question

myren avatar image
myren asked

Dimensioning of inverter cables - is this really correct 4 cables???

It was brought to my attention by our technical drawing department, that there should be 2 x positive and 2 x negative cable for the battery. The cross section of the cables seems quite big, but due to the voltage drop I understand, but 4 cables?? is this really what Victron recommends?? Can´t see how we are going to fit 4, 70mm2 cable in 1642082367992.png


1642082449584.png


system design
1642082367992.png (220.6 KiB)
1642082449584.png (35.0 KiB)
1 comment
2 |3000

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

You did not mention which model of inverter / charger you are planning to install and also the length of the cable run.
0 Likes 0 ·
3 Answers
myren avatar image
myren answered ·

Lets say 5000 multiplus II 0 - 5 m cables We use Scankab 50mm2 xtreme with amp rating of 242

Seems excessive with 4 cables for 83 amps ( 4000w )

1 comment
2 |3000

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

The manual says recommended and max capability of the product. You're free to make your own calculations. Guessing from what you give use, you have a 48V system. The manual table says 200A and upwards on a short run using 70mm cabling.

Maybe your tech people misread?


0 Likes 0 ·
wkirby avatar image
wkirby answered ·

So a 5KVA MultiPlusII with continuous output of 4KW = 83A - agreed. Add losses +4% = 86A.
Let's make it 100A. So if you have selected a nice cable of 50mm² which is rated at 242A continuous? Then that will be perfectly adequate for your needs and you need 1x cable for each positive and negative.

The table in the manual is for general guidance based on a general cable. Nicer cables with better thermal performance of insulation can carry higher current than the table suggests and so then you need to do your own calculations - like you have done.

2 |3000

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

sailalibi avatar image
sailalibi answered ·

So if we used 2 50 mm2 cables do they both have to be fused (now looking at 2 fuse blocks with fuses)? Seems to me that a single 4/0 cable with 1 big fuse and block would suffice!

2 |3000

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