Victron multi plus 3000 battery bank size

[HngrFatz]

I started reading the manual for the Victron multi plus 3000 and I noticed it shows a minimum battery bank of 400ah. I’m assuming this has to do with maximum discharge current but that’s just a guess. I am planning a 3-100ah SOK battery bank for my system as I’ve seen others using it. Is there any reason it wouldn’t work besides having less capacity?

If it is due to discharge rate the 3 SOKs would give me equal or more discharge current than 2-206ah SOKs so I’d think I’m good.

 

[rmaddy]

The recommendation is more for how long the battery will last if you run the inverter at full power. And it's probably for lead based batteries that can only use 50% of that.

You have 3 12.8V 100Ah batteries. That's 3840Wh. The 3000VA inverter (volt amps, not watts) will run about 1.5 hours if you tried to max it out.

The 3 SOK 12V 100Ah batteries in parallel give you 300A of max continuous discharge. 2 SOK 206Ah batteries would only give you 200A. You need almost 300A to run the inverter at full power.

tl;dr - you're fine with your batteries and that inverter unless you need to max the inverter's power for more than 1.5 hours.

 

[HngrFatz]

The recommendation is more for how long the battery will last if you run the inverter at full power. And it's probably for lead based batteries that can only use 50% of that.

You have 3 12.8V 100Ah batteries. That's 3840Wh. The 3000VA inverter (volt amps, not watts) will run about 1.5 hours if you tried to max it out.

The 3 SOK 12V 100Ah batteries in parallel give you 300A of max continuous discharge. 2 SOK 206Ah batteries would only give you 200A. You need almost 300A to run the inverter at full power.

tl;dr - you're fine with your batteries and that inverter unless you need to max the inverter's power for more than 1.5 hours.

I didn’t consider the lead acid aspect, that makes sense. We plan to use an inverter generator during heavy loads and to charge the bank. In a couple months I will add 600w of solar to the roof to minimize generator use.

 

[Lilikoi_Heavy_Industries]

Are you designing this system around batteries you already own?

If you're considering things like integrated lithium server rack batteries in the future (I don't know your install form factor, etc), you may want consider designing for 48v. I love the 48v MultiplusII so far and plan on testing it with some 48v 100ah server rack batteries (either 1 or 2 at a time) soon.