Add Portable Panels to Factory Solar Tab 400

JeffroNC

What would be the best way to add some portable panels to my system? Can I add them in parallel with the installed panel? I have the Victron controller.
I know panels can be connected in parallel using a junction box. Should it affect the installed solar when I don't plug them extra panels in?
Ideally I would install a connector that on the outside for the additional panels and use the Victron to mange all of them. I could tie in to the the connectors coming down from the roof in back of the closet.

jkjenn

I asked, essentially, the same question in a different way and was thinking very much along the lines you are. Unless you were using the same panel specs, I think you want an either or, and not necessarily to combine them: 
https://tab-rv.vanillacommunity.com/discussion/8185/2-different-solar-arrays-would-a-switch-work

TNOutback

@JeffroNC did you reach a decision on adding PV to your factory install on your 400?  I want to be able to do the same thing, for those times when the roof-mounted panels are shaded and a portable set would work better.

Michael49

TNOutback said:

@JeffroNC did you reach a decision on adding PV to your factory install on your 400?  I want to be able to do the same thing, for those times when the roof-mounted panels are shaded and a portable set would work better.

I'm also interested in the same thing. If anyone does this would love to see how they have it set up. 

In order to keep things simple - couldn't I just buy a portable suitcase solar with a built in controller and attach it directly to my battery with some alligator clips when I want to use the portable solar? (I also have the factory installed rooftop solar on my 400).

Sharon_is_SAM

@Michael49, yes, you can attach the suitcase directly to your battery and charge in addition to your factory installed solar.  Because the battery is in a little, hard to get area, you may want to install some pigtails that can stay put on the battery and would make your access easier.

rfuss928

Sharon_is_SAM said:

@Michael49, yes, you can attach the suitcase directly to your battery and charge in addition to your factory installed solar.  Because the battery is in a little, hard to get area, you may want to install some pigtails that can stay put on the battery and would make your access easier.

Keep in mind that any DC outlet can also be an input.  Also the BAT +/- connections in the trailer to TV pigtail can be used.

Sharon_is_SAM

@rfuss928, so you can plug a combined solar panel/charge controller into an inside 12v outlet and charge the battery?  Would it require a higher voltage due to resistance?

Michael49

Sharon_is_SAM said:

@rfuss928, so you can plug a combined solar panel/charge controller into an inside 12v outlet and charge the battery?  Would it require a higher voltage due to resistance?

I'm curious about this as well. Would like the simplest way to charge the battery with portable panels.

rfuss928

Many battery maintainers come with a "cigarette lighter" plug for connection to the vehicle.  This is a common means of connecting to 12V systems.  There will be some wiring from the receptacle to the battery but probably no more than would be added by wiring some other connection method.  As always, wiring length should be kept to a minimum and the controller should be located at the battery end of the wires from the panels for best control of charging voltage.

Remember wiring losses are proportional to current. Therefore, the highest losses are when the panel output is highest and losses are the least impactful on the amount of energy available to charge the battery.  In contrast, when array output is very low or the charger is in the low amp float stage, voltage loss is also very low and most likely insignificant to system performance. 

In most cases, it is very unlikely you will ever see maximum rated output from a portable solar array and will most often be operating at 50% or less. 

COHiker06

Was Zamp solar a factory option on the 2018 Tab 400?  On my new-to-me 400 there is a Zamp connector on the bottom left side of the tub around the Propane tank and at first glance looks like it is spliced to the 12v lead from the 7-pin. 

Sharon_is_SAM

They eliminated the solar outlet with the 400 and 320 with the 2018 model year.  The solar outlet should be very close to the battery which is under the bed, so, not sure this will work so well due to voltage loss.

COHiker06

Thanks for sharing the wisdom. I get to trace that wire run and see where it terminates but I get to find where I'll run the new solar wiring!!

rfuss928

This is the supplemental 80w panel I use when the 136w roof array isn't keeping up.  I originally connected at a 12v outlet but now have added a connector where the added current will show on the existing solar amp meter.  I use a small inline PWM charge controller at the trailer end of the output wire.  This is our seventh season with the roof panels and third with the supplement.

DenisP

I just added a Furrion Solar Outlet to our 400 with factory solar. I purchased  a Renogy 100 watt suitcase during Amazon Prime sale.  The installation was pretty straightforward  Will be very convenient when rooftop solar is in the shade  

Tabfortwo

We added the solar suit case and charge through the seven pin plug works flawlessly. 

dCliffhanger

rfuss928 said:

Remember wiring losses are proportional to current. Therefore, the highest losses are when the panel output is highest and losses are the least impactful on the amount of energy available to charge the battery.  In contrast, when array output is very low or the charger is in the low amp float stage, voltage loss is also very low and most likely insignificant to system performance. 

In most cases, it is very unlikely you will ever see maximum rated output from a portable solar array and will most often be operating at 50% or less. 

I don't think losses are proportional to current. Losses are proportional to voltage drop which is proportional to  Resistance which is proportional to the length of and gauge of the wire.  The amount of electricity, current, has no impact on losses. However, the amount of power loss (volts x current=watts) is less when the voltage is kept higher as the voltage drop is fixed per foot so the % loss is lower with a higher starting voltage. That is a good reason to wire panels in series to yield higher voltages.

rfuss928

dCliffhanger said:

I don't think losses are proportional to current.

Absolutely incorrect  again!!!  As I explained to you two weeks ago in another thread:

V = I x R   =>   Voltage drop (V) equals the current in the wire (I) multiplied by the resistance (R) of the wire.

This is the most basic of all electrical principles!

Power losses, what really matters, is Watts = V x I.  a little algebra reveals Watts = I x I x R

So the real effect is that wiring losses (power losses) are proportional to the current squared.

falcon1970

V is simply voltage rather than voltage drop.  With a constant voltage (120v from the mains) as the resistance increases (as with a long or undersized wire) the current through the wire will decrease.  That is why, with a long and/or undersized extension cord, the cord will heat up and the power tool at the end will lose power--and maybe fail.

JEB

Tabfortwo said:

We added the solar suit case and charge through the seven pin plug works flawlessly. 

I like this idea. Where did you get the 7 way adapter?  My suitcase uses SAE connectors and I’d like to find one that would let me use it on the 7 way plug. 

dCliffhanger

rfuss928 said:

dCliffhanger said:

I don't think losses are proportional to current.

Absolutely incorrect  again!!!  As I explained to you two weeks ago in another thread:

V = I x R   =>   Voltage drop (V) equals the current in the wire (I) multiplied by the resistance (R) of the wire.

This is the most basic of all electrical principles!

Power losses, what really matters, is Watts = V x I.  a little algebra reveals Watts = I x I x R

So the real effect is that wiring losses (power losses) are proportional to the current squared.

Ok let's get this over. I apologize and stand corrected.  I didn't notice your prior explanation. The perspective I was taking was that the variables we have control over are the gauge and length of the wire (a key resistance component) and, indirectly the voltage, by whether panels are connected in parallel or series. The amperage becomes pretty much a dependent variable we don't have direct control over. If panels are in series they give higher voltage rather than higher amps which results in less loss on whatever length run you have to your battery controller and battery.  One could argue that the reduced loss is due to the lower current, or due to the lower voltage drop. But, I failed to acknowledge the impact that higher amperage has on resistance and, in fact, wrongly stated it had none. My physics must be getting old along with me.

Tabfortwo

It's the 120 watt go power. It comes with all the adapters. 7pin , zamp , battery alligator clamps and direct wire. Pretty sweet set up were able to switch from trailer to what ever we need.

rfuss928

JEB

This is the adapter I made.  A 7 pin socket with a pigtail and connector.

JEB

Tabfortwo said:

It's the 120 watt go power. It comes with all the adapters. 7pin , zamp , battery alligator clamps and direct wire. Pretty sweet set up were able to switch from trailer to what ever we need.

Understood. Thanks.  Go Power uses Anderson connectors, so the 7 pin adapter is one I’ve seen before.  Unfortunately it won’t quite get me where I need to go, which is 7 pin to Zamp/SAE.  Both this is helpful.

JEB

@rfuss928:  Thanks, this looks like it would work. 

rfuss928

JEB

Use pin #4 and #1 in the 7 pin socket for the + and - leads of your matching connector.

JEB

@rfuss928.  Got it. Thanks. 

rfuss928

Here is a convenient online calculator for voltage drop and power losses in wires.  You can easily evaluate the effects of varying wire length, wire AWG and amps.

http://www.myrclog.com/ecalc/WireCalc/Default.aspx