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Setting up a 1kw off grid solar system in the Philippines

Loniko

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Oct 12, 2020
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Hey guys,

So I recently purchased land in the Philippines (let's not discuss the how) and want to put an off grid solar system onto the property as the local electricity supply is more than unreliable and expensive the same time.

So I'm totally new to this and tried to wrap my head around all the things needed.
Even though I am a total newbie, I would love to tackle the setup myself.

I'm thinking of around 1kw of solar panels, either 3x/4x 300W or 3x400W. That should be more than enough for my needs as the biggest consumer would be the fridge. I don't intend on running an AC with that system.
MPPT charge controller. So there is 20A, 40A and 60A available as far as I know from my research. Which one to choose?
Inverter. There are hundreds of them. From 100USD to more than 600USD (fully off grid 48V 6000W) on the local online shopping platforms. Is more expensive better?
Batteries. Definitely want to go for LiFePo4 batteries. Best deal I could find were 3.2V 100Ah. There are also 3.2V 200Ah.
Should the system run on 24V or 48V?

My biggest worry would be connecting all the batteries and me hopefully not messing anything up.
I know it probably would be easier to just get an electrician, and I agree with you here, but the local electricians can lay cables inside a house and seeing their wiring gives me shivers. Those who are trained are from other islands or the biggest cities and only come out when you purchase their systems which I found to be way more expensive than buying everything yourself.

I hope I'm not too confusing. I probably missed a few things or am thinking the wrong way? That's why I'm here.

Please help me out. ?

Thanks a lot
 
The minimum amp rating of your charger controller is related to the battery voltage. Let's say you want to be able to accept all the power the panels can produce and set the array at 1200W. With a 24V battery you would need a controller capable of at least 50A (50 x 24 = 1200) while with 48V, 25A.

What are you doing for an inverter or is this going to be a DC only system?
 
And here I go again...

Link #5 in my signature for your solar hours at your location, panel orientation and tilt.
Link #1 in my signature for an energy audit - what you want to run, it's power requirements and how many hours per day.

Do the above, and you can properly size a system, determine battery capacity, kW of solar and other components.

Assuming great sun, the fridge will consume about 40% of the yield from your 1kW of panels.
 
The minimum amp rating of your charger controller is related to the battery voltage. Let's say you want to be able to accept all the power the panels can produce and set the array at 1200W. With a 24V battery you would need a controller capable of at least 50A (50 x 24 = 1200) while with 48V, 25A.

What are you doing for an inverter or is this going to be a DC only system?

Is there a limit on charge controllers? Cause as I said the biggest I could see online was 60A.

Inverter: see the attached file. That will work?
 

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And here I go again...

Link #5 in my signature for your solar hours at your location, panel orientation and tilt.
Link #1 in my signature for an energy audit - what you want to run, it's power requirements and how many hours per day.

Do the above, and you can properly size a system, determine battery capacity, kW of solar and other components.

Assuming great sun, the fridge will consume about 40% of the yield from your 1kW of panels.

So the starting (surge) watt usage for the fridge is a constant?

With a 1kW system I would generate 4-5kW a day, or am I wrong?
 
Is there a limit on charge controllers? Cause as I said the biggest I could see online was 60A.

Inverter: see the attached file. That will work?

You can get much higher current ones but the price goes up. Quality brands such as Victron have 100A chargers, but you have other options if you don't want that quality level. Can you post a link to those inverters? Depending on your budget you may find an all-in-one to be acceptable.

If you get a separate charger the battery capacity tends to set your safe power level. You might have a charger and panels that can supply 100A but a battery that can not be safely charged at 100A so you can never actually produce that sort of power from your solar array with a separate charger / inverter that is not part of a coordinated ecosystem such as what Victron offers. Coordinated separate systems allow you to limit the power to the battery but still produce full solar power to run loads during the day. Some all-in-one inverter chargers have this ability too.

Example only, not a recommendation to buy
 
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You can get much higher current ones but the price goes up. Quality brands such as Victron have 100A chargers, but you have other options if you don't want that quality level. Can you post a link to those inverters? Depending on your budget you may find an all-in-one to be acceptable.

Example only, not a recommendation to buy
Here's the link: https://s.lazada.com.ph/s.YlMwP

I'll take screenshots if you can't access the site.

What would be a Victron equivalent to that inverter from the link?
 
So the starting (surge) watt usage for the fridge is a constant?

With a 1kW system I would generate 4-5kW a day, or am I wrong?

Surge depends on the model/features - some are inverter-type and have very little surge. Likely that you'll use other items that consume more power.

Depends on what link #5 says, but I assumed 5kWh as a typical residential fridge uses about 2kWh, thus 40%
 
Surge depends on the model/features - some are inverter-type and have very little surge. Likely that you'll use other items that consume more power.

Depends on what link #5 says, but I assumed 5kWh as a typical residential fridge uses about 2kWh, thus 40%

I working on a 1kWh fridge. And that will be the biggest consumer. There will only be a fan (50W) and lights. A water pump during the heat of the day to fill up the water tank. But that's about it.
 
Water pump will likely be your biggest surge.

Would it have a significant impact if batteries (~20kWh) are full and it's full sun?

Edit: Water will be pumped to a tank on the hill and from there it is gravity fed to the house. So the pump is likely gonna run every other day for an hour or two max.
 
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Would it have a significant impact if batteries (~20kWh) are full and it's full sun?

Edit: Water will be pumped to a tank on the hill and from there it is gravity fed to the house. So the pump is likely gonna run every other day for an hour or two max.

No. Surge is independent of solar and batteries. It's a property of the motor. Your INVERTER needs to be able to handle the surge of the pump.

My 2kW inverter couldn't run my 3/4hp pump due to the high surge.
 
No. Surge is independent of solar and batteries. It's a property of the motor. Your INVERTER needs to be able to handle the surge of the pump.

My 2kW inverter couldn't run my 3/4hp pump due to the high surge.
Ok, noted. The screenshot above from the inverter states that it could run a 1hp or for the bigger version a 2.5hp pump.
So there shouldn't be any issue with that as long as I don't put in a bigger pump than recommended.
 
I can't find any instructions for that inverter so it's hard to say if it is good or not beyond what's on the page. If you can dig up a manual for it someone can cast their eye over it and give a better opinion.
 
I can't find any instructions for that inverter so it's hard to say if it is good or not beyond what's on the page. If you can dig up a manual for it someone can cast their eye over it and give a better opinion.
What would I need to look for specifically?
I'll look at Victron models and see if I can compare them somehow.
 
If you plan on using it to charge the battery when mains is present you'd need to confirm it is safe for a lifepo4, ie you can adjust the voltages, times, tail current to properly suit a lifepo4 battery. It does say lithium on the box but with a lot of this stuff it's more shoehorned than proper support. The same would go for low voltage shutdown.
 
If you plan on using it to charge the battery when mains is present you'd need to confirm it is safe for a lifepo4, ie you can adjust the voltages, times, tail current to properly suit a lifepo4 battery. It does say lithium on the box but with a lot of this stuff it's more shoehorned than proper support. The same would go for low voltage shutdown.
I'll see if they have a manual.

So this one would be suitable for a 48v system?
 
I'm not familiar with that one either but it's a brand I know, SRNE. If I can find the manual for it I'll take a look.
 
I'm not familiar with that one either but it's a brand I know, SRNE. If I can find the manual for it I'll take a look.
I checked their website but couldn't find that model there. Must be an older one.
The ones I did find on the website have a maximum load power of 960W.
That's not enough to power air condition and fridge at the same time?

In general: SRNE is a good choice?
 
Their MPPT chargers seem to be OK. Renogy uses them too, so that's something. If they were complete junk I wouldn't expect that.

Here's the datasheet for the SRNE inverter. It looks like a high frequency inverter while the other one you linked to seems to be a low frequency design. The difference often boils down to short term over-rating. A high frequency inverter can have trouble starting heavy motors while low frequency ones usually cope OK. Given that you want to run a water pump I would get a low frequency inverter.

That said I don't have any experience with either of those inverters so at best I would just be making an educated guess with them.
 
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