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stwg34 avatar image
stwg34 asked

Parallel Multiplus + LifePO4 busbar connection question

Hi I'm working on an off-grid setup involving 3 parallel Multiplus2 48/5000 inverters (single phase 230V output), along with currently 4 diy LifePO4 13,4kWh battery banks (potentially extending to 8 batteries in total.), on the DC side I also got one 250/85 MPPT charger.
I also already have got 2 lynx power-in's potentially extending that one to 3 power-ins, in order to tie all of the above together.
And that's just where my question and confusion lies ...

1) following the parallel inverter setup manuals it seems to be best to alternate inverter, MPPT and battery connections on the (Lynx) busbar .. with a draw-back of not being able to use a battery shunt.
2) my initial idea was to combine the batteries on one side (occupying 2 Lynx power in's) and link that setup to my 3rd Lynx power-in which would host the MP's and the MPPT that setup would allow me to have a shunt between the inverters and the battery bank(s) .

I do know that setup 1 is advised for 'large' setups, although I'm not sure what determines a large setup. ..

I can see the benefits of setup 1 , but the big advantage of setup 2 is the use of the shunt .. which I would lose in setup 1.
Any thoughts on this setup ?

SmartShuntmultiplus in parallelbattery connection
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2 Answers
iammotorhomeless avatar image
iammotorhomeless answered ·

@stwg34 electricity likes to flow the path of least resistance

I have my battery bank in the middle of the busbar, my RS 450/200 (has two sets of cables) one either side of the battery.
Then my two MP II 48/5000 are wired, one on each outside end

I realy don't know if it makes that much difference, as my busbar is a pair of Victron Lynx Distributor bars
but in my mind... "I sleep happier" :)

edit... sorry forgot to answer your question.
save your money, and don't have a shunt... the Multiplus2 and MPPT charger will give you the same info as a shunt.


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stwg34 avatar image stwg34 commented ·
Txs, I totally get the peace of mind with a clean distribution of loads and batteries across the busbars.

And if the shunt doesn't add much , not installing it saves me a bit of additional setup.

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iammotorhomeless avatar image iammotorhomeless stwg34 commented ·

@stwg34 Unless you are running some DC loads, that you need to monitor, the info that you get from the shunt, can be got from the battery BMS and the Multiplus2 and MPPT charger

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Alexandra avatar image
Alexandra answered ·

@stwg34

If you keep a short bus bar, so not totally critical the order they are placed.

Current share becomes more of an issue on the long stretched out ones.

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