Damaged Batteries

[Amine]

Hello Everyone

I have a question and i hope you guys can help, my setup is 4 batteries forming 48V 200Ah and one Mecer inverter 5KVA/5KW, for almost two years everything seemed to work seamless with no issues, i have been away for 5 months and i left my system like i did every time, the power mode set to utility (see attached settings).

Last weekend i returned home to find out that my batteries have been bloated and leaked but still functioning (see photos), do you  have any idea what would have caused it ? knowing that the load was very minimal and only once a week when the garden boy comes and maintain the garden using a common tools and appliances.

 

Kind regards

[Richard Mackay]

Almost impossible to determine. Electronics can go ape and only if you are around can you deal with it.

I reckon these systems should be shut down (disconnected) when not being used for such a long time.

[Amine]

11 minutes ago, Richard Mackay said:

Almost impossible to determine. Electronics can go ape and only if you are around can you deal with it.

I reckon these systems should be shut down (disconnected) when not being used for such a long time.

Thanks for your reply, i agree, it is difficult to determine or even troubleshoot the issue, but it worked well for years by my brothers and my in laws we have same setups everything was bought same time done by same people, and this is the first incident..

Now i need to replace the batteries but i can not do so if i haven't found what caused it to prevent it from happening again.

 

[Ant]

I don't have experience with SLA batteries only lithium. The visual clues show over charging caused this.

Looking at your values in the lower left corner your Bulk Charging Values and Float Charging values seem too high ? Check the battery manufacturers specification for the correct values. What temperature does the environment around the batteries fluctuate too ?  Operating Temperature can have a part to play if it is exceedingly high...

I hope you find the problem !

[Amine]

9 minutes ago, Ant said:

I don't have experience with SLA batteries only lithium. The visual clues show over charging caused this.

Looking at your values in the lower left corner your Bulk Charging Values and Float Charging values seem too high ? Check the battery manufacturers specification for the correct values. What temperature does the environment around the batteries fluctuate too ?  Operating Temperature can have a part to play if it is exceedingly high...

I hope you find the problem !

Thanks for your answer

The Bulk and float modes values were set by an "electric engineer", if i look at the datasheet;

Bulk charge : 14.6V~14.8V @25C (if we take the lowest value 14.6 multiplies it by the number of battery system 48V  it equals 14.6Vx4=58.4V)

Float charge : 13.6V~13.8V @25 (if we take the highest value 13.8V multiplies it by the number of battery system 48V  it equals 13.8Vx4=55.2V)

We have same setup and equipments in different premises and all are functioning properly with no issues, this is the first incident.

 

 

[iiznh]

I see corrosion on those battery poles, my first guess would be continuous overcharge of the battery that caused hydrogen venting. Maybe start by checking the float voltage charge with a multi-meter. Maybe the charger is outputting the an incorrect voltage.

Next guess a battery that is failing and pulling the bank down causing the bulk charge to run an already fully charged battery.

Sorry my experience with FLA is limited, read up on them, but using them proved to be a pain in the butt so I moved on to LiFeSO4

[Amine]

1 minute ago, iiznh said:

I see corrosion on those battery poles, my first guess would be continuous overcharge of the battery that caused hydrogen venting. Maybe start by checking the float voltage charge with a multi-meter. Maybe the charger is outputting the an incorrect voltage.

Next guess a battery that is failing and pulling the bank down causing the bulk charge to run an already fully charged battery.

Sorry my experience with FLA is limited, read up on them, but using them proved to be a pain in the butt so I moved on to LiFeSO4

Thanks a lot for your input, i have checked the voltage of each and every battery individually as well as the amps going in and out, and all seem correct as what the Mecer inverter is displaying, im also wondering if it wasn't the batteries themselves and not the overcharge and over-discharge situations.. but in same time i want to hear from your experiences maybe i've missed something or i'm not aware of it....

[iiznh]

Start off by:

Switch off eskom and put a load on the inverter something large enough to make the batteries work, about 2KW +- (maybe more but just for 10 minutes),  measure each battery with a voltmeter individually. Post your readings.

If any battery is not pulling its weight keeping the volts up and I had to do fault finding I would:

1.Disconnect them all from the bank & inverter. Let them settle for 30 minutes before continuing. Inspect for any bulging on the sides. Wash off the acid on top of the battery with baking soda. (wear safety glasses, you do not ant that acid to get into your eyes). Wash off any acid off your hands with plenty water & baking soda.

2. Measure their resting voltage. Check Electrolyte levels.  

3. Do a load test, you might need to find a suitable large load but with such a large battery you might need to find some camping 12V appliance that can get the job done) a bad battery will have a large drop when it needs to supply current. Eg my 50Ah car batery dropped from 12.8V to 8.6V with a +- 50A load (bunch of car bulbs in parrallel). in the end I replaced this battery. You could try equalising each battery individually and retesting them with the load... If one is bad... then likely you will have to replace them all since using different batteries will lead to all kinds of problems