Yet another solar question

Syd

Hi everyone! Just joined because you lovely people seem to know what you are talking about, which is fantastic in the era of the Internet.

I have searched through this community, and through a lot of other forums, etc, but have not found the answer (nor question) to what I need to know. This is going to sound really dumb...

We are new to RV. Decades of tenting has not prepared us for some things. When we bought our 2019 T@B 400 (not BDL), we decided to buy a solar panel for those times that we could not be in a power site (like overflow, or Walmart). I know that the leads from the controller attach to the battery, and how they do, as I have successfully tested this and charged the batteries a bit. What I am wondering is - can I attach the controller to the 40 amp fuse by the battery shut off in some way? If so, how? Please explain like I am 5.

I will have other questions about an inverter, but that will wait until we buy one.

Thank you in advance!

pthomas745

What is the reason to shut off your solar panels?

pthomas745

You just want a fuse on the solar panel wiring?

Syd

@pthomas745 - not thinking about shutting off the solar panel, as I can unplug it. It is a portable one. I like the idea of the breaker between the solar controller and the battery, but I am also thinking convenience wiring-wise. If I want to unclip the controller, I have to open everything up. Having an option to reach into the side storage door to clip/unclip the solar controller (so there is no trickle loss on a shut off battery) is all I am looking to do.

Is it safe/possible to clip onto the breaker? If so, where does the black/ground wire clip in order to make the charge circuit? Am I overthinking this? 

pthomas745

The parasitic drain from the controller is very low.   I'm not sure where your solar controller is, but if you have access to the two wires heading into the battery, you could splice in a connector that you could just pull apart.  An Anderson or SAE connector for example.

Sharon_is_SAM

Wire a “pigtail” to the battery that then connects via Anderson or SAE as @pthomas745 suggests.  

trimtab

Who is Anderson?  no, really, where can I get info on that..please?

Sharon_is_SAM

There are MC4 connectors, but they can be a chore to get apart - right @pthomas745!

Here is an SAE connector.

And here is an Anderson:

Syd

I like the idea of adding a connection between the battery and controller. The portable unit we bought uses the SAE connectors, and I need an extension anyway, so I'll look for ends. 

Thank you for your help! I knew you guys would provide answers that I would not have thought about.

ScottG

@Syd, I second the idea of just adding a pigtail directly to the battery using whatever connectors suit your fancy. You can then run the pigtail out to any convenient location, making your panel and controller much more user friendly.

Note that there should be a fuse on the positive line connecting the controller to the battery. That fuse is sized for your controller and may be considerably smaller than the 40A breaker that protects the trailer wiring. You may need to incorporate such a fuse into your new pigtail.

Lastly, pay careful attention to the polarity of any new connections you make--make sure positive is always connected to positive, and negative is always connected to negative. The wiring of SAE connectors is not standardized across brands and if you are not careful you could inadvertently reverse the polarity between your controller and battery.

CrabTab

I went the SAE route to bring solar into the tub area on our 320. The main reason was that I could readily find a side wall port to get a finished look. Anderson connectors, MC4 and even Furrion all work, you just need to decide on a system.



This is the product I ordered.

https://www.amazon.com/gp/product/B07SWHKZZ9/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

As @ScottG recommends, be aware if you go the SAE route that some manufacturers (Zamp?) use the pins opposite of the 'standard' wiring protocol (I suppose for proprietary reasons) The item I purchased even comes with a polarity switching adapter, just in case...

pthomas745

The SAE cables are designed with polarized plugs, just like the many polarized plugs you have in your home.  What the SAE cables/ports are designed to prevent is having the big metal part carrying the positive charge, which could result in sparking from an energized cable.  These type of plugs have been used for years with this polarity setup in battery chargers, motorcycle accessories, etc. 

Using and wiring an SAE is pretty simple, but it does take a bit of thought to get them right.

Marceline

CrabTab said:

I went the SAE route to bring solar into the tub area on our 320. The main reason was that I could readily find a side wall port to get a finished look. 

Dumb question: Do you remember what bit you used to make the hole? I only had a step bit on hand and it wasn't quite big enough. 

CrabTab

@Marceline, NOT a dumb question! I used a hole saw to drill through the aluminum. It was pretty easy. I didn't use the included mounting screws, opting for small machine screws with lock nuts.

Marceline

CrabTab said:

@Marceline, NOT a dumb question! I used a hole saw to drill through the aluminum. It was pretty easy. I didn't use the included mounting screws, opting for small machine screws with lock nuts.

Do you remember the hole saw size by any chance? I think I'm going to have to come up with another plan since I already drilled something that looks to be about 7/8" and its just a tiny bit too small but of course I can't use a hole saw now. Doh! Maybe I just need to get a step bit that's one size bigger. It's always something.

Denny16

Try a hand drill and a large pipe reamer to enlarge the hole.
cheers

CrabTab

It looks like a 1" hole @Marceline. That gave me just a bit of extra clearance on the inner lip of the port. A bigger step bit would be my choice, but only because it'd be an excuse to collect another tool  If you feel like you're very close on size a half round file could get you there, albeit with more effort.

Denny16

I used a hole saw type drill to cut large holes.  Do a test hole on a scrap to test the size, with the fitting being installed.
cheers

Marceline

CrabTab said:

It looks like a 1" hole @Marceline. That gave me just a bit of extra clearance on the inner lip of the port. A bigger step bit would be my choice, but only because it'd be an excuse to collect another tool  If you feel like you're very close on size a half round file could get you there, albeit with more effort.

Thanks!