Solar-a-fication of a 1996 LX450
- Thread starter rhyary
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- #22
Unlike most solar installations where the connections are MC4 and very hard to disconnect, my setup has quick connects every where. So disconnecting the panels and storing them is easy.
No real need to run the engine while everything is connected.
However running the engine would only bring voltage up to 14.2. The panels produce 18 to 19 volts. So no issue with voltage.
I can't drive with the panels. They have to be either secure or taken off the roof.
Transport will have to be next project.
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No real need to run the engine while everything is connected.
However running the engine would only bring voltage up to 14.2. The panels produce 18 to 19 volts. So no issue with voltage.
I can't drive with the panels. They have to be either secure or taken off the roof.
Transport will have to be next project.
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- #23
Shunt:
The shunt tells the Remote the net amp going in and out of the batteries. All connections on the shunt are the negative side. Battery on one side, all loads are on the other.
In my case only the refrigerator and the controller remote are on the load side.
The refrigerator negative in the picture looks like a red wire, but its not. It is black on the other side while the positive wire of the refrigerator is all red.
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The shunt tells the Remote the net amp going in and out of the batteries. All connections on the shunt are the negative side. Battery on one side, all loads are on the other.
In my case only the refrigerator and the controller remote are on the load side.
The refrigerator negative in the picture looks like a red wire, but its not. It is black on the other side while the positive wire of the refrigerator is all red.
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- #24
Wiring diagram:
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I get why you might want to seal the back-side of the power pole connectors, but I think it is a bad idea. There is no body to body seal in that design, so any water that migrates thru between the bodies (and it will at least a little) now becomes moisture trapped inside the connector. The intentional design of the contacts is that they will wipe the contact zone clean of corrosion on every mate and de-mate. I do not know about that brand, but the Anderson's are silver, not tin plated. Gold is better at resisting corrosion, but silver is better for conductivity in contacts.
Was it me I would delete the RTV from the vehicle mounted connector and mount it pointed up. Add the cap for when unplugged if you don't already have that. Leave the RTV in the connector(s) attached to the panel(s). Now you've shielded the contacts from direct water while allowing them to breathe and dissipate any moisture that does make it's way into the contact cavities.
Sign me as a recently laid off Sub-Seas submersibles/robotics electrical connector designer.
Was it me I would delete the RTV from the vehicle mounted connector and mount it pointed up. Add the cap for when unplugged if you don't already have that. Leave the RTV in the connector(s) attached to the panel(s). Now you've shielded the contacts from direct water while allowing them to breathe and dissipate any moisture that does make it's way into the contact cavities.
Sign me as a recently laid off Sub-Seas submersibles/robotics electrical connector designer.
Why not use MC4 connectors that come on most quality panels? They were designed and proven for outside applications
Also much less in cost
Why not use MC4 connectors that come on most quality panels? They were designed and proven for outside applicationsthen Anderson plugs.
That was my thinking as well!!
Until recently you could only get the MC4's already terminated on not terribly flexible 10 ga. wire intended for permanent & stationary installs. As best as I can tell the MC4 won't readily work with larger gauge wires. I consider 10 ga. to the absolute smallest gauge that should be used in a 12 VDC solar system. Not for high current, because there isn't any, but for voltage drop considerations. Fully charged lead-acid is 12.7 volts. 50% discharged is 12.06 volts. Not a lot of margin there and even a 3% voltage drop is excessive. Search for the "Handy Bob" blog on this. It is a long and repetitive read, but the jist of it is that voltage drop is the biggest hidden enemy of solar system performance.Why not use MC4 connectors that come on most quality panels? They were designed and proven for outside applications
of course, any voltage drop is a loss of electrical energy and best avoided if it can be done easily and cheaply.
A reasonably designed charging system will give you a higher voltage than the 12.7V you mention, though. More like 14.5V typically. And the panel itself could be anything more than that. You often see panels that are rated at 20V or so Voc. With MPPT, there is even some feedback loop taking into account the battery voltage.
So, sure, a poor connector in the charging system is not great, but if you were to lose even 0.2V, say, after the controller, it'd be like going from 14.5V to 14.3V for charging your 12V battery. It'll still charge fine, just a tad slower. It's not like the battery would go from 12.7V to 12.4V or anything like that. And if the connector losses are before the controller, it would not affect the charging voltage much if at all.
So, I would not be paranoid about connectors and cables in the big picture, assuming you use reasonable size cables and connectors. Get a slightly bigger panel than you think you'd need in a perfect world and you're good to go. It may even be cheaper than buying those ultra-expensive unobtainium-plated zero-loss connectors we all crave...
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I have purchased Mc4 connectors from different sources and they all do not terminate the same. The installs I have done no $$$$pecial tool were used.
Unless the panels are loose and you'll be around to move them semi-frequently to keep them pointed at about 90° to the sun you'll have losses starting at the PV's themselves.
That panel voltage quoted by the mfg's & vendors is usually the open circuit voltage, no way they'll produce that when connected to anything.
The Anderson connectors may not be the best choice, but they are any easy to source choice that when sized correctly are appropriate to use in such a system.
For the controller to work best it needs to either be located in the same box as the battery(ies) or for it to have a remote temperature sender. Since the wiring between the controller and the battery will have the lowest voltage in it it makes the most sense to me to keep it as short as possible.
I'm not saying that it needs to be 0/ cable for a 100W system, but paying attention to these details is the difference between a marginal system and one the works well in spite of the obvious compromises.
Bumping the panel output is a dilemma that I'm working thru right now with a fixed panel system. I can go with a single 100W panel and use the PWM controller that I have, or I can go with both 100W panels that I have but I'll need to move to an MPPT controller that can deal with higher input voltages as both panels have MC4's on them and for the length of the run 10ga. is too small to run 200W thru. So I'd put the panels in series to double the voltage rather than the current and not pay the warm/small conductor voltage drop penalty. That, however, has me paying for a second controller. Nothing is ever simple....
If you are not using your factory roof rack #12 wire will fit easily in the factory roof racks mounting holes if you dont want to drill into your roof.
if you look at the typical curves for various irradiances on a given panel, the Voc does not change a lot but of course the Isc does. And the MPP is at a voltage that's not that much smaller than Voc, it's usually right at the bend in the curve. Which is where the MPPT will keep you at of course.