question

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bellpr asked

Sizing a Smart Shunt for LiFePo4

I will have 600 - 900ah of LiFePo4 batteries in my RV. Each 12 volt Battery is rated at 300ah with a 100Amp Continuous output and 200Amp Peak output. The Batteries will be wired in Parallel, keeping the system at 12 volts DC. 500Amp x 12v = 6000 Watts. 1000Amps x 12v = 12000 Watts. My RV has a 50Amp Service connection. Should I use a 500Amp Smart Shunt or the 1000Amp Smart Shunt? I think the 500Amp Smart Shunt with Bluetooth should be fine?

Lithium BatterySmartShunt
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2 Answers
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kevgermany answered ·

It's more the loads you'll be putting on the system than the battery size. So you'll have to guess at what you will use when/at the same time. Then work out shunt size. Also the voltage will be higher than the nominal 12V, which adds a little margin on 12V.

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Nev avatar image
Nev answered ·

The 500A shunt will be fine. Even with 3 of your proposed batteries at best 300A could be sustained. Expect less. Do you even have any appliances likely to occasionally exceed that for more than a few minutes?

Our RV 300Ah 4 cell LiFePO4 battery with no internal BMS limitation has started the 3.9l TD truck engine having to deliver a measured brief peak of 740A possibly a few thousand times over the last 8 years of fulltime travel. The 300A Juntek shunt and the now 2 year old series added 500A Victron SmartShunt still look pristine.



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