MC4 Higher than 40a???

[rafrojack]

Alright, so I'm working on a system with (4) 175w Renogy mono panels. They're putting out 9.8a each, 39.2a total (at least). MC4 connectors are only rated to 30amps. We'll be running 6 awg for the wiring. The solution would be 1) Finding MC4's with a higher rating or 2) Using a combiner. I really like the perks of running a parallel system but I understand that I can just series them (system has an EPEVER 60a 150V).

Looking for thoughts, insight, advice. Thanks!

 

[gnubie]

You can get higher rated MC4 connectors but they aren't the sort of thing you run into typically because domestic installations rarely have that sort of current flowing in the strings of panels.

https://au.element14.com/w/c/connectors/power-entry-connectors/power-entry-connectors/prl/results?st=Mc4

When you are dealing with more than 2 strings (which might be a single panel) in parallel you should have fusing between each string and the common wiring, typically this is done in a combiner box but you can get MC4 inline fuses too. With your all in parallel configuration on the common wire will be carrying 40A so unless you have the need to terminate with MC4 at the charger end you may not even need to handle that sort of current with MC4 connectors.

Are you talking about having a bus wire running around and fitting T connectors so you can hook each panel into the common bus wire? Curious as to how you are doing things.

 

[chrisski]

Building my first system, and I think you'll have trouble finding an MC4 connector for 6 Gauge. Most are made for 10 gauge with a few for 8 Gauge.

I consider that a design limitation, or a speed limit. What I did with my 6 panels, 100 watts each, I set them up 3 in series, with 2 sets of these in parallel (3S2P). When I went from 12 VDC to 36 VDC, it really reduced the size of the wire I needed for my voltage calculator. Each string of solar panels will be 10 gauge wire fed into a combiner that has an 6 Gauge run to the charge controller. This 6 gauge is another one of the design limitations I had because that's the largest wire that would go in my charge controller. With 6 Gauge wire and 600 watts of panels, I found I could only place the combiner 10 to 15 feet away from the battery before loss kicked in. The 6 Gauge wire is bare wire into the charge controller and terminal block for me, so no connector needed.

I think for higher rating, its different connectors, unfortunately, I don't know what those connectors are. Andersons are a common connector, and I have 50 amp Anderson connectors for a small portable panel to hook to a charge controller. The Anderson plugs come in higher Amperges. One drawback to the Anderson connectors is they are not nearly as waterproof as an MC4 connector. MC4 has an IP67 rating, which means it can be rained on and sprayed with a jet of water, but once you see the Anderson plugs, you'll see they are more exposed to the elements.

A few weeks ago, I found some MC5 and MC6 connectors, but these had no technical descriptions and as far as I know it was a vendor mislabeling an MC4 connector.

 

[Ampster]

Looking for thoughts, insight, advice

To me I would start with what I am powering. I know you like the perks of paralleling the panels but there are benefits to putting some in series so the voltage is higher and you can use off the shelf parts and thinner wire. Your charge controller could handle at least two of them in series.

 

[Supervstech]

FYI, 10Ga mc4 crimp tool is readily available around $30

8ga mc4 crimp tool is special order, around $300

6ga mc4 will be VERY expensive if available at all...

 

[toms]

Get rid of the MC4 connectors, use a good crimp butt joiner covered with adhesive filled uv resistant heatshrink.

Far cheaper and more reliable.

 

[HRTKD]

Another option is to bring the output of each panel into a combiner box. The advantage of that is you can still run regular MC4 and 10 gauge wire to the box, and then whatever gauge you want out of it, down to the controller.

 

[eXodus]

Alright, so I'm working on a system with (4) 175w Renogy mono panels. They're putting out 9.8a each, 39.2a total (at least). MC4 connectors are only rated to 30amps. We'll be running 6 awg for the wiring. The solution would be 1) Finding MC4's with a higher rating or 2) Using a combiner. I really like the perks of running a parallel system but I understand that I can just series them (system has an EPEVER 60a 150V).

Looking for thoughts, insight, advice. Thanks!

you can go half way,
2 in series each and those two in parallel. So you are running only 20A

You don't need a combiner box just a regular 2- > 1 MC4 adapter

 

[iceledoar]

Another option is to bring the output of each panel into a combiner box. The advantage of that is you can still run regular MC4 and 10 gauge wire to the box, and then whatever gauge you want out of it, down to the controller.

For combining PV in parallel this is my preferred method, it also allows for some nice breakers to be added, instead of fuses.

 

[eXodus]

For combining PV in parallel this is my preferred method, it also allows for some nice breakers to be added, instead of fuses.

where do you put the combiner box?

 

[Forbisher]

Alright, so I'm working on a system with (4) 175w Renogy mono panels. They're putting out 9.8a each, 39.2a total (at least). MC4 connectors are only rated to 30amps. We'll be running 6 awg for the wiring.

How many feet between your panels and SCC?
What do you think are the advantages of parallel connecting?
How about connecting 2S2P for a lower 20 amps and higher voltage so you can run smaller cable?

 

[iceledoar]

where do you put the combiner box?

As close to the panels as possible or conveniently located to reduce total wire length, both from the panels and the home run.

 

[efficientPV]

More than two panels in parallel have to be fused individually. Just think of 30A going into that one panel with shorted bypass diodes.

 

[eXodus]

As close to the panels as possible or conveniently located to reduce total wire length, both from the panels and the home run.

yeah I don't want that out on the roof. Possible the worst environment for a box with breakers.

 

[iceledoar]

Yea, I’d probably put it somewhere inside

 

[rafrojack]

You can get higher rated MC4 connectors but they aren't the sort of thing you run into typically because domestic installations rarely have that sort of current flowing in the strings of panels.

https://au.element14.com/w/c/connectors/power-entry-connectors/power-entry-connectors/prl/results?st=Mc4

When you are dealing with more than 2 strings (which might be a single panel) in parallel you should have fusing between each string and the common wiring, typically this is done in a combiner box but you can get MC4 inline fuses too. With your all in parallel configuration on the common wire will be carrying 40A so unless you have the need to terminate with MC4 at the charger end you may not even need to handle that sort of current with MC4 connectors.

Are you talking about having a bus wire running around and fitting T connectors so you can hook each panel into the common bus wire? Curious as to how you are doing things.

Thanks for your reply! So what I decided to do was just run all four into a combiner box (total amperage is 33.48amps actually) with a 40a fuse. Coming out of the combiner will be 6 awg PV wiring to the controller. Well within standards here. The link you provided shows single MC4 connectors but I was looking for a 4 to 1 connector to combine them that is rated for 40amps (which I still haven't found). If, I was able to find that then I wouldn't need the homemade combiner box.

 

[rafrojack]

Building my first system, and I think you'll have trouble finding an MC4 connector for 6 Gauge. Most are made for 10 gauge with a few for 8 Gauge.

I consider that a design limitation, or a speed limit. What I did with my 6 panels, 100 watts each, I set them up 3 in series, with 2 sets of these in parallel (3S2P). When I went from 12 VDC to 36 VDC, it really reduced the size of the wire I needed for my voltage calculator. Each string of solar panels will be 10 gauge wire fed into a combiner that has an 6 Gauge run to the charge controller. This 6 gauge is another one of the design limitations I had because that's the largest wire that would go in my charge controller. With 6 Gauge wire and 600 watts of panels, I found I could only place the combiner 10 to 15 feet away from the battery before loss kicked in. The 6 Gauge wire is bare wire into the charge controller and terminal block for me, so no connector needed.

I think for higher rating, its different connectors, unfortunately, I don't know what those connectors are. Andersons are a common connector, and I have 50 amp Anderson connectors for a small portable panel to hook to a charge controller. The Anderson plugs come in higher Amperges. One drawback to the Anderson connectors is they are not nearly as waterproof as an MC4 connector. MC4 has an IP67 rating, which means it can be rained on and sprayed with a jet of water, but once you see the Anderson plugs, you'll see they are more exposed to the elements.

A few weeks ago, I found some MC5 and MC6 connectors, but these had no technical descriptions and as far as I know it was a vendor mislabeling an MC4 connector.

Ahh. To be clear you're going from 36VDC from 12VDC is not affecting your system? Your MPPT will step it down to the correct 12v settings for charging, correct? Or are you running a pure 36VDC system with a converter for 12vdc loads?

 

[rafrojack]

To me I would start with what I am powering. I know you like the perks of paralleling the panels but there are benefits to putting some in series so the voltage is higher and you can use off the shelf parts and thinner wire. Your charge controller could handle at least two of them in series.

Thanks for the reply! How would what I'm powering come into play?

 

[rafrojack]

FYI, 10Ga mc4 crimp tool is readily available around $30

8ga mc4 crimp tool is special order, around $300

6ga mc4 will be VERY expensive if available at all...

I don't use crimp tools for MC4 :D

 

[rafrojack]

Get rid of the MC4 connectors, use a good crimp butt joiner covered with adhesive filled uv resistant heatshrink.

Far cheaper and more reliable.

I do like this idea :D