Advice on Solar Power Inverter

[BriansBrain]

Hello Necks
I am looking at increasing Brian's power
But... I need to keep all the costs down.
So...
I'm after some advice on the Type of Solar Inverter I need to Power the TX
Which make or model or version would be best for Brian.

Location: South Gran Canaria Spain = plenty of Sunshine
Requirements: Power a Single Phase AC 230v FM Transmitter.
Consumption: Continuous +/- 1000w 16hrs a day 8:00 > 00:00.
Use 100% of available power from solar panels in the daytime.
Share the load with panels and the power grid when cloudy.
Use 100% of the power grid at night.
NOTE: Without any Batteries

Thanks in advance.

[sinus trouble]

Hello Brian!

This could be a tough one? Simple Ohms law would suggest?

1000W / 12V = 83A which is a considerable current to maintain! I do understand the weather in the Canary Islands? However Solar panels are a poor regular source of power! Similar to wind turbines!

The reason Batteries are used is not to actually power the system as such? They are there to keep the system stable!

You could opt for a higher voltage Inverter? Say 24V? But even then, The high power generation cycles of the panels will be lost and lead to very poor efficiency!

[sinus trouble]

Also just to add?

If you use the Inverter in conjunction with the Grid? I guess you would need some sort of sophisticated controller to alternate between the two? I doubt they can both be "ON" together!

[sinus trouble]

Another theory??

Most Inverters (Even cheapy ones) have an "Alarm" system that could be modified to activate a relay or contactor in the event of a power shortage?

Just a theory? I would not recommend attempting unless you are sure you know what you doing?

[Albert H]

Pretty much any solar system requires batteries for power stability. Way back in the 80s, I ran a station in California (similar amounts of sunshine to you), and used a combination of solar panels and a little wind turbine to charge the batteries. We used "leisure" batteries, that are designed for long-term use, and found that we could run a rather inefficient 150 Watt transistor transmitter that required around 45V for 14 hours a day without use of a mains supply. This also allowed us to install the gear very high up a mountain and use stacked Yagis to point the signal at our target city and provide some useful antenna gain. The only problems came during the two stormy periods each year....

One of our number was a power supply designer, and came up with a charge regulation system that optimised the supply fed to the batteries, and switched the batteries as required to maintain the required voltage and current. There was a subcarrier telemetry system that reported the state of battery charge and the incoming and load currents (and heatsink temperatures!). The charge controller was the most complicated part of the whole set-up!

These days, charge controllers use FETs to switch currents about, and very high power Schottky Diodes are cheaply available. In those days, we had to make do with big stud-mounted silicon diodes (mostly samples from International Rectifier) and thyristors in chopper circuits...

The one thing that I most remember was that there was no way to make a suitable power supply without batteries!

[BriansBrain]

Thanks for the reply Mr. sinus

1000W / 12V = 83A which is a considerable current to maintain!

I did mention I was looking for advice on the Type of Solar Inverter I need
I was NOT thinking of using 12V

I do understand the weather in the Canary Islands? However Solar panels are a poor regular source of power!

I am not looking for the regular source of power from Solar panels
As I mentioned... I am looking to Use...
100% of available power from solar panels in the daytime.
Then Share the load with panels and the power grid when cloudy.
100% of the power grid at night.

The reason Batteries are used is not to actually power the system as such? They are there to keep the system stable!

I will be using the power grid for stability

[BriansBrain]

If you use the Inverter in conjunction with the Grid? I guess you would need some sort of sophisticated controller to alternate between the two? I doubt they can both be "ON" together!

That is why I was asking...

I'm after some advice on the Type of Solar Inverter I need.

[BriansBrain]

Thanks for the reply H

Pretty much any solar system requires batteries for power stability.

Actually if you do some research many Grid-Tie Solar Systems do NOT use batteries

GT.jpg

[BriansBrain]

The one thing that I most remember was that there was no way to make a suitable power supply without batteries!

I am NOT after a suitable power supply
Read my first post again..... I would like to Use...
100% of available power from solar panels in the daytime.
Then Share the load with panels and the power grid when cloudy.
100% of the power grid at night.


This is the Solar Inverter that is available locally that I am thinking of using.
NOTE in the main features: Inverter Running Without Battery

Omega UM 3000W 24V MasterPower @311E - 1.JPG

Omega UM 3000W 24V MasterPower @311E - 2.JPG

[BriansBrain]

This is how I worked out what sort of power to expect
Using
http://www.solarelectricityhandbook.com ... iance.html

Solar insolation is a measure of solar irradiance over of period of time - typically over the period of a single day.
The Average Solar Insolation figures for: Gran Canaria
Measured in kWh/m2/day onto a horizontal surface.
This irradiance calculator takes data collated over a 22 year period to provide monthly average insolation figures.
This information is then used to calculate the average daily power generation a photovoltaic system will produce in any given month.

Average over the year: 5.339
The quick & dirty workout for estimated watt-hours per day.
Let's say you have 4 x 250W panels and the insolation number is 3, then the calculation is 4 x 250 x 3 = 3000 watt-hours per day.

Solar Irradiance Figures Gran Canaria.JPG

SO - 3 panels of 460W Solar insolation number is 5.339 = 3 x 460 x 5.339 = 7367 watt-hours per day.
OR - 4 panels of 460W Solar insolation number is 5.339 = 4 x 460 x 5.339 = 9823 watt-hours per day.

[sinus trouble]

Those Master Power things seem pretty kosha!

Whats the damage to the wallet on those products?

[Albert H]

If you look at the Mater Power units, you'll see that they have a DC 27V "Charging" output. They will only work with batteries connected! In my old job, I had to design and build back-up power facilities for computer suites and broadcasting facilities. ALL of them - without exception - had banks of batteries. This didn't matter whether you were in a country with lots of solar power, or in a windy country with wind turbines.

All of these SM Inverters use battery back-up.

If you really wanted to build a bespoke power supply solution - powering tour rig from a solar regulator when there's sun available and falling back on the public supply when there's no sun - you probably could, but it's unlikely to ever be completely break-free or truly stable without batteries to drive the inverter during the "change-over" phase of operation......

Also - if you have batteries, you might never need to use power from the grid at all - the excess that you panels generate may well be enough for the hours of darkness!

Don't dismiss the idea of using battery back-up - modern batteries need almost no maintenance, and will last for years of charge / discharge cycles.

[BriansBrain]

Whats the damage to the wallet on those products?

The one I am looking at is 311 Euros Locally = £262.99

[BriansBrain]

If you look at the Mater Power units, you'll see that they have a DC 27V "Charging" output. They will only work with batteries connected!

It clearly states in the PDF for the unit I am looking at above
Inverter Running Without Battery

Capture.JPG

[BriansBrain]

Here is another example....

OUYAD HY3222VMII
3kw solar hybrid inverter work WITHOUT or WITH battery

OUYAD HY3222VMII - 3kw solar hybrid inverter work WITHOUT or WITH battery.jpg

[BriansBrain]

https://www.ouyad.com/ProductsSolarInverter_164.html

Capture.JPG

[jvok]

The whole house solar systems usually have the inverter feeding back into the grid, and then your loads just run off the mains as normal. Net metering means you only pay for the difference (or get paid if you're generating more than you use). These systems don't need batteries because the mains picks up the slack to keep a stable voltage, but they also can't work without the mains so aren't a backup power source on their own. If you have a power cut even on the sunniest day of the year you still lose power completely.

Systems that operate independently of the mains still need the battery bank.

[Albert H]

THAT was really my point! Also, the advantages of using DC from batteries are worth the expense - you can't beat the perfection of the DC from a good quality battery.

My Californian system used "Leisure" batteries and was charged (mostly) from the sun in the daytime, and wind at night. The system actually had two battery packs, and used them alternately. The telemetry system allowed comprehensive remote monitoring, and warned if anything was marginal. The excess heat reported one night was found to be due to a fried blower - and led to a redesign for the Mk2 system, so that all cooling was passive - the bigger heatsinks cost more, but the risk of overheating was entirely overcome.

[jvok]

Seems like it wouldn't be too hard to combine solar and mains chargers to feed the one battery either if thats the route you want to go

[Krakatoa]

Look up the Huawei Sun2000 series. They are quite popular right now, and the battery is optional, plus it has all the necessary connectivity for power monitoring and administration.