With all the pending doom and gloom regarding energy prices and power cuts, I have decided to put a small independent solar system into the house. I am fortunate enough to have a flat roof, south facing and rather than have the space wasted, I will be putting in a 400w 2'650wh system. The idea is to hook up my radio shack full time to the battery but build it large enough to run a small 12v telly, 12v LED lighting system and keep our freezer running for 2 or 3 days if necessary.
The system will consist of 4x 100w panels, a 30amp MPPT conntroller, 1 x 200amp Lifepo4 battery and a 2000w PSW inverter. I hope this will be enough to subsidise my power needs and offer a little peace of mind should the worst come around. I have received all the parts, just need to get around to putting it all together
TheOldHObbit wrote: ↑Fri Oct 14, 2022 9:07 pm
With all the pending doom and gloom regarding energy prices and power cuts, I have decided to put a small independent solar system into the house. I am fortunate enough to have a flat roof, south facing and rather than have the space wasted, I will be putting in a 400w 2'650wh system. The idea is to hook up my radio shack full time to the battery but build it large enough to run a small 12v telly, 12v LED lighting system and keep our freezer running for 2 or 3 days if necessary.
The system will consist of 4x 100w panels, a 30amp MPPT conntroller, 1 x 200amp Lifepo4 battery and a 2000w PSW inverter. I hope this will be enough to subsidise my power needs and offer a little peace of mind should the worst come around. I have received all the parts, just need to get around to putting it all together
Cool project. Sounds like you have specced it out well. Just one thought ( sorry if it;s obvious) Don't make the mistake that I made of mounting the panels flat on the roof. I came to regret that little cut corner.
Graceful Degradation! Prepping's objective summed up in two words. Turning Disaster into Mild Inconvenience by the power of fore-thought
Have any of you looked at the low end grid tie inverters?
There's some with a induction clamp based ammeter that goes round (I assume) the incoming live. I'm unsure how these are intended to work, but from some of the descriptions I've read it seems they're intended to stop producing power if you would be exporting to the grid. How that clamp can detect anything other than a net current is beyond me, and I suspect either all is not as it seems or my interpretation of their use is wrong.
Whatever the intended use, these don't seem safe to me, unless that clamp is supposed to sense the grid down and cut the power for safety, but I still wouldn't trust that.
I've heard if you export to the grid without a smart meter you get billed for what you export.
deckard wrote: ↑Sat Oct 15, 2022 9:31 am
Have any of you looked at the low end grid tie inverters?
There's some with a induction clamp based ammeter that goes round (I assume) the incoming live. I'm unsure how these are intended to work, but from some of the descriptions I've read it seems they're intended to stop producing power if you would be exporting to the grid. How that clamp can detect anything other than a net current is beyond me, and I suspect either all is not as it seems or my interpretation of their use is wrong.
Whatever the intended use, these don't seem safe to me, unless that clamp is supposed to sense the grid down and cut the power for safety, but I still wouldn't trust that.
I've heard if you export to the grid without a smart meter you get billed for what you export.
not seen the ones with clamp ammeters, but if you Google 'balcony solar' or emphase, you'll find some tied micro inverters that are ok up to a few hundred Watts of solar. The safety and legality of installation is debatable. Some just use a 13A suicide plug to push power into the domestic ring. If grid is down they switch off. Unlikely to generate enough to be exporting, but as I understand it, any you export is exported for free.
Never heard of being charged for outgoing energy. I hope someone can refute that.
Graceful Degradation! Prepping's objective summed up in two words. Turning Disaster into Mild Inconvenience by the power of fore-thought
Andy: What would you suggest as a good fusing arrangement for a 400W design charging multiple 7AH AGM batteries? Any particular products you would recommend?
One big fuse at one end then common across the other terminals so it's got one supply then outputs all come off it
Then the outgoing ive got a big inverter so that's got its own overload trips supplying it s got its own internal fuses but it's slightly smaller than the rated fuse so it trips before I've got to go dismantling and resoldering internal fuses
Yorkshire Andy wrote: ↑Fri Oct 14, 2022 9:42 pm
Just remember fuse it fuse it and fusebox everything ..
When you see how hot a big battery can get wires you'll get why it needs fusing
Also make sure that inverter cables are crimped properly
I hope I have done enough for the fuses, I have a 200amp at the battery and an inline fuse from the PV panels of 30amp 1000v. When I have the stuff mounted on the board, and the battery where I want it, I will order pre-made heavy duty cables at the right length. This is all new to me and electrics are certainly not my strong point, but hopefully I have judged it about right. My run from the panels to the controller is about 5m so I have ordered 6mm for the job. Thank you all for your responses........
