Living offgrid with small solar system(s)

[George Harmony]

Yeah....Never power outage @gary. ????

Our indoor pool Herr Naam several times mentioned in this thread about space for solar panels. Perhaps he have seen the harbor freight examples on youtube of the package with 15watt solar panels which are huge compared to this dutch example posted before, 10x260wp panels.

[IMHO]

I have this with a couple of extra extension poles to clean my dormer windows (6M off the ground) - I imagine it should do the trick for roof mounted panels using a ladder or scaffold:

[IMHO]

Number of panels required is less than I thought. On the back of each panel there should be a rating plate/label which will tell you the peak voltage at peak current of the panel.

Assuming each panel to be 34.4volts at 5.2 Amps at peak power. A string of 5 panels in series would give 172 Volts at 5.2 Amps so three parallel strings would give the power required at peak power (a total of 15 panels). Size of the individual panels is 1.67 x 0.67 metres so the total area for 15 panels is 16.78 sq Metres.

It is quite likely that the available panels will be different from the example I have given but you should be able to calculate the number required by applying some simple maths.

Please note:- You can't just connect the three strings of panels together without a protection diode in series with each string. The reason for this is because if for some reason the voltage of one string went down (shade, bird "stinky stinky" or whatever) then the remaining strings of panels would present a high enough voltage to make a spectacular show of destruction of the shaded string.

The specs you are working on are going to be either STC or NOCT lab specs both of which are based on low ambient temps (20-25c) and a brief flash of light between 800 - 1000W/m2. In Thailand you're not getting anything like that performance with up to 40c ambient temps, cell temps regularly in the 60c range, and up to ~1700W/m2.

Time to start looking at the temperature coefficient specs too?

The panels I have used in the example are the same as I have in my installation. At the high point in the day each is producing around 176 watts. Using the information on the rating labels they should be producing 179 Watts. So it seems that my losses including diode drop, thermal, cable/termination and dust amount to 3Watts (that's 1.67%). Not significant enough to worry about.

One small point to note is that my panels are rated at 200Watts which is misleading because the peak voltage and current is the figure of merit not the maximum possible voltage and maximum current.

Got the spec sheet for your panels?

There's no magic - so that means you've maybe found panels with very low temp. coefficient.

[Gary A]

A question for a good sparky. Would it work if I would connect a 500 watt grid tie inverter to the the AC side of an 800 watt off grid battery powered inverter. The grid tie inverter needs to see line voltage or it will shut down. I'm afraid to try it without some advice. That would allow the charge controller more power to charge a bigger battery bank. I could then add batteries to my battery bank and use more power from the battery bank when the sun goes down.

My batteries are BSB AGM sealed. Yesterday I emailed the supplier. Today I got an answer. He said it would be a bad idea to add two new batteries to the three year old bank. So it appears that I cannot add batteries. Since he lost a sale, I have to believe him.

[Crossy]

A question for a good sparky. Would it work if I would connect a 500 watt grid tie inverter to the the AC side of an 800 watt off grid battery powered inverter. The grid tie inverter needs to see line voltage or it will shut down. I'm afraid to try it without some advice. That would allow the charge controller more power to charge a bigger battery bank. I could then add batteries to my battery bank and use more power from the battery bank when the sun goes down.

My batteries are BSB AGM sealed. Yesterday I emailed the supplier. Today I got an answer. He said it would be a bad idea to add two new batteries to the three year old bank. So it appears that I cannot add batteries. Since he lost a sale, I have to believe him.

You could make up a new bank then arrange to switch between them when they are full / discharged, either manually or automagically.

[George Harmony]

I've asked you b4 @Gary to your experience to add new battery to an old one. It seems thus that you did not do this before.

Coming back to the pump topic. As explained before I have till now a tiny system for my water supply. I only need 150ltr per day which I fill it in a watertank +/- 3m high. For this i use the first pump on the pict which sucks water out of a (pvc pipe) well, filter it and push it up to my watertank. Only 2.1 amp pump, 3.2 ltr per minute. For this a 2x20Wp panel with a (dummy)battery of 7Ah is enough and without any cycle use during peak hours and within 1 hour i get what I want , 150ltr. It works fine for almost a year now.

Its now still connected to a solar array of total 80Wp and still with 3x7Ah vlra batteries, also for my lighting and other stuffs. The fan you see on the pict is running during the day, also without drawing from the batteries and the buildin battery is then charged for evening use. Pls dont laugh, ive lived a year with only 3x7Ah batteries and still do.

Ordered more panels, not installed yet, and now its time to look for a suitable lifepo4 batteries and more loads, like outdoor lamps, a fridge and an electric wok

Ok, suppose I have a similar setup with a waterpump with 20x bigger capacity, so 20x2.1 amp. Is it so that I can pump 20x3.2ltr water per minute = 64 x 60m = 3840 ltr phour x 4hours = 15360 ltr per day. ????? If yes how many solar panels i must have?? Is it 20x40wp, total 800Wp???

The question is, is there a brushless pump which I can achieve the above with total of 800Wp panels,preferably without drawing from the batteries like my tiny setup above.? If its feasible, i can start to design a pool: length, width, depth based on the capacity of the (filter) pump.

[Gary A]

A question for a good sparky. Would it work if I would connect a 500 watt grid tie inverter to the the AC side of an 800 watt off grid battery powered inverter. The grid tie inverter needs to see line voltage or it will shut down. I'm afraid to try it without some advice. That would allow the charge controller more power to charge a bigger battery bank. I could then add batteries to my battery bank and use more power from the battery bank when the sun goes down.

My batteries are BSB AGM sealed. Yesterday I emailed the supplier. Today I got an answer. He said it would be a bad idea to add two new batteries to the three year old bank. So it appears that I cannot add batteries. Since he lost a sale, I have to believe him.

You could make up a new bank then arrange to switch between them when they are full / discharged, either manually or automagically.

I have him quoting a 2 volt tubular sealed set now.. Likely expensive.

[Muhendis]

Number of panels required is less than I thought. On the back of each panel there should be a rating plate/label which will tell you the peak voltage at peak current of the panel.

Assuming each panel to be 34.4volts at 5.2 Amps at peak power. A string of 5 panels in series would give 172 Volts at 5.2 Amps so three parallel strings would give the power required at peak power (a total of 15 panels). Size of the individual panels is 1.67 x 0.67 metres so the total area for 15 panels is 16.78 sq Metres.

It is quite likely that the available panels will be different from the example I have given but you should be able to calculate the number required by applying some simple maths.

Please note:- You can't just connect the three strings of panels together without a protection diode in series with each string. The reason for this is because if for some reason the voltage of one string went down (shade, bird "stinky stinky" or whatever) then the remaining strings of panels would present a high enough voltage to make a spectacular show of destruction of the shaded string.

The specs you are working on are going to be either STC or NOCT lab specs both of which are based on low ambient temps (20-25c) and a brief flash of light between 800 - 1000W/m2. In Thailand you're not getting anything like that performance with up to 40c ambient temps, cell temps regularly in the 60c range, and up to ~1700W/m2.

Time to start looking at the temperature coefficient specs too?

The panels I have used in the example are the same as I have in my installation. At the high point in the day each is producing around 176 watts. Using the information on the rating labels they should be producing 179 Watts. So it seems that my losses including diode drop, thermal, cable/termination and dust amount to 3Watts (that's 1.67%). Not significant enough to worry about.

One small point to note is that my panels are rated at 200Watts which is misleading because the peak voltage and current is the figure of merit not the maximum possible voltage and maximum current.

Got the spec sheet for your panels?

There's no magic - so that means you've maybe found panels with very low temp. coefficient.

Spec. sheet?

No chance IMHO These panels came from China. All the spec is on the label on the back of the panel.

[Naam]

Our indoor pool Herr Naam several times mentioned in this thread about space for solar panels. Perhaps he have seen the harbor freight examples on youtube of the package with 15watt solar panels which are huge compared to this dutch example posted before, 10x260wp panels.

i never mentioned anything about "space" de@r sol@r boy but was interested in the "size" of an average solar panel and its power generation.

i also never went to youtube to look at some harbor freight examples

[Gary A]

German ingenuity;

Batteries not included;

https://onedrive.live.com/?authkey=%21AFDbbgX8yqCnkXY&cid=841C36C60BF92CC5&id=841C36C60BF92CC5%211342&parId=root&o=OneUp

[Crossy]

German ingenuity;

Batteries not included;

https://onedrive.live.com/?authkey=%21AFDbbgX8yqCnkXY&cid=841C36C60BF92CC5&id=841C36C60BF92CC5%211342&parId=root&o=OneUp

That is of course an April 1st - this however is not, 80,000 AA batteries to power a train.

[IMHO]

German ingenuity;

Batteries not included;

https://onedrive.live.com/?authkey=%21AFDbbgX8yqCnkXY&cid=841C36C60BF92CC5&id=841C36C60BF92CC5%211342&parId=root&o=OneUp

That is of course an April 1st - this however is not, 80,000 AA batteries to power a train.

The cell he shows appears to be an 18650 - the same rechargeable Li-ion used by Tesla to torches

[Crossy]

German ingenuity;

Batteries not included;

https://onedrive.live.com/?authkey=%21AFDbbgX8yqCnkXY&cid=841C36C60BF92CC5&id=841C36C60BF92CC5%211342&parId=root&o=OneUp

That is of course an April 1st - this however is not, 80,000 AA batteries to power a train.

The cell he shows appears to be an 18650 - the same rechargeable Li-ion used by Tesla to torches

Yeah, but it doesn't quite have the same impact as 80,000 AA batteries

[George Harmony]

forget about any quotation George. technically there is no feasible way to satisfy my power demand by PV. the aircons and the lack of roof and land space makes any attempt futile.

I understand that with all your loads it will be difficult to be offgrid with solar but you did mention about space problems ....Herr Naam.

Something else. Above posted pict you see 2 pumps. One 2.1 amp 3.2 ltr per min. The other smaller submersible pump says in specs 1.2 amp 14ltr per min... Woawoawoa .....

[Muhendis]

forget about any quotation George. technically there is no feasible way to satisfy my power demand by PV. the aircons and the lack of roof and land space makes any attempt futile.

I understand that with all your loads it will be difficult to be offgrid with solar but you did mention about space problems ....Herr Naam.

Something else. Above posted pict you see 2 pumps. One 2.1 amp 3.2 ltr per min. The other smaller submersible pump says in specs 1.2 amp 14ltr per min... Woawoawoa .....

C'mon naam. Use some ingenuity. Put 'em 'atop each other. You,ll get ten times more power that way

[George Harmony]

This guy claims that a pump like i posted before can pump about 15000 ltr per hour and he runs it directly from an array of solar panels total 400wp without using a battery. The pump specs i posted before says 13000ltr per hour and was described by our indoor pool specialist as 600% more efficient as his own pool pump.

What is the truth???

Go to 6minute+ of this vid cause the intro is boring.

https://m.youtube.com/watch?v=bPvPJuvLw9Q

[IMHO]

This guy claims that a pump like i posted before can pump about 15000 ltr per hour and he runs it directly from an array of solar panels total 400wp without using a battery. The pump specs i posted before says 13000ltr per hour and was described by our indoor pool specialist as 600% more efficient as his own pool pump.

What is the truth???

Go to 6minute+ of this vid cause the intro is boring.

https://m.youtube.com/watch?v=bPvPJuvLw9Q

@George, that pump is experiencing none of the challenges a pump faces in a pool environment. If you want to pump water out of your pool it's probably OK though

Here's some reading: http://www.troublefreepool.com/threads/830-Hydraulics-101-Have-you-lost-your-head

[Naam]

sorry, obviously i did mention space primary reason why "lack of roof space" direction south:

[Naam]

C'mon naam. Use some ingenuity. Put 'em 'atop each other. You,ll get ten times more power that way

i have to consult first with @Sol@rGeorge to verify the validity of your @dvice.

p.s. how many layers are technically possible?

[Muhendis]

C'mon naam. Use some ingenuity. Put 'em 'atop each other. You,ll get ten times more power that way

i have to consult first with @Sol@rGeorge to verify the validity of your @dvice.

p.s. how many layers are technically possible?

You'll have to do it by trial and error. Keep going 'til the bottom one stops producing electricity then you know you've gone too far.........

[George Harmony]

Thanks@imho for that interesting article.

Other considerations that are very important when choosing a pump are:

Minimum flow rate for three turnovers per day or one in 8 hours.

Three per day or one in 8hours??? Anyone can explain?

Edited April 26, 2016 by George Harmony

[IMHO]

Thanks@imho for that interesting article.

Other considerations that are very important when choosing a pump are:

Minimum flow rate for three turnovers per day or one in 8 hours.

Three per day or one in 8hours??? Anyone can explain?

There are only rules of thumb.

Sometimes just turning over 1/2 the pool volume in a 4 hour period would do the job. Other times 3 turnovers in 12 hours is still insufficient to keep the water clean - the demands vary based on the pool usage and the amount of contaminants that need to be removed.

If you undershoot, you're going to have a pool which could be unsafe to use for days or even weeks.

I generally run my pump for at least 7 hours/day (2 turnovers), but if we have a pool party, I'll need to run it overnight in order to have clean water the next day. I couldn't imagine how long it would take to clear up if my pump was only capable of 1 turnover in 8 hours.

Edited April 26, 2016 by IMHO

[Muhendis]

Thanks@imho for that interesting article.

Other considerations that are very important when choosing a pump are:

Minimum flow rate for three turnovers per day or one in 8 hours.

Three per day or one in 8hours??? Anyone can explain?

There are only rules of thumb.

Sometimes just turning over 1/2 the pool volume in a 4 hour period would do the job. Other times 3 turnovers in 12 hours is still insufficient to keep the water clean - the demands vary based on the pool usage and the amount of contaminants that need to be removed.

I don't have a pool but curiosity is getting the better of me. How do you measure the cleanliness of the pool water?

[IMHO]

Thanks@imho for that interesting article.

Other considerations that are very important when choosing a pump are:

Minimum flow rate for three turnovers per day or one in 8 hours.

Three per day or one in 8hours??? Anyone can explain?

There are only rules of thumb.

Sometimes just turning over 1/2 the pool volume in a 4 hour period would do the job. Other times 3 turnovers in 12 hours is still insufficient to keep the water clean - the demands vary based on the pool usage and the amount of contaminants that need to be removed.

I don't have a pool but curiosity is getting the better of me. How do you measure the cleanliness of the pool water?

Simple - look at it. It should look like drinking water. Even easier to judge of you have underwater lights - they show up everything that's in the water

[Gary A]

I got the price to change from my generator and 1 HP submersible pump. The complete solar system and DC pump would cost 124,000 baht. That choked me up some. I can buy a lot of gasoline for that much money. The fruit trees my wife waters are not worth that much. I have to hope for rain to refill my pond.

Edited April 26, 2016 by Gary A

[George Harmony]

1hp pumps like attached pict r here available as from 450 to 1200usd. From wasser to grundfos. How much is the solar system then to run such a pump??

[IMHO]

1hp pumps like attached pict r here available as from 450 to 1200usd. From wasser to grundfos. How much is the solar system then to run such a pump??

What's the startup current draw?

[George Harmony]

I dont know. I was just wondering why @gary got a rather expensive offer while the pump itself is not so expensive.

Ive just read this:

Hello! Im attempting to run a 240 V well pump on a Xantrex SW4048 inverter via a 120/240 V, 4 KVA step-up transformer. The pump will start and run if no other load is present, but with even a few lights on, the inverter overloads and trips out. I called the pump motor manufacturer and they confirmed that the two-wire, 1 hp pump pulls 48 amps at 240 V for about 0.2 seconds during startup. However, since the inverter is supplying 120 V, the actual current the inverter has to supply is 96 amps! The surge ratings for the Xantrex SW4048 from the literature I have says 110 amps for 0.01 second, 77 amps for 0.1 second, and 73 amps (resistive load) for 5 seconds.

http://www.homepower.com/articles/solar-electricity/design-installation/ask-experts-running-well-pump-grid

[George Harmony]

I dont know. I was just wondering why @gary got a rather expensive offer while the pump itself is not so expensive.

Ive just read this:

Hello! Im attempting to run a 240 V well pump on a Xantrex SW4048 inverter via a 120/240 V, 4 KVA step-up transformer. The pump will start and run if no other load is present, but with even a few lights on, the inverter overloads and trips out. I called the pump motor manufacturer and they confirmed that the two-wire, 1 hp pump pulls 48 amps at 240 V for about 0.2 seconds during startup. However, since the inverter is supplying 120 V, the actual current the inverter has to supply is 96 amps! The surge ratings for the Xantrex SW4048 from the literature I have says 110 amps for 0.01 second, 77 amps for 0.1 second, and 73 amps (resistive load) for 5 seconds.

http://www.homepower.com/articles/solar-electricity/design-installation/ask-experts-running-well-pump-grid

[George Harmony]

I dont know. I was just wondering why @gary got a rather expensive offer while the pump itself is not so expensive.

Ive just read this:

Hello! Im attempting to run a 240 V well pump on a Xantrex SW4048 inverter via a 120/240 V, 4 KVA step-up transformer. The pump will start and run if no other load is present, but with even a few lights on, the inverter overloads and trips out. I called the pump motor manufacturer and they confirmed that the two-wire, 1 hp pump pulls 48 amps at 240 V for about 0.2 seconds during startup. However, since the inverter is supplying 120 V, the actual current the inverter has to supply is 96 amps! The surge ratings for the Xantrex SW4048 from the literature I have says 110 amps for 0.01 second, 77 amps for 0.1 second, and 73 amps (resistive load) for 5 seconds.

http://www.homepower.com/articles/solar-electricity/design-installation/ask-experts-running-well-pump-grid