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Re: DC coupled battery help on FIt system

Posted: Sun Aug 20, 2023 6:59 pm
by resybaby
Thank you all for your advice, still looking through the kindly provided link, but am going to be taking your sage advice Nowty.
Have always done 100% of the house ma8ntenance myself, on everything, if i couldnt do it before i learned it, obviously not going to be much good for the future.
Have found an extremely helpful keen young mcs reg one man band sparky who has patiently answered many of my questions and i get a good feeling of (i have met millions of tradesmen during my career on building sites and that feeling is generaly uncommon im afraid to say) and so i am most certainly going to use his services, and leave my wife 8n his future capable hands.

many thanks all for your time guidance and expertise, but im still glad i mess about with pipes more than wires ;)

Re: DC coupled battery help on FIt system

Posted: Mon Aug 21, 2023 12:05 pm
by Kommando
When I analysed my daytime usage there are peaks that are not covered by solar but they are of short duration, the bigger KwH usage not covered by the solar is the background usage overnight. So to keep it simple I charge a battery bank off grid using dedicated panels during the day, Grid-tie inverter takes care of most \of the daytime usage with a MK2 PV Router diverting excess to immersion. Then a simple timer setup switches the house onto the batteries overnight, if the batteries are low this can be overridden. This means the battery bank can be smaller, G98 covers the Grid-tie inverter for upto 3.68Kw and the extra inverter to control the batteries is off grid so no need for G99/G100. In winter the batteries can be kept unused as a backup for powercuts.

Re: DC coupled battery help on FIt system

Posted: Tue Aug 22, 2023 7:22 am
by resybaby
That is a great idea Kommando, pains me to look at the rest of my remaining large roof and just see concrete tiles as 'wasted panel space'. Would of been certainly something id look at if sufficent time wasnt a specific issue.

Thank you all for your help with all of this, i am far more confident in what im going to ask my lovely sparky to construct now, just which battery to pick..

Re: DC coupled battery help on FIt system

Posted: Tue Aug 22, 2023 7:36 am
by Joeboy
resybaby wrote: Tue Aug 22, 2023 7:22 am That is a great idea Kommando, pains me to look at the rest of my remaining large roof and just see concrete tiles as 'wasted panel space'. Would of been certainly something id look at if sufficent time wasnt a specific issue.

Thank you all for your help with all of this, i am far more confident in what im going to ask my lovely sparky to construct now, just which battery to pick..
https://camelot-forum.co.uk/phpBB3/view ... =14&t=1194

https://camelot-forum.co.uk/phpBB3/view ... =14&t=2316

Re: DC coupled battery help on FIt system

Posted: Tue Aug 22, 2023 8:13 am
by Stinsy
Kommando wrote: Mon Aug 21, 2023 12:05 pm When I analysed my daytime usage there are peaks that are not covered by solar but they are of short duration, the bigger KwH usage not covered by the solar is the background usage overnight. So to keep it simple I charge a battery bank off grid using dedicated panels during the day, Grid-tie inverter takes care of most \of the daytime usage with a MK2 PV Router diverting excess to immersion. Then a simple timer setup switches the house onto the batteries overnight, if the batteries are low this can be overridden. This means the battery bank can be smaller, G98 covers the Grid-tie inverter for upto 3.68Kw and the extra inverter to control the batteries is off grid so no need for G99/G100. In winter the batteries can be kept unused as a backup for powercuts.
While your idea will work, there are better solutions. Just get a standard battery inverter with a CT…

Re: DC coupled battery help on FIt system

Posted: Tue Aug 22, 2023 11:15 am
by Kommando
Stinsy wrote: Tue Aug 22, 2023 8:13 am
Kommando wrote: Mon Aug 21, 2023 12:05 pm When I analysed my daytime usage there are peaks that are not covered by solar but they are of short duration, the bigger KwH usage not covered by the solar is the background usage overnight. So to keep it simple I charge a battery bank off grid using dedicated panels during the day, Grid-tie inverter takes care of most \of the daytime usage with a MK2 PV Router diverting excess to immersion. Then a simple timer setup switches the house onto the batteries overnight, if the batteries are low this can be overridden. This means the battery bank can be smaller, G98 covers the Grid-tie inverter for upto 3.68Kw and the extra inverter to control the batteries is off grid so no need for G99/G100. In winter the batteries can be kept unused as a backup for powercuts.
While your idea will work, there are better solutions. Just get a standard battery inverter with a CT…
Yes there are better solutions but mine has been built up over the years adding on extra items which are all 2nd hand with one exception, so once I buy one piece of kit it limits me on the next upgrade unless I start again. The only new item I bought was the grid tie inverter solely for the G98 cert. Rest is SMA and not G98 so has to stay off grid but I have all the hardware and software to monitor and control. My payback period is much shorter with the lower prices I pay.