A design dilemma we frequently bump into is whether to recommend the Victron Multiplus 2000VA inverter/charger, or to bump someone up to one of the 3000VA models. We don’t want to sell people more than they need, but we also don’t want to limit future expansion. The relatively small price difference between the two options frequently leads people to one of the 3000VA models.
With a 3000VA inverter, you obviously get about 50% more output potential than you would with a 2000VA inverter. This extra output means you can run more appliances at the same time, or bigger appliances. With a 3000VA inverter, you can run a 15,000 BTU air conditioner. That’s not going to happen with a 2000VA. On some large induction cooktops, you won’t be able to get the heat much above medium on a 2000VA inverter, but you can do whatever you want with the 3000VA.
In terms of charging, the 12/3000 models have a charge rate of 120A. The 12/2000 models have a charge rate of 80A. This means that if you have a 400A lithium battery bank, taking it from near empty to 100% State of Charge will take 5 hours with the 12/2000, versus 3.4 hours with a 12/3000 model.
With the inverter/charger just by itself (no kit) the price difference between the Multiplus 2000 and a Multiplus 3000 is about 30%. If you buy the inverter/charger in a kit, you would be looking at a 10-20% price difference between the two inverter ratings. That price difference, just a couple hundred dollars, delivers 50% more performance and adds capabilities that may not have been possible.
Due to output current limitations of batteries, we recommend at least 100Ah of lithium battery capacity per 1000VA of inverter capacity. That doesn’t mean you can’t run a Multiplus 3000VA on a 200Ah battery bank, but expect your 3000VA to perform like a 2000VA until you get more batteries. With some lithium batteries that have very sensitive Battery Management Systems (BMSs), the startup current draw of a 3000VA inverter/charger may trick the batteries in an undersized battery bank into going into a protected mode, assuming there is a short circuit. This can sometimes be remedied by turning the inverter ON/OFF/ON/OFF and finally ON again.
We like to sell expandable systems, and it’s great that you can almost always add more lithium batteries and more solar panels if you have the space. But, once you have an inverter installed, your only option for getting more inverter output would be to add another inverter or replace the one you have with a bigger model.
There are two versions of the Multiplus 3000, and they are slightly larger than the Multiplus 2000. The chart below shows the specifications of our Victron inverter/chargers.
If a Multiplus 3000VA physically fits, and if at least 300Ah of batteries can fit, go with the more powerful inverter, even if your current loads and battery bank don’t support it. There may come a day when you are grateful for the extra power.