Blue Sea Amperage

[scdock]

I was reading the post on Double Pole Breakers and got to wondering if the installed Blue Sea switch, with 48v capacity, is sufficient for my solar array. I currently have 4 190w panels which are rated for an open circuit voltage of 24.09. The panels are wired in series/ parallel which, if my calculations are correct, would provide a max voltage of 48.18. Am I creating a hazardous situation by having a potential .18v over the switch capacity? I'll appreciate your expert advise.

[TedS]

Are you confusing voltage with amperage? What is the Blue Sea part number?

[scdock]

It's the 9003E switch, rated for 48v, 350A continuous, and 600A intermittent.

[howson]

I was reading the post on Double Pole Breakers and got to wondering if the installed Blue Sea switch, with 48v capacity, is sufficient for my solar array. I currently have 4 190w panels which are rated for an open circuit voltage of 24.09. The panels are wired in series/ parallel which, if my calculations are correct, would provide a max voltage of 48.18. Am I creating a hazardous situation by having a potential .18v over the switch capacity? I'll appreciate your expert advise.

Based on a google search I assume we're talking about GoPower! 190W panels? https://gopowersolar.com/products/hi...-solar-module/



When the post states "serial / parallel" to me that means two each of the 190W panels wired in series, then those two series panels (effectively now 380W panels) are wired in parallel. So double the voltage in the specs and double the amperage.

So under controlled laboratory conditions technically the shutoff is just a wee bit under-rated. Unless you're in a cold climate, with the sun perfectly overhead, with no loss in your wiring...it should be OK. It's highly unlikely the panels are going to generate their full potential. I have yet to see 1200W from mine (though they do climb up into the 1100W range for very short periods.)

Conclusion: you're on the ragged edge of the switch's capability but I think it's (just barely) OK.

That opinion is worth what you've paid for it.

Howard

[scdock]

Thanks for the reply Howard. You're correct on the Go Power panels. I figured it would have to be absolutely perfect conditions to hit the full voltage but wanted to get an opinion whether I'm most likely okay or "oh sh$t, you better get that changed out now!!".

[TucsonJim]

I have 800 watts of solar on my roof. It's two parallel circuits of 400 watts each. I've never hit the rated voltage in several years of camping. And you're looking at "open circuit voltage". That is with no loads applied. You'll never hit Voc. But you may hit the rated DC voltage of 20.4 volts which would be 40.8 volts on each leg.



Jim

[Scott'n'Wendy]

It will 'see' open circuit voltage in one situation..... when closing...but you will almost never do that I'm thinking? Even then it will likely be less than 48v.
I think you will be just fine for the reasons Jim and Howard said.
Curious though. Why a 350 amp breaker on 760w of solar panels?

[scdock]

It's the amperage rating on the Blue Sea 9003E switch. It isn't a breaker but a cutoff switch.

[TedS]

It's the 9003E switch, rated for 48v, 350A continuous, and 600A intermittent.

According to UL listing, I think you are OK.

UL 1107 defines the specific testing criteria for electric power switches-this includes marine battery switches. UL 1107 requirements and tests include:

Limits the spacing between exposed live parts to reduce the risk of short-circuits between terminals.

• Limits the spacing between exposed live parts to reduce the risk of short-circuits between terminals.
• Defines the temperature limits of all housings, knobs or other insulating materials during maximum current consumption.
• Defines the temperature limits of power terminals during maximum current consumption.
• Requires that one and only one switch undergo the entire series of rigorous tests in the standard.
• Requires the product to perform within temperature limits at 110% of rated continuous and intermittent current.
• Requires a vibration test be conducted for 12 hours in three axis planes while passing 110% of rated current and maintaining temperature limits.
• Requires a shock test be conducted with 5,000 vertical impacts of 10 g's, following that the product must pass 100% of rated current while maintaining temperature limits.
• Requires a cold and hot soak test at -40 Deg C and 60 Deg C where the product must be operable.
• Requires a drop test at a product temperature of -40 C from 3 feet above a plywood floor.
• Requires a dielectric strength test where 2,000 Volts DC must not be able to pass between open terminals or between terminals and mounting surfaces.
• Requires that an ignition protection test be conducted per UL 1500 to ensure gasoline fume environments do not present a safety hazard. In order to pass UL 1107, a battery switch must also pass UL 1500 Ignition-Protection Test for Marine Products.
• Requires a cycling test while the product is under full current and voltage load for a minimum of 1,000 cycles.
• Requires that switch information be provided on the product such as maximum ratings, knob positions, and rear terminal identifications.

[scdock]

Thanks for the additional information Ted. Unfortunately I didn't take the electrical engineering path in college but will lean on those who did. Good to know I'm not likely to burn my trailer down due to an overloaded switch.