Wire too big for Victron charge controller

[team karst]

Originally Posted by noelex 77

..
Nevertheless, circuit protection on the input side of controllers is needed in some instances…).

What instances would that be?

[Statistical]

Originally Posted by team karst

What instances would that be?

One instance would be when it is required by regulation like most land based installations.

No such requirement exists in ABYC then again until recently no such requirement existed for ELCI/GFCI in ABYC regs either. They aren't exactly proactive when it comes to safety.

At one point solar arrays on boats were pretty tiny. Sometimes one or two panels 100 or 200w. Today we have people building 2kw sometimes even 5 kw arrays. It is a lot of power. Either it is a lot of voltage or a lot of current or a bit of both.

[noelex 77]

Originally Posted by team karst

What instances would that be?

Jedi summarised it nicely in post # 101.

The three or more panels in a string is good rule of thumb, but you can calculate if circuit protection is definitely needed. In some instances three panels in parallel is just OK without any fusing on the solar panel side. This article shows how to do the calculations:

https://explorist.life/how-to-fuse-a...y-not-need-to/


It is often said on sailing forums that circuit protection is only required on the battery side of controllers, but this is not correct. Unfortunately, many marine solar installations are inadequately fused (even when installed by professionals) as a result of this mistaken belief.

Note that if circuit protection is required on the solar panel side of the controller, each solar panel in the string will require a fuse or circuit breaker. This does not replace the need for a fuse between the controller and the battery.

[team karst]

If Isc is accommodated by the wiring, its OK, right? OTOH, I see shock protection as a looming threat on series installs, which could develop a hazardous situation if and when folks work on the panel side of the energy equation. I have seen upwards of 1200V developed by large arrays. It wasn’t on a boat, but we are working towards a hazardous limit in a wet environment. GFCI I predict will be indicated.

[s/v Jedi]

Originally Posted by team karst

If Isc is accommodated by the wiring, its OK, right? OTOH, I see shock protection as a looming threat on series installs, which could develop a hazardous situation if and when folks work on the panel side of the energy equation. I have seen upwards of 1200V developed by large arrays. It wasn’t on a boat, but we are working towards a hazardous limit in a wet environment. GFCI I predict will be indicated.

There is no return path via ground so there is no safety hazard except for those who will one pole in each hand, in which case we have natural selection doing it’s thing

BTW this is DC so very dangerous. My array, before being ripped off by hurricane Ian, was 120V DC.

[team karst]

Originally Posted by s/v Jedi

There is no return path via ground so there…., DC.

It so happens one of my panels does have an internal leakage path to DC-. Not yet resolved[emoji15]

But yes, those defects would require two independant faults, which most standards dont address.

Open question: does any installer hipot the array as part of commissioning?

[Statistical]

Originally Posted by noelex 77

Jedi summarised it nicely in post # 101.

The three or more panels in a string is good rule of thumb, but you can calculate if circuit protection is definitely needed. In some instances three panels in parallel is just OK without any fusing on the solar panel side. This article shows how to do the calculations:

https://explorist.life/how-to-fuse-a...y-not-need-to/


It is often said on sailing forums that circuit protection is only required on the battery side of controllers, but this is not correct. Unfortunately, many marine solar installations are inadequately fused (even when installed by professionals) as a result of this mistaken belief.

Note that if circuit protection is required on the solar panel side of the controller, each solar panel in the string will require a fuse or circuit breaker. This does not replace the need for a fuse between the controller and the battery.

I will add that while add that even when a fuse/breaker is not needed in many jurisdictions (on land) a PV side disconnect (switch) is required. Since breakers can also serve as a switch they are often used to cover both roles.

ABYC has no such requirement on either OCP or a PV side disconnect. In fact it says nothing about it at all. I think ABYC is a good but it is often slow to react to changes. Arguably marine solar has changed a lot in the last 20 years. Today people are in some instances putting up solar arrays which rival off grid land intalls. If ABYC says "don't do X" you probably shouldn't do X but if ABYC is completely silent on X it doesn't necessarily mean that X is a good idea.

On edit: clarifying that code for land based installations require PV side disconnect

[s/v Jedi]

Originally Posted by Statistical

I will add that while add that even when a fuse/breaker is not needed in many jurisdictions a PV side disconnect (switch) is required. Since breakers can also serve as a switch they are often used to cover both roles.

ABYC has no such requirement on either OCP or disconnect. In fact it says nothing about it at all. I think ABYC is a good but it is often slow to react to changes. Arguably marine solar has changed a lot in the last 20 years. Today people are in some instances putting up solar arrays which rival off grid land intalls.

Where does it say a disconnect switch is required? I don’t believe Victron has it in their diagrams and they don’t adhere to ABYC. You can always just disconnect the panel connector.

[Statistical]

Originally Posted by s/v Jedi

Where does it say a disconnect switch is required? I don’t believe Victron has it in their diagrams and they don’t adhere to ABYC. You can always just disconnect the panel connector.

I never said Victron requires it. In many land jurisdictions a DC disconnect on the PV side is require for code compliance regardless of what Victron says or doesn't say. I thought it was clear but I updated it for clarity.

I fully admit there is no such requirement on a boat. That doesn't mean it is a good thing just it isn't required. Until recently ELCI/GFCI weren't required on boats either despite being used on land for 30+ years. They didn't only become a good thing when ABYC finally belatedly added those requirements they were always a good thing the ABYC requirements were just lacking.

"You can always just disconnect the panel connector."
Panel connectors should not be disconnected under load. This is why a PV side DC disconnect is standard mandatory equipment in most land jurisdictions.


Look I am not saying there is any legal requirement for you to put a PV side disconnect on your boat. I am saying the exact opposite that no such requirement exists (to my knowledge). The question is if that lack of a requirement is a good thing. If you were putting solar power on your off-grid cabin in most parts of the world it would require a PV side DC disconnect. Moving that cabin to be floating on water certainly doesn't reduce risk.

[SailingHarmonie]

Originally Posted by team karst

If Isc is accommodated by the wiring, its OK, right?

Yes, with the caveat that the panels themselves are part of the "wiring" and you need to look at the maxiumum current carrying capacity of the panels and fuse for that, if needed. In many solar systems on boats,there is one panel per controller, so in this case, if the wire is sized correctly, there is no need for a fuse on the supply side because there is no hazard from a short.

Originally Posted by team karst

OTOH, I see shock protection as a looming threat on series installs, which could develop a hazardous situation if and when folks work on the panel side of the energy equation. I have seen upwards of 1200V developed by large arrays. It wasn’t on a boat, but we are working towards a hazardous limit in a wet environment. GFCI I predict will be indicated.

Except... there is no path to ground, or back from ground to the panel. A GFCI or RCD mounted at the panel will NEVER see a mismatch between current flow on the positive and negative lines out of the panel, even if it is runnning straight through your heart...

Which raises a question.... are there RCD that work on DC? Never had a reason to track them down, but I assume there are some odd places where they would be helpful....

[Nicholson58]

I can’t imagine the difficulty and hazard of not having disconnects on the PV panels. My solar charge controller even notes “do not power or depower the controller with solar panels connected. Three breakers on the left are two pole, one per panel. Right breaker is the controller output to the battery.

[team karst]

Originally Posted by SailingHarmonie

…



Which raises a question.... are there RCD that work on DC? Never had a reason to track them down, but I assume there are some odd places where they would be helpful....

Got a substation near? US subs run 125Vdc all around. Many in ROW use 220dc. Run outside in wet environments too.

There are fairly simple ground detectors in use. These dont use current difference, but instead look at Volt balance of both legs vs earth.

[team karst]

Originally Posted by s/v Jedi

-..
- Soldering creates hard spots. People who write that soldering creates the best contact are wrong. A high pressure crimp as with a battery lug has better contact. For smaller wiring it isn’t the contact resistance (we call it insertion loss) that is the problem with soldering, but it creates a hard spot that is likely to break copper strands just next to the soldering (copper work-hardens and any movement must be spread out over a length of wire, but the solder abruptly ends that and a stress riser is created)….
You can solder these connections, but you need specific skills, techniques and practice to eliminate those issues. I still do soldering, but I try to prevent it where I can. ...

NASA has speced anti-wicking tweezers to deal with this. Never used them myself.

[CharlieJ]

Such a simple question by the OP and 118 responses.

What do ya'll think about carrying guns aboard cruising recreational boats?

[team karst]

Imagine having this level of “help” on a real job. 🤯