system desing for 1/2 horse power motors

[Usmandj]

Dear All,
I've currently installed a solar system at my gas filling station. I am using 5 panels of 240watts
240x5= 1200 watts
and using 2000w pure shine inverter and a charge controller. My battery bank is of 600Ah.

sun shines at my location for 8 hours a days and give me 30A per hour on average.

I've few question if some one could help me out.

Is my system enough for running 3 1/2 horse power motors?
How much time should my batteries take to recharge?

My problem is that my motors run fine in day time but at night when sun is down my battery bank gets empty and there is not enough load as we have approximately 50 customer in 12 hours at night?

can any body suggest me what to do?

[Sunking]

Simple you need a lot more panel wattage and much larger batteries.

[Wy_White_Wolf]

You have 3 strikes against your system. Unless you correct all 3 the problem will remain.

1. Your array is way undersize.

2. Your battery bank is way undersize.

3. You've over estimated the daily insolation available. No place averages 8hrs insolation a day and for off-grid you need to design for worst case which would be the average for the worst month. We would need to know your location to help with this one.

How many of these motors are you trying to run and how long per day do they run?

WWW

[russ]

You are posting from Pakistan? Are you in an area affected by the monsoon season?

You do seem to get good sun - PV Watts has no locations in Pakistan şisted but in a neighboring state in India the annual average insolation is listed at 6 kW/m2/day.

[Wy_White_Wolf]

GAISMA has data for Pakistan

http://www.gaisma.com/en/dir/pk-country.html

Most loactions seem to have winter lows of under 3 hours with a couple being under 2 hours daily average. You can't design an off-grid system based on 8 hours and expect it to work when you only have an average of 2 hours insolation available.

WWW

[Mike90250]

You need to consider the starting surge for the motors, and choose an inverter that can manage the required current surge.

I would suggest a 24V system, as that reduces the amps in half, from a 12V system. Saves on wire losses, which are critical when starting a motor.

My well pump is 1/2 hp, and consumes 1,000 watts while running, and likely at least 5,000 when starting for 1 second.

[Usmandj]

Thanks you all for you concern...

this is my area details as far a sunlight is concern.

http://www.gaisma.com/en/location/multan.html

I've installed 2 more panels today now I've 1440watts and my ampere went up to 40A. as per my understanding 1/2 horse power motor takes 373 watts.
so
373 x 3 =1119 watts.I still have leverage of 321 watts.

its is very rare that all three motors start at a same time. there is always one or two minutes delay.

Even I've installed two more batteries of 200Ah each so my total battery bank is now of 1000Ah. After dust all my motors run for more then 90 min each.
so
3x90=270mins

I've an other question for you guys...

I've installed an other system with 4 panels of 140 Watts each. but if i see the ampere that these panels are generating, these are nearly equals to my 240 watt Panels. I just want to know what is the contribution of watts in recharging of batteries as both of the panels are generating same amount of amperes.

[Mike90250]

... as per my understanding 1/2 horse power motor takes 373 watts. .....

In theory, maybe. Only. In actual life, with real motors and loads, my 1/2 pump pulls 1,000 watts from the inverter. If your motor is not fully loaded, it may draw a little less, but I doubt it will be as low as 500w.

[russ]

Look at the operating curves for the pump from the manufacturer - that will give you an indication of the running amps with various outlet conditions.

Mike told you about the startup current

[john p]

Mike 1000 w does seem very high for a 1/2 hp motor. I have a 3/4 hp window aircon and at full running it draws 820w. on that basis 1000 for 1/2 hp seems very high.
I just remembered for a while a long time ago I was running a 1/2 hp powered saw bench off a 800w MSW inverter . Iremember a few times it tripped in starting but was ok after starting. it cut 1/2" plywood sheets ok.

[Usmandj]

my 1/2 pump pulls 1,000 watts from the inverter.

I've checked its ampere, one motor takes more then 6 ampere on starting just for 1 sec but then get stable at 3.71 or 3.72...I am not very much a technical guy neither have experience with electric devices. I am working just to learn new ways to produce energy. So, please dun laugh at my silly questions

My other question still needs an answer that why my 240 watt panel and 140 watt panels is producing same amount of amperes and how what is the contribution of watts in charging the batteries.

[Wy_White_Wolf]

.....My other question still needs an answer that why my 240 watt panel and 140 watt panels is producing same amount of amperes and how what is the contribution of watts in charging the batteries.

What are the panel voltages and how are the wired together? What charge controllers are you using?

We also need to know the total time the motors are running in a day instead of just the "after dusk" time?

One big thing I see missing in all your thoughts is allowing for system inefficencies. Usually that is somewhere around 30% to 50% depending on charge controller and system design. I'm guessing your array needs to be at least twice the size it is now and the battery bank needs to be at least 4 times it's current size to get you though the night and at least 1 cloudy day.

WWW

[Mike90250]

Mike 1000 w does seem very high for a 1/2 hp motor. ...

That's a loaded 240V ac well pump, with no power factor correction. Reading is directly off the XW's control panel. It's real. Tables show about 750w - 1hp, but don't account for PF losses. I think I'd calculated the motor draw, and was expecting to see about 800w pull, but had no # for PF and it's loss. This was 3 years ago when I was pump shopping, and I don't have all that data at hand anymore.

[Usmandj]

What are the panel voltages and how are the wired together? What charge controllers..

Well, m using Phocos charge controller CX40. All panels are connect parallel. It was in series 1st but my vendor suggest me to connect them parallel. are you talking about voltage that they are producing or they are capable of producing?

[Wy_White_Wolf]

...are you talking about voltage that they are producing or they are capable of producing?

What is the VMP rating of the panels? It should be listed in the panels specifications.