Halfway Parallel Wiring Method

[Robert T]

My first post! I hope this is appropriate for this forum, I considered using Beginner Corner, apologies if it should have been there.

I'm building a lifepo4 12v battery bank out of 4 Epoch 460Ah Essential batteries (powering a Quattro). I've read the options in Wiring Unlimited, searched the forums, and watched Will's videos on wiring configurations. And I'm still unclear on which method is I should use. It "sounds" like busbars is the technically the best but everyone seems to just use the Diagonal method for simplicity? So far I'm planning on using the Halfway configuration, using 4/0 gauge, and making all 6 battery connections equal length. Is there any good reason for me not to do the Halfway method? Thank you!

 

[FilterGuy]

That looks pretty good... Here is my thought process.

Start with two in parallel with diagonal connections.


That is a balanced pair of batteries as long as the interconnects are the same.

Now, think of the two as a single battery. Parallel two sets of the balanced pairs and do a diagonal tap off of the two sets


If the new interconnects are the same and you do diagonal taps, the battery connections are all balanced.

Now flip the top 2 around to put all the terminals near each other:


I was going to say this is a better layout than your layout, but as I studied it I realized it is the same as yours but with different positioning of the batteries

 

[Robert T]

Thank you for detailed response, I appreciated the info, I will go with Halfway.

 

[Robert T]

I asked Epoch, they told me "When running in parallel we suggest you run to the buss bar." So I will probably will go with that.

 

[GXMnow]

Equal length cables from each battery to a thick bus bar is the best way to ensure they share the current equally.

That being said, your original design would work fine, but I would use either double cables or a much thicker gauge for the center "X" of cables that are carrying two batteries vs the rest of the cables only handling a single battery. The main thing is, what will be your maximum current? If your peak current cam be handled by 2 batteries, it really doesn't matter. At light currents, they will stay in balance without an issue. At very high currents, the different total resistances and current could cause a small imbalance. Then when the load or charge current is lower, the batteries will balance together when running in parallel.

 

[Robert T]

^Really good info, thank you! I will only be using 100-200A which seems pretty light.