Newbie from Philippines with a 300W setup

[workpod]

Newbie from Philippines with a 300W setup: Upgraded to 600W

My additional solar panels arrived and now on the roof giving me 600W potential of solar power.

Got a used 30A MPPT for a bargain at 50% less than a PWM controller I previously bought. But I doubt it's a real MPPT. Previous owner said he ordered it from eBay but is now upgrading to a 60A MPPT, so he no longer needs it.

So I connected my 3 panels on a PWM and the other 3 panels on the 30A MPPT.

So far so good. Panels reading as of 11:00AM
3 panels on 30A PWM: 14V 18A+
3 panels on 30A MPPT: 14V 18A+
Connected in parallel so both controllers are parallel charging my batteries at 14V 36A to 37A while also supplying power to the inverter. Which could be 504W to 518W.

Considering my work area consumes 144W to 192W, or even with house lights and work area both connected to the solar setup consumes 192W to 264W is a very good indication that my consumption is 50% to 52% of what I'm producing at peak hours.

Since not everytime is peaked out, realistically the production will only be 13V 16A average from my 600W panels. Or 208W production on a moderate cloudy day. If that's the case and have a cloudy day, I'll only have my work area on solar there by consuming 192W max of the 208W average or 92% consumption. And still have my rectifier/charger on standby in case my batteries go below 70% DOD.

So instead of 7:00AM to 4:00PM I'll be on solar during the peak hours at 10:00AM to 2:00PM to keep my batteries way over the 70% to 80% DOD (consuming only 20% to 30%). Although I'll be experimenting the best hours that I'll be connecting to the solar setup but still have my batteries at 70% to 80%.

I'll try 10:00 to 2:00PM on one day, then 9:00M to 3:00PM on another day, 8:00am to 4:00PM on one and finally try 7:00AM to 4:00PM. And see how it goes.

I'm actually very excited to see my electric bills by end of the month.

[Sunny Solar]

Just as I suspected you had something sucking up some amps besides the computer and fan and light.

"When I did the current draw test just now, directly connecting my computer, monitors, modem to the inverter outlet, I get 12V 12A to 16A or 144W to 192W. "

[workpod]

Workpod I noticed this and it seems high current use??

12V 22A to 30A -- Work area with my desktop computer, dual monitors, modem/WIFI, speaker, electric fan, light (ampere meter needle jumping between 22A to 30A

I measured my desktop computer with just one 24" monitor and it draws at max 12a.but on average 10a.. Assuming yours is about the same and another 5a for another monitor. It would seem you have a big power hungry fan and or lighting??

Got it why the large draw on my work area.

My computer desktop along with the dual monitors, modem/WIFI are all connected to my Intex 1500VA/900W UPS. And the Intex UPS is connected to the battery inverter. This is to make sure that I wont trip off when I switch power between solar and mains.

When I was doing the test of current draw yesterday, the Intex UPS was also recharging its dual 12V9A batteries in series for a total of 24V9A or 216W, while also supplying power to my computer setup. Standby consumption of the Intex UPS is less than 0.5A

When I did the current draw test just now, directly connecting my computer, monitors, modem to the inverter outlet, I get 12V 12A to 16A or 144W to 192W.

[workpod]

Hi,

The OP's power usage is during day time, wouldn't it be easier if he just add 300watts solar panel and a Mppt charge controller to the existing system, use a small generator for rainy day as backup?

Got that covered.

After a taste of having an offgrid setup, I can't let go and just leave my living room on solar. So I'm sticking to my plan and have the work area on solar but this time with a charger/rectifier as Sunking suggested.

I wont be putting the workarea on the solar setup all the time from 7:00AM to 4:00PM. Just only between 10:00AM to 2:00PM where the power production is at its peak. And add solar panels to make my solar setup to 600W.

I already placed an order of another 3 units of the same 100W solar panels. They have no available MPPT charge controller only PWM. Supplier said panels and controller should by ready by Saturday. If not then Monday.

I'll scout around for a high amp charger/rectifier this weekend for the inverter. This is in case for a cloudy or rainy day or in case I'll extend my computer use until the evening to keep my batteries happy.

Follow my progress on working offgrid at my Going Solar series at http://www.workpod.org/renewable-energy/going-solar/

[workpod]

@Sunking
Thank you very very much. I really appreciate the time and the understanding.

Workpod I noticed this and it seems high current use??

12V 22A to 30A -- Work area with my desktop computer, dual monitors, modem/WIFI, speaker, electric fan, light (ampere meter needle jumping between 22A to 30A

I measured my desktop computer with just one 24" monitor and it draws at max 12a.but on average 10a.. Assuming yours is about the same and another 5a for another monitor. It would seem you have a big power hungry fan and or lighting??

My desktop is an Intel Core2 Quad CPU Q8400 with 700GB and 500GB harddrives, 8GB RAM, video card is AMD Radeon 7750 with 1GB RAM, monitors are 22-inch AOC 2236V and 24-inch Acer P241W.

My CPU power supply is VP-PRO 500W. Max output current draw of 34A at 12V or a max power of 408W.

Electric fan is a 65W stand fan, light is 2W LED light.

[paulcheung]

He has a video card which draw about 200 watts alone.

[Sunny Solar]

Workpod I noticed this and it seems high current use??

12V 22A to 30A -- Work area with my desktop computer, dual monitors, modem/WIFI, speaker, electric fan, light (ampere meter needle jumping between 22A to 30A

I measured my desktop computer with just one 24" monitor and it draws at max 12a.but on average 10a.. Assuming yours is about the same and another 5a for another monitor. It would seem you have a big power hungry fan and or lighting??

[paulcheung]

Hi,

The OP's power usage is during day time, wouldn't it be easier if he just add 300watts solar panel and a Mppt charge controller to the existing system, use a small generator for rainy day as backup?

[Sunking]

@Sunking
Wow, that costly huh.

I probably go for the 2 hour = $340 considering I'll be replacing the batteries every year.

Well that is USA cost. Not sure about your but I would guess higher.

OK then for 2 hours you are looking at a battery capacity of 400 watts x 2 hours x 3 days autonomy = 2400 watt hours or 2.4 Kwh. That would be 100 AH for 24 volts, or 200 AH @ 12 volts. Perfect you got that already if I understand you have 2 12 volt 100 AH batteries already.

OK that said in your country it might be easier and cheaper to run at 12 volts as 24 volt charger/recitifers may not be common. So in 12 volts you are looking for a minimum 60 amp charger/rectifier, or 30 amps @ 24 volts. That will give you roughly 40 amps to run th einverter and equipment connected to it, and 20 amps for recharge assuming the IT equipment is still turned on. Otherwise 60 amps recharge when turned off. . Here is the part you might like. Based on these numbers you can go up to 4 hours in the event of an once in a while extended outage before you need to shut down. Secondly recharge time assuming your IT stuff is still on line will be 3 to 6 hours and ready to go again.

Lastly upgrade that inverter. get a good 800 to 1000 watt True Sine Wave inverter that is efficient at the load you intend to run.

Good Luck

[workpod]

@Sunking
Wow, that costly huh.

I probably go for the 2 hour = $340 considering I'll be replacing the batteries every year.

[Sunking]

Well it's the ampere reading I got when I connected the ampere meter between the battery and the inverter.

I don't have a problem with the wattage, it is the hours.

Power outage is 1 hour to about 4 hours max on a weekday. Worse on weekend which is 8 hours. But I don't mind the weekend outage. It's the 4 hours max outage that I'm trying to avoid.

OK this i swhat I was driving at. You need to make a economic decision here and how much pain in the wallet you can handle, and what is acceptable.

One heck of a difference between a battery that can last on hour vs 8 hours. Forget money for a second and think weight and cycle life. For this application I am thinking 33% maximum discharge rate for whatever hours you decide on. So what that means is for each Kwh requires 3 Kwh of battery. A Kwh of battery capacity weighs in around 55 pound, so a 150 pound battery for each Kwh of usable energy. So think about that 9 hour battery would weigh around 1350 pounds. It would also mean a much larger rectifier to get the battery fully recharged in 10 to 12 hours.

Now think about cost. In the USA a middle of the road hybrid battery will cost around $130 to $150 Kwh. A 11 Kwh battery to run 9 hours is a whooping $1550 USD. Not trying to bust your chops here but be careful what you ask for and be reasonable. Be sure you think necessity that will be acceptable, and not jump to I want. It can get real expensive fast.

But here is the range of price I would see in the USA just for the battery based on $140 Kwh of storage, 33% daily DOD, 400 watt load.

1 hour = $170
2 hour = $340
9 hour = $1550

[workpod]

Are you sure? That is a huge amount of power for a battery system. 400 watts x 9 hours = 3600 watt hours. Is your power out for that length of time each day?

Well it's the ampere reading I got when I connected the ampere meter between the battery and the inverter.

Power outage is 1 hour to about 4 hours max on a weekday. Worse on weekend which is 8 hours. But I don't mind the weekend outage. It's the 4 hours max outage that I'm trying to avoid.

And it's not everyday that I get a power outage. Probably a max of 2 times a week. And the frequency is about twice a month. Often times no power fluctuations for a couple of months. It only comes during rainy days which is between May to November.

[Sunking]

@Sunking
Awesome. That will really really help a lot.

Basically I need my computer setup fluctuation free to run from 7:00AM to 4:00PM max. That will be 9 hours max. Mondays to Fridays.

Power required to run the computer setup would probably be 400W based on my previous readings.

Are you sure? That is a huge amount of power for a battery system. 400 watts x 9 hours = 3600 watt hours. Is your power out for that length of time each day?

[workpod]

@Sunking
Awesome. That will really really help a lot.

Basically I need my computer setup fluctuation free to run from 7:00AM to 4:00PM max. That will be 9 hours max. Mondays to Fridays.

Power required to run the computer setup would probably be 400W based on my previous readings.

[Sunking]

@Sunking
Yes, I could connect the living room to the solar between 6:00PM to 10:00PM. The lights at 24/7.
Cost per kWh is Php10.00 or US$0.23
0.8kWh is equivalent to Php8.00 or US$0.18

You do not have the capacity.

I can understand the computers as that is how you make your living and you can justify that because it is mission critical. So here is my advice as a professional who designs data centers and telephone offices. Determine how much power your IT equipment uses, and how long you would need to run it in a 24 hours period. Once armed with that we can customize you a James Bond UPS.