[srini1785]

Originally Posted by diyguy

Is there any sensor that i can use between the terminals of the battery that can detect over draw of current and break the circuit there?

You can try something like this :
https://www.electronicscomp.com/5a-1...YaAoUkEALw_wcB

and get very Arduino about it or as @Aroy suggested just use a fuse and be done with it.

[diyguy]

Originally Posted by Aroy

Just put a fuse on the "Live" wire of the output of inverter (that is in series) and every time there is an overload the fuse will blow.

Thank you for the reply. If i am not wrong the output of the inverter will always show a high value since all load is channeled through this line even when the mains power is there. In such a case, i do not want regulation. This overload protection, ideally, has to come into force only when the mains power has stopped and the inverter is generating the output from the battery. Further i want the load to be cutoff and automatically cut-in when the load is reduced, for eg we switch off a few devices. The apc inverter works this way for us, its just the Luminous that sucks.
I have a barrage of sonoff devices that can do this but i have not thought of a scenario of how to kick this in, only when mains power is down.

[deep_bang]

Originally Posted by diyguy

Thank you for the reply. If i am not wrong the output of the inverter will always show a high value since all load is channeled through this line even when the mains power is there. In such a case, i do not want regulation. This overload protection, ideally, has to come into force only when the mains power has stopped and the inverter is generating the output from the battery. Further i want the load to be cutoff and automatically cut-in when the load is reduced, for eg we switch off a few devices. The apc inverter works this way for us, its just the Luminous that sucks.
I have a barrage of sonoff devices that can do this but i have not thought of a scenario of how to kick this in, only when mains power is down.

Right. The best way is to have a DC MCB at the output of the battery. That way, it will trip only if the current goes over a certain level from the battery.
You will need to calculate the current based on the VA rating, voltage (12v) and find the current. The DC MCB will need to be for this rating. You want to limit it a little under the current you calculate as we may not have taken into account of some factors like efficiency, power factor etc.

[R2D2]

So my inverter batteries crossed 9 years and 8 months old this month. They turn 10 in Apr '23. I topped em off with DIW after 3 months in Nov (a very acceptable gap IMHO). Compare it to the top up after 6 weeks back in t0he heat of summer causing me concern that the bank was failing. Not so, it was just the searing temps that caused it to use up more water.

I was always curious to find out how much electricity the inverter + battery consumes each month and the set was disconnected (both +ve and -ve cables) for 17 days from 24/11 to 11/12. Why 11th? Because the meter is read by the MSEB on 10th of the month and bill generated around 18th. An old battery bank like this one should normally have increased internal resistance and require more power to recharge. I'll update this thread.

Anyway, leaving a battery bank idle for 17 days gives me a good indicator on how the batteries fare when they're not being float charged. The good news? They're absolutely fine, each battery was 12.54 volts (~84% SOC) after being idle for over 2 weeks. TBH I was expecting a sharp drop in voltage but I am absolutely delighted with the Exides and will replace them only when they fail be it next year or even later. Exide Invatubular - I recommend these without a moment's hesitation. More expensive than the competition but the performance and long lasting nature of these products leave me with no doubt. Well done Exide I only wish your car batteries were as reliable.

[aim120]

Originally Posted by R2D2

So my inverter batteries crossed 9 years and 8 months old this
Anyway, leaving a battery bank idle for 17 days gives me a good indicator on how the batteries fare when they're not being float charged. The good news? They're absolutely fine, each battery was 12.54 volts (~84% SOC) after being idle for over 2 weeks. TBH I was expecting a sharp drop in voltage

Just because the battery has resting voltage of 12.54v doesn't mean its in good health.
A lead acid battery will loose its charge by 10 to 15% after its even after a few hours after its not being float charged. But the next drop in charge rate is slow around 10 to 15% every month its sitting idle. Faster rate if the temperature is colder.

So for all we could know the battery capacity or SOH can be as slow as 40% based on my experiences with exide. My exide tubular batteries lasted just shy of 10 year (3 months short) but it was a short tubular battery.

Tall tubular has much longer life and distill water topping interval is also much longer.

[R2D2]

Originally Posted by aim120

Just because the battery has resting voltage of 12.54v doesn't mean its in good health.

What it shows me there are no internal shorts and that's what I mean by good health. One of the batteries has a brown greasy substance floating which I read on the some US forums is basically caused by shedding of plate material though I am not sure how it floats.

These are tall tubulars and refilling interval is approx. every 1.5-3 months depending on the season with 3-3.5 litres of water.

Either way, both batteries at >80% SOC after this time and I am a happy camper. The batteries are humming along again. I am hoping they cross the 10 year mark. Also, temps of >27 C the baseline voltage cause higher self discharge if left idle this is as per the manual and mandate a correction in charging voltage..an easy job with my processor controlled APC 2.2 KVA Smart UPSes but not the Microtek inverter.

[R2D2]

Not surprisingly I saved 53 KWh over this 17 day period translating to a saving of Rs 670. Consuming <300 units a month costs you less, a lower price/unit which is basically to encourage people to use less power.

The inverter consumes a little over 3 units a day. Yes, it was a nuisance to deal with the sudden and frequent but short lived power cuts of 3-15 mins MSEDCL is famous for in my residential area.

[sagarpadaki]

Originally Posted by R2D2

Not surprisingly I saved 53 KWh over this 17 day period translating to a saving of Rs 670. Consuming <300 units a month costs you less, a lower price/unit which is basically to encourage people to use less power.

The inverter consumes a little over 3 units a day. Yes, it was a nuisance to deal with the sudden and frequent but short lived power cuts of 3-15 mins MSEDCL is famous for in my residential area.

Good to know the amount of power an inverter consumes to keep the batteries topped up. I assume it also depends on the size of the battery.

Which inverter are you using?

[R2D2]

Originally Posted by sagarpadaki

Good to know the amount of power an inverter consumes to keep the batteries topped up. I assume it also depends on the size of the battery. Which inverter are you using?

Yes it depends on both the inverter circuit efficiency and the battery size, age etc. I use a Microtek and the batteries are 200 AH each in series. They've served me well so far. Touch wood

[Prowler]

Originally Posted by R2D2

The inverter consumes a little over 3 units a day. Yes, it was a nuisance to deal with the sudden and frequent but short lived power cuts of 3-15 mins MSEDCL is famous for in my residential area.

This is the reason why I added a small circuitry in between the UPS and the mains as well as the UPS output and the power input which shuts off the power to the UPS when the mains is available and routes the mains directly to the mains input of the office/home normally but once in a week supplies the UPS for a few hours to keep it charged.

My usage is the UPS consumes about 2 units every day when left on. With the little circuit in place it saves the 2 units. The schedule for the charging the UPS is controlled by a timer as of now. When I get the time, I will have to add some extra bit to get the SoC and accordingly time it.

They increased the power rate very high in Tamil Nadu which leaves you looking for any available means to save power.

[R2D2]

Originally Posted by Prowler

This is the reason why I added a small circuitry in between the UPS and the mains as well as the UPS output and the power input which shuts off the power to the UPS when the mains is available and routes the mains directly to the mains input of the office/home normally but once in a week supplies the UPS for a few hours to keep it charged. .

Darned good idea I admit. Was this circuitry a DIY or did you use one of the gadgets that switches on appliances every so many hours/days?

Also, what happens when the power is cut by the power Co.? I assume that results in no backup via the inverter unless you manually bring it back online?

My usage is the UPS consumes about 2 units every day when left on. With the little circuit in place it saves the 2 units. The schedule for the charging the UPS is controlled by a timer as of now. When I get the time, I will have to add some extra bit to get the SoC and accordingly time it.

How many batteries and what size?

They increased the power rate very high in Tamil Nadu which leaves you looking for any available means to save power.

Your price/unit has gotta be lower than rip off Maharashtra!

[Prowler]

Originally Posted by R2D2

Was this circuitry a DIY or did you use one of the gadgets that switches on appliances every so many hours/days?

I am using Sonoff Wifi Switch to schedule the power on/off. I am using the old type which tells you the power consumed.

Also, what happens when the power is cut by the power Co.? I assume that results in no backup via the inverter unless you manually bring it back online?

My DIY circuit uses a relay (12 V and contacts rated at 5 A) which are fed from the mains so when the mains power is available the Input is supplied from the mains directly. The moment the power goes off, the UPS is connected to the Input. The UPS sits in quiescent mode drawing about 70 mA from the battery.

The batteries are 3 x 12 V 85AH Amaron Automotive types.

Your price/unit has gotta be lower than rip off Maharashtra!

Now each unit costs Rs.11 as we use more than 1000 units every 2 months.

[revvharder]

Hello everyone, so after going through lots of pages on this thread i went ahead and purchased an Exide battery but what has started is an unfortunate chain of events.

In March i had purchased the EL150 battery and it was delivered to me by the dealer and later on fitted by an electrician, the place where i live sees a power cut off around 1 to 2 hours daily but now it has reduced. So after 3 months i noticed that only one of the cells has dropped to 3/4 th mark so instinctively i lifted the battery and checked for any cracks/damages which there weren't any and neither the battery was wet so i assumed it was normal due to regular usage now around October i noticed it has seeped down to 1/4th level so i filled it and since then cell started to leak rapidly and getting empty in 1 month so i called the customer care, the guy arrived and upon first inspection checked the battery and wanted to take it to service centre but upon further inspection a crack was revealed below where the handles are attached and it was obscured by the rope of the handle and even he agreed that it's not normal to have a crack here and it must have happened during transportation but cracks are covered only for the 1st month so it will not be covered under warranty and suggested me to visit the dealer, even the dealer arranged another inspection and the result was the same. The dealer has refused to replace battery on his cost and company too has washed off their hands, he has told me that he is in communication with Distributor so that somehow the battery is replaced.

Do suggest me how should i proceed further.

[R2D2]

Originally Posted by revvharder

Do suggest me how should i proceed further

This is physical damage and unless pointed out in time the assumption will be the customer did it.

What you can do is wait till the electrolyte level drops in that cell and use m-seal or similar to seal the crack. Once dry, which will take a day or so, top off with DW/DIW. Do not overfill. ALternatively, draw out the fluid with a hydrometer till it is lower than the level of the crack in the case. Do not discard it. Dry the exterior and proceed to apply M-Seal. Let that dry and refill the electrolyte back into the battery cell. Be careful you're dealing with acid and explosive gas emissions.

About cracks in the battery case - you should keep a close eye on the battery once it is delivered. These are heavy items (my 200AH weigh 60-65 Kgs each when filed with about 20 litres of electrolyte) and impacts whilst being placed on the ground/floor or being transported could cause damage to the case.

If you see electrolyte leaks or if the level drops faster in 1-2 cells than the others in a new battery something is wrong. Also, you must never forget to register the battery for a warranty claim. In the past one had to call their toll free # to register it. Not sure how it works now. The warranty card will guide you properly.

[R2D2]

And the Exide Invatubular battery set turned 10 this month, purchased in Apr 2013. TBH I am chuffed.

Nothing much to add over the previous update except for the normal DW/DIW top up back in mid Feb.