சுதர்சன் சாந்தியப்பன்

Calculating Ampere-Hour AH requirement

sudarsun — Sun, 20 May 2012 17:07:21 +0000

We are in a sorry state of erratic and long power cuts, due to shortage of power production by the nation against the increasing load conditions. To add fuel to this fire, a wholesome of abled people putting their hard earned money on to power backup solutions, where they store the power during power availability and consume the stored power during outage. On the whole, this looks simple and elegant, but this is not doing any good to the state which shed’s power at different locations to balance against shortage in power production. So theoretically, in a place where a family consumed 1kW per hour, would consume 2.5kW per hour during power availability and generate 1kW during power outage. Yes, you are right. The equation is not balanced, because atleast 30-50% of power is wasted during the backup-retrieve cycle.

Ok, coming to the point. What is the solution? Go for harvesting solar power, availability in abundance and omni present. And most interestingly, rationed to perfection based on the amount of un-shadowed free space a family has. I will just limit this article to calculating the battery provisioning when you go for a solar-inverter solution. Let’s say I want to have power backup for 2 hours and my load is 1kW. What would be ideal inverter solution for this load condition?

Normal Power	1000 Watts
Power Factor	80 %
Inverter Rating	1000W/80% = 1250 VA
Number of Backup Hours	2 Hours
Energy To be Stored	1000×2=2000Wh
Inverter Battery Voltage	24VDC
Battery Amp-Hours	2000/24=83AH
Add @30% AH Margin	831.3=108AH~100AH*

So, for this configuration you need a 1250VA Inverter with 2x12v 100Ah battery bank. Let me explain the calculation,

Power Factor: In AC (alternating current), Power = Voltage x Current x Power factor unlike in DC, Wattage = Voltage x Current. Power factor is measure as the cosine of the phase angle between voltage waveform and current waveform. For home use, the power factor will be <1 and >0. When PF is lower, the efficiency of the system suffers a lot.
Battery Voltage: For 1250VA inverter system, the choice of battery bank is 24V instead of 12V. The rationale for this choice is to limit the current from the battery to the inverter unit. If you use a 12V battery bank, for full load there will be a current of 1250/12=104A following from the battery to the inverter. You may have noticed the thickness of the battery wire be very high. Despite that the power loss on those wires when the current is 100A, would be much higher than it is with 50A on a 24v system. For a 24v system, the peak current shall be 1250/24=52A. At 100A, with 1m cable between battery and inverter, the resistance should be 0.00001 ohms.
AH Margin: Although battery AH rating says considering absolutely draining of the battery, we will not be able to do that for normal SMF battery. Meaning, we should not discharge below 10V and likewise should not charge beyond 13.6V per 12v battery. In order for the AH rating to work, we have to apply atleast 20-30% margin.

பெரிதழல் மனமே..

sudarsun — Mon, 07 May 2012 18:26:55 +0000

ஊற்றுநீர் பெருக்கி தாகம் தனித்த,
கீற்றுடை பெருமான் நீன் கமலம்,
போற்றிப் பெரிதுவக்கும் எண் பனித்த,
ஏற்றிக் பெரிதழல் ஆரும் மனமே..

பொருள்: ஞானத்தேடல் எனும் தாகத்தை தனிக்க ஊற்றுநீராக உள்ளத்தே ஒளியை பெருக்கிய கருணை கீற்றுடைய எம்மான் இறைவன், உன் பத்ம பாதத்தை எண்ணங்களை பனித்து எண்ணங்களால் எப்போது தொழுது பேரின்பம் கொள்ளுமே, இச்சையினால் மோகத்தீயை பெருக்கி அவ்விச்சையினாலே ஆரும் மாயமனம்.

Maha rajbhog

sudarsun — Fri, 20 Apr 2012 10:26:18 +0000

Vanilla Chocochips

sudarsun — Sun, 15 Apr 2012 05:17:50 +0000

Butter Pecan Ballet

sudarsun — Wed, 04 Apr 2012 10:33:55 +0000

Solar Panel contd.

sudarsun — Mon, 26 Mar 2012 17:24:21 +0000

Installation of additional 130Wp is in place now to make the power plant worth 300Wp. The new panel added has a spec of 17Vmp against the 16.4Vpm of the 170Wp panel group. So eventually I may be losing some power. I am using 10sqmm copper cable to reduce the transmission losses. I had measured the impedance of the cable to 1mΩ. So at 20A, I will be losing about 0.4W only. But the cost of this wire is around 70Rs/m. I am able to produce about 221W during the mid day, and about 170W around 10AM. Upon little bit of investigation, it is found that the solar panels shell out less power at increased temperature. It is also said that at 60-70°C, the efficiency is around 70%, which is matching with my measurements. So, thinking about a water cooling solution; basically augmenting a solar water heating solution with the solar panel to establish double benefits. Every day with the solar panels is a day of new learning and I am enjoying it.

The Cozy Dog

sudarsun — Mon, 26 Mar 2012 17:19:29 +0000

Scotch and Brownie

sudarsun — Mon, 26 Mar 2012 17:18:55 +0000

Caribbean Almond Fudge

sudarsun — Sat, 17 Mar 2012 19:53:03 +0000

Caribbean Delight has become my another favorite chocolate flavor. Where were these flavor before? How did Ibaco discover these? I am so thrilled that very good flavors are coming out mesmerizing my lust for icecreams. With chocolate fudge and chips the taste improvised to a greater horizon. And a chocolate brownie as a bonus was impressive around the apex. Cashew and Almond nuts added their contribution to my slavery. Overall, I am so Ibaco’d !

Butterscotch Bliss

sudarsun — Sat, 17 Mar 2012 19:52:01 +0000

Yummy, my favorite Butterscotch in a different package at Ibaco. The moment I start thinking about butterscotch, my eyes go wide and desire for icecream goes wild. Here comes the updated version of Butterscotch from Ibaco enchanted by butterscotch sauce and chocolate fudge, sprinkled with chocolate chips and gems. Awesome.