Hello, I am a leader of a boy scouts group in Belgium and last year I got the chance to build a portable solar energy unit which will be used for our summer camps to power fridges, lights and charge electronics.
This unit consists of solar panels, a smartsolar MPPT, a lead-gel battery bank and a victron multiplus 48/1200/13-16 inverter. I also added a raspberry pi running the venus os software to amulate a GX device. This raspberry pi is connected to the MPPT and the Multiplus using a ve.direct and ve.bus cable.
The setup works great, but there is a problem of having only limited output power and peak power (1000W and 2000Wp) because of the relatively small multiplus choice. This caused the inverter to sometimes turn off when too much power was drawn from it, for example when turning on multiple fridges at once. To remedy this, we are looking to upgrade the output side of our setup by adding an additional inverter. What I currently see as possibilities and their limitations:
- Adding another multiplus 48/1200/13-16 in parallel. This would be the cheapest option and would double the output power and peak power. However, as these small multiplus devices have only 1 ve.bus port, I would be unable to daisy chain both inverters together and to the raspberry pi, so I don't think this would be an option unless if I step away from the GX functionality.
-Adding a Phoenix inverter to the battery bank: As this would lead to a totally separate operation from the multiplus, this would lead to 2 separate AC output: one high power from the Phoenix and one lower power from the original Multiplus. This is quite confusing for people not familiar with power electronics who will be operating the mobile energy unit in the future. It also makes the original Multiplus quite redundant as the phoenix inverter will probably be capable of running the whole all the loads. This would make the Multiplus into an overqualified battery charger, only used to charge the batteries before we leave for the camp using the grid. This would also be more expensive than the other option.
-Not sure about this one, but I read about cascading inverters and I am wondering if I could cascade two multipluses together without linking them with a ve.bus cable. The first multiplus would take power from the battery bank and supply it to the second multiplus. The second multiplus would however have to be configured to not charge the batteries and only discharge them, because otherwise it would create a loop of charging and discharging the same battery bank. I'm also wondering if the output power of the second multiplus is limited to 1000W continuous, or if this 1000W is only the power it can draw from the batteries and, once supplied with input power, the total power it can deliver increases by the input power amount.
As you can see, all of these options have their downsides and I would like to know the thoughts of some people more familiar with Victron products on them, as well as maybe some other suggestions?