My Camper builder installed a Victron Multiplus 12V-2000VA-220V charger/inverter in my new Van.
But they tucked it into the high end corner, on its side, against the wall and ceiling of the cabinet so now the outgoing airflow
of that Multiplus is completely blocked.
I need to know the internal placing of the ventilator in the hope with some external vents I can create some vortex airflow inside the Multi that runs WITH the internal ventilator’s flow to at least get some air flowing in and out the Multiplus.
Obviously a better location of the device should have done but that is simply not possible anymore without completely re-arrange the whole cabinet. Basically the builder messed-up and I have to correct it.
The multiplus (and other devices like the MPPT tracker and the Orions, produce heat warnings when working hard.
I already fit 5 thermostat controlled ventilators in the cabinet’s (3 in the door blowing in, two at a side panel extracting) so at least the hot air gets blown out the cabinet. (Measured 55 degrees Celsius ambient in the cabinet, 75 Celsius actually at the casing of the Multiplus!)
Its draws in at the bottom of the unit and vents out the top back. I am assuming you don’t want to add vents behind thetr. Could you space it a bit away a bit from the back? Mount it on something like blocks to stand it off from the back board?
It will derate like crazy at higher loads and will tempmwarnjng and shut down if used for extended periods like that. At the end of the day whats the duty cycle of your full 1600 watt load?
Whats the purpose of the strip? Surely changing that and slipping the inverter down a bit will give a bit of relief at the top?
Hi, thanks for your answer.
What you see in the picture as a ‘strip’ is not a strip. It’s just the part of the board the Multiplus is screwed onto. Visual disillusion. These black dots are actually black caps hiding its screws.
I’d been looking into fitting the MultiPlus any other possible way, but like said, it is screwed (internally) onto that board. To unscrew you need to remove the cap of the Multi which is impossible since I can’t reach the top screws. (I’v got 1 cm space). I think they build the whole cabinet after they fit the device. Going backwards is sort of re-building that whole area… I am not going to do that…
And even so, imagine I could ‘space’ it some distance from that back wall, I immediately have a problem to run the cables in on the bottom/side since they are all cramped and jammed into its plastic guide. I probably end up the have to run new cables or to extend them…
If I could at least remove the cover then I could drill a hole in it and fit a vent onto it to suck a way the hot internal air… just to try to cut a hole not knowing what’s directly behind is a gamble I am not willing to take… I might damage the interior and then need to break away that Multi… 
I am thinking now of fitting a ventilator extra that pushes air into the Multiplus from the bottom/bottom-side. With my hand it feels like some hotter air is coming out at the top so in pushing some air in at the bottom I hope to get some airflow inside the Multiplus that cools the interior. Also, I fit 3 big ventilators directly into the cabinet door directly opposite of the Multi that actually blow against that Multi. So it cools its casing at least a bit…
Really all you need to do is get the air moving faster and clearing the heated air before it accumulates. So i guess 
. Not much that can be done without colossal effort or weird 3 printed ducting
Yesterday received two small ventilators specially made by some guy in the Netherlands to fit on the bottom casing of the Multiplus.
Normally they both blow into the Multi but since that wouldn’t make sense in my case since its outgoing air vent
is blocked, I turned the top ventilator to suck from the Multi where the bottom one blows.
This should now establish some air vortex inside the Multi, see my photo.
And indeed, you feel a nice warm airflow coming from the top ventilator. Last night I had it run on shore power for several hours to load my leisure batteries and the combined ventilators both on the Multi as fit in the cabinet’s door kept the temp of the airflow leaving the Multi at around 35 degrees Celsius. (I ‘hang’ the temp sensor in the airflow leaving the Multi, its ventilators actually always work until the 220V is switched off. These vents are pretty silent.)
For the moment I am pretty satisfied.
Since these small Multiplus fitted ventilators always run I am confident it actually keeps the interior cool before the Multi really needs to work hard. This way heating up takes longer and that’s a plus too.
So you’re now circulating air around the first part of the MP instead of blowing it through the whole unit. Your toroidal transformer wont be happy about that.
Air flow short circuits like this generally lower the cooling capacity, since part of the exhausted hot air gets sucked irght back in on the intake. Common issue in all sorts of air cooled applications like building ventilation, air-to-water heatpumps or generator cooling.
The first few pictures do show some space left between the MP and the cabinet wall. Id bet placing both fans to blow through the MP would overall increase cooling, despite the smaller air outlet, compared to circulating it at the connection side
No, I thought of the issue of just circulating between both vents. First of all I put a shield inside that cover to separate the incoming airflow (to direct into the interior of the MP) from the outgoing air flowing to the ‘suction vent’ from the inside. So the incoming and outgoing airflows are separated by a hard border and can only mix when they are inside the interior of the MP. Together with the internal MP ventilator it must mix and replenish the inside air.
Before there was hardly any movement of air felt by my hand coming out of the MP. Which makes sense since the air inside is simply trapped and at best natural airflow would replace it very slowly. Now the vents actually boost that natural airflow. And the difference is noticeable.
The hot air being blown out is on top and blows directly towards a set of suction vents that move the warm air out of the cabinet. I might make some outside shield between the two ventilators to even outside the MP separate the two airflows. But I think 80% is taken care of by simple natural convection. Hot air stays up so the ventilator sucking in outside air is not getting that.
Second, what on the picture might look like some space between the unit and its wall. There is none. It’s screwed tight against the wall on the back, its top is touching it too and on the top (which is actually the side of the unit) there is just 1 cm at best. No way I can put some ventilator somewhere to circulate air into that small space.
Third, the metal front of the MP is directly hit by the strong airflow of the three ventilators in the cabinet door. So any heat that can dissipate through that metal casing is cooled down since that casing is kept cool. (Best would be to make a ventilation hole in that casing and fit another ventilator. But don’t want to risk of damaging anything inside. No way I can dismount that casing. Its screw are unreachable unless I break the whole cabinet down… )
So I’ll guess there is not so much more I can do.
(Well, I have a roof fitted aircon unit. It blows its cool air via the backdoor under the bed where the tech. cabinet is and thus that space is kept very cool. This cool air is then taken by the three ventilators to be blown into the cabinet. It helps a lot but its actually crazy to run the aircon to keep the inverter cook that in fact, is working hard to supply the aircon of 220V from the battery. I also need shore power or the batteries are drained in 3-4 hours time..)
