question

jean-paul-1 avatar image
jean-paul-1 asked

46 volt battery pack instead of 48 volt posible ??

Hello,

I have 24 lead-acid 2 volt, 1100 Ah batteries (48 Volt on 3 multiplus 48/5000 in paralel). Now 1 battery is worn out (it goes to 60 degrees as soon as charging starts).

My question:

Can the multiplus 48/5000 work with a 46V pack instead of 48V? Of course I will have to change absorption and float parameters and charging current limits but can it work? I would think it can since the "re-charge" lower limit is set at 42 volt now (the system starts charging from the grid at this level) and it all works fine. I realize that the use range will be reduced but like said, that isn't a big issue for me as such.

The alternative is to replace the old battery with a new one (about the same Ah) but that's not an ideal setup of course.

I don't mind loosing 2kWh of storage with only 23 instead of 24 batteries. In real life it's only 1 kWh anyway but I do mind replacing the complete battery pack because one battery fails ....

Any advise or remark is welcome.

Thks,

Jean-Paul

48v battery
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

4 Answers
Alexandra avatar image
Alexandra answered ·

@Jean-Paul

can you confirm it is the Multiplus not the Muliplus II?

According to the datasheet the input range is 38 to 66v. And Plylontec run at lower voltages like the ones you are proposing, so you should be fine.

You would just need to be more aware of the fact that you will now have a higher amperage draw under larger loads so are more likely to have greater voltage sag on the lead acid bank. (A bit of punishment for lead acid) And therefore more likely to overload, you sort of have a derating.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

seb71 avatar image
seb71 answered ·

Should work.

In case of LiFePO4 batteries, which for 48V nominal should have 16 cells, some manufacturers only use 15 cells.

As you said, you need to adjust all the voltages accordingly (not just the charging voltages, but also the cut off voltages, etc.) to account for the removed cell.

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

seb71 avatar image seb71 commented ·
Ninja'd. :)
0 Likes 0 ·
jean-paul-1 avatar image
jean-paul-1 answered ·

@ Alexandra: yes, Muliplus, not the II. Higher amps I didn't think about but with a load of 8-9 kW the difference is about 7-9 amps out of the battery which should not create too many problems I hope.

@ seb71: thks

WIll take the bad one out, reprogram the MPPT's and the Multiplus and see what happens then. I will adapt all voltages and see what happens.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Garry Kemp avatar image
Garry Kemp answered ·

I have the same problem with a 48v system - one failed cell. There is a 16 week delivery time for the replacement cell. I would be interested to know if I could temporarily run as a 46v system to preserve the integrity of the remaining cells until my replacement cell is available. My battery pack is 700ahr 24 x 2v gel cells. I have a Victron Quattro 48v/10000/140 inverter - can the settings be adjusted to compensate for the missing cell and if so can anyone help me out with the settings please? I purchased my off grid system as a pre wired package, so don’t the experience of assembling it and setting the parameters.

I hope you can help!

Garry

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Related Resources

Additional resources still need to be added for this topic