Mounting Victron Multiplus to main mast bulkhead

[workmaster2n]

I'm getting ready to purchase and install a Victron Multiplus inverter/charger. After looking around the boat, I think the best place to install it will be in a cabinet against the main mast bulkhead (we have a catamaran).

I like the idea of mounting it against the bulkhead because the bulkhead should have plenty of strength, whereas if I mounted it on one of the other cabinet walls, I'd have to glue a piece of ply to the wall in order for there to be enough strength to support the inverter (my cabinet walls are all a thin foam board type material).

My bulkheads are ply covered in glass, so is there anything I need to do other than just screw the installation plate into the bulkhead? My previous boat was foam cored, so installing anything into a bulkhead involved routing out the foam and filling with epoxy. Do I need to do something similar with ply? To be safe, I'll put some sealant on the mounting plate and screw, just in case water somehow finds its way into this cabinet one day.

For reference, the unit weighs 19 kg.

[ggray]

I just installed one on our cat.

Where are your batteries? Good to have i/c close to batteries

[Jammer]

I use these and Devcon Plastic Welder, which is the consumer branding for Plexus MA300 methacrylate adhesive. Epoxy works too, but is slower to cure, a little more sensitive to surface preparation, and not quite as strong.

[CrispyCringle]

I second that the I/C should be close to the batteries, 5 feet or so, ideally. You didn't say what size inverter, but the DC cable requirements are large. I think I used 75 sq mm on my 2000VA Multiplus. What ever it was it was large and pricey. And you dont want a long run of wire because then you need even larger wire. You can download the install manual and see what the requirement is. But Im not an electrician, so what do I know.

[SailingHarmonie]

Another consideration for a unit like this. You really might not want an inverter/charger sharing your living space. They are quite noisy. At higher loads (both charging and inverting) there is a very audible 60 (or 50) Hz hum. The cooling fan is also fairly loud and turns on and off at unpredictable times.

I do not have great hearing, but I still find these kinds of intermittent, and irregular noises to be extremely annoying and distracting.

Your milage might vary, but it is something you should be aware of as a potential issue.

[MerMike]

Originally Posted by Jammer

I use these and Devcon Plastic Welder, which is the consumer branding for Plexus MA300 methacrylate adhesive. Epoxy works too, but is slower to cure, a little more sensitive to surface preparation, and not quite as strong.

He didn't say which model Multiplus he had, but a Multiplus II is 42 lbs. There's 5 attachment points so 8.4 lbs per bolt. That doesn't sound too bad. But let's say you slam off of a wave and momentarily experience a 1G impact. I'm no engineer, but that seems like a lot to ask from a non-mechanical attachment.

[Tin Tin]

Consider mounting on alloy plate (eg checker plate - will also dissipate heat) or rails that rest on the floor/base that will take most of any slamming load. The unit is not recommended to be attached to flammable material. I would put as close to batteries as will allow. Under a rear bunk is a common place, properly ventilated and mattress insulates the sound. Where is the current battery charger?

[Jammer]

Originally Posted by MerMike

He didn't say which model Multiplus he had, but a Multiplus II is 42 lbs. There's 5 attachment points so 8.4 lbs per bolt. That doesn't sound too bad. But let's say you slam off of a wave and momentarily experience a 1G impact. I'm no engineer, but that seems like a lot to ask from a non-mechanical attachment.

You have to stop and consider the fact that they're no more or less mechanical than the fiberglass that they're attached to, which depends on the inter-layer bond for its strength.. There are some good things about them. They spread out the load, they don't compromise the watertight integrity of the surface they're attached to, and they're easy and practical to install.

[u4ea32]

Originally Posted by Jammer

I use these and Devcon Plastic Welder, which is the consumer branding for Plexus MA300 methacrylate adhesive. Epoxy works too, but is slower to cure, a little more sensitive to surface preparation, and not quite as strong.

Tell me about these studs. Who makes them? Where did you buy them? How well do they work?

[Matt Johnson]

Originally Posted by u4ea32

Tell me about these studs. Who makes them? Where did you buy them? How well do they work?

You can buy they from McMaster Carr. Or you can buy Weld Mount studs and do a similar mounting procedure.

[s/v Jedi]

I recommend you glue a piece of GPO3 fiberglass to whatever you want to mount it to and drill and tap that for the Victron bracket.

https://www.mcmaster.com/products/gpo3-fiberglass/