Battery Requirement for Victron Multiplus 3000

[scdock]

I saw a post on the GD Solar Facebook page that indicated a Victron 3000 Inverter/Charger requires at least 400ah of battery capability. I currently have 2 BB 100ah batteries. Am I really 2 batteries short? If I stay with 2 is that going to create issues with the Inverter? I'm still trying to figure out the grand world of solar in a RV.

[ncitro]

I saw a post on the GD Solar Facebook page that indicated a Victron 3000 Inverter/Charger requires at least 400ah of battery capability. I currently have 2 BB 100ah batteries. Am I really 2 batteries short? If I stay with 2 is that going to create issues with the Inverter? I'm still trying to figure out the grand world of solar in a RV.

I think this is a combination of needing that much capacity because of how much the typical user with an inverter uses, but mainly because of the current rating on a single 100ah Battle Born battery. I believe that’s 100A sustained, so four batteries would give you 400A max draw, which if you maxed out the inverter you might need.

[howson]

I saw a post on the GD Solar Facebook page that indicated a Victron 3000 Inverter/Charger requires at least 400ah of battery capability. I currently have 2 BB 100ah batteries. Am I really 2 batteries short? If I stay with 2 is that going to create issues with the Inverter? I'm still trying to figure out the grand world of solar in a RV.

The issue is a 100aH Battle Born can sustain a maximum output of 100amps. Since you have two batteries, that means the Multiplus will invert the 200A of 12vDC to 20A of 120vAC (ignoring losses). (Rule of 10 when inverting: 100A of 12vDC = 10A of 120vAC; 200A of 12vDC = 20A of 120vAC; etc.)

Your Multiplus is capable of inverting up to 250A of 12vDC which will output as 25A of 120vAC. To do that for a sustained period a third battery is required since two batteries can "only" sustain an output of 200A.

I have four batteries because that's the maximum space (and budget) I had for batteries. Three is the minimum recommended by AMSolar for the 3000VA Multiplus for the reasons outlined above.

Clear as mud?

Edit: You beat me to it, Neil!

[scdock]

Thanks for the clarification gentlemen. Glad the prices have come down on the BB batteries!!! I'll look to add at least a 3rd and maybe a 4th later on. I generally on use the microwave for short periods of time, a coffee maker, string lights outside, and a portable radio (plus the DW hair dryer and curling iron).

[Jlawles2]

I think the recommendation is probably to account for voltage sag also. The more batteries you have for supplying amps, the less the voltage sag. In flying FPV drones the 1.5 and 1.8 Ah batteries would see hits of 50+ amps for short durations, but the voltage sag could be as much as 1 volts or more (running 4 cell batteries at 16.8 volts). I watched my batteries cell voltage sag from 3.6 volts to 3.2 volts per cell (watch call volt recovery after landing) during a couple of hard pushes at the end of battery life. Those run from 4.2V per cell down to 3.2V per cell before damage may occur.