine 2200VA/1980W and have a 48V input. I tested one with the microvwave oven AND toaster simultaiously, and it can handle the load. I'll put one "Inverter" for high consumption loads, the other one for the rest of things. I know these are not meant to work continuously, but I already have a smaller SUA1000 unit working as a UPS, and it has no problem providing power for about 20hours at around 30% load. I tested this during power outages to power my critical computer stuff.
I'll modify the APC units to be ableto better handle extended battery use. First mod, cooling: temperature controlled fan controller with 3 fans blowing over the transformers and MOSFETS. The case already has a fan, I'll replace it with a better, more silent one to extract hot air. I'll also put heatsinks on the transformers. Second mod: Schottky diode on the positive cable to the batteries, so that it won't charge the batteries off the power grid at night. I will put a bypass switch so I can charge the batteries off the UPS when required.
The transfer switch will connect to the main panel, and it'll provide connection to the inverters. When the batteries go below a set voltage, the SMT2200s will get power from the grid and they'll act as voltage regulators. When battery voltage reaches a set voltage, the UPSs will act as inverters.
So far only the panels have been installed on the roof:
I still have not decided where tu put the batteries, I'll elaborate on that later along with some other doubts that I have.
So, I'm open to comments/suggestions.
Comment