Gel battery losing charge fast and weird inverter behavior

[Hassico]

I have a solar system comprised of 4 Welion gel batteries 12v 150Ah each, 6 panels 545 watts, and a Growatt 5000es inverter.

Recently, the batteries are getting discharged fast, losing voltage under very low load (less than 1 amp at 230 volts), even with just the inverter connected to it. In a couple of seconds from charging it to 100%, it drops to 49v until reaching the cutoff voltage at 44v. I noticed that when the batteries are charging, when they reach a 100%, they remain at the floating charge at 54.5 for a couple of minutes, then they start discharging even with nothing connected or under enough sunlight and with utility charging, then the inverter tries to charge them back to the float charge and this behavior loops back again, totally weird behavior.

Link to video shows what is happening: https://ufile.io/ox8ft55s

This behavior might be why the batteries can no longer hold charge or this is happening because the batteries are bad and no longer really usable.

Are the batteries really dead or something with the inverter or....? And what can I do to save them if possible?

 

[sunshine_eggo]

I'm not sure what to make of your video.

GEL typically charges to around 14.0-14.2V/12V, and it needs to stay there for 2-4 hours.

Your 150Ah batteries may be limited to 30-45A of charging, but your 3270W of PV may charge them at 60A, which will shorten their life.

Are all four of your GEL 12V at the same voltage when at peak absorption?
Did you fully charge all 4 batteries as 12V before putting them in series?

 

[pollenface]

What is the bulk/absorption voltage and duration?

 

[Hassico]

I'm not sure what to make of your video.

GEL typically charges to around 14.0-14.2V/12V, and it needs to stay there for 2-4 hours.

Your 150Ah batteries may be limited to 30-45A of charging, but your 3270W of PV may charge them at 60A, which will shorten their life.

Are all four of your GEL 12V at the same voltage when at peak absorption?
Did you fully charge all 4 batteries as 12V before putting them in series?

we did not balance their charge before connecting them, I did not know or think about that during the installation bcz we brought someone to install the system altogether. How can I check if the batteries have the same voltage at peak absorption?

 

[Hassico]

What is the bulk/absorption voltage and duration?

It is 56.4v, probably the default voltage set by Growatt. Since everything is in default, the inverter handles the charging and I do not know if it assigns a duration or not, as per the manual there is a duration but not for gel batteries.

 

[Brett V]

Sounds like the batteries were overcharged. are they swollen at all?

 

[Hassico]

Sounds like the batteries were overcharged. are they swollen at all?

No, they look the same as day one

 

[pollenface]

Your 150Ah batteries may be limited to 30-45A of charging, but your 3270W of PV may charge them at 60A, which will shorten their life.

I note AC charging is 80A

Growatt SPF 5000 ES User Manual (Page 41 of 42) | ManualsLib

www.manualslib.com

 

[sunshine_eggo]

we did not balance their charge before connecting them, I did not know or think about that during the installation bcz we brought someone to install the system altogether. How can I check if the batteries have the same voltage at peak absorption?

When peak voltage is hit (56.4V), measure each 12V with a voltmeter.

 

[sunshine_eggo]

No, they look the same as day one

Please post a picture of the side of the battery where the various parameters are listed.

 

[Hassico]

Please post a picture of the side of the battery where the various parameters are listed.

These are the details of the battery:

 

[Hassico]

I note AC charging is 80A

Growatt SPF 5000 ES User Manual (Page 41 of 42) | ManualsLib

www.manualslib.com

What would be a good charging current?

 

[pollenface]

What would be a good charging current?

0.1C-0.25C (15-37.5amps) would be my preference.

Your picture states "less than 45A initial charging current"

I've personally killed a few batteries of my own by over charging them to the point that they would not supply standby power to an inverter overnight. Everyone makes mistakes, the best thing to do is learn.

 

[SamDeleted]

It seems your batteries might be goosed sorry


Your options for restoring gel batteries are slim, some discharge completely (10.5v bat) and then slowly recharge to full (repeat a few times) it's supposed to help, I can't attest to it

 

[SamDeleted]

You could also get a charger like a Ctek or noco , with a battery reconditioning setting

That might help, at this point it won't hurt to try

 

[Hassico]

Do you think switching to lithium in my case would be better. I have a budget of about 2000$. The thing stopping me from buying one is, what if the same problems with the gel batteries happen with the lithium one. And bcz there is a flood of unknown never heard of brands of lithium batteries in Lebanon.

Do you think this battery is a good choice:

Felicity LPBA48300, 300Ah 15kw lithium battery – Starz Electric

starzelectric.com

Or I am better buying cells and bms and build my own big battery?

Thanks in advance.

 

[SamDeleted]

Do you think switching to lithium in my case would be better. I have a budget of about 2000$. The thing stopping me from buying one is, what if the same problems with the gel batteries happen with the lithium one. And bcz there is a flood of unknown never heard of brands of lithium batteries in Lebanon.

Do you think this battery is a good choice:

Felicity LPBA48300, 300Ah 15kw lithium battery – Starz Electric

starzelectric.com

Or I am better buying cells and bms and build my own big battery?

Thanks in advance.

$2,000 should be enough to sort you out in lithium or lead acid (but not sure what prices are like out there?)

You have right now 4 x 12v-150ah batteries. 44v low cut off (makes 70%dod) all equals about 5kwh of usable battery capacity.

So that's what you need to look for if you go lithium, at least 5kwh of capacity

 

[Hassico]

$2,000 should be enough to sort you out in lithium or lead acid (but not sure what prices are like out there?)

You have right now 4 x 12v-150ah batteries. 44v low cut off (makes 70%dod) all equals about 5kwh of usable battery capacity.

So that's what you need to look for if you go lithium, at least 5kwh of capacity

What do you think i can do with the gel batteries if I get lithium? I bought the gel for $250 each, and some people buy them for around $50 each but I want to put them to good use rather than just selling them for $200.

And do you think the six 545 watts panels I have can charge the 15kwh felicity battery I sent earlier to 100%?

 

[sunshine_eggo]

You could also get a charger like a Ctek or noco , with a battery reconditioning setting

That might help, at this point it won't hurt to try

There is no "reconditioning" GEL or AGM batteries. The "reconditioning" option on Noco and similar chargers will damage GEL/AGM.

Do you think switching to lithium in my case would be better. I have a budget of about 2000$. The thing stopping me from buying one is, what if the same problems with the gel batteries happen with the lithium one. And bcz there is a flood of unknown never heard of brands of lithium batteries in Lebanon.

GEL and LFP are completely different. If you see the same problem, it's not because of the batteries. Again, I can't explain what I'm seeing in your video. You haven't really given us an accurate picture of how you're using the system.

Has this issue arisen along with a change in usage? Are you relying more on utility charging, etc.?

What do you think i can do with the gel batteries if I get lithium? I bought the gel for $250 each, and some people buy them for around $50 each but I want to put them to good use rather than just selling them for $200.

If your batteries are damaged as it may appear, they're worth scrap value.

 

[Vigo]

Since you are only needing to replace 5kwh of battery capacity (in the case that your current gel are useless) then you CAN get that capacity from a lifepo4 setup for $2000. If you go with 'no name' you can actually potentially do ~10kwh.

Considering the settings in the Growatt were not tailored to the batteries you have, and given the symptom you described, i suspect the current batteries are basically destroyed, at least as a 'set'. There may be 3 of them still usable as 12v batteries and 1 which is 'broken', but as a 48v pack i doubt you will get any further use from them.