Marine Considerations in a System Build

[Fryguy1111]

Hello, are there any specific marine considerations that should be prioritized in a solar system build for a boat? I understand some marine basics, like not using wire nuts, and using heat shrink tubing instead of electricians tape, using type 3 strand wire instead of solid wire, and using copper crimp connectors. I thought I read about using marine grade solar power cables, but I'm not too sure about that. Are there any other things one should be aware of?

 

[Bob B]

Don't use any glass fuse holders. If you are using any of the smaller fuses, use a maring spade type fuse holder.

 

[daholmes111]

A good source of marine electrical info is Pacific Yacht Systems (YouTube). Also Nigel Caldwell's book. PV panels and cables are made for long term weather exposure. If there are any panels marketed specifically for salt water I'm guessing they will be VERY expensive.

 

[Justin Laureltec]

@Fryguy1111, an important consideration is using not only stranded wire (which is true for all DC power) but specifically marine-grade stranded wire, which is tinned copper - each copper strand has been tinned so that the copper doesn't basically instantly start corroding in the moist and salty conditions found in marine environments. Ditto for your crimp lugs, you don't just want copper, you want tinned copper lugs. For your solar wiring, same deal, you want to use tinned copper cables everywhere possible. The wires that come with your panels won't typically be tinned copper, but you want everything from there back to be the proper cable.
Otherwise, of course you want everything you're using to be marine-grade and to have ABYC certification. For your battery switches/breakers you want the Blue Sea/Bussman battery switches (like the 9003e for a simple on/off switch, though there are lots of other options) and the Blue Sea/Bussman OEM 187-series surface- or panel-mount breakers are marine rated and freaking awesome little switches. There are also the MRBFs (marine-rated-battery-fuse) which are fuses that mount in a little holder directly onto your battery M8 posts or threaded inserts and you then takeoff your power leads from there... very good in tight areas where you might not have room to mount a full ANL fuseholder or such.
For your shrink tubing you really want to use 3-1 adhesive-lined shrink tubing to ensure that you get full sealing when you shrink it down.
Per ABYC, any busbars or fuseholders that you have of course need to have covers on them.
Any electrical devices like inverters or solar controllers should have an IP rating or at least drip-resistance when mounted in particular orientations, and anything going in an engine room needs to be ignition-protected...
...lots and lots more things like that; your inquiry is a bit broad to be able to address in total, so if you have specific questions, feel free to post them here and I'll answer what I can. ABYC regs and marine applications for power generation/distribution components are a large part of our business (roughly 40%), so we stock pretty much everything a boater might need to generate/distribute power and we know pretty much everything about what we stock, so there's a good chance that I -if not indeed several other members of this forum- might be able to help you with specific questions. Maybe start with a rough description of what you have vs. what you want to do?

 

[SolarRat]

Justin, when looking at charge controller options for my boat I noticed IP ratings of 43 and 22 for the Victrons. I'm used to at least an IP65 for most things I use on the boat. Can you explain how you would enclose/cool these IP43/22 devices in a marine environment? Are any of your controllers rated higher than that? Thanks!

 

[Justin Laureltec]

Justin, when looking at charge controller options for my boat I noticed IP ratings of 43 and 22 for the Victrons. I'm used to at least an IP65 for most things I use on the boat. Can you explain how you would enclose/cool these IP43/22 devices in a marine environment? Are any of your controllers rated higher than that? Thanks!

Sadly not; the drip- and light-spray resistance ratings of IP22 / 43 respectively are all that are offered in the solar controller range. The reasoning is that the controllers shouldn't be mounted outside in any case; for a multitude of reasons, the controllers should be mounted as close to the batteries as possible, and the assumption is that your house bank is going to be in a reasonably protected environment in any case.
Cooling is not an overwhelming necessity for the SmartSolar and BlueSolar controllers; they're exceptionally efficient, so as long as all of your connections are good, the controller won't be generating much heat. The only times I've ever seen these devices overheating is when a connection and/or intermediate component (such as the Blue Sea knockoff breakers that are all over Amazon) has gone bad... a bad connection generates heat. So long as all connections are secure, all crimps are good, cables are adequately sized, and all intermediate components are good, these controllers generate remarkably little heat and can therefore generally be mounted pretty much anywhere where they'll be protected from the elements. I've even seen several of our customers literally manufacture a waterproof cover from a Tupperware container just a bit bigger than the controller itself, caulked or otherwise affixed to the mounting surface around the controller, and although that's not manufacturer-supported and as such I can't personally recommend it, I will say that they haven't experienced any problems with the installation.

 

[SolarRat]

Thanks for your reply. Mounting it out of the rain is not a problem, but protecting it from 90% humidity is. I'd have to mount it in it's own waterproof and virtually air-proof housing and I'm afraid it would get way too hot in 100 degree weather.

Oh well, looks like I may have to lean towards a marine unit like Midnite's "The Kid" even though the reviews are all over the place. Or maybe I'll just use a cheap throwaway and replace it every year .

 

[Justin Laureltec]

Thanks for your reply. Mounting it out of the rain is not a problem, but protecting it from 90% humidity is. I'd have to mount it in it's own waterproof and virtually air-proof housing and I'm afraid it would get way too hot in 100 degree weather.

Oh well, looks like I may have to lean towards a marine unit like Midnite's "The Kid" even though the reviews are all over the place. Or maybe I'll just use a cheap throwaway and replace it every year .

Well the humidity isn't an issue, it's the direct spray and etc. that's the issue. Victron components are all designed to be put on marine craft, that was their original demographic to begin with until people discovered the RV/off-grid applications. The solar controllers are fully potted inside with their own proprietary admixture (I've cut one open and it feels like a siliconized acrylic mix to me, but I can't say for sure) and the only area susceptible to moisture is the actual cable connection terminals, which is always the weak spot in any controller.
Regardless, I can say that we've sold this to put on everything from 300' yachts to 60' trawlers to 20' pontoons and they work perfectly well in the salt air... could always add a film of dielectric grease or A-Special to your terminals if you were really concerned about it!

 

[SolarRat]

They definitely look more like a marine unit than most brands, which is why I was surprised with the low IP rating. If you say the innards are potted and protected then I'll put them back on the short list! Thanks again.

 

[Justin Laureltec]

They definitely look more like a marine unit than most brands, which is why I was surprised with the low IP rating. If you say the innards are potted and protected then I'll put them back on the short list! Thanks again.

A little hard to see, but even on the smaller MPPTs (this is a SmartSolar MPPT 75/15), if you look down in there you can see the component potting in (naturally) Victron Blue. The bigger MPPTs are even better sealed than the small ones because the front chassis(and thus the potting mold) wraps down around the front.