Solar Panel Wiring

o1marc · 08-02-2019, 01:37 PM

So I'm running into an issue wiring the panels. It's pretty self explanatory because the + & - leads can only plug in one way. But when I get to the end, the male and female connectors are the wrong colors. I can easily swith the wires going into the controller, but I'm not comfortable with red for Neg and black for Pos.

TheHubbardBus · 08-02-2019, 04:36 PM

I prefer not to impose roles on my wiring. Let them discover who they want to be, then be there for them no matter what. That's what unconditional love is all about.

Seriously though - are you saying you were supplied with pre-terminated wiring that was terminated incorrectly? If so, either send it back or swap the connectors.

o1marc · 08-02-2019, 05:29 PM

Quote:

Originally Posted by TheHubbardBus

I prefer not to impose roles on my wiring. Let them discover who they want to be, then be there for them no matter what. That's what unconditional love is all about.

Seriously though - are you saying you were supplied with pre-terminated wiring that was terminated incorrectly? If so, either send it back or swap the connectors.

This is where I ended up. I could rewire the ends, but can't find pins from anywhere but China. I can order some ends, but that 3 days before I get them. HD does not carry any solar panel accessories at all in store.

PNW_Steve · 08-02-2019, 07:58 PM

https://www.amazon.com/s?k=mc-4+conn...b_sb_ss_i_1_13

CMORGANSKOOL · 08-03-2019, 08:42 AM

Cut those ends off and put the correct connectors on the correct color wire. Problem solved. If you have any other solar questions you I'm happy to help as I've recently been through a crash course in solar, battery banks, inverter and all the associated math. I have tables and formulas and all the goods. And remember not to overload your charge controller.

30amp can handle about 300 watts of panels in parallel at 12v. You can run multiple controllers on one battery bank to handle the charge load.

TheHubbardBus · 08-03-2019, 09:06 AM

So if you had only two panels and were paralleling them together, you wouldn't have this problem, right? Your terminals are switched because you're daisy-chaining the MC4s, which is not the way they were designed to be used.

HazMatt · 08-03-2019, 09:22 AM

In these modern times, gender-bias has gone the way of the kerosene lantern.
Kinda quaint in it's simplicity, but irrelevant, except under dire survival situations...

Quote:

Originally Posted by TheHubbardBus

I prefer not to impose roles on my wiring. Let them discover who they want to be, then be there for them no matter what. That's what unconditional love is all about.

Seriously though - are you saying you were supplied with pre-terminated wiring that was terminated incorrectly? If so, either send it back or swap the connectors.

As to voltage-bias, am I incorrect in presuming the PV panel's electrons only flow in one direction?
Not wanting to toss down the Race Card here, but wouldn't this necessitate switching the wires from where they connect to the panel?

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TheHubbardBus · 08-03-2019, 10:49 AM

Quote:

Originally Posted by HazMatt

As to voltage-bias, am I incorrect in presuming the PV panel's electrons only flow in one direction?

What this thread needs is an energetic discussion of random drift.

Or, another (very slightly) relevant Simpson's image (don't mean to ride your coattails, but you've got great taste)

HazMatt · 08-03-2019, 11:01 AM

For that, let's consult with reknowned astrophysicist, Neil DeGrasse Tyson:

Quote:

Originally Posted by TheHubbardBus

What this thread needs is an energetic discussion of random drift.

Or, another relevant Simpson's image (don't mean to ride your coattails, but you've got great taste)

HazMatt · 08-03-2019, 11:08 AM

Or maybe even an irreverent image...

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TheHubbardBus · 08-03-2019, 11:09 AM

Gotta go make holes now. Good to be doing it with a grin on my face.

o1marc · 08-03-2019, 11:15 AM

Quote:

Originally Posted by CMORGANSKOOL

Cut those ends off and put the correct connectors on the correct color wire. Problem solved. If you have any other solar questions you I'm happy to help as I've recently been through a crash course in solar, battery banks, inverter and all the associated math. I have tables and formulas and all the goods. And remember not to overload your charge controller.

30amp can handle about 300 watts of panels in parallel at 12v. You can run multiple controllers on one battery bank to handle the charge load.

They have crimped pins on the end that would be gone if you cut them off.

o1marc · 08-03-2019, 11:25 AM

Quote:

Originally Posted by TheHubbardBus

So if you had only two panels and were paralleling them together, you wouldn't have this problem, right? Your terminals are switched because you're daisy-chaining the MC4s, which is not the way they were designed to be used.

I wired them in parallel per the directions from the manufacturer.

AutoBrad · 08-03-2019, 11:52 AM

Quote:

Originally Posted by o1marc

I wired them in series per the directions from the manufacturer.

Both of the illustrations in that photo show them being wired in parallel (all positive connections wired together and all negative connections wired together).

"In series" is the method where you connect the positive to the negative to increase the voltage of the panels or batteries.

CMORGANSKOOL · 08-03-2019, 12:19 PM

The crimp pins and the crimper are available on amazon for dirt cheap. Highly recommend you get a crimp tool, some pins and a tool for the connectors too. The right tool makes this and future projects super easy.

If you don't want to cut and change the connectors you could just put color coordinated tape on the cables.

Danjo · 08-03-2019, 01:12 PM

Quote:

Originally Posted by AutoBrad

Both of the illustrations in that photo show them being wired in parallel (all positive connections wired together and all negative connections wired together).

"In series" is the method where you connect the positive to the negative to increase the voltage of the panels or batteries.

Looks that way to me

o1marc · 08-03-2019, 01:17 PM

Quote:

Originally Posted by AutoBrad

Both of the illustrations in that photo show them being wired in parallel (all positive connections wired together and all negative connections wired together).

"In series" is the method where you connect the positive to the negative to increase the voltage of the panels or batteries.

My mistake, corrected in post.

o1marc · 08-03-2019, 01:32 PM

Quote:

Originally Posted by CMORGANSKOOL

The crimp pins and the crimper are available on amazon for dirt cheap. Highly recommend you get a crimp tool, some pins and a tool for the connectors too. The right tool makes this and future projects super easy.

If you don't want to cut and change the connectors you could just put color coordinated tape on the cables.

Just ordered 10pr. of connectors and a set of crimpers. I could cut and splice, but I really don't want any unnecessary splices in this system. Am I looking for higher input voltage (series) , or higher input current (parallel)?

CMORGANSKOOL · 08-03-2019, 01:46 PM

Each 12v panel in series increases the voltage by 12v so 2 would be 24, 3 36, 4 48 and so on, but you have to match the voltage to the controller, like some are just 12v mine is 12 and 24, and you have to match the voltage to the battery bank so if you have 24 volts you need two 12v batteries wired in series and a 24 volt inverter. The benefit of using 24, 36, 48 volts is you have lower amps and can run smaller gauge wire. 2 100w 12v panels in parallel are 16 amps. 2 12v 100 watt panels in series is 8.3 amps. 12v systems require 0ga, 4ga or 6ga wire depending on load to carry the current. You want the panels as close to the charge controller as possible, and the battery bank as close to the controller as possible and the inverter as well. I have a 3 ft run from the panels to the controller and a 3ft run from the controller to the battery. 12" from the battery to the inverter. The easiest way to set it up is to mount the inverter, controller and fuse box on a board or square of plywood. Ideally you want a fuse and switch between the panels and the controller and a fuse between the controller/battery bank, fuse battery/inverter. and a breaker between the battery and inverter

https://www.amazon.com/InstallGear-G...gateway&sr=8-3

https://www.amazon.com/ZOOKOTO-Circu...s%2C131&sr=8-7

Rate your fuses based off the load. 8.3 amp per 100 watts of power for the panels, and your battery is probably 100 amp. If you have a 200 amp draw inverter like mine you need two 100 amp batteries to power it.

CMORGANSKOOL · 08-03-2019, 01:58 PM

I just walked my dad through setting up a system in hawaii.

So for example if you have 1 30 amp controller you may want to run your system as 24 or 36 volts to keep the wire size down and amperage down. You can run 3 100w panels on 1 30 amp controller (24.9 amps) but you can run 600w at 24v (25 amps) safely. You can also run higher voltage longer distances with less voltage drop. I wouldn't worry too much about connections. You real losses come from using wire that's too small, cheap connectors and under size fuses where the amperage isn't allowed to pass and the excess power is dissipated as heat. I recommend 12v because it's cheap and easy and parts are readily available at local stores if you have a break down traveling. It's much harder to find 24 volt supplies, and 36/48 volt are only available for commercial applications so they'd be very difficult to source on the road. Just use heavy wires and connectors.

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