Finally Arrived Victron Multiplus II

DIDDLYV

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The victon Multiplus II I ordered the end of May came yesterday. Time to measure roof order panels and rest of stuff to go solar. Have the Battery Cells for 2 310 AH LiFePO4 batteries on hand and the BMSs for them
 

TAS CPA

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The victon Multiplus II I ordered the end of May came yesterday. Time to measure roof order panels and rest of stuff to go solar. Have the Battery Cells for 2 310 AH LiFePO4 batteries on hand and the BMSs for them
Mine is on the bench right now trying to figure out how it's all going to fit. It is WAY too tall to be standing upright anywhere in our TT.
 

DIDDLYV

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I am 1800 miles from home and have not seen it yet. When I get home will where to put it then put the batteries some place that makes sense and minimizes 12 volt heavy current runs. Thinking the solar charge controllers will be easy and not really distance critical like the main battery cables to the Multi plus unit. Just did the dimensions it is roughly 21.5 x 11 x 6 I may stick it in the current battery location.
 
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TAS CPA

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I am 1800 miles from home and have not seen it yet. When I get home will where to put it then put the batteries some place that makes sense and minimizes 12 volt heavy current runs. Thinking the solar charge controllers will be easy and not really distance critical like the main battery cables to the Multi plus unit. Just did the dimensions it is roughly 21.5 x 11 x 6 I may stick it in the current battery location.
By the time you include the cable/ventilation spacing, it is a lot taller than 21". Just my rough measurements, but seemed like it needed at least 30" if you are going to allow for the 10cm of air flow spacing specified.
 

DIDDLYV

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By the time you include the cable/ventilation spacing, it is a lot taller than 21". Just my rough measurements, but seemed like it needed at least 30" if you are going to allow for the 10 cm of air flow spacing specified.

The current battery compartment has something like a 19 inch door and a large void above and below the door so there is plenty of vertical space and also good ventilation as the bottom is open to the environment. I am assuming the unit must be mounted vertically and not on its side.
 

TAS CPA

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The current battery compartment has something like a 19 inch door and a large void above and below the door so there is plenty of vertical space and also good ventilation as the bottom is open to the environment. I am assuming the unit must be mounted vertically and not on its side.
Wish I had the space to mount vertically. You're lucky. Would have simplified a lot of the installation. Mine will be on its side, so I'll be adding two fans, one drawing air in, the other pushing it out of the compartment.
 

DIDDLYV

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Just got home a read the manual. Looks like they are recommending using 6 ga wire to connect the 50 amp legs of the shore power to the unit as well as 6 ga wire to wire L1 and L2 to the RV distribution panel with the Power assist mode L1 out put to the distribution panel can be boosted to 75 amps. Not that that would ever happen as don't think I have 75 AMPs worth of current draw if everything in my RV is running and I certainly don't plan on running a 10 hp irrigation pump or a welder. That silliness aside everything I have read says one should use 4ga wire for 50 amp circuits the manual recommends 6 guage wire for all AC inputs and outputs. Have any of you wired up a vitron multi using 4 ga or is 6 ga the max that will fit into the terminals? If the wire will fit I am not opposed to running 4 ga. Who knows until I pull the distribution panel I don't know if the wiring on my e 292 xl is 6 or 4 gauge. If it is six will probably just add 6 ga to get from the distribution panel and back taking AC to the Multi Plus and then back to the distribution panel.
 
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TAS CPA

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Don't know what the max awg the actual posts can take, but even at the 6 awg, people are having to remove the gland and use a step bit to open up the entry just to fit the 6-4 wire.
 

DIDDLYV

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The multi plus II may have solved that problem there is a 4.25 x 1.125 oval opening that has a smooth edge all the way around to run all the cables to the unit thru. Closer look that opening is just for the DC connections 2 x for positive and 2x for negative. There are 4 plastic knock outs or drill to proper size for the AC in and AC out cables. The system is capable of taking 2 AC inputs Reading the manual closer that is 6 ga minimum I have a large 50 amp cord I need to replace the connector on I can test it in the terminals easy enough. Heavy as hell so think, it is a 4 ga cord, it is what came with the trailer.
 
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Boondock Saint

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LMK your experience getting 4 up through the AC IN hole. If you can do it, with a 4 cond 50A cord. please post a pic. Thx.

.
 

DIDDLYV

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well let the fun begin. First test will involve pulling the face plate (for lack of a better term) to allow direct access to see if 4 AWG wire even goes into the connectors, if it won't then getting that heavy of a cable in thru the bottom is not an issue any longer if it does fit may have to drill the case out and use some rather large cable clamping devices for the inputs out put ac
 

DIDDLYV

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Just for the record the documentation sucks. The unit has a 1 0 II toggle switch. Being not totally clueless have determined the 0 is off. Guessing the 1 may be in the charger mode only the II inverter on if AC not present or in the power boost mode if limited amps like a 15 amp driveway surfing boosted by multiplus to run the AC and if AC not present in charger mode or if in the booster mode and running less than specified amp load excess power goes to charger. Guess I will know once all is hooked up and the micro wave clock does not come on when in the 1 psn without shore power.
 

Boondock Saint

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It's like every damned rocker switch that has a 0 and a | symbol, I can never remember which is On or OFF.

You just have to learn to speak "VICTRON"


.
 

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DIDDLYV

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0 1 is binary so 0 being zero means zero volts as in Off is how I remember it but the I and II is binary for 3 and no help at all
 

DigitalDave

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“…ventilation as the bottom is open to the environment.” Can the multiplus be mounted in an open (to the elements) compartment?
 

DIDDLYV

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I have been busy past few days. The positive leads from the solar panels go into a breaker switch then into the respective SCCs. All wires from the roof to the SCCs are the same length by color. All the black negative lines from the roof to SCCs and from SCCs to Bus Bars are equal. The positive feeds to the breaker switch are equal length as are the feeds from the bottom of the breaker to the SCC + connection. The red wires to the breaker and on to the positive bus bar are also equal length. I have wired a bypass switch with resistor to pre charge the capacitors for the SCCs.

sccs.jpg
The main 12 volt wiring is shown below. The Victron MultiplusII 3000 12 120 calls for 2 1/0 feeds for the positive and Negative leads to the MultiplussII. That coupled with the fact 2 40 Amp SCCs are significantly less expensive than one 60 or 80 amp SSC necessary for 4 210 what solar panels has caused me to make essentially 2 parallel systems that Join at the common Black Covered and Red Covered bus Bars. The smaller gauge red and black wires coming into the respective bus bars from the left connect to the existing 5th Wheel 12 volt bus bars that feed the Distribution panel and take electricity where ever Elkridge wired stuff. I did not change any of that. I did disconnect the shore power feed from the distribution panel breakers and put in a covered 50 amp junction box on the floor behind the distribution panel and connect the heavy black 50 AMP 4 wire AC cable to the AC input of the MultiplusII. I also ran the same type cable from the AC output back to the distribution panel hooked up the exact same way the original shore power was connected.
I am installing 2 310 AMP LiFePO4 batteries. The bottom battery connects to the Red wiring closest to the MultiplusII. I have installed a 150 AMP fuse on each of the battery feeds. Primarily because I am running 150 amp day BMSs on each of the batteries. The feed for each battery goes thru the fuse to the respective cutoff switch and on to the bus bar on the positive side. I have wired a 50 Ohm 100 watt resistor as a bypass across each of the cut off switches to pre charge the capacitors of the Multiplus II. At the red covered busbar the DC positive lines run to the MultiplusII and the positive battery connection from the SCC are connected. In retrospect I probably could have made do with one bypass and charged the MultiplusII capacitors and the SCCs by intially having the breaker between the SCCs and bus bars in the off postition charged the MultiplusII capacitors for 20 seconds or so then turn on the SCC breakers. Resistors and switches are inexpensive and the redundancy appeals to me so there you are.

On the negative side the black 1/0 cable will run from the P- on the respective BMSs on to the shunt and then to the Black Covered bus bar where the negative runs from the MultiplusII and the 2 SCCs join.





main 12volt.jpg
 

JoeHam

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Nice write up.

Of course it makes no difference that the wires from the solar panels to the SCC are equal. But, it is important that the wires from each of your parallel batteries to the busbar are equal in length.

Safe to assume that is the case ?
 

HRTKD

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That's a lot of work! You plan to secure all the wires, right? Since it is a mobile environment, every wire needs to be secured to prevent strain on the connections. That's all I can come up with for constructive criticism. Good job!
 
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