Batteries discharging very quickly but only 19 months old

[Warlok]

Hi again, I have 4 of these batteries. (Series 48v)

 

As far as I know I have been looking after them. (lately). Only discharged them to 42 volts maybe 4 times. The other times I don't let them go below 80% SOC. Lately I have noticed that they drop very quickly. (70% after 30 min drawing 350-500w) Usually the could last through load shedding (2.5 hours) to reach 70%

My inverter settings are as follows:

The bulk and float charge settings are right according to the spec sheet. It's only after I started looking at the graphs carefully I've noticed that the batteries never stay long at 56.8v, maybe 20 minutes and then goes back to float

Could this be my problem? I would do anything to try and save them as a lithium battery is $$$$$ out of my reach (for now). If it is, how can I increase the time it stays on bulk and is it safe to do so?

Last question.

I've read about equalization somewhere, I think someone said not to do that to these type of batteries. Is it true? I will try that as well to try and save my batteries. If all else fails i will have to save up for a lithium battery.

ps...

Just finished my new dash in node red. Got switching on SOC and change to sbu / uti on a timer working.

 

 

[Coulomb]

18 hours ago, Warlok said:

As far as I know I have been looking after them. (lately). Only discharged them to 42 volts maybe 4 times.

42 V is a very deep discharge, depending on the load. Four of those might just finish off a lead acid battery bank.

Quote

The other times I don't let them go below 80% SOC.

That part is good.

Quote

It's only after I started looking at the graphs carefully I've noticed that the batteries never stay long at 56.8v, maybe 20 minutes and then goes back to float

My guess is that you have an Axpert inverter, and the premature float bug is slowly ruining your battery through chronic under-charging. Lead acid does not like under-charging.

Quote

If it is, how can I increase the time it stays on bulk and is it safe to do so?

Depending on the model of your inverter, you may be able to extend the absorb stage by using either timed absorb, or the equalisation facility (with a lower than usual equalisation voltage). These have risks; overcharging a sealed lead acid battery can dry them out, and you can't replace the water. But chronic under-charging is bad too.

I suggest attempting to extend the absorb stage, preferably using the timed absorb setting if you have it (usually setting 32). Try extending it to about 40-60 minutes and see if you can recover some of your run-time. I doubt that you will be able to get anywhere near new capacity, but you might be able to live with the battery if you can recover some capacity.

Quote

I've read about equalization somewhere, I think someone said not to do that to these type of batteries. Is it true? I will try that as well to try and save my batteries. If all else fails i will have to save up for a lithium battery.

Equalisation is another way to achieve much the same thing. You could set the equalisation to happen every day or perhaps every second day, and set the equalisation voltage to the same as your absorb/bulk voltage (56.8 V). You are supposed to reduce that voltage in summer, if your average battery temperature is over 25°C. Reduce it by about half a volt (to 53.3 V) if your battery voltage averages 30°C while charging. The advice not to do that is likely based on the fact that usually equalisation is performed at significantly higher charge voltages; just don't do that (the equalisation voltage is one of the ~8 settings related to equalisation).

[Cyon]

On 2020/11/03 at 5:43 PM, Warlok said:

I have 4 of these batteries. (Series 48v)

with battery balancers? 

[Warlok]

On 2020/11/05 at 12:21 PM, Barryv said:

with battery balancers? 

Hi Barryv. No, not with battery balancers. Actually never knew they existed until you mentioned it. Only thought they were used for lithium cells.

[Warlok]

On 2020/11/04 at 12:54 PM, Coulomb said:

42 V is a very deep discharge, depending on the load. Four of those might just finish off a lead acid battery bank.

That part is good.

My guess is that you have an Axpert inverter, and the premature float bug is slowly ruining your battery through chronic under-charging. Lead acid does not like under-charging.

Depending on the model of your inverter, you may be able to extend the absorb stage by using either timed absorb, or the equalisation facility (with a lower than usual equalisation voltage). These have risks; overcharging a sealed lead acid battery can dry them out, and you can't replace the water. But chronic under-charging is bad too.

I suggest attempting to extend the absorb stage, preferably using the timed absorb setting if you have it (usually setting 32). Try extending it to about 40-60 minutes and see if you can recover some of your run-time. I doubt that you will be able to get anywhere near new capacity, but you might be able to live with the battery if you can recover some capacity.

Equalisation is another way to achieve much the same thing. You could set the equalisation to happen every day or perhaps every second day, and set the equalisation voltage to the same as your absorb/bulk voltage (56.8 V). You are supposed to reduce that voltage in summer, if your average battery temperature is over 25°C. Reduce it by about half a volt (to 53.3 V) if your battery voltage averages 30°C while charging. The advice not to do that is likely based on the fact that usually equalisation is performed at significantly higher charge voltages; just don't do that (the equalisation voltage is one of the ~8 settings related to equalisation).

Thanks Coulomd.

Actually an Axpert clone. when I bought it, I never knew that there was clones. As I said before, the salesman was there to make money. Searching the internet for inverters, no where were stated that "this is a clone" and "that's the genuine thing". Another guy at Solarmid (small solar shop where I live) told me that it's fine, but I should never use more that 50% load, otherwise it will pop the mosfets. Highest it goes is 35% load for my needs. This Node Red screenshot is at 10:00 in the morning with everything I need running, (including air-con @ 24 degrees)

 

I have noticed that all my batteries are a bit round at the short side (about a 1 mm curve). I don't know if this was the design, but overcharging could cause swollen batteries, but I never took them above 56.8v.

I will change the absorb time to see what happens. The inverter uses your and Weber's firmware and I'm working off the Aussieview manual.

 

 

Thank you Coloumb.

 

[Cyon]

On 2020/11/07 at 9:40 AM, Warlok said:

Hi Barryv. No, not with battery balancers. Actually never knew they existed until you mentioned it. Only thought they were used for lithium cells.

Look at Victron Battery Balancers. 

[excitedphoton]

Your problem is that they are lead acid batteries.

If discharger behavior has changed already to what you experienced previously then you've probably toasted them.

Sorry mate.

 

 

[Warlok]

16 hours ago, excitedphoton said:

Your problem is that they are lead acid batteries.

If discharger behavior has changed already to what you experienced previously then you've probably toasted them.

Sorry mate.

Thanks @excitedphoton"toasted" was not the word I used, but yes, they are pretty buggered

If I could give anybody advice, rather get a lithium battery. The benefits far outweigh the extra cost.

just for interest sake, check out this video on stolen batteries

 

[excitedphoton]

On 2020/11/19 at 1:42 AM, Warlok said:

Thanks @excitedphoton"toasted" was not the word I used, but yes, they are pretty buggered

If I could give anybody advice, rather get a lithium battery. The benefits far outweigh the extra cost.

just for interest sake, check out this video on stolen batteries

 

 

I see facebook marketplace is full of stolen narada and shoto batteries.  Leoch seems to have dissapeared.