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diy solar

diy solar

Hello folks from somewhere in Spain.

Chispas

Solar Wizard
Joined
Jul 12, 2024
Messages
664
Location
Spain
Hola Tod@s , my first post to this forum, ive done some reading & browsing here but there's so much to look at.
. Can you believe that ? Swapping batteries over for power. Our next upgrade was a gift of 2 Sonnenschein 6v gel batteries from a mate who worked in telecoms & some old, odd 12v panels.We were still on 12v but now we could run a DVD player & some PC speakers, so Friday night was film night !
Fast forward via other versions, including our first inverter to the present. Our current set up is 460W of odd, unmatched panels, a trojan t 1275 + battery, blue sky mppt charge controller , morningstar suresine 300 inverter & a Sterling Power 60A battery charger. We also have a petrol generator for bigger, occasional loads, pumping water, maybe 3 or 4 times a year for an hour or two & some woodworking tools, maybe a saw bench.Despite its limitations it's a well put together system, designed and built by a good friend of mine, who, sadly, died suddenly 2 years ago. Moving forward, we are considering a move away from 12v to be able to run 2 chest freezers, one operating as a fridge.Most people I ask about this upgrade say go to 48 V, dont mess about but our current loads are tiny, a laptop, lighting, charging a few devices, occasional cordless tool and the satellite modem, its power supply rated at 2 A. Our philosophy is small is beautiful, we really dont want or need massive redundancy in a system, an oversized panel array would be useful, maybe? I have some ideas that I would like to post on these forums, but first i need to do some reading. Its good to be here, im looking forward to your input, but also sharing what we have learned during our time off grid.
 
Can you define your loads in terms of watts and hours of use per day? Looking for total watthours consumed.

That will define the size of the inverter/panels/batteries which in turn defines the voltage it is best to operate at.
 
Can you define your loads in terms of watts and hours of use per day? Looking for total watthours consumed.

That will define the size of the inverter/panels/batteries which in turn defines the voltage it is best to operate at.
Yep got you. The biggest load will be a fridge freezer that we don't yet own, the inconvenience of the two freezer set up is if they both start at the same time.Our current system is fine, we ran the generator for charging for a total of about 5 hours last winter.Im trying to find out the start-up current of a fridge freezer, but all manufactures publish is the annual kWh consumption.We're looking at one 200L fridge freezer that's rated at 200Kwh a year & 0.542 Kwh an hour.Im a little wary about jus trying to extrapolate for the start-up current from this hourly use, a mate had a bad experience doing this with a Xantex inverter, had to sell it.Our Trojan battery is rated at 134ah c8 & yep i know, its a rubbish way of measuring battery capacity, but the voltage rarely dropped below 12.30 in mid-winter.

robbob2112

2112 ? prog rock time ? My favourite Canadian band.
Edit. our appliances are 220 here in Europe.
 
Yep got you. The biggest load will be a fridge freezer that we don't yet own, the inconvenience of the two freezer set up is if they both start at the same time.Our current system is fine, we ran the generator for charging for a total of about 5 hours last winter.Im trying to find out the start-up current of a fridge freezer, but all manufactures publish is the annual kWh consumption.We're looking at one 200L fridge freezer that's rated at 200Kwh a year & 0.542 Kwh an hour.Im a little wary about jus trying to extrapolate for the start-up current from this hourly use, a mate had a bad experience doing this with a Xantex inverter, had to sell it.Our Trojan battery is rated at 134ah c8 & yep i know, its a rubbish way of measuring battery capacity, but the voltage rarely dropped below 12.30 in mid-winter.

robbob2112

2112 ? prog rock time ? My favourite Canadian band.
Edit. our appliances are 220 here in Europe.

2112 - Rush

 
Last edited:
Yep got you. The biggest load will be a fridge freezer that we don't yet own, the inconvenience of the two freezer set up is if they both start at the same time.Our current system is fine, we ran the generator for charging for a total of about 5 hours last winter.Im trying to find out the start-up current of a fridge freezer, but all manufactures publish is the annual kWh consumption.We're looking at one 200L fridge freezer that's rated at 200Kwh a year & 0.542 Kwh an hour.Im a little wary about jus trying to extrapolate for the start-up current from this hourly use, a mate had a bad experience doing this with a Xantex inverter, had to sell it.Our Trojan battery is rated at 134ah c8 & yep i know, its a rubbish way of measuring battery capacity, but the voltage rarely dropped below 12.30 in mid-winter.

robbob2112

2112 ? prog rock time ? My favourite Canadian band.
Edit. our appliances are 220 here in Europe.
I was able to run 2 freezers on 1kW voltronic inverter from a 12V battery.
Now in my car I installed parking AirConditioning device and I am using 2kW (5000W peak) 12V Easun Power sine inverter (price 130 eur on Aliexpress), that does the job.
The freezer in summer can run 24h with very little stops, so you need to add some Ah to your battery, to keep in running.

Below you can see power consumption over last 30 days for my fridges:

1721332453445.png
1721332481737.png

imho 12V is ok, as long as you don't need to deliver more than 3kW of power continuously.
 
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I was able to run 2 freezers on 1kW voltronic inverter from a 12V battery.
Now in my car I installed parking AirConditioning device and I am using 2kW (5000W peak) 12V Easun Power sine inverter (price 130 eur on Aliexpress), that does the job.
The freezer in summer can run 24h with very little stops, so you need to add some Ah to your battery, to keep in running.

Below you can see power consumption over last 30 days for my fridges:

View attachment 229585
View attachment 229586

imho 12V is ok, as long as you don't need to deliver more than 3kW of power continuously.
Thanks for replying, but what are the freezers rated at ? How long can the inverter sustain peak power for ?
 
if u have 300W inverter, then it will struggle to carry those two freezers and your normal load.
Most inverters are rated for continuous use and peek/surge. In most cases the surge is about 50 to 100% continuous power for a very short time like 2 to 5seconds - see below parameters from https://www.morningstarcorp.com/products/suresine/

1721424507963.png

Now you need to give us an idea what is the power rating of your devices in total (or all devices that can be run at the same time) so the total contentious power can be estimated.
 
satellite modem, its power supply rated at 2 A.
The modem power supply actually says 1 - 2 A, Currently on for about 4 to 5 hours a day, a 65 W power supply for a laptop 4/5 hours. Winter use for these devices is about half. Lights, 5 x 5W LEDs 6/7 hours use winter, 2 or 3 lights 2/3 hours summer, 2 x mobile phone chargers 2A each. As you can see, the continuous power use is absurdly small, hence the 300W inverter, even with occasional charging of a cordless drill battery (80 W charger 45 mins max) . The suresine is an exception in that it's rated to give 600 W peak for 15 minutes at 25c. Victron claims its inverters will give %130 for 30 minutes or %150 for 5 mins. These suresine inverters are legendary in the telecoms sector & other harsh enviroments, not sure how a aio unit would stand up ? Also I've read that they don't handle surge very well ???
Below you can see power consumption over last 30 days for my fridges:
What make and model are they ?
 

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