Victron Multiplus and Multiplus II modifications

rh5555

I'm hoping to start a thread here for Victron Multiplus and Multiplus II users to contribute their discoveries and modifications.  I'll start this off:

Get shore power at your outlets even when the Multiplus is turned off.

I have found it annoying that in order to have120V power in my TAB, the Multiplus needs to be turned on, even if connected to shore power.  Sometimes it is inconvenient to turn on the Multiplus - maybe you don't want the hum and batteries do no really need to be charged but you want to use the microwave.  For about $25, I offer a simple solution:

This involves disconnecting the trailer 120V power from the Multiplus output and inserting a 120V DPDT relay into the circuit as shown.  Shore Power still feeds the Multiplus input, but also feeds the trailer if the relay is not powered.  The relay is only powered if 120V is present at the Multiplus Output (either pass-thru power of inverter power) in which case the trailer power is connected to the Multiplus output as before.

ScottG

I understand that the Multiplus acts as the battery charger when on shore power. However, is there a reason shore power has to pass through the Multiplus on the way to the 120VAC distribution panel?

I.e., why not just split the 120VAC shore power when it enters the trailer, and send one branch to the Multiplus for battery charging, and the other to the AC breaker panel for distribution to the regular 120VAC circuits?

I under the impression--perhaps mistaken--that the 120VAC circuits powered by the Multiplus inverter are separate and wired directly to the Multiplus.

rh5555

What you describe is how it used to be when the inverter wasn't beefy enough to run things like the microwave and the A/C.  With the introduction of the Multiplus, containing a 3kW inverter, all circuits are powered by the inverter when you're not connected to shore power (and you turn the inverter on).  It is then simplest to run all power via the Multiplus - with the downside that shore power isn't passed through when the Multiplus is off.

elbolillo

Let me share our experience with the Multiplus I installed in our ‘23 Tab 400. We took delivery in November of ‘22 and I installed the Victron Multiplus along with 4x 100ah LiFePo4 batteries. We have traveled 18,000+ miles. The vast majority of the time we have been boondocking. Even with heavy inverter usage, we are able to keep the batteries topped off with solar. However, we have spent a number of weeks in Tucson at a campground where we have had shore power. Once the batteries have been topped off we simply do not notice any significant noise from the Multiplus.

This really is the beauty of these systems. We no longer lug a generator on our trips and have never gotten below 60% battery capacity. 

ScottG

Thanks, @rh5555. I suspected I might be wrong and that the inverter was wired up to all the regular 120VAC circuits in the the new Multiplus systems. Clever mod with the relay!