Two separated battery banks

[RickL]

I currently have three SOK 206ah batteries in parallel for my boat house bank. The battery bank has a 10 foot run of 2/0 cables running to the main distribution panel with a Victron 12/3000 Multiplus. I also have a large solar set up. Everything works great but I really could use more battery capacity. The battery compartment does not allow me to add more batteries in that location. I do have space on the opposite side of the boat that would also have a 10 foot run. I do not know the exact length of the original wires as they are buried within the boat structure.
How critical is it to have the same length cables as 10 feet probably has a fair amount of resistance vs the battery banks themselves?
Thanks

 

[DIYrich]

The system will work the closer batteries harder. May not get the full output of the farther batteries. IMHO, not ideal, but not the end of the world. You get more capacity, but maybe slightly degraded.

 

[Warpspeed]

If the cable lengths to both batteries are the same (or very close) it should work fine.

 

[MisterSandals]

I currently have three SOK 206ah batteries in parallel for my boat house bank. The battery bank has a 10 foot run of 2/0 cables running to the main distribution panel with a Victron 12/3000 Multiplus. I

So all 3 batteries are located together, right? How are the 2/0 wires for the 10ft run connected to the battery bank? Both + and - to one battery, or + wire to battery 1 and - wire to battery 3 ?

Happen to have a pic?

 

[RickL]

If the cable lengths to both batteries are the same (or very close) it should work fine.

That is the issue as the existing systems cabling I cannot accurately measure as it is not accessible. I can estimate 10 feet plus or minus 2 feet. I am considering throwing a shunt in the new bank and maybe adjusting the cable length after some usage. Just a thought. Looking for ideas and brainstorming

 

[RickL]

So all 3 batteries are located together, right? How are the 2/0 wires for the 10ft run connected to the battery bank? Both + and - to one battery, or + wire to battery 1 and - wire to battery 3 ?

Happen to have a pic?

The 3 bank is wired correctly with the plus to number one battery and the negative to number three. As I cannot get an accurate measurement of the 10 foot cable (plus or minus 2 feet) that raises the dilema of the second battery bank cable length. I may go with 10 feet and a shunt to se how balanced the system is. My normal current draw is 25 amps with occasional heavy draw. I can then adjust the cable length to try and balance the system unless someone has a better idea.
Thanks

 

[OffGridForGood]

I wonder if you can just measure the cable resistance, and try to match the new to the existing. Would this be measured in micro-ohms?

 

[RickL]

I wonder if you can just measure the cable resistance, and try to match the new to the existing. Would this be measured in micro-ohms?

It may be an option but I do not have the equipment to measure that low of resistance. I am looking at all options so thanks

 

[robbob2112]

This type meter will let you measure the micro-ohms. The link is for all 3 types of leads. You only really require the 4 wire leads. It can be had on aliexpress for about 1/2 the cost.

Amazon.com

 

[RickL]

This type meter will let you measure the micro-ohms. The link is for all 3 types of leads. You only really require the 4 wire leads. It can be had on aliexpress for about 1/2 the cost.

Amazon.com

Thanks. I will look in to it