Newbie from Philippines with a 300W setup

[SunEagle]

Okey so previously without solar I was consuming an average of 300kWh per month.
It follows that being connected to the grid alone, I'm consuming 3,600kWh per year.
The power company charges for about $0.23 per kWh so total for the year is $828.

Now given that my total setup is $1,600
After setting up a solar battery system I'm consuming an average of 175kWh per month from the power company.
Which could mean I'm producing an average of 125kWh per month so in a year it's 1,500kWh average a year.

So $1,600 divide by 1,500kWh is $1.06 per kWh. This is the power cost of the new solar battery setup per kWh.
Compared with the POCO cost, my solar battery setup actually costing me $0.83 more.

Now how many years until I get ROI of $1,600? And how long my batteries would last? I don't know yet.
Let's say my batteries will only last for 2 years. And 2 sets of 100h Motolite truck batteries at $136 each or $272 for two.

Let's say cost from POCO is $0.23 multiplied by average 125kWh produced a month is $28.75. So in a year it is $345.
Theoretically, the ROI would be $1,600 divided by $345per year is 4.63 years.

But then again, I have to replace the batteries every two years so let's add three sets of $272 for a total of $816. This brings my total cost to a whooping $2,416

So let's recompute: $2,416 divided by $345 per year is about 7 years and 2 months.

It's like getting mortgage of a house that's payable in 7 years. And after the 7 years, you have no more obligation to the bank. The house is all yours.

So by year 8, you only have to buy batteries for $272 for two or maybe but that time with the current trend of technology the cost batteries either goes down or up. So let's stick with $272 for two.

So by year 8, you will have $272 divided by cost from POCO of $345 per year is about 9 months and 15 days. And the rest of the months until the year 10 is your savings. And the cost of my solar battery system during the year 8 is only costing me $0.18 per kWh ($272 divide by 1,500kWh per year). But on year 9, it's not costing me anything since the $272 is already paid for during the year 8, and so will be the odd numbered years after year 8.

Given that the cost of batteries will go up, so does the power cost of the power company. This year alone the cost of power from POCO is now about $0.26 how much more in 7 to 8 years.

Solar panels will last 20 to 25 years but after that, the solar panels' current efficiency will only be 90% down to 80% but still can be used. After 20 to 25 years, how much would you think the cost of solar panels will be?

So does this prove that having a solar battery setup is achievable in terms of total ROI? Or I'm just dreaming?

And if I do just dream: bragging I have electric power, helping your neighbors charge up their cellphones or gadgets in case of emergencies, watching TV, listening to music, cooling down when everyone around you is cursing the long brownout is still priceless for me.

Well actually you are using the wrong formula. As of now it seems that your battery system is producing about 125kWh / mth but that is based on your current use and historical use and not necessarily what your batteries are generating.

To determine the actual amount of kWh your system can produce you use the battery Ah rating x voltage x % of discharge.

So if your system is say 600Ah at 12volts and you discharge it daily about 25% your usage would be 600 x 12 x .25 = 1.8kWh per day. Or about 54kWh per month which is saving you about (54kWh x $0.23/kWh = $12.42) or about $150/yr. If you use more than 25% of the battery capacity per day then your output is higher but you also start to shorten the lifespan of the battery and will have to replace it sooner. At that $150/yr savings and the need to replace the batteries every couple of years will come to a payback way more than 10 years.

Now if you reduce your usage (tell your cousin it just hot and deal with it. LOL) then your solar battery system can start to save you a larger portion of your usage but it will still take a while to pay for itself.

[ILFE]

[workpod]

Okey so previously without solar I was consuming an average of 300kWh per month.
It follows that being connected to the grid alone, I'm consuming 3,600kWh per year.
The power company charges for about $0.23 per kWh so total for the year is $828.

Now given that my total setup is $1,600
After setting up a solar battery system I'm consuming an average of 175kWh per month from the power company.
Which could mean I'm producing an average of 125kWh per month so in a year it's 1,500kWh average a year.

So $1,600 divide by 1,500kWh is $1.06 per kWh. This is the power cost of the new solar battery setup per kWh.
Compared with the POCO cost, my solar battery setup actually costing me $0.83 more.

Now how many years until I get ROI of $1,600? And how long my batteries would last? I don't know yet.
Let's say my batteries will only last for 2 years. And 2 sets of 100h Motolite truck batteries at $136 each or $272 for two.

Let's say cost from POCO is $0.23 multiplied by average 125kWh produced a month is $28.75. So in a year it is $345.
Theoretically, the ROI would be $1,600 divided by $345per year is 4.63 years.

But then again, I have to replace the batteries every two years so let's add three sets of $272 for a total of $816. This brings my total cost to a whooping $2,416

So let's recompute: $2,416 divided by $345 per year is about 7 years and 2 months.

It's like getting mortgage of a house that's payable in 7 years. And after the 7 years, you have no more obligation to the bank. The house is all yours.

So by year 8, you only have to buy batteries for $272 for two or maybe but that time with the current trend of technology the cost batteries either goes down or up. So let's stick with $272 for two.

So by year 8, you will have $272 divided by cost from POCO of $345 per year is about 9 months and 15 days. And the rest of the months until the year 10 is your savings. And the cost of my solar battery system during the year 8 is only costing me $0.18 per kWh ($272 divide by 1,500kWh per year). But on year 9, it's not costing me anything since the $272 is already paid for during the year 8, and so will be the odd numbered years after year 8.

Given that the cost of batteries will go up, so does the power cost of the power company. This year alone the cost of power from POCO is now about $0.26 how much more in 7 to 8 years.

Solar panels will last 20 to 25 years but after that, the solar panels' current efficiency will only be 90% down to 80% but still can be used. After 20 to 25 years, how much would you think the cost of solar panels will be?

So does this prove that having a solar battery setup is achievable in terms of total ROI? Or I'm just dreaming?

And if I do just dream: bragging I have electric power, helping your neighbors charge up their cellphones or gadgets in case of emergencies, watching TV, listening to music, cooling down when everyone around you is cursing the long brownout is still priceless for me.

[workpod]

@livingincebu
Although I somewhat agree with the solar gurus that we cannot TOTALLY achieve ROI however we can achieve at least partial ROI with our offgrid setup.
And based on my opening post I have already reached my goals as:

1. To at least save a third or half of what I'm paying to the power company
2. To get rid of the nuisance of getting frequent brownouts especially during my work hours

On the first goal, the average I pay to the POCO is around $70. After the solar setup, with my regular usage of the system I pay an average of $40. So that's already a decrease of about 40% of what I'm usually paying to the power company.

On the second goal, I also got rid of the nuisance of getting frequent brownouts. I can even sleep better during an all-nighter brownout because at least my electric fan keeps me cooler than not having it during brownouts.

As for the ROI, from the $30 that I saved a month from paying to the POCO, I'm setting aside at least $20 a month for a total of $240 a year. The total cost I spent originally was around $1,300. I upgraded my solar panels to be 600W total that brought my total cost to $1,600.

Now $1,600 divided by $240 a year gives me about 6 years and 7 months for a total ROI. Which can never be achieved unless I utilize my offgrid setup and take in recharging from neighbors with their cellphone, rechargeable fan/radio, 7Ah batteries which by the way does happen once my neighbors were aware I had gone solar.

But still not a total ROI. Which I really don't mind. The most important is I'm still powered up and online even there's a whole week of no power or longer. I'll just have to inform my online clients that my area is in a week long or longer of brownout so instead of spending 8 hours a day online, I'll just be around at least 4 hours a day online. It's much better than not to be online at all and not able to communicate.

And also, some guys buy $1,000 bicycles when they only ride it for a couple of hours on weekends when they can just take a walk or jog on a local neighborhood. And some guys buy $500 fancy phones and then buy other $500 models when they actually only need one cellphone. And some guys buy a car when they can actually save by just taking the taxi, bus or jeepney. These guys including me don't think about ROI on the car. It's the convenience that I can go out anytime, anywhere and with peace of mind.

Each to their own purpose. Rock the boat all you want but these guys wont budge. They'll just sit around contented having what they want.

And the monthly or yearly savings will give me $720 in 3 years or $960 in 4 years to prepare me for the next battery replacement and other parts or upgrades. In fact, I could replace a new set of batteries every 2 years if I want and still have enough left to add another panel.

[SunEagle]

workpod, you and I are similar, in that we earn (at least part of) our incomes online.

Many solar gurus tell us that we can never get a ROI of our hardware, it still reduces the cost of our electric bill AND allows us to work online during brown outs / power cuts. So, those savings would have to be figured in to the overall costs of a solar system. I think, after adding the savings the solar system secures for us, perhaps we do get an ROI after all.

I have one solar array here that is basically a small business. I use it to charge batteries for locals. So, I provide the array, the controller and wiring. They provide the batteries to be charged every day. Want to talk about not getting a return on investment there? If mains power is ever run to the area, I can then buy my own batteries. Until then, the neighbors / customers are paying for my solar array, one charge up at a time.

I agree that if you have the panels and charger and your "customers" bring you their batteries to be recharged you could actually make a profit.

When you look at the cost of a solar battery system and divide that amount by the yearly kWh it can produce you usually find it will cost $1.25 to $1.50/kWh. That is usually a lot more than what an Electric Utility will charge you per kWh.

If the cost of "lost production" due to the Utility power going down is high, then having a backup like a generator can easily pay for itself and maybe even a battery system will also pay for itself if the "lost production" costs are very high.

There are a lot of different possibilities concerning Utility costs and "production loss" costs that will change the overall results.

I try not to discourage people wanting to build a solar battery system. I just try to point out that in most cases the cost/kWh for a battery system is much higher than using the Utility or a generator during brief times of a power outage.

[ILFE]

April 2014 - 174kWh (Period covered Mar 16 to Apr 16) about US$40.46
May 2014 - 173kWh (Period covered Apr 16 to May 16) about US$40.25
June 2014 - 229kWh (Period covered May 16 to June 16) about US$53.28 *
July 2014 - 440kWh (Period covered June 16 to July 16) about US$102.37 *

*Visiting cousin and wife from London can't stand the heat. Aircon in full blast. Back to London last week of July 2014.
Also, rainy season has started late May 2014. Cloudy skies is expected onwards.

workpod, you and I are similar, in that we earn (at least part of) our incomes online.

Many solar gurus tell us that we can never get a ROI of our hardware, it still reduces the cost of our electric bill AND allows us to work online during brown outs / power cuts. So, those savings would have to be figured in to the overall costs of a solar system. I think, after adding the savings the solar system secures for us, perhaps we do get an ROI after all.

I have one solar array here that is basically a small business. I use it to charge batteries for locals. So, I provide the array, the controller and wiring. They provide the batteries to be charged every day. Want to talk about not getting a return on investment there? If mains power is ever run to the area, I can then buy my own batteries. Until then, the neighbors / customers are paying for my solar array, one charge up at a time.

[workpod]

Update on electric bill (Apr 2014 to July 2014)

April 2014 - 174kWh (Period covered Mar 16 to Apr 16) about US$40.46
May 2014 - 173kWh (Period covered Apr 16 to May 16) about US$40.25
June 2014 - 229kWh (Period covered May 16 to June 16) about US$53.28 *
July 2014 - 440kWh (Period covered June 16 to July 16) about US$102.37 *

*Visiting cousin and wife from London can't stand the heat. Aircon in full blast. Back to London last week of July 2014.
Also, rainy season has started late May 2014. Cloudy skies is expected onwards.

[workpod]

Update on electric bill

Got my electric bill today. Including my previous bills for comparison:
Dec 2013 - 312 kWh (Period covered Nov 16 to Dec 16) about US$72.56
Jan 2014 - 301 kWh (Period covered Dec 16 to Jan 16) about US$70.00
Feb 2014 - 303 kWh (Period covered Jan 16 to Feb 16) about US$70.46

Mar 2014 - 246 kWh (Period covered Feb 16 to Mar 16) about US$57.21 - I started my off grid solar setup Mar 1 2014

Decrease in grid power consumption of about 57kWh in 15 days. About 3.8kWh average per day.

Decrease on electric bills of about US$13.25 within about 2 weeks. Still inconclusive so far. Best to wait and compare the next 3 months bills.

[inetdog]

Float is the most gentle kindest recharging there is. Every utility company uses nothing but Float and rare EQ charge once a year.

The only reason for Bulk and Adsorb is to speed things up but it comes with a cost, less cycle life. There are not enough Sun Hours in a day to use Float on solar. He will be connected to the utility.

(Assuming FLA rather then AGM for the following: )
But if the usage will cycle the battery, will that not lead to stratification regardless of how gentle the recharge is?
And if so, will the Float-based charger ever produce gassing to stir and destratify the electrolyte? Or will that only happen during EQ cycles?

[Shockah]

Float is the most gentle kindest recharging there is. Every utility company uses nothing but Float and rare EQ charge once a year.

The only reason for Bulk and Adsorb is to speed things up but it comes with a cost, less cycle life. There are not enough Sun Hours in a day to use Float on solar. He will be connected to the utility.

Once again, I learned sumptn here... Thanks!!!

[Sunking]

Ah...

So no bulk, no absorption?

Is that "healthy" if the OP cycles a Deep Cycle Battery the projected 2 to 3 days a week?

Float is the most gentle kindest recharging there is. Every utility company uses nothing but Float and rare EQ charge once a year.

The only reason for Bulk and Adsorb is to speed things up but it comes with a cost, less cycle life. There are not enough Sun Hours in a day to use Float on solar. He will be connected to the utility.

[Shockah]

Simple the rectifier voltage is set to Float Voltage.

Ah...

So no bulk, no absorption?

Is that "healthy" if the OP cycles a Deep Cycle Battery the projected 2 to 3 days a week?

[Sunking]

Pardon my ignorance, but I am still baffled on what protects the battery from being overcharged by the rectifier...?

Thanks.

Simple the rectifier voltage is set to Float Voltage.

[Shockah]

...Get a inexpensive 24 volt 50 amp rectifier, connected to a 24 volt 200 AH Deep Cycle AGM battery connected to a 24 volt 1 Kva inverter and he gets exactly what he wants for a whole lot less investment. It is called a Dual Conversion UPS. It uses grid power when available, and switches to battery when grid fails. When restored it the battery recharges and inverter is back on the grid. There is nothing to do as it is automatic.....

Pardon my ignorance, but I am still baffled on what protects the battery from being overcharged by the rectifier...?

Thanks.

[Shockah]

Overcharge?

You are looking for something like this.

^^^ No problems with overcharging the 24 volt battery bank? ... Or will the Inverter also be a CC?

Great thread !!! :thumbup: