Syed Jahanzaib Personal Blog to Share Knowledge !

May 7, 2021

5kw Hybrid Solar System – Short Notes

Filed under: Solar System — Tags: , , , , , — Syed Jahanzaib / Pinochio~:) @ 12:46 PM

Dueto daily long hours loadshedding, highest inflation increasing day by day & its huge impact on electricity bill,  I finally decided to acquire a 5kw Hybrid Solar system to power my house. Since I was tight in budget therefore I acquired some low budget equipment’s in some sections (like battery & inverter).

Following are few short notes for the system I have experienced so far, its pros/cons & general stats sharing. I got this 5kw system installed from a local solar installer in last April 2021 with aim in mind to reduce my electricity bill & to avoid daily 6-8 hours electricity load shedding.

Details of system is as follows …

  • Tesla 5kw Inverter (PK) – HLE 2020 Model / QTY: 1
  • 445w Longi Solar Mono crystalline PERC solar panels / QTY: 10 (Total 4450 Watts) , Connected in SERIES
  • Raised mounted structure (consists on steel garters)
  • 4mm DC wire from panels to the inverter (length was around 50 feet + )
  • Safety Box: Including Batteries/Panel DC Breakers, Utility IN/OUT AC Breakers (TO/From Inverter) , Tomzen 3in1 AC Volt/Amp Protector
  • Battery Parameters Settings: (its for Phoenix Tall Tubular Acid Batteries 185ah, QTY: 04 )
    * Source Priority: SBU (SOLAR BATTERY UTILITY)
    * Battery Charge Priority: SOLAR ONLY !
    * Battery Type: USER
    * Battery Max charge Volts …
    – CCV: 58.4
    – FCV: 54.0
    * Battery Cut-off Volts: 42.0 (This is the point where inverter will stop using batteries & will shutdown if utility line is absent. I would suggest to set it at 44 minimum)
    – Battery Recharge Volts: 46.0 (This is a point where Inverter will stop discharging/using batteries, but if the utility power is not present it will keep using till Cut-Off values that is 42.0 in our case). Also this is the value, on which Output-2 will be turned off if the system is running on batteries to support extra backup time for output-1 load (critical load). set it according to your requirements by looking at attached battery chart.
    – Battery Re-discharge Volts: 50.0 (This is the value on which system will start reusing batteries if there is NO utility or lesser solar/utility input)
    * Battery Max Charge current: 20 amps (this is for 4x185ah acid tall tubular batteries)

See the Batteries table 

In summer, the system starts producing electricity early in the morning & onwards. After  8am I can see around 1000+ watts & gradually increased as sun rises. I have high buildings behind/beside my roof therefore it takes some times for the sun light to reach at panels. After 11am it starts its full production that is around 3000+ watts in average. In peak I have observed upto 3500 watts PV output as well in peak.

 


PROS:

In general , electricity consumption at my house remains under 1000 watts. Probably I have to add few extra items to get full benefits of this system including AC’s.

No Loadshedding: After installing this system , I never had to worry about daily long loadshedding. Most of the time I even dont know when the utility goes off (loadshedding) , I realize about the utility failure/absence when I hear the loud generators noises from around the neighborhood. In sunny Time, I am able to run full house load including ground + 1st floor, Tv, 2 fridges, 6-7 Ceiling AC.DC Fans, 3 water pumps, ironing & every other electrical peripherals. Of course we take precautions to not operate all the heavy equipment (like 2 HP water Pump, 1 HP submersible boring pump & ironing) simultaneously, thats some management we have to take care of.

Monthly Electricity Bill Reduction: I observe around 45-50 % of reduction in monthly units consumption.

Energy Saving Appliances: After replacing few of electrical appliances with inverter based technology devices, I see noticeable reduction in power consumption. This mainly includes inverter Fridge, & above all, ac/dc inverter Ceiling Fans (which we have lots of). This really helped in late night hours as well either on utility or battery backup. 

WEB/Mobile Access for viewing usage stats:

Tesla have provided nice web base portal to access the inverter usage stats. Also it have mobile app called TESLA LIVE as well. Screenshots attached.

CONS:

Household Appliance Usage Management: After installing the solar system. You really have to do a lot of your household electrical appliances usage very carefully. Example you should be using all the heavy load that includes, water pumps, ironing, laundry machines etc at peak hours. & in off peak time, you should use minimum electrical devices to save the power (utility & batteries both)

Batteries Maintenance: I choose lead acid batteries (tall tubular) which have shorten life cycles, also they requires routine maintenance of battery acid refilling every 1-2 months (depends on usage & weather). Also it is better to place them at Dry & cool place (which I unfortunately dont have). They requires high time to recharge & they gets discharge quickly on heavy load. Also you need to set  suitable batteries parameters at inverter settings to provide you with the required backup while keeping the batteries life healthy.

Inverter Maintenance:

This inverter model have 2 dust filters (right & left sides). They requires frequent cleaning on a weekly or every 15 days basis. Every time I pull them out, they are always full of dust. This inverter have 2 fans as well at bottom side. It is recommended that using blower device, you clean the internal dust as well on every other quarter. (This requires some precautions like completely turn off the inverter operations, removal of lower protection cover box, wearing safety equipment as well.)

Panel Maintenance: (P.I.T.—)

In our area, we receive lot of Dust in about every season,(In Karachi, we are used to bear hot weather for about 8-9 months a year). Dueto dusty seasons, I have to clean the panel every 2 weeks. Even in 2 weeks, the panels usually covered in dust totally. I acquired Hyundai Water Pressure Pump (105 bar) & it helps in cleaning, but still, it requires efforts to clean the panel this frequent & dueto raised structure and no proper place dueto poor design of fitting & weak roof ,it sometimes annoys a lot.

4500 watts of panels with raised mounting customized structure

Some tips for Battery Settings

After a month of battery less operation, It came to my knowledge that even in broad day light, if your home load suddenly exceeds (like 2Hp motor start torque) then the inverter gets trip because it doesnt have utility line or batteries to support the additional sudden jerk, thus it trip itself. therefore I added 4 Tall tubular batteries (which is cheaper as compared to Lithium batteries) to support the inverter operations in load shedding time as well. I selected Phoenix tall tubular batteries which were more like a budgetary solution. Model was

Phoenix Tall tubular Power Cube Series Mode: Tx1800 – 185ah / QTY: 4


Life Expectancy of Good Quality Tall Tubular Batteries

Charge Cycles [at 80% DOD]

One charge cycle is equal to discharging a fully charged battery up to 80% of its capacity and then fully charging it again. The charge cycle for tubular battery is around 800-1400. However, a low DOD [depth of discharge] increase the charge cycles of a battery. Therefore I would recommend that you donot discharge less then 50% , so in my case for 48v  (4 batteries) , it would be around 48 / 48.5  +/-The actual charge cycles may differ from manufacturer to manufacturer

Life Expectancy

There are lots of conditions like ambient temperature, depth of discharge and number of charge cycles that affect the life expectancy of a battery. However, in identical conditions, tubular batteries have a higher life expectancy than flat batteries.


Solar Parameters Settings for minimizing Utility consumption :

  • Saving Utility Units Consumption:

If you have no/less loadshedding, its better to utilize battery power at high level to save utility units/bill consumption. But using battery at high level will reduce your battery life (particularly with normal lead acid battery)

  • Charging batteries via SOLAR Only ***

If you want to charge the batteries using only SOLAR power (recommended) , then set the charging source priority to **ONLY SOL**

  • Output Source Priority ***

Set this option to SBU , which means that it will first use SOLAR power, if its fail or less, then it will switch to batteries, if batteries are discharged/not useable, then it will switch to Utility. This is is best setting if your want to cutoff utility usage when Solar & Batteries power are available. If your area experience high amount of loadshedding, then its better to use S-U-B , which means batteries will be used as last resort thus you maybe able to use the battery power in absence of utility.


Battery Utilization Chart (Single Battery)

You may multiply settings by number of batteries you have …


Inverter Restart Process.

At some occasions (example Error: Soft Bus Fail), I need to completly restart the inverter (Cold restart).

I assume you must have the safety box including input/output breakers for batteries, solar, grid etc.

Steps to Reboot solar Inverter/UPS
———————————–

** Turning OFF

1) Turn OFF inverter/UPS button. its black small button at right downside of UPS/Inverter.
2) Turn OFF ALL breakers including Solar / Battery / In & OUT (IN is utility Line , OUT is power going to home).

This way when UPS will not have any source of current input including solar, utility & battery, it will eventually turn off completely.

** Turning ON (Always wait few seconds between each action)

3) Turn on the (I) IN AC breaker (Its as grid power input for inverter)
4) Turn ON the UPS/Inverter Button 
5) Turn ON the (S) Solar DC Breaker (Solar Panel power going to inverter)
6) Turn ON the (B) Battery DC Breaker (Batteries power going to inverter)
7) Turn ON the (O) Output AC Breaker (Inverter Output going to your house)


Some Final Thoughts on Local Tesla HLE 202 0 Model:

TESLA is a good cost effective (value for money) solution only. It do have software glitches. Mobile app is not 100% accurate particular in POWER STATS section & battery charging is also incorrectly shown even if battery is full. The inverter doesn’t let you know how much power is being drawn from the GRID, you have to perform manual calculation to see how much power is being used by battery or grid. (For GRID usage, I have installed 3in1 voltage protect which does shows the current AMPS usage along with total used data.

** The worst part of TESLA is lac of support. if you ever in need of principle support you will be in deep shit (my experience is for KHI).

Next time I would prefer to purchase ip65 capable inverter which is essential for Dusty environment like Karachi.

 

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