Anyone with SMA Sunny Islands 6048 set their battery system to 42 volts?

[road glide]

My 2 Forklift 48v GNB Tubular LMX 24-85-13 have 3 bad cells each. Thinking of leapfrogging past the bad ones with 2 gauge copper connector and cutting the lead connectors. Under "new battery" start and in the manual they will accept 42-50 volts.
Anyone try this or have thoughts?

 

[1201]

Paging @Hedges

 

[Hedges]

It is my understanding that works, but I haven't tried it.
I think others have set 46V nominal to better fit 16s LiFePO4 voltages.

 

[1201]

the manual says it can operate from 41-63v

 

[road glide]

the manual says it can operate from 41-63v

I have the SMA SI 6048 manual. 240 pages. Mine says 42-50.
On my master when initial "new battery" comes up only shows 42-50.
I can try 42 after reboot that should work but interconnects on cells must be removed. ( cut connect & isolate bad cell)

 

[Hedges]

Operating voltage range is different from allowed nominal.
Because the range includes 60V, I at first thought could use 5x 12V batteries in series. At max charging current that would suck down more watts. But not the case.

 

[road glide]

Page 71 of manual towards bottom..

For FLA and VRLA: Nominal voltage of the battery 42 V to 52 V adjustable in 2 V steps;
default setting: 48 V. (I tried that the other day for a moment and it worked. Went to 42 and back up)

We have sun coming after rain this week (Friday) So, Saturday and beyond I can test this application.
So in my limited knowledge of solar.....advice is always given to go past 12, 24 and 36 to a 48 volt system if your budget allows. That being said 42 volts is much better than the lower battery voltage systems..Logical?

End goal: Get the 2 batteries to charge fully rather than the 3 cells in each hindering that charging and suffer with a few less volts. Later this year replace bad cells...

 

[1201]

Page 71 of manual towards bottom..

For FLA and VRLA: Nominal voltage of the battery 42 V to 52 V adjustable in 2 V steps;
default setting: 48 V. (I tried that the other day for a moment and it worked. Went to 42 and back up)

We have sun coming after rain this week (Friday) So, Saturday and beyond I can test this application.
So in my limited knowledge of solar.....advice is always given to go past 12, 24 and 36 to a 48 volt system if your budget allows. That being said 42 volts is much better than the lower battery voltage systems..Logical?

End goal: Get the 2 batteries to charge fully rather than the 3 cells in each hindering that charging and suffer with a few less volts. Later this year replace bad cells...

Please let us know how/if it works so it can be added to the general knowledge base

 

[Hedges]

Sure hope so; the manual describes this (incorrectly naming 48V as highest nominal.)

Page 108 "Failure of individual battery cellsIf individual battery cells fail over several years of continuous operation, the nominal voltage can be set in the range from 42 V to 48 V. Up to three individual cells can be removed and the plant can still continue to operate."

https://files.sma.de/downloads/SI4548-6048-US-BE-en-21W.pdf

 

[road glide]

It's been a few days since I did it. But I distinctly remember going up to 50 and arrowing down to 42 (which is what I need) and back up to 48 default. Thought i found a donor battery in Lake Tahoe for $150. 36 volts 18 cells but the donor cells 30 inches tall are not correct. The label was unreadable... I need 85-13 (20 1/2 tall, 6 1/8 long and 4 7/8 wide.

Our solar is off due to the last week of rain and over 2023 really did not use it much. Relied on grid. We can go either way with no grid or grid. But we have just finished one major project and my goal is to revamp and renew my 6.8 system this year...

Sure hope so; the manual describes this (incorrectly naming 48V as highest nominal.)

Page 108 "Failure of individual battery cellsIf individual battery cells fail over several years of continuous operation, the nominal voltage can be set in the range from 42 V to 48 V. Up to three individual cells can be removed and the plant can still continue to operate."

https://files.sma.de/downloads/SI4548-6048-US-BE-en-21W.pdf

What they intend to convey is if cells go bad you can go to as low as 42 but logically you are not going upwards with failing cells. So 48-42 is correct but the new battery mode shows 42-50

 

[Hedges]

If 52V is supported, you could start with 26 cells, allowing more to be removed when failed.

"For FLA and VRLA: Nominal voltage of the battery 42 V to 52 V adjustable in 2 V steps; default setting: 48 V"


Dimensions of cell may be less important than capacity and chemistry.
You can always strap it outside the case and run cables to it.