hammertoe1
New Member
- Joined
- Apr 6, 2022
- Messages
- 10
Hi All! I'm about to (hopefully) embark on my first residential solar project. I've got an engineering background, and previous converted a deliver van into a fulltime camper and installed solar in two campervans. So I've got some experience in solar, but on a much smaller scale. I'm also into home automation, and previously setup a home security setup with Home Assistant on a Raspberry Pi and a string of Zigbee door contacts/ PIRs.
Last year we moved from the UK to Barbados and this year we are hoping to purchase the house we are currently renting from our landlord. One of the first projects on my list will be to replace the old slightly leaky roof, and install a solar power system in the house. The house is a 3-bedroom, single level villa-style house with a swimming pool. Based on the readings from our electrical meter, we used about 250 kWh ofelectricity in a week, so approx 35 kWH a day. Our current electricity bill is around US $500 a month, and only going to be increasing. I think our largest power draws are: 2 x split wall-mounted a/c units in two of the bedrooms, the pool filter motor, and the dishwasher and washing machine (cold feeds only, heats the water).
My plan is to go for an off-grid system, but retain the grid supply on the odd occasion we need it (maintenance of solar, or prolonged overcast days). There are frequent power cuts here, and so I'd like a battery-based system, rather than grid-tie. Also for grid-tie I'd need to get it installed by a certified installer. With off-grid, that shouldn't be necessary.
My proposed setup:
- 48v system
- 10kW panels mounted on the roof
- LiFePO4 batteries, either rack-mount, or buying raw cells from China and a suitable BMS
- 2 x Victron solar chargers, one each for half the panels
- 2 x Victron Quattro charger/inverters to supply 2 x 120v legs, with 240v across both (split-phase)
My back-of-the-envelope estimations on sizing is that we want to go for (and can fit) approx 10kW of panels on the roof. The roof is slightly sloping south facing. Barbados has sun all year round, and I don't think much variance. We have a dry season and a wet season, but still seems to be a lot of sunshine regardless.
I've used Victron kit before and quite liked it. The Quattros seem pretty good from what I can see, and can be run in parallel in split phase and can have grid feed for backup. My thinking of the setup above is that I'd have some redundancy should something fail, I can at least limp by on one charger, or one inverter. The 240v is just a nice-to-have really. As far as I know, none of the appliances here in the house use it, but the house is completely wired for 240v European sockets throughout. And certain appliances like my espresso machine from the UK are 240v. If we installed a hot tub in the future I guess that might be 240v.
As for battery sizing, as I said, we seem to use approx 35kWH a day. I'm hoping this may come down a bit, as when we buy the place we'll be installing ceiling fans which will reduce the A/C usage. But then I'd also like to build a home office, so there may be a bit more draw there, and possibly install a hot tub at some future point. So I'm thinking we'd go for a max 35kWH battery. Maybe even smaller. I've learned from my campervan days, that you a best to err on the side of oversizing the solar rather than the batteries -- no point having batteries you can't charge properly. I'm hoping the solar panels will be enough to run some of the daytime load whilst charging the batteries, so we may even be able to get away with less than 35kWH battery if I'm happy to use grid power now and then, or to run the a/c less if needed.
We currently have solar hot water heating, and my thinking is I might be able to save some power if I can get the dishwasher and/or washing machine to take a hot water feed in, rather than just taking cold water and heating it. Also things like the pool filter pump can be timed/automated to run when power is spare as necessary.
The roof of the house is clay tiles, and it does leak a little bit in heavy rain. We had an inspection and it seems the waterproof membrane needs replacing throughout as now 30 years old and starting to degrade. Most of the other houses around us have tin roofs, and so we'd probably replace the clay tiles with a tin roof for easier maintenance, and I presume would be then easier to mount the solar panels on the roof. My plan is to do most of the installation myself, but if I'm getting the roof replaced, then I'd likely get the roofers to install some unistrut or whatever for mounting the solar panels on whilst they are up there.
Anyways... that is the plan! I welcome any feedback
Last year we moved from the UK to Barbados and this year we are hoping to purchase the house we are currently renting from our landlord. One of the first projects on my list will be to replace the old slightly leaky roof, and install a solar power system in the house. The house is a 3-bedroom, single level villa-style house with a swimming pool. Based on the readings from our electrical meter, we used about 250 kWh ofelectricity in a week, so approx 35 kWH a day. Our current electricity bill is around US $500 a month, and only going to be increasing. I think our largest power draws are: 2 x split wall-mounted a/c units in two of the bedrooms, the pool filter motor, and the dishwasher and washing machine (cold feeds only, heats the water).
My plan is to go for an off-grid system, but retain the grid supply on the odd occasion we need it (maintenance of solar, or prolonged overcast days). There are frequent power cuts here, and so I'd like a battery-based system, rather than grid-tie. Also for grid-tie I'd need to get it installed by a certified installer. With off-grid, that shouldn't be necessary.
My proposed setup:
- 48v system
- 10kW panels mounted on the roof
- LiFePO4 batteries, either rack-mount, or buying raw cells from China and a suitable BMS
- 2 x Victron solar chargers, one each for half the panels
- 2 x Victron Quattro charger/inverters to supply 2 x 120v legs, with 240v across both (split-phase)
My back-of-the-envelope estimations on sizing is that we want to go for (and can fit) approx 10kW of panels on the roof. The roof is slightly sloping south facing. Barbados has sun all year round, and I don't think much variance. We have a dry season and a wet season, but still seems to be a lot of sunshine regardless.
I've used Victron kit before and quite liked it. The Quattros seem pretty good from what I can see, and can be run in parallel in split phase and can have grid feed for backup. My thinking of the setup above is that I'd have some redundancy should something fail, I can at least limp by on one charger, or one inverter. The 240v is just a nice-to-have really. As far as I know, none of the appliances here in the house use it, but the house is completely wired for 240v European sockets throughout. And certain appliances like my espresso machine from the UK are 240v. If we installed a hot tub in the future I guess that might be 240v.
As for battery sizing, as I said, we seem to use approx 35kWH a day. I'm hoping this may come down a bit, as when we buy the place we'll be installing ceiling fans which will reduce the A/C usage. But then I'd also like to build a home office, so there may be a bit more draw there, and possibly install a hot tub at some future point. So I'm thinking we'd go for a max 35kWH battery. Maybe even smaller. I've learned from my campervan days, that you a best to err on the side of oversizing the solar rather than the batteries -- no point having batteries you can't charge properly. I'm hoping the solar panels will be enough to run some of the daytime load whilst charging the batteries, so we may even be able to get away with less than 35kWH battery if I'm happy to use grid power now and then, or to run the a/c less if needed.
We currently have solar hot water heating, and my thinking is I might be able to save some power if I can get the dishwasher and/or washing machine to take a hot water feed in, rather than just taking cold water and heating it. Also things like the pool filter pump can be timed/automated to run when power is spare as necessary.
The roof of the house is clay tiles, and it does leak a little bit in heavy rain. We had an inspection and it seems the waterproof membrane needs replacing throughout as now 30 years old and starting to degrade. Most of the other houses around us have tin roofs, and so we'd probably replace the clay tiles with a tin roof for easier maintenance, and I presume would be then easier to mount the solar panels on the roof. My plan is to do most of the installation myself, but if I'm getting the roof replaced, then I'd likely get the roofers to install some unistrut or whatever for mounting the solar panels on whilst they are up there.
Anyways... that is the plan! I welcome any feedback