[R2D2]

Originally Posted by Thad E Ginathom

..if a battery has died because of lack of water, am I right in thinking it will be too badly damaged to recover?

You may be able to recover it depending on if the battery was >80% charged and the duration of time the plates were exposed to air.
It's best to never let the electrolyte drop low and expose the plates. They will become inactive when exposed to oxygen. Besides charging a battery with low or no electrolyte can be dangerous.

I visually check my inverter batteries every 1-2 months and top off DW every 3 months. Floats are not always reliable as they can be stuck or damaged. Water should be consumed more or less evenly across cells. A large difference in float levels between cells in a battery is a cause for investigation.

Originally Posted by RaceHorse

Not to take a further risk I turned off the UPS mode. I hope I can live without the backup for a few days. Now Inverter is one of the items added in the list of things to be repaired after lockdown. Thanks for all the advice.

Not sure what you mean by turning off UPS mode, because in my inverter the UPS mode switch only changes the switch over time (it's faster in order to power PCs and other similar gear but not as fast as a purpose built IT equipment UPS like an APC) during power failure. This of course differs from model to model.

I'd recommend disconnecting & bypassing the inverter (some models have a bypass switch) and then powering it off so the batteries aren't being continuously charged.

Originally Posted by Gansan

^^ For the past one year or so I notice water level in one particular cell is lower than others, though still above the plates. That particular cell takes double the quantity of water as compared to the other cells. Can it be remedied? I thought it was due to aging. Battery is exactly 5 years and 10 months old.

Age related damage is 1 reason, the other is sulphation due to stratification. That's why mfrs recommend an equalisation charge every 6-12 months for stationary batteries. My Exide inverter batteries are 7 years old and all cells consume water evenly.

[Gansan]

^^ For the past one year or so I notice water level in one particular cell is lower than others, though still above the plates. That particular cell takes double the quantity of water as compared to the other cells. Can it be remedied? I thought it was due to aging. Battery is exactly 5 years and 10 months old.

[RaceHorse]

Originally Posted by R2D2

Not sure what you mean by turning off UPS mode, because in my inverter the UPS mode switch only changes the switch over time (it's faster in order to power PCs and other similar gear but not as fast as a purpose built IT equipment UPS like an APC) during power failure. This of course differs from model to model.

I'd recommend disconnecting & bypassing the inverter (some models have a bypass switch) and then powering it off so the batteries aren't being continuously charged.

Thanks for correcting me, the switch to bypass the inverter mode is at the backside of Inverter, turning off UPS mode button which is in front solved the load problem only.

[civic-sense]

It looks like, my two Amaron SMF batteries attached to the Luminous Inverter are on the verge of dying. It has crossed three years last month. Does that sound a bit less, since similar batteries in cars go upto 5+ years?

[Gansan]

Originally Posted by R2D2

That's why mfrs recommend an equalisation charge every 6-12 months for stationary batteries.

What is that, can you elaborate? Is it done at the battery shop?

[R2D2]

Originally Posted by civic-sense

It looks like, my two Amaron SMF batteries attached to the Luminous Inverter are on the verge of dying. It has crossed three years last month. Does that sound a bit less, since similar batteries in cars go upto 5+ years?

Assuming those SMF batteries are specifically for inverters i.e. deep discharge, which car batteries are not, I would not recommend SMF batteries for hot tropical weather. The convenience of no top ups is greatly outweighed by the longer life and lower costs of flooded batteries.

Originally Posted by Gansan

What is that, can you elaborate? Is it done at the battery shop?

A equalization charge is done at 15.8-16v DC about 2.63-2.66v/cell to a fully charged battery. You will require a charger that supports this function or a manual charger. The higher voltage causes cells to gas freely which in turn mixes the stratified acid + water layers leading to an evenly distributed mixture. How long it takes depends on the condition of your battery and the recommendation by the battery manufacturer. For e.g. Exide provides this info and I quote:

To ensure that every cell in a battery bank is maintained in healthy state to give enhanced life and performance, it is advisable to give equalising charge at least once in a year.

Under constant potential mode during operation passive layers form on the plates. This causes variation of sp. gravity & voltage from cell to cell. To take care, the battery bank is to be put on constant current charging at 6% of rated capacity up to 2.75VPC, followed by an extended charge for 12 to 24 hours on constant current charging at 3% of rated capacity.

This helps the cells rejuvenate with fresh layer of active material. All the cells will show approximately same sp. Gravity and voltage. Since low current is given during 3% rated amps of the Ah capacity, this will not affect the activated portion of the plates, but will remove the patches of sulphate from the plates back to the solution, increasing the sp. Gravity of cells. Therefore, it is important to give equalising charge, once in a year, if not earlier.

Please consult your battery owners manual or the manufacturer's website or technical support for exact instructions.

[prithm]

Originally Posted by R2D2

A equalization charge is done at 15.8-16v DC about 2.63-2.66v/cell to a fully charged battery. .

Doesn't regen mode of Bosch C7 do same ?

[R2D2]

Originally Posted by prithm

Doesn't regen mode of Bosch C7 do same ?

Yep, it does. But it times out after a 4 hours (IIRC) and resets to normal charging. Also, the C7 is meant for automotive batteries with thinner plates compared to the thick plates, meant for deep discharge, in inverter or UPS batteries.

So, if your battery is an inverter model a manual charger may be required as the 4 hour long regeneration mode may be insufficient to mix the electrolyte plus desulphate the plates.

[prithm]

Originally Posted by Thad E Ginathom

I noticed that the sides of the battery have some very slight swelling. I'm guessing... this is bad news? The battery was bought in December 2015, after the previous battery and inverter had spent several days under water. It has been run to flat two or three times, due to know realising that the input mcb had tripped.

I hate to say this Thad san, but Same Pinch. Couple of posts before yours, I shared my "Back from Vacation" woe story. One of the battery is indeed showing slight bulge, but every one (Luminous engineer, my electrician) are saying that it is nothing to worry and has life in it for couple of years.

All batteries in my series ran flat for couple of days until the UPS itself shut down for protection.

One thing that I am still not able to understand is that my 150 Ah batteries show sinusoidal water level in floats. The peaks being the two terminals and middle cells, troughs being the -1 floats from either terminals. What might be causing this phenomenon ?

[R2D2]

Originally Posted by prithm

One thing that I am still not able to understand is that my 150 Ah batteries show sinusoidal water level in floats. The peaks being the two terminals and middle cells, troughs being the -1 floats from either terminals. What might be causing this phenomenon ?

Either due to sulphation or deteriorating plates. Give it a 15.8-16v DC equalisation charge till Sp Gr in all cells is equal.

[zaheermk]

Hi Friends,

I have shared a spreadsheet in which I have made a short calculation for deciding on the Inverter Rating and Battery Capacity, which can be edited to each of our requirements and checked. I think it is self explanatory, shown below is how it looks like.

What needs to be filled by us are the number of units of each appliances (yellow cells) we need to get working on the inverter, along with the available options for Inverter Rating and Battery Capacity (orange cells), to understand, if the inverter is capable of supporting the total load, and if yes, what the battery backup time is, with the total load. The Power Rating mentioned in the sheet are standard/common values and can be edited (yellow cells) if you find a different rating on your specific model.



Please note that some 1.2 (or more) factor of safety needs to be considered for both... meaning, if the total apparent load is 1000W, then inverter should be at least 1200W and if backup time with a 100Ah battery is what you need, then you should go in for at least 120Ah battery. Kindly also note that, we might have some 7-8 appliances connected on the inverter line, but we might be using only 3-4 appliances at a time, so the Inverter Rating and Battery Capacity can also be realistically decided based on it.

With best regards.

[prithm]

Originally Posted by R2D2

Either due to sulphation or deteriorating plates. Give it a 15.8-16v DC equalisation charge till Sp Gr in all cells is equal.

Thank you R2D2 san. Sorry for the delay in response though.

So,

• Do I need to disconnect the batteries from series and run each battery with Bosch C7 in R mode ?
  
• Approx. how long do I need to run each of them with Bosch C7 ? The reason why I am asking is cause there isn't enough wiggle room in UPS rack for me to directly observe the bubbles through the refill holes ?

[R2D2]

Originally Posted by prithm

Thank you R2D2 san. Sorry for the delay in response though.

Do I need to disconnect the batteries from series and run each battery with Bosch C7 in R mode ?

Yes, you will need to disconnect the batteries as regen is not supported in 24 V mode.

Approx. how long do I need to run each of them with Bosch C7 ? The reason why I am asking is cause there isn't enough wiggle room in UPS rack for me to directly observe the bubbles through the refill holes ?

TBH this is a bit of a wimpy charger (only 7A at max) for large inverter batteries because it was primarily designed for smaller automotive ones. Regen would be best done with a manual charger where you can control the voltage and/or current.

You can give it a try though individually on each battery. The regen mode lasts for 4 hrs max at about 1.5-2A. I checked the current using a clamp meter when my car battery was totally dead. But I would add that running the regenerating process on any battery in an enclosed space is not recommended. You must keep an eye on water level, Sp. Gr. and temperature.

[anand253]

Hello all - Our 7 yr old Sukam Shiny 1.5 KVA inverter is unable to support load and have been recommended to replace the inverter (understand that the board has conked off and replacement would cost ~4k w/o any warranty). It was connected to two 150AH sukam tall tubular batteries (about 3 years old and in good condition as per the electrician.

I see Luminous & Microtek available online and dealer recommending Luminous Eco Volt+ 1650. Would you guys have any recommendation on the brands. Location is Chennai...

[saket77]

^^ I have good experience with Microtek. Having 2 of them with us, it has never ran into trouble in the last 7-8 years with us.

Guys, one query. I collected around 2 liters of AC condensed water overnight. I checked it with a water TDS tester and it shows a level of around 35. I counter checked the level with the supplies I have from a local hardware shop which ranges between 30-50 across a few bottles, meaning the supply’s quality is not consistent. So, is the collected water with 35 TDS good enough for inverter Battery?

Thanks.