Solar panels

[glalt]

I have lost track of solar panel improvements. My wife needed water for her newly planted fruit trees. I already had a DC submersible pump. It needs about 280 wats of power. I thought sure that I would need two panels connected in Parallel. I sent her to buy the most powerful panel the dealer had. I thought sure that 320 watts would be the best they had. She came home with a 450 watt Jinko panel. I had no idea that high of wattage panel was available. Tomorrow I'll connect it and see what happens. I'm betting the pump will run fine, at least during peak sun hours and she needs probably less than a couple hours a day.

I still have a 5,000 watt generator and 1 HP submersible pump That would work but it is a pain in the butt for her starting the generator and keeping gasoline in it.

[marcus1]

Hi Glalt..
Interested to know how your new panel works..
I have a few panels to keep my emergency power supply topped up via a trickle feed to my batteries and supply outdoor garden lights on a continuous basis, but a 450 Watt panel is huge.
May I ask the cost of said panel..????..
Many thanks...Marcus.

[glalt]

Hi Glalt..
Interested to know how your new panel works..
I have a few panels to keep my emergency power supply topped up via a trickle feed to my batteries and supply outdoor garden lights on a continuous basis, but a 450 Watt panel is huge.
May I ask the cost of said panel..????..
Many thanks...Marcus.

She paid 4,000 baht for that panel. I thought it was amazing that the wattage has gone up and the prices have gone down. I'm going to connect it today and I will post how it is working. The panel is the same physical size as the old ones. The dealer told her that those Jinko panels are available up to 600 watt. The panel is directly connected to the pump, as in no batteries needed. The next goal for the solar industry is to come up with batteries for a reasonable price. The future for solar is looking good. Other than one expensive 310 watt panel, all the rest of the seven old panels I have at the house are 250 watt.

[marcus1]

Many thanks glalt for the update on price....Bargain I feel.
I agree as regards battery prices, the last 130 amp wet cell deep cycle battery I bought last year cost around 6000 Baht and that was a bottom of the range battery, I could of spent up to 15000 plus but could not justify the price for what I need.
Solar is the way of the future for sure and hopefully with time batteries will become more affordable.
Thanks again for your update.

[glalt]

I need a buck DC converter to drop the panel voltage from 48.5 volts to 40 volts. A local store says they have one and I'll try it tomorrow. The DC water pump is 24 volt but is MPPT. If the voltage is higher than 45 volts the pump is protected and just won't run. The MPPT controller will run the pump from 18 volts to 45 volts. As a last resort, I can buy a couple cheap car batteries to get 24 volts. Since the batteries won't get discharged very much, they should last for a long time. I already have a spare MPPT charge controller. I'll avoid batteries if possible.

I'm sure the panel is a good one. As a small amount of shadow drops the amperage as expected but not as much as I had thought.

[bluejets]

Galt,
There are these units on Ebay and probably other places as well for around AU$50.00.
https://www.ebay.com.au/itm/DC-Adjusta ... wgZteCsJZ

[glalt]

Apparently the local guy doesn't trust me to connect his device and insists on connecting it himself. If he is willing to come out here, that's up to him. If his device fries it will be his fault. Us farangs are stupid, LOL. I didn't want to order one myself because of the time involved.

[glalt]

Absolutely no sunshine today. Completely clouded over. The guy showed up and connected the Buck device. I was disappointed that he set it at 30 volts. Those devices apparently lower the amperage as well and the voltage. Hopefully the panel has enough wattage in the sun to run the pump, if not, I watched him adjust it and will see if I can get a higher voltage myself.

[Barney]

Absolutely no sunshine today. Completely clouded over. The guy showed up and connected the Buck device. I was disappointed that he set it at 30 volts. Those devices apparently lower the amperage as well and the voltage. Hopefully the panel has enough wattage in the sun to run the pump, if not, I watched him adjust it and will see if I can get a higher voltage myself.

glalt
Did you measure and take any readings today, even though it was cloudy, at the settings he used , input volt and current, output voltage and current?
Stepping the input volts down will usually up the current output.
Just curious why you think the setting at 30 volts, for a 24 volt pump, won’t operate the pump and need changing.


Sent from my iPhone using Tapatalk

[glalt]

The panel voltage itself stays constant sunny or cloudy at 48.5 volts. The buck converter shows 30 volts going out. The amperage varied from 2 to 3 amps. Not enough for the smart pump to work.

I'm no techie for sure but I think that if the voltage goes down, the amperage will follow. I could be wrong. If the pump works OK when the sun is shining, no problem, job completed. I can't check the amperage with the pump connected because it stays at 0. It is a smart pump. I have to short out the positive and negative wires from the panel to check the amperage.

[deankham]

Would the current not go up if the voltage drops, assuming the resistance stays the same?

At least that is what I remember from Ohms law at school.

Interesting discussion though. The out-laws are trying to grow some flowers and vegetables in one of their rice paddies and were asking me about setting up a solar system to run the pump from there adjacent pond.

I was assuming you'd have to charge batteries then run the pump. Did not think about running the pump directly from the solar cell.

[kopkei]

There are these units on Ebay and probably other places as well for around AU$50.00.
maybe better lazada? https://www.lazada.co.th/catalog/?q=dc% ... verter_3_1
as info

[glalt]

We have two solar irrigation systems on two different farms. They were installed professionally. I'm not smart enough to understand how they work. The largest system runs off 6 320 watt panels. They run when there is sun and automatically shut down when there in no sun. The panels and pumps are controlled with a rather large electronic box that has all sorts of circuitry inside. There are no batteries. Both systems work great.

I bought a small rather expensive MPPT pump and one 450 watt panel. The MPPT pump converts extra voltage into usable amperage automatically. The problem with this is that the pump cannot operate with more than 45 volts. The pump protects itself from too low or too high voltage. I had thought I could get by with that panel putting out a constant 48.5 volts. The pump is apparently smart enough that it refuses to work with 48.5 volts. That's why I need to reduce the panel voltage. The pump needs 284 watts to run. I never got past the voltage times amps formula, thus by reducing the voltage, I lose wattage. Today looks sunny so I'll find out if 30 volts from the buck controller is enough. If it does not work with 30 volts, I will try to adjust the buck converter to put out more voltage. I want to avoid using batteries.

[glalt]

Help! I am absolutely totally baffled. Checking the panel, it is putting out 48.5 volts. Checking the amperage with my FLUKE multi meter, it says 9 amps. I reduced the buck voltage to 24 volts and no success. I found that the maximum voltage that I can get from the 20 amp buck converter is 30 volts. No luck there either. I decided that the pump probably had a problem. I took it home and connected it to 24 volts of batteries. The pump runs fine. The question is if the pump runs on 24 volts of batteries, why won't it run on 24 volts from the buck converter?

[deankham]

What current does the pump need to run?

I've had issues in the past with portable battery packs where I can run things like computers, lights, charge phones, but it is not able to run a vaccum cleaner, due to it not being able to deliver enough current to get the motor running.

Hopefully someone has a better idea of these things and can give some advice.

[glalt]

This thing is making me crazier than I already am. I went back and turned on the panel and the pump runs. It is drawing about 5.5 amps. The panel is putting out about 8 amps at this time of day. I shut it off and it wouldn't start again. I left it alone for about 20 minutes, turned the panel back on and it started running. If it works that way again tomorrow, I'll hook the hoses back on and let the wife give it a good run. The only thing I can think of is the smart pump has a timer built in to protect it for some unknown reason.

[pal52]

it sounds to me the panel is on the limit for the starting current for the pump.
Even a smart pump needs more current for starting under load.
If it shows running at 5.5 Amps it needs more to initially start under load.
Try turning off the water inlet to the pump so it does not start under load then turn the water inlet back on

[glalt]

That's one more thing to try. It is a submersible and under water all the time but I could pull it out of the water to see if it will start and then put it back under water if it starts to run.

My wife knows EVERYTHING and (really knows nothing) wants me to call the professionals who installed the the two large systems. I'm stubborn and insist on getting the small system up and running myself.

[bluejets]

If the motor will not run it's simply not enough power from the panel.
Buck converters will output the set voltage constant within the input range.
Current draw is wholly dependant on the motor itself.
The panel ability to provide 9 amp under short circuit may not be an indicator as the voltage drops to zero.
Cannot comment on your converter as no detail provided.
The one I linked to ( fixed the link, sorry) has specs listed and for an input of between 20 and 70 vdc it will output the set level.
This is maintained up to a max of 30A load and/or 800w.
Have no detail on the motor but depending on protection the motor may or may not have, it might be wise to use some type of low power input cut-out.


Model: AP-D5830A
Input Voltage: DC20V-70V
Input Current: 20A maximum
Output Voltage: DC2.5V-58V (Adjustable)
Output Current: 30A maximum
Output Power: 800W maximum
Conversion Efficiency: 92-96% (Efficiency and Output Voltage and Current Input Related).
Operating Temperature: -20 to 50℃.

[glalt]

I'm beginning to think that the 384 baht buck converter is not up to the job. It does appear that the motor starting surge is just too much for the cheap converter. If the pump starts today with full sun, I'm going to call it good enough for now and order a higher quality converter. Since the existing converter will only output 30 volts, it is suspect.