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georgeleonardo avatar image

Is it ok to add a second LiFePo4 battery later?

Hi! I was told that I shouldn't add a second battery later on, that they need to be together from the beginning. I wanted to start with a "Victron Energy LiFePO4 Battery 12,8V / 200Ah Smart" and add a new one later if needed. Would that be possible?

Lithium Battery
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4 Answers
tozz avatar image
tozz answered ·

Additional question, as I'm about to add extra batteries as well: Do the old and the new batteries have to be of equal SoC before adding the new batteries to the system?

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They have to have the same voltage down to 0.01V per cell.

Alternatively, they can be connected through resistor until the voltage equalize.

After equalization the resistor is removed.

Equalization is performed on the batteries disconnected from the system.

marekp avatar image
marekp answered ·

Hi,

If batteries are of the same voltage and chemistry, there should be no problem in connecting them in parallel. Older battery will probably have lower capacity than the new one, but voltages will have the same.

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tharbarn avatar image
tharbarn answered ·

How about fitting a new one alongside the older one each having a fuse. Then remove the fuse on the older one and use the new one for approximately the same time as the older one? Then use both together? That's my plan if I need to add in another battery. You can always pop in the fuse of the older one if you need it during the newer one, "running in"

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Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

I would say it depends on how much later and how much the battery is used in that time.

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Can you elaborate on your answer? Why does it matter?