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Old 3rd November 2017, 07:58   #1096
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Originally Posted by aim120 View Post
The newer battery beside it being a higher capacity means it will have a higher voltage then older batteries.
All the other batteries seem to be maintaining the threshold voltage of close to 14v at the moment. So what are my options, do i put a new 80ah battery or something else?
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Old 3rd November 2017, 13:27   #1097
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I am getting overall feedback that either the 80 ah series is not in stock or has been discontinued. In this case, if i put the 100 ah, the only issue is the battery will not be optimally charged, therefore reducing the life of the battery, is it not?
For a 80AH Lead-acid battery, the charging current may well be 8 A (A 10 percent charge rate is equal to 0.1C) and for a 100 AH it will be 10 A. This by itself will not be an issue about the life of the battery.

In an ideal world, you replace all the batteries when they have reached their useful service period. But in your case, your cost of replacing all 22 batteries will be quite high. So if you are sure that all the remaining batteries are 'normal' , then go ahead and replace the failed battery with the 100 AH.
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Old 3rd November 2017, 13:55   #1098
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then go ahead and replace the failed battery with the 100 AH.
Thank you Sir, just placed an order for this unit: http://www.batterywale.com/batterywa...aka/Bangalore/
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Old 17th November 2017, 09:32   #1099
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Things are working well and back in order now... Many thanks guys!
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Old 20th November 2017, 10:26   #1100
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Default Re: Inverter Batteries

I was a bit concerned at the high power bills and narrowed my suspicions to 2 appliances at home that remain switched on 24/7.

a) The inverter
b) The fridge

So I thought I'd do some an investigation into exactly how much power my Su-Kam 1500 VA sine wave inverter consumes. The inverter is attached to two Exide IT750 200 AH batteries.

I used a Fluke 374 True RMS AC/DC clamp meter to measure the AC current drawn and voltage thereby calculating the consumption.

a) When charging batteries, battery at >70-80% SOC (assumed, they were disconnected for a week) - 1.7-1.8A, 234 VAC 50 Hz

b) After leaving the system on overnight, the batteries were fully charged. When float charging, with the battery at 100% SOC - 0.9-1.3A, 235 VAC 50 Hz

So, in both cases, the inverter consumes 421W when bulk/absorption charging and between 211-306W when float charging.

At the current consumption slab & MSEB's price/unit (₹9.50 incl. taxes), that translates to a consumption of approx ₹4/hour @ bulk/absorption charge and approx. ₹2.5/hr (median of wattage taken) when float charging.

In a nutshell, at float charge this inverter system costs me around ₹60/day to run! YIKES! I think I need to get a solar panel to charge these batteries!

The fridge is one of those "smart-alec" inverter models with light sensors and other gimmicks. It's difficult to gauge its power consumption because compressor speed varies. But it is rated for ~1.6A @ 230V so max consumption should be approx 370W at full throttle.

PS - Is anybody using solar power to charge inverter batteries? Would appreciate some inputs.

Last edited by R2D2 : 20th November 2017 at 10:30. Reason: PS
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Old 20th November 2017, 14:55   #1101
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Originally Posted by R2D2 View Post
I was a bit concerned at the high power bills and narrowed my suspicions to 2 appliances at home that remain switched on 24/7.

a) The inverter
b) The fridge

So I thought I'd do some an investigation into exactly how much power my Su-Kam 1500 VA sine wave inverter consumes. The inverter is attached to two Exide IT750 200 AH batteries....



So, in both cases, the inverter consumes 421W when bulk/absorption charging and between 211-306W when float charging.


In a nutshell, at float charge this inverter system costs me around ₹60/day to run! YIKES! I think I need to get a solar panel to charge these batteries!


PS - Is anybody using solar power to charge inverter batteries? Would appreciate some inputs.
I have a 3 KVA UPS which is connected to a local server. It might be of interest here to compare our readings. When the UPS is running with an always-on load (a server with router, switch which together consume about 100 VA typically) it consumes about 135 VA to 160 VA depending upon the temperature ( let us ignore for now the variation due to the extra fans brought into play inside the UPS ). When the load is switched off, the no-load quiescent current is about 0.18 A (40 VA). Apparently my UPS is not causing any dent in the power bill.

But I noticed that as the battery is reaching the end of its useful life, the consumption sky rockets. So it stands to reason that an older battery takes more current and it has a raised temperature as well.

I have asked for Solar cells and a 48V charger for my batteries from a Coimbatore based company who gave a quote for around 25k for a 500 VA set up. I didn't want a full 3 KVA set up as it would cost several hundred thousands.
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Old 20th November 2017, 16:13   #1102
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I have a 3 KVA UPS which is connected to a local server. It might be of interest here to compare our readings. When the UPS is running with an always-on load (a server with router, switch which together consume about 100 VA typically) it consumes about 135 VA to 160 VA depending upon the temperature ( let us ignore for now the variation due to the extra fans brought into play inside the UPS ). When the load is switched off, the no-load quiescent current is about 0.18 A (40 VA). Apparently my UPS is not causing any dent in the power bill.
Wow! That's way different from my situation. Hope you don't mind me asking for some clarifications:

a) Is the load measured on the DC side or AC side of the UPS/inverter? I measured it at the AC end i.e. the live wire going to the inverter input when mains power is on. The same live wire serves as a power input to the home fan/lighting MCBs when the mains fails.

b) Is your UPS a line interactive or an on-line UPS?

c) Which brand & model is it?

Quote:
But I noticed that as the battery is reaching the end of its useful life, the consumption sky rockets. So it stands to reason that an older battery takes more current and it has a raised temperature as well.
Yes, that thought did cross my mind as the batteries are around 4 years and 8 months old. But they don't give a single problem. Each water top up lasts exactly 4 months at which the floats drop to the Min mark. Each cell consumes water equally. The expected life for the batteries is 6-8 years if maintained properly, as I do.

In light of this, replacing the batteries is not required just yet and @ Rs 40K for the pair I hesitate to replace them at this point in time.

Quote:
I have asked for Solar cells and a 48V charger for my batteries from a Coimbatore based company who gave a quote for around 25k for a 500 VA set up. I didn't want a full 3 KVA set up as it would cost several hundred thousands.
MH has expensive electricity among many other things. And a unit cost is only creeping upwards. We are paying for the SEB's inefficiencies, T&D losses, power thefts, among other things.

I'll need to seriously consider solar panels because the inverter is consuming more than I expected. The next "upgrade" will be a solar inverter for sure.
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Old 20th November 2017, 18:31   #1103
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Default Re: Inverter Batteries

An update with measurements at DC cables/wires.

DC amps (battery cables) - 0.3A which means the batteries are at 100% SOC and being float charged. Voltage 27.66 VDC

Voltage @ battery posts/terminals; Battery A 13.80 and Battery B 13.86

It's the AC amps that denote power consumption. It represents the the "hidden" cost of using inverters, something that users normally overlook.
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Old 21st November 2017, 09:54   #1104
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Wow! That's way different from my situation. Hope you don't mind me asking for some clarifications:

a) Is the load measured on the DC side or AC side of the UPS/inverter? I measured it at the AC end i.e. the live wire going to the inverter input when mains power is on. The same live wire serves as a power input to the home fan/lighting MCBs when the mains fails.

b) Is your UPS a line interactive or an on-line UPS?

c) Which brand & model is it?



Yes, that thought did cross my mind as the batteries are around 4 years and 8 months old. But they don't give a single problem. Each water top up lasts exactly 4 months at which the floats drop to the Min mark. Each cell consumes water equally. The expected life for the batteries is 6-8 years if maintained properly, as I do.

In light of this, replacing the batteries is not required just yet and @ Rs 40K for the pair I hesitate to replace them at this point in time.


I'll need to seriously consider solar panels because the inverter is consuming more than I expected. The next "upgrade" will be a solar inverter for sure.
a: I measure it in the AC side. I used a clamp meter earlier and these days I use Kill-a-watt type of consumption meter - something like this : http://alchemy-media-marketing.com/h...r-monitor.html

This meter tells me the current consumption, power consumed, Power factor and the duration.

b: It is an online UPS. So it should be consuming more current/power than the interactive domestic inverters. But it is an old version and it doesn't supply sine wave. The server and the electronics don't seem to mind in all these years.

c: It was made by a local company Southern Enterprises. I doubt if they exist any more now.

Earlier we used to have about ten computers and their CRT monitors hooked to this supply. Now only a server is connected. I found that it doesn't cost much to run with barely 100 VA as its load - hence I continue to use it.

The same Power monitor tells more interesting bits of information. The PF is a pathetic .75 in this UPS. My inverter refrigerator is no better either - it has a PF of .70
Philips 9 W LED bulbs run at .70 PF too.

So you see, for my current need, I could live with a solar panel of just 500 VA.

Incidentally Tamil Nadu EB is no different from MH - they are equally grossly inefficient and suffer the same malaise. I pay commercial charges for this set up and it comes to about Rs.9 if total consumption is less than 200 units and Rs.11 if higher IIRC.
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Old 21st November 2017, 12:43   #1105
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a: I measure it in the AC side. I used a clamp meter earlier and these days I use Kill-a-watt type of consumption meter - something like this
I've used this meter earlier this year and found it to be inaccurate on the Amps and Wattage readings. The PF doesn't bother me too much. I returned it to the seller who I know personally. The conclusion was these meters are not accurate on inductive loads and especially on "inverter" type inductive loads like fridges I obviously relied more on my Fluke clamp meter than the consumption meter.

Obviously my Su-kam inverter is grossly inefficient considering it requires 1.5A of AC current to float charge two batteries @0.3A! Heck! I need to consider solutions including Solar panels or even replace the darn thing with a better product. And so the search begins.

PS - to gauge its efficiency in inverter mode I simulated a power failure. Amps at the battery 16.1, AC output/consumption 1.7A.

Last edited by R2D2 : 21st November 2017 at 12:58.
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Old 21st November 2017, 14:06   #1106
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I've used this meter earlier this year and found it to be inaccurate on the Amps and Wattage readings. The PF doesn't bother me too much. I returned it to the seller who I know personally. The conclusion was these meters are not accurate on inductive loads and especially on "inverter" type inductive loads like fridges I obviously relied more on my Fluke clamp meter than the consumption meter.

Obviously my Su-kam inverter is grossly inefficient considering it requires 1.5A of AC current to float charge two batteries @0.3A! Heck! I need to consider solutions including Solar panels or even replace the darn thing with a better product. And so the search begins.

PS - to gauge its efficiency in inverter mode I simulated a power failure. Amps at the battery 16.1, AC output/consumption 1.7A.
The Chinese built Power monitor is no match against the Fluke meters. Anyway in my case, I double checked with a clamp meter as well as the DMM.
There is a Sukam charging unit which can be retrofitted to the existing Inverter setup. What it basically does is , it uses the Solar panel to charge/run the Inverter. Only when the available power is not sufficient, it switches to the mains power. So it may be worth to consider a Solar panel with about 500 VA capacity - at least to take care of the float charge requirement.
In my case it will help to run completely off the solar power when it is available - say about 6 hours in a day which translates to about 30 units a month. At the current rate, it will take several years to defray the cost of a solar panel for me.
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Old 21st November 2017, 16:09   #1107
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There is a Sukam charging unit which can be retrofitted to the existing Inverter setup. What it basically does is , it uses the Solar panel to charge/run the Inverter. Only when the available power is not sufficient, it switches to the mains power. So it may be worth to consider a Solar panel with about 500 VA capacity - at least to take care of the float charge requirement.
Thanks for reminding me, I had completely forgotten about those retrofit solar kits.

It could save me ₹1500-2000/month (excluding the rainy season) in energy bills which my darned white elephant of an inverter (GRRR ) consumes to float charge the batteries. Depending on the price, I may be able to recover the cost in 2-4 years.
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Old 26th November 2017, 11:47   #1108
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I request some guidance from the experts on this thread. I have gone through the thread and now have a basic understanding of how to arrive at the correct specs, but I have never purchased an inverter before and hence the request.

Background: I live in Vasant Kunj, Delhi (rented place). Previously we lived in Dwarka, and our society had 24 hours basic power backup (all lights and fans). I was given the impression that Vasant Kunj hardly had any power cuts (this was when I was generally asking people about the area before deciding to shift here).

However after we have moved (about five months ago) we've been have frequent power disruptions. In almost every case so far, the power supply is resumed within an hour's time. However, since the colony here does not have any power backup, these power cuts are inconvenient, because both my wife and I work out of home a lot.

The Plan: I want to put a solution in place before summer hits Delhi. My assumption is I might be able to negotiate better during the winter months, plus I don't have to rush the decision making.

Family members include myself, my wife, my two dogs and our maid (who lives with us). Currently my thinking is that I will get every room's lights and fans hooked up so that we are free to use whichever room is required. In reality we are very sensitive to wastage of power so lights and fans of rooms that are not in use are usually kept switched off.

That amounts to nine tubelights and nine fans, two air purifiers and one desktop and modem.

The spec I am considering is a Su-Kam 2.5 kva/36v inverter (rs 11,000) and three Exide IT 500 12v/150 ah tall tubular batteries (Rs15500 per battery).

While a lower spec can easily handle our requirements during the winter, I am trying to plan ahead for our brutal summer season.

Of course, my entire investment could become a white elephant if the electricity supply during the summers becomes fantastic and we don't have a single power cut. However, if the power situation worsens, then I will be put in an uncomfortable (literally!) situation, since I prefer planning ahead. Also the nature of my work is highly unpredictable, and involves travel, so during the high pressure times I like to focus on the job at hand and not have to worry about electricity supply!

Thank you for taking the time to read this post. I would be very grateful for your inputs before I move forward.

Last edited by Lone Ranger : 26th November 2017 at 11:49. Reason: fixed typo
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Old 26th November 2017, 16:06   #1109
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That amounts to nine tubelights and nine fans, two air purifiers and one desktop and modem.

The spec I am considering is a Su-Kam 2.5 kva/36v inverter (rs 11,000) and three Exide IT 500 12v/150 ah tall tubular batteries (Rs15500 per battery).

Of course, my entire investment could become a white elephant if the electricity supply during the summers becomes fantastic and we don't have a single power cut. However, if the power situation worsens, then I will be put in an uncomfortable (literally!) situation, since I prefer planning ahead. Also the nature of my work is highly unpredictable, and involves travel, so during the high pressure times I like to focus on the job at hand and not have to worry about electricity supply!
Ok here are some thoughts, since the power consumption of appliances other than the air purifiers is known I think you're all set to cover the summer too even if the power outage is a lengthy one. But do exercise your discretion on which appliances should be switched on and running on inverter power during this time. For e.g. a desktop PC may be a luxury at this time. It's better you use a laptop which is far more power efficient.

Also, the white elephant bit. In case you haven't read my posts below, let me tell you that inverter will be consuming quite a bit of electricity to keep the 3 tubular batteries charged and topped up. So don't be surprised to see that instead of bills going down during frequent outages your bill actually goes up. It's the inverter at work keeping your batteries in tip top condition. Therefore, I'd recommend you also consider a solar inverter to save power.
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Old 26th November 2017, 17:37   #1110
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In case you haven't read my posts below, let me tell you that inverter will be consuming quite a bit of electricity to keep the 3 tubular batteries charged and topped up. So don't be surprised to see that instead of bills going down during frequent outages your bill actually goes up.
@R2D2, I have read almost all your posts on this thread, including the one where you mentioned the increase in your power bills Yes, I am prepared mentally for increased power bills. I would like to go the solar way but I rent this place and don't have a feasible way to mount the solar panels. Thank you for the tip on luxury vs need - in my case the desktop/internet is the need and the fan then will become the luxury . By the way, the air purifier consumes between 35-120 watts per unit depending on the speed it is running, it should average out at 80 watts since it usually runs in the middle setting.
What is your opinion on the prices that I have been quoted? Do they seem competitive?
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