The Alternative Energy Thread - Generators, Solar, UPS, Wind

[Nabs]

Checked prices a few months ago, it was around 50K for 3.2 KW and 75K for 5.2 KW. Prices must have gone up now considering rupee devaluation.

[masoodkt1]

Dear Brother
I do agree with you not to go 500vDC it is very dangerous . Are you suggesting that I should restrict to the minimum [ i.e. 120 volt DC ]. Pl clarify
Thanks

[Nabs]

I don't have much experience in this field, been doing research for my own DIY project for past few months, so don't consider my opinion as an expert opinion.
I have also considered buying VMIII model. I haven't decided on exact volts yet, but I will try to keep operating solar panel volts within 150-180 range for this particular model.

Do install DC breakers as well, I got them from AliExpress.

[talhawaleed]

Thank you for Sharing the Above Spec related to inverter as was very helpful.

Advice No 1:

1. Consider buying 250 Watt Ploy type solar panels as first they are cheap, secondly it’s easy to find and later much easier to expand your system size. Perform a short circuit current and open circuit Voltage test on solar panels before buying. Issue with 300watt solar panels is, that they are not readily available in market, once you want to expand the size of your system, then you cannot do so without buying a solar panel of configuration which you bought earlier as you have to stick later with what you bought the first time.

2. Issue with 250Watt mono type solar panels is, that they have different VOC’s and if you are not expert then you can mess up with things and buy solar panels of different VOC which may cause reduction in solar panels output or resizing of an array.

3. Since maximum VOC of your inverter as per specs shared are 500Volts DC so with 250 watt poly type solar panels with maximum voc of 37 volts, you should be able to connect 13 solar panels in series to make it a total 481Volts VOC system which is under the specs. Which means, you will be able to connect 3250 watt solar panels in one string with this inverter.

4. Remember, use proper MC4 connectors, never use AC circuit breakers instead of DC circuit breakers. Electricians and installers tries to use AC circuit breakers instead of DC as they are cheap and end result is, that you end up loosing all your energy in these circuit breakers in form of heat.

For example, if your solar panels are generating 2500 watts of power but after passing through AC circuit break, you may end up getting 500Watt as rest 2000 watt will be lost in AC circuit breakers. That is a sort of losses you encounter once you use wrong circuit breakers.

1. Buy two rolls of 6mm flexible cables in black and red and never compromise on quality of these cables and wire positive with red and negative with black. Tell the installer that you don’t want to see any joints into these cables. Pay special attention to as what he is doing as most of them don’t know they job properly and try to compromise on equipment and quality just to increase their profits.

2. Study the thread “ Maintaining UPS/Car batteries” install the batteries using electrolyte prepared with de-ionized water.

3. I would recommend four lead acid batteries of phoenix UGS 220 prepared with de-ionized water.

4. Before commissioning the system, consult me to input the proper variables or how to program the inverter as otherwise results will be same that it will kill your batteries very quickly if charging rates and cut off voltages are not properly programmed. Again consult Maintaining/UPS car batteries thread and variables discussed are applicable on solar inverters as well. i dont expect any installer has proper information as how to adjust the specs of these inverters. I have seen many and witnessed all of them screwing with customers investment.

P.S: kindly share the detail data sheet of this inverter so that i may verify the specs properly to check if VOC is 500Volts or not and other parameters.

[talhawaleed]

This inverter has an mppt and VOC range, if inverter will be below minimum VOC then system will never produce any power. System is built so that you may connect 13 solar panels of 250Watt with voc of 37 volts in series to make it a 481 Volts VOC system. remember, if you are a novice then 500Volts is very dangerous for you. Proper installer uses proper DC circuit breakers and DC surge arr esters and provides a way to disconnect the array once someone intends to perform a maintenance service on solar panels. do the installation properly, it is very safe for someone who knows as how to deal with the system or someone who knows his work.

Remember, their are vast number of advantages related to using a system with higher VOC. Inverters which offers a higher VOC are expensive as they are desirable and further, you must also study the low voltage power losses of a system and recommended wiring thickness for a PV system with certain VOC voltage and distance of inverter from solar panels. All makes a huge difference in what you are suppose to harvest as compared to what you are getting.

This is where everyone is making a mistake.

[talhawaleed]

sorry, i noticed as someone has already shared the axpert vm 111 solar inverter spec. this is a very good inverter with 4000watt solar charge controller.

which means, either you can connect 13 solar panels of 250watt in series to make it a 481 Volts VOC system with 3250 Watt solar array

or

you may connect 16 solar panels with this inverter to make it a 4000Watt solar system by connecting 8 solar panels of 250 watt with VOC 37 volts in series and make an identical array and connect two arrays in parallel with the inverter.

[masoodkt1]

I did see this very late. At first I am planing to erect the solar system by myself. For connecting the 16 Nos of solar panels I will prefer to use 2 arrays connected in parallel with each having 8 individual panels of the array connected in series so that the maximum DC voltage will remain 8x37 = 296 volts. Still a high value so extra safety precautions has to be taken. Thinking to connect a normal open switch after 4 panels of the array of 8 panels in series but I have to check the line loss due to presence of such switch. It will be better if I can find a switch with high ampere capacity say 20amp which is high value as the solar panel of a single array will be providing almost 7amp current Will connect 2 pole 20A DC MCB after the parallel connections of the 2 arrays, looking for such item could not find yet. I think I will have to get it from AliExpress. The only fear is that our custom department is very EEMANDAR so I am afraid to loose such a small item,
The fabrication of a variable deflection type panel stand is still an issue. Looking for a SAMAJHDAR steel worker to carry out a clean job.

[nowshad1]

Dear Mr. Talha
I ve 3KW inverter (Axpert VM II) connected with 6 panels (330W, 46.6Voc, 9.29Isc each) in series, panel data sheet is attached. The system has 2 tabular batteries of 200 Ah each. Panels are at 28-30 ft away from inverter connected with 10mm DC wire. The system voltage is often good (240-250V) as appearing on inverter but current is too low resulting in less power.
Only in hot weather (70 deg tilt) on peak hours input power comes around 1300W for around 2 hours, for remaining day it is below 700W. In cold weather (40 deg tilt), voltage is above 200V in peak hours but current fluctuates between 1 to 0 Amp resulting less power. The system is in Mingora.
Please advise how to increase current to get more power

[capsat]

please correct me if i understand about your system specs correctly.

1. what is inverter DC voltage input rating - ( VM II 3000 is 24 volt driven )
2. what is connected battery voltage. 12V most likely
3. batteries are connected in series or parallel ?

46.6 vDC x 6 = 279.6 VDC (as mentioned connected in series)
330 w x 6 = 1980 watts

what are peak sunlight hours from sunrise to sunset in your area. - connect a digital multimeter over the solar panel connector and check for the peak voltage

2ndly you may need armored DC cable between panel & inverter slot to manage severe weather conditions.

in ormara at a facility we use 10 mm dc cable drop 15 meter to connect inverter indoor still voltage drop is approx 5%.

my assessment: the connection between panels & inverter shall be improved wrapped in corrugated conduit to protect from severe weather or changed to military grade DC cable.

[nowshad1]

Thanks for the reply;
It is 24V inveter, 2 batteries of 12V are connected in series. Peak hours in Summer around 5 hours, while in winter it is around 3 hours. Panels are connected with each others though their own wires (wires with panels). While panels are connected with inverter through 10mm DC wire. This wire is protected inPVC pipe but exposed on roof to sunlight.
The problem is that in winter aound 11 am, the voltages is plus 200V while current fluctuates from 1 to 0, having no or small Wattage.

[capsat]

sir when the weather is better and you can access the panels. Check panel connections

most likely problem is panels inter-connection recheck all, if it is done by twisting and nitto tape. open all 1 by 1 & check. when redoing connections please use soldering iron & heat shrink tube. That will ensure smooth flow from all panels.

i reckon the current from panels is not enough to provide Juice (as in voltage & amps) to run any appliances.

allow me to suggest, wrap old baby blankets below the terminal area around the batteries to avoid freezing

[talhawaleed]

As far as i remember, maximum Voc which your inverter accepts is 500Volts DC. If you read the specs from your inverter, the VOC voltage of your system comes out to be 46.6 * 6=279.6 Volts, read again, that not does falls even close to MPPT tracker range. You need to least add four more solar panels in series with the current system.

Further tilt angle for Winters is around 50 degrees pointing towards south and during summers is roughly 20 degrees. All year angle is 33 degrees if your mounts does not have a flexibility to change the angles.

further you can use 6mm DC wires, that should not have a joint inside, use proper MC4 connectors as that could also be a reason for a limited current.

distance is not mostly an issue with high Voltage systems.

[Atif_Jawaid]

Hello Talha bro my inverter battery ki dead which was purchased in 2017 march .... niw i decided to purchase the Phonex tubbler battery ... abd also want to upgrade my system from 900 watts inverter to 3.2 kva vmiii inverter
Kindly recommend the inverter and battery both

In inverter
Tesla vmiii
Inverex vmiii

In battery
Phonex tubbler
Inverex tubbler

Your input in this ragard is highly accepted
Thank u

[talhawaleed]

I was trying to look for spec of these inverters, like in case below,

https://w11stop.com/files/axpert/tesla-vm-iii-3kw.pdf

all three you have mentioned are developed by voltronic power and i think these are same products and models developed by Voltronic power and being sold under difference names in Paksistan. I maybe wrong as i could not see the data sheet online for remaining two.

you would be able to add solar panels with these inverters at any stage if you like so its a good thinking you are upgrading from ordinary UPS to off-grid solar inverters. specs of tesla are good and recommended. if its a same product then buy the one which has a better after sale service and repair centers based in your city.

yet again i could not read the specs of inverex tabular batteries. Pheonix tabular batteries are also good.

P.S: ok, data sheet of axpert vm iii is also posted above and its a same product as tesla vm iii

[drshaheer1]

Dear Talha
I was surfing sites to see where we messed up our solar system.
We have just shifted to our new home in Ghauri Town. You might know that ghuari Town residents are not allowed wapda light. Well, we got installed solar system as described here
1. Inverex aerox 5.2 KW
2. 10 inverex solar panels 325 watts each
3. 4 Phoenix batteries UGLT-200 (150 AH each)
I don't know much about electricity, but I think all the panels are connected in parallel mode as they produce 4500 watts.
Problem which we are facing is that
1.
During the day, if switch on any appliance of 1000+watts, the system draws power from solar plus batteries, eating up batteries. Where as we have installed capacity of 3200+ watts.
2. The system shows batteries as 100% charged. However, when night falls, the batteries drain before the sun comes, and that too at negligible load. Yesterday, our load, as I saw in LCD panel, was around 200 watts. at that time we had switched on a few LED bulbs and tube lights. nothing more than this. From 10pm onward, every thing was switched off, and batteries were showing 56% charge. However at 5 am in morning, the batteries drained to zero. Today, due to rain, we could not light up anything until 2 pm. After 2 pm, the charging started and by the sun set, the batteries were 50% charged. With only led bulbs, about 100 watts of load, the batteries drained at 9 pm and we were sitting in darkness. I don't why the system quickly charges and discharges the batteries. The setting of inverter and solar charger are as per the setting available in Inverex AEROX 5.2 manual.
Can you figure out problem in our system and help us in getting it fixed, please

[anon36782927]

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[mani9999]

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[drshaheer1]

we are not concerned about battery drain during day. normally, before sun sets, the battery is charged 100%, showing 56 volts, as the setting for fully charged battery is set to be 56 V. but during the night, at minimal load of 100-200 watts, the batteries drain to zero.
yes, we can modify the panel setting, but it would solve the problem of day time running. which is not a concern, as today, due to bright light, it supported 2200 watts without taking anything from battery. my only concern is about battery back up time. how to increase it and how to diagnose the underlying problem. the system show batteries as 100% charged in about 2 hours and drains in almost same time.

[drshaheer1]

you might got me wrong, or i mightn't have explained well. the panels produce 450 volts @ 3250 watts. I don't know if they are connected in parallel or in series, but they produce 450 V DC as shown in LCD panel and app.

[drshaheer1]

can you let me know what were your cut off before and what cut offs you have set now? any improvement in back up?