Off grid in South East Asia

[trigger]

hi all..
I'm planning a solar setup in Thailand and have been given the quote below ..


I'm planning too run 7x 1.1kw single phase 230v air blowers 24/7 on this and I'm thinking or from my honest basic knowledge that I have not enough batteries here .
I thought I would be better with a single 10kw inverter also ?

Any thoughts and advice greatly appreciated

 

[timselectric]

Something seems off about the battery.
It says lithium, but the picture says deep cycle gel.

 

[trigger]

They have quoted for gel batteries - i noticed that too .
i calculated ill use 124.8kwh per 24hr . I then reduced that by 50% as it's pretty bright over here so I'd use a min of around 62.4kwh drain from batteries each night (not sure if this is the correct math to calculate) .

 

[timselectric]

Led acid batteries can only be discharged to 50%, without causing damage. So, those batteries only have a usable capacity of 125ah.
One cloudy day could deplete the batteries.
I would get more batteries or have a backup plan. (Generator or grid)

 

[trigger]

cheers for the info pal ... so are you saying there's enough battery storage there provided the suns out?
we do have a 5.5kw genny as backup .
malc

 

[timselectric]

cheers for the info pal ... so are you saying there's enough battery storage there provided the suns out?
we do have a 5.5kw genny as backup .
malc

It looks like it, according to your figures.
If you end up using the generator a lot. You can decide on more batteries then.

 

[xjaw4]

You need a much larger battery and a much larger array to power that sort of load constantly.

7 X 1.1 kw * 24 hr = 184.8 kwh per 24 hr period. if 7.7 kw all the time 7.7 kw / 48v = 160 amps not counting on the losses of the inverter which could be 5 - 15% If the inverter is 90% efficient it would be drawing roughly 178 amps to operate for 20 hr on battery power it would require a 3564 AH rated battery (at the 20 hr rate) If lead acid one would double that or more to keep the depth of discharge to 50% or less.

A battery is limited not only in capacity but also in how quickly it can charge and discharge. A 250 AH lead acid battery pack could in theory provide 300 watts for 20 hrs. If the load is higher than that the capacity is going to drop quickly. As the load increases and current draw from the battery goes up so will the voltage drop and the inverter will shutdown

480 watts per panel * 20 panels = 9.6 kw even with 12 hrs of full sun and a massive battery that array could not produce enough power to run the 7.7 kw load more than 3 hrs past sunset. at least 36 panels required even with 12 hrs of sunlight to power a 7.7 kw load for 24 hrs


It is much more affordable to work to reduce the power requirements than to try to generate more power.

If you can find a more efficient blower motor to reduce your power requirements, it would help make the system you need to buy that much smaller. Search for a (ECM) electronically commutated motor

 

[conquistador]

Are you sure you will run 7x 1.1kw single phase 230v air blowers 24/7? This is quite big fans. Is this for a chicken farm or something?
Could you post an approximate price they quoted you for all this material plus installation?

 

[trigger]

HI,

I can reduce the load to 4x 1.1kw blowers but that would be the absolute minimum I could go . I would then need to run the other 3 from a genny for a while during the day .
Its for a fish farm where we grow tilapia in confined raceways and we must supply o2 24/7 . We run 4 blowers on the raceways where we grow fish and a further 3 in the lake to areate and move water ...
I do plan to upscale eventually but as its a start up im stuck with a limited budget for the first step and really want to stay away from running Generators 24x7 .
I dont mind adding some panels and batteries to the quote I've had if you could reccommend roughly how many I would need , to take into consideration a not so sunny day .
As for price I've had some wild ones at either end of the spectrum
I've been dealing with this company a while and they seem pretty decent to be fair . The total price is around $8k and then it'll cost me another $1k or so to have it forwarded from China to Thailand .
Oh and there's no labour included , we plan to DIY the install over a 3-4month period . I'll hopefully do a thread on here once we get going

 

[conquistador]

So you probably use these swimming paddles which can be seen in the shrimp ponds?
Depending where you are in Thailand, air pollution like this smoke from Malaysia will reduce your panel output, maybe to 70% of the panel rating. Then on days of dark rainclouds, the output will be considerably lower, like 20% only.
As this is a kind of "life support" system, you might wish to think about redundancy. Maybe better 3 or 4 of 3kW or 5kW inverters instead of one big one. Otherwise you will be in trouble if there is something with the inverter or the battery.
For 1kW of power needed, I'd go for 2kW of Panel.
450W panels are around 4500B locally.
Make sure your chinese supplier can deliver via Thailand direct line, otherwise you will also pay customs and tax on your purchase and it might sit for weeks with customs.

 

[conquistador]

The Wh for your battery is easily calculated. 12V x 250Ah = 3000Wh for each battery. Being Lithium you might get 80% out of it, but if you get Lead Acid, then max 50%. This means, with 4 batteries, you can run a single fan for a couple of hours in the best case, because each fan takes 1000Wh every hour.