MPPT sizing

[twistedtree]

While using single pole switching will disconnect the source/load, if you want true isolation you need to disconnect both sides. Not saying one way is better than another, just saying.

I see those switches are indeed two pole.

Yes, they are. I should know what ABYC says about this, but I do know NEC requires that you open both wires.


Another thing that I keep forgetting to bring up is that 60V is the dividing line between "low voltage" and "high voltage" for ABYC and others. It's pretty easy with series panels to get voltages over 60V which triggers all the same requirements as AC wiring, like connections being made inside enclosures, etc. Just something to keep in mind when doing solar. This particular build falls just short of 60V, if I recall correctly, but it's close.

 

[J.T kearney]

MPPT Sizing

Mr. Twisted Tree and all,
I reached out to several marine solar installers and they said you don't need a disconnect between the panels and controller. But I'll put one in for under 30 bucks, but they look very lightly built. And yes DBL pull for sure (I keep thinking of dc circuit). They have some nice waterproof packages on some solar sights. I'll be installing the panels off the stern of the flybridge this spring. Would like raise or lower them so I'm looking for some good hardware for install.
Thanks again every one (I've got to cook the turkey I've had in the fridge before it starts stinking it up)
J.T.

 

[Bmarler]

Mr. Twisted Tree and all,
I reached out to several marine solar installers and they said you don't need a disconnect between the panels and controller. But I'll put one in for under 30 bucks, but they look very lightly built. And yes DBL pull for sure (I keep thinking of dc circuit). They have some nice waterproof packages on some solar sights. I'll be installing the panels off the stern of the flybridge this spring. Would like raise or lower them so I'm looking for some good hardware for install.
Thanks again every one (I've got to cook the turkey I've had in the fridge before it starts stinking it up)
J.T.

it's true you don't need to have a disconnect before the controller, partly because you have the plugs at the panels, and you can also de-power the panels with shading. (a blanket) but it gives you complete control when commissioning the system to have them in place. mine are adjacent to the controllers themselves so they're protected from the environment. i think TT showed an enclosure for his disconnects that would provide rain protection. that would work as well, your choice.

 

[twistedtree]

it's true you don't need to have a disconnect before the controller, partly because you have the plugs at the panels, and you can also de-power the panels with shading. (a blanket) but it gives you complete control when commissioning the system to have them in place. mine are adjacent to the controllers themselves so they're protected from the environment. i think TT showed an enclosure for his disconnects that would provide rain protection. that would work as well, your choice.

Agreed. Just keep in mind that you cannot (should not) plug or unplug the panel MC4 connectors under any load. That are not meant for make/break of any kind. It's typically embossed right on the plug. This is actually one of the strongest arguments for having a disconnect switch, since otherwise you need to throw that blanket over the panels before making any connections or disconnects, which on a windy boat may be easier said than done.

 

[J.T kearney]

MPPT Sizing

Yes, especially with Bi facial panels I'd need to rap them up like sausages. Definitely going with the disconnect. I've never dealt with ferrels before. Does it take a special tool to crimp these on? I'd really like to go with 4 gauge wire and 60 amp fuse at battery. Victron video states it keeps the amps limited to 50 on the battery side. I'll check on the sights that were posted earlier for ferrels.
Thanks again all
J.T.

 

[twistedtree]

You can get ferrule kits with a crimper on Amazon. Just be sure it covers the wire sizes you need.

 

[J.T kearney]

Looking at this unit for a disconnect between panels and MPPT. There are others with a lower ampacity rating but this is in the 60's so it may be better. The Victron 100/50 requires a minimum 52 amp fuse but no greater than 70 on the battery side, so 60 it is. I'm thinking of a MRBF on the bank terminal with 4 gauge wire to the blue sea 6006 on/off switch. This will be about a 15 to 20 foot run(round trip) between the fuse and switch. The distance from the switch to MPPT will be about a foot. My big ? today is can I go down a size for my connection between switch and MPPT( because of wire size limitation at the controller)? I was thinking of 6 gauge at this connection. The from controller to switch (1 foot) and then to panels. It's the connection point at the MPPT that really throws a wrench in this design for me. They require minimum 52 amp fuse but only have capacity for a 6 gauge wire. Marginal at best!!!
Thanks again all
Here is the link-if it doesn't automatically connect-cut and paste in your browser.
https://www.amazon.com/Disconnect-W...panel+disconnect+switch&qid=1701805184&sr=8-9

 

[Bmarler]

Looking at this unit for a disconnect between panels and MPPT. There are others with a lower ampacity rating but this is in the 60's so it may be better. The Victron 100/50 requires a minimum 52 amp fuse but no greater than 70 on the battery side, so 60 it is. I'm thinking of a MRBF on the bank terminal with 4 gauge wire to the blue sea 6006 on/off switch. This will be about a 15 to 20 foot run(round trip) between the fuse and switch. The distance from the switch to MPPT will be about a foot. My big ? today is can I go down a size for my connection between switch and MPPT( because of wire size limitation at the controller)? I was thinking of 6 gauge at this connection. The from controller to switch (1 foot) and then to panels. It's the connection point at the MPPT that really throws a wrench in this design for me. They require minimum 52 amp fuse but only have capacity for a 6 gauge wire. Marginal at best!!!
Thanks again all
Here is the link-if it doesn't automatically connect-cut and paste in your browser.
https://www.amazon.com/Disconnect-W...panel+disconnect+switch&qid=1701805184&sr=8-9

i hate how those terminals are so small that you can't get the wire you want in there. you'll be fine with #6 in that short run if you have to. i'd still rather keep it all #4 and use a good crimp lug/ferrule that fits the terminal, but maybe that's not in the cards for you.
a 63 amp breaker on the input side is certainly overkill, but i guess it's really just a disconnect, so the higher amperage doesn't matter that much. the panels are current limited anyway, so i don't see any harm.

 

[J.T kearney]

mppt Controller

Hi
I saw a few disconnect switches that were in the 30 amp range but quit a bit lower in voltage. What do you think my minimum #'s for voltage and amps should be? I'll be looking for a rack system for the panels off the stern flybridge rails which are 1 1/2 inch aluminum!!!
Cheers J.T.

 

[Bmarler]

Hi
I saw a few disconnect switches that were in the 30 amp range but quit a bit lower in voltage. What do you think my minimum #'s for voltage and amps should be? I'll be looking for a rack system for the panels off the stern flybridge rails which are 1 1/2 inch aluminum!!!
Cheers J.T.

Are you wondering about the input side or output side? Maybe I’m just confused about where you’re putting the 60 amp breaker.
I built my panel mounts out of this stuff: https://www.google.com/search?q=ext...EDGIMBGMcBGK8BwgIIEAAYgAQYsQM&sclient=gws-wiz

There are tons of sizes of it and different brackets and hinges, etc…

 

[J.T kearney]

MPPT Sizing

Hi
Those #'s are regarding the disconnect switch between the panels and controller. I guess that is really overkill!!
Will be looking through your parts list. Looks like a ton of stuff!
Thank you J.T.

 

[J.T kearney]

Hi
Sorry about the late response! The 60 amp fuse will be at the battery connection. From fuse to a on/off switch next to controller. From controller to the on/off breaker switch to the panelshttps://www.trawlerforum.com/forums/images/icons/icon14.gif

 

[Bmarler]

Hi
Sorry about the late response! The 60 amp fuse will be at the battery connection. From fuse to a on/off switch next to controller. From controller to the on/off breaker switch to the panelshttps://www.trawlerforum.com/forums/images/icons/icon14.gif

Maybe edit your post and put a space after the word “panels” so the link works.

 

[SteveK]

Maybe edit your post and put a space after the word “panels” so the link works.

The link is the thumbs up icon

 

[Bmarler]

The link is the thumbs up icon

duh... thanks

 

[Bmarler]

Hi
Sorry about the late response! The 60 amp fuse will be at the battery connection. From fuse to a on/off switch next to controller. From controller to the on/off breaker switch to the panelshttps://www.trawlerforum.com/forums/images/icons/icon14.gif

that sounds like a plan.