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randy-reyes avatar image
randy-reyes asked

Paralleled Battery Wiring Order for Lynx Power In/Distributor

Hello,


Does it matter how I wire my 3 LifePO4 batteries to a Lynx Power In/Distributor as far as the order of positive/negative connections of each battery from left to right on the Lynx?

In other words, should the positive connections be connected to the busbars in reverse order of the negative connections to reduce imbalanced current draw of the paralleled batteries?

Examples that have caused my confusion:

From 'Wiring Unlimited'

1629170734463.png


vs.

From Lynx Power In Manual - Design

1629170843958.png

If I wire like the 2nd reference picture (from the Lynx In Manual: system design) than the current flow would go through the furthest right battery more than the furthest left battery, hence why 'Wiring Unlimited' (first picture) recommends having the flow go diagonally through the battery bank. So shouldn't the second picture show negative/positive cables connected in reverse order of each other? So confused.....


Max amps through my entire system will be 300amps


Thank you in advance!

battery charging
1629170734463.png (28.8 KiB)
1629170843958.png (46.8 KiB)
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Curtis avatar image Curtis commented ·

Did you ever figure this out? I’ve got the same conflicting info and trying to wire 3x 24v 200AH batteries in parallel…

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6 Answers
randy-reyes avatar image
randy-reyes answered ·

Bump... please help...

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Glen Carter avatar image
Glen Carter answered ·

I had the very same question, however, I am dealing with 8-100Ah batteries and 2-Lynx Power-In modified to use 100A mega fuses on each battery.

I thought about wiring

  • Battery1 + and Battery8, 2+/7-, .... to the same input position
  • All batteries wired normally and put Shunt/negative cable on opposite end of Lynx
  • Then I came up with the idea of the normal wiring layout, however, adjust the cable length to each battery so each battery has the same path length from the Lynx output terminal to the battery terminal.

One question I have is .... Is the Lynx 1,000A busbar large enough to eliminate the need to worry about anything other than each battery should have the same length cables? My thinking is the path of least resistance might only be affected by the cables to the batteries. In addition, larger battery cables will even lessen the length effect.


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Ed Jones avatar image Ed Jones commented ·
Simply put, yes.


If your system is only pulling 300A, don't sweat it. If you have 12 Quattros and many, many batteries then it's time to worry about it.

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Mark Anderson avatar image
Mark Anderson answered ·

Did you ever get an answer on this?

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ahtrimble avatar image
ahtrimble answered ·

Lynx PowerIn is a bus bar (1000amp).

Wire the batteries directly to the PowerIn via the 4 connection points (grouped together on the bottom - or grouped together on the top if you have inverted the units) for each PowerIn. The "prongs" are for connecting multiple Lynx units together...or adding things like Class-T fuses, battery switches, etc.

For 8 batteries, simply use 2 PowerIn units joined together.

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jmp avatar image jmp commented ·

OP is asking something more nuanced about the order -- compare the wire ordering from pic 1 to pic 2

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jmp avatar image
jmp answered ·

Was anyone able to get a solid answer on this? I'm using a Power-In with four 240AH batts in parallel and have the same question, but it seems elusive.


thanks

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ahtrimble avatar image ahtrimble commented ·
What exactly didn't get answered?
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semlohnhoj avatar image semlohnhoj ahtrimble commented ·
I think his question is not related to using external bus bars connected to the end terminals of the PowerIn but to how you connect the batteries to the PowerIn itself.

E.g. should you connect battery 1 negative to the left negative terminal of the PowerIn and battery 1 positive to the right positive terminal of the PowerIn (as per the wiring unlimited suggestion for a bus bar but unlike the Victron recommendation)?


I went with Victrons recommendations but I do see the issue however the bus bar is very short and thick, and I'm running at 48V with total currents under 150A across 4 sets of batteries so the cable lengths are the major issue in my case.


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ahtrimble avatar image ahtrimble semlohnhoj commented ·

This article explains it and pictures show it in detail


https://ahtrimble.com/2023/02/20/victron-lynx-powerin-used-as-a-battery-busbar/


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semlohnhoj avatar image semlohnhoj ahtrimble commented ·
Yep, that's how I wired mine, however wiring the positive and negative at reverse ends of the bus bar is what he's asking about which would give a better current balance to each battery on the assumption that all battery cables are identical lengths. But like I say, the solution is just adjust your cables lengths a little anyway to compensate for doing it the way we do it.
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regman54 avatar image
regman54 answered ·

What's common between the two drawings are the accumulated lengths of the positive and minus circuits from the batteries to their respective devices. Both drawings accomplish the same thing. Both drawings are wired correctly so follow the directions relevant to whatever device you have. Don't over think it.

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