I've been commissioned to build an off-grid system for a client building a home in Belize.
We ran calculations today and found he should rarely need more than 10KWh/day, most days he will probably use closer to 5KWh, and a maximum of 3500W instantaneous.
The catch is that he wants a good reserve capacity to avoid running the generator to the greatest extent possible. I am planning the system around a 5 day reserve capacity (at 6KWh/day).
5kWH x /.93 inverter efficiency x 5 days autonomy / 50% DoD / 48V = 1120Ah 48V battery bank
I have selected the Trojan L-16-RE-2V 1110AH as the most sensible cells for this application.
To achieve at least a C8 charge rate on sunny days, I need to provide at least 1110Ah / C8 * 48V = 6660W PV array. I am looking at this as a bare minimum as I'd like to achieve C12 (4440W) on all but the worst cloudy days. He can always shut off a couple strings in the dry season, and limit use of his maximum capacity to the rainy season. I am thinking of running 32 250W 60 cell poly panels, I can get them at a good price and if we hook it up with 4 strings per charge controller, it would be simple to shut off two strings in the dry season (6000W total), and crank them back up in the wet season (8000W total capacity).
Since his power requirements are pretty modest, I believe that he doesn't need to go crazy with his inverter selection. I use the Outback FP1 FX3048T and I am suggesting the same system for his needs, with the addition of a 2nd Flexmax 80 for obvious reasons.
The one I'm really struggling with is the backup generator selection. I do not know what ~6000W generator would be a good choice which is propane/butane compatible (fuel choice by necessity in Belize ) Please help me with suggestions on a good generator. Looking at this Generac right now - http://www.electricgeneratorsdirect....or/i10669.html
Any other comments/criticisms or suggestions are welcome and coveted, I want to make sure I get his system build to support him for many years, TIA
The worst solar insolation month here in Belize is 4.0 - http://www.gaisma.com/en/location/belize.html
We ran calculations today and found he should rarely need more than 10KWh/day, most days he will probably use closer to 5KWh, and a maximum of 3500W instantaneous.
The catch is that he wants a good reserve capacity to avoid running the generator to the greatest extent possible. I am planning the system around a 5 day reserve capacity (at 6KWh/day).
5kWH x /.93 inverter efficiency x 5 days autonomy / 50% DoD / 48V = 1120Ah 48V battery bank
I have selected the Trojan L-16-RE-2V 1110AH as the most sensible cells for this application.
To achieve at least a C8 charge rate on sunny days, I need to provide at least 1110Ah / C8 * 48V = 6660W PV array. I am looking at this as a bare minimum as I'd like to achieve C12 (4440W) on all but the worst cloudy days. He can always shut off a couple strings in the dry season, and limit use of his maximum capacity to the rainy season. I am thinking of running 32 250W 60 cell poly panels, I can get them at a good price and if we hook it up with 4 strings per charge controller, it would be simple to shut off two strings in the dry season (6000W total), and crank them back up in the wet season (8000W total capacity).
Since his power requirements are pretty modest, I believe that he doesn't need to go crazy with his inverter selection. I use the Outback FP1 FX3048T and I am suggesting the same system for his needs, with the addition of a 2nd Flexmax 80 for obvious reasons.
The one I'm really struggling with is the backup generator selection. I do not know what ~6000W generator would be a good choice which is propane/butane compatible (fuel choice by necessity in Belize ) Please help me with suggestions on a good generator. Looking at this Generac right now - http://www.electricgeneratorsdirect....or/i10669.html
Any other comments/criticisms or suggestions are welcome and coveted, I want to make sure I get his system build to support him for many years, TIA
The worst solar insolation month here in Belize is 4.0 - http://www.gaisma.com/en/location/belize.html
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