Adding 2nd Parallel FLA Bank to Existing System

[RicoPobre]

tldr; can I add a second 48 v battery bank(4 12v lead acid batteries) to my system easily? How can I mitigate any problems?

I have looked at previous threads using search and learned quite a bit but I still have a few questions and need some advice.

At the end of February 2022, I installed a solar system here on my off grid property. Here is my system:
12-240 used panels (2880 watts), panels installed with 4 banks of 3 in series.
48v 60 amp PowMr MPPT charge controller
48v 2500 watt Xijia inverter
4 12V Walmart Deep Cycle batteries in parallel

The system has performed very well for me over the past year. I run little to no load overnight and evening usage is supplemented with a 48V 15 amp Meanwell battery charger running from a Predator inverter generator(usually an hour or two during the winter). Basically when morning comes around(before sunrise), my batteries are usually between 50 and 51.4 volts.

My refrigerator and freezer are on timers. I have a 12 volt 180 ah LiFePO4 battery in my cabin that charges devices and run 12 volt appliances. I charge it up with a LifePo4 charger during the day. I also have a Bluetti EB3A that I charge up during the day from my main solar system.

I've thought about going with LiFePO4 for my main system but I really I can't afford it right now with many other things to do. Plus I get a lot of cold nights during the winter so I really don't want to have to deal with ruining my cells because I charged during the cold.

Being that I'm in Arizona and summer is coming. I'd like to increase my main system battery capacity. I survived last summer by running a generator way too long. I'm building a subsystem to take care of the cooling now so I'm really not needing it for that. I know I'm going to need to run my refrigerator and freezer longer, like all night. I'm also wanting to add a second freezer. Basically I probably need a bit more overnight power. But my budget is eternally stretched to breaking point. I know I can probably do it with what I have, but I know I'm stretching it.

What I would like to do is add a second battery bank of 4 12V Walmart deep cycle batteries. They will be the same as the ones I have installed, just one year newer? Is this going to be a problem? How I mitigate any potential problems? I've thought of getting an HA02 battery equalizer for each bank, are they helpful?

thanks in advance!

 

[12VoltInstalls]

What I would like to do is add a second battery bank of 4 12V Walmart deep cycle batteries.

With 1 year old batteries that may not be a good idea. They may not last well and for $430 for 4 new ones that is LiFePo range.

My latest experience with everstart group 27’s is two fold issues:
1) they are not labeled ‘Maxx’ nor is any warranty indicator on the label. But they are apparently only 12months warrantee…
2) my older group 27s are out of warranty but are still good testing voltage after being disconnected for two weeks- the new ones are what was dragging me to 12.1V quickly apparently as that’s where they went: 12.0xVolts

They will be the same as the ones I have installed, just one year newer? Is this going to be a problem?

I do not recommend doing it.

How I mitigate any potential problems? I've thought of getting an HA02 battery equalizer for each bank, are they helpful?

$400 is the cost of cheap LiFePo 140Ah, and you can buy a low$ temperature controller to activate a relay/contactor that is rated for over the max amps of your SCC output. And at 8 years that will have cost 1/3 to half less then these newer NOT warranteed things Walmart is selling.
The Grp29 is ‘Maxx’ with two year warranty

 

[RicoPobre]

With 1 year old batteries that may not be a good idea. They may not last well and for $430 for 4 new ones that is LiFePo range.

My latest experience with everstart group 27’s is two fold issues:
1) they are not labeled ‘Maxx’ nor is any warranty indicator on the label. But they are apparently only 12months warrantee…
2) my older group 27s are out of warranty but are still good testing voltage after being disconnected for two weeks- the new ones are what was dragging me to 12.1V quickly apparently as that’s where they went: 12.0xVolts

I do not recommend doing it.

$400 is the cost of cheap LiFePo 140Ah, and you can buy a low$ temperature controller to activate a relay/contactor that is rated for over the max amps of your SCC output. And at 8 years that will have cost 1/3 to half less then these newer NOT warranteed things Walmart is selling.
The Grp29 is ‘Maxx’ with two year warranty

I'm a 48v system so $400 is actually $1600.

 

[12VoltInstalls]

I'm a 48v system so $400 is actually $1600.

Yes.

 

[RicoPobre]

Yes.

So $1200 extra I don't have now....and $1200 for not much more capacity than I have now....I'm really looking at spending $2400 to get what I need in LiFePO4. Again, money I don't have. And that $2400 will run my predator generator for about 7200 hours.Over an 8 year period is about 2 to 3 hours a day of running it which is what I am doing now. Basically, I gain nothing by going with LiFePO4 vs my status quo.

 

[12VoltInstalls]

If you keep up on battery maintenance and maintaining 13.2+ with 13.8 float daily with them you might win the gamble. Are those a ‘Maxx’ version or the 1-year version ?