Solar advice

CharlieRN

Greetings all.

The invoice for my T@B 320 BD references a 133w solar panel but a check with the nuCamp factory confirms the information that folks on this forum have suggested, namely that the 2021 BD package uses a 105w solar panel (by Sunflare.) The factory also confirmed that the controller used with the package is the Victron 75/10.

Views on how adequate the stock solar panel is vary, but I think I'd like to be able to add a portable, auxiliary solar panel in the 100w range.  I recognize that I will need an upgraded controller to handle the added wattage from an auxiliary panel. On a related issue, I plan to have the dealer install a pair of 6v golf cart batteries for added power storage. While the additional capability may not always be needed, the extra cost for the complete upgrade is relatively modest, and seems worthwhile from a cost:benefit perspective.

My thought was that upgrading to a 20 amp controller should be enough for an auxiliary panel of 100w to be comfortably used in conjunction with the stock 105w panel (205w/12v ~ 17.1 amps). Combined with a pair of 110 ah/6v storage batteries, I would then have a reasonably competent boondocking package. I'm a newbie to the solar power world however, so would like to ask for some feedback on the above from the wiser and more experienced on this forum.

Sharon_is_SAM

If you are going to upgrade your batteries, you should upgrade to 225 amphr capacity using a pair of 6v batteries wired in series.  When you don’t have enough sun, you will at least have an extra power margin with the higher amphr battery bank.  

pthomas745

On the basics, your 2 6v batteries are a good upgrade.  The newer fridges are very efficient, but the extra battery power puts you in good shape to handle that load, with extra capacity when the sun isn't as good.

Several owners have setups like you want.  Here are some threads with discussions to pass the time until one of the solar pros checks in.

https://www.google.com/search?client=firefox-b-1-d&sxsrf=ALeKk02rgHkXt5HrcDmQi8M1OuhWS15bcw:1606243785179&ei=yVW9X8LGCtPS-gTi4LaoCQ&q=solar+on+roof+and+portable+site:tab-rv.vanillacommunity.com&oq=solar+on+roof+and+portable+site:tab-rv.vanillacommunity.com&gs_lcp=CgZwc3ktYWIQAzoECAAQR1D3DlifQmCsSWgAcAJ4AIABdIgBgxaSAQQzOS4xmAEAoAEBqgEHZ3dzLXdpesgBBMABAQ&sclient=psy-ab&ved=0ahUKEwiCz_Ox7JvtAhVTqZ4KHWKwDZUQ4dUDCAw&uact=5

4ncar

...what @Sharon_is_SAM said, or as it would be in my case 235ah... same same🤣

morey000

there's a general 'rule of thumb' for sizing panels and batteries.  Good to have about 1 watt = 1 Ahr.  i.e. if you have a 130W panel, that'll be good to fill up/maintain a 130Ahr battery.  Of course- so many variables on that.  We have a lot of sunny days here in AZ.  

CharlieRN

4ncar said:

...what @Sharon_is_SAM said, or as it would be in my case 235ah... same same🤣

Thanks but that part's already in the mix:

" . . . [also] plan to have the dealer install a pair of 6v golf cart batteries for added power storage . . . [the added charging] combined with a pair of 110 ah/6v storage batteries . . . "

That would give me 220ah which may be enough storage most times, but still leaves me anxious about shady locations, unfavorable orientation and cloudy days.

Sharon_is_SAM

@CharlieRN - If you install a pair of 6v batteries in series, and each has a 110 amphr capacity, then you will only have 110 amphrs of capacity.  Only the voltage is additive.  If you want around 225-235 amphr capacity, you need to install 2 6v batteries each with 225-235 amphr capacity.

4ncar

Deleted so as not to confuse others, is I often get!🤦🏻‍♂️

Pong

Regarding the solar controller: if you get a solar suitcase for portable power, you can choose one with a built in controller, so then no need to change that. I believe that will work in concert with the installed rooftop solar and controller. If I’m wrong (very possible as I'm also new to all of this- picking up my Tab 320BD on Friday), hopefully someone will correct.

Sharon_is_SAM

@4ncar - You can install 12v batteries in parallel for the TaB for additive amphrs, but two 6 volts must be installed in series to get a 12v output.  Four 6v batteries can be used by connecting in series and parallel.  

https://tab-rv.vanillacommunity.com/discussion/12148/ganging-6-volt-batteries

4ncar

Shows you why I shouldn’t write when sleepy...🤦🏻‍♂️

Sharon_is_SAM

@CharlieRN - @Pong is correct.  Adding a portable suitcase with built in controller is the easiest way to add back up solar.  

However, if you want to only have 1 charge controller, you do need the 20 amp unit.  In addition, there are wiring challenges that involve combining the roof panel wiring with a pigtail that must be accessible from the outside of the TaB to allow you to plug in your suitcase. It can be done, but I think most owners who add a portable panel just use the built in panel controller and hook up at the battery.

I don’t know if you are planning on adding a shunted battery monitor, but if you do, the controller negative battery lead needs to be placed on the load side of the shunt, or you will not get a true state of charge reading.  

Sharon_is_SAM

Here is another discussion regarding attaching portable panels.
https://tab-rv.vanillacommunity.com/discussion/8921/add-portable-panels-to-factory-solar-tab-400

Tundra57

Not sure if it is mentioned here, but it is inadvisable to use multiple panels with the same controller unless they are identical.

If your external is not, you just need to add an extra controller for it and parallel the battery outputs. The controller can be external or internal. Mine for my external 200 W renogy panels is internal.

bergger

Sharon_is_SAM said:

@CharlieRN - @Pong is correct.  Adding a portable suitcase with built in controller is the easiest way to add back up solar.  

This is what I did as a backup.  I had NuCamp put an solar plug on the side of the trailer wired directly to the batteries.  I have had a GoPower 80watt suitcase for several years that I used with my old trailer.  It has it's  own controller and I can now plug it into the 400 for extra charging.  We have not had to use it yet but nice to have the option.

I also recently got a Jackery 1000 with 200 watts of solar panels.  We use it as a back up for out internet as our power is less than reliable at the house and my wife works from home.  I need to test it out to see if I can actually plug the 400 into the jackery with the pigtail as an emergency backup.  More curious about it than anything.   

CharlieRN

Thanks to all for the comment and advice. There are many more variables in the solar power equation than I was expecting!

I was not aware until I read as much in the replies in this thread, that it's not advisable to mix solar panels, and can't simply add, say a Renogy suitcase panel. The design of the Sunflare panel does not easily lend itself to portable use. I'd need to make a frame for the Sunflare and would then have to find someplace to store a rather large item. As folks have suggested, the easiest approach is to stick with the standard nuCamp solar package and augment it with a suitcase array with it's own controller.

Thanks also for the links to other threads discussing similar power issues. They too provided some very helpful information.

Mooree

We've been living full-time RVs for just over a year now, traveling North America and seeing all the amazing wilderness we can get in our 5th gear RV. Until a month ago, we relied mainly on 3400-watt generators to charge the batteries and turn on the lights. I was considering buying one of Renogy's portable solar panels. At this point, I really wish we'd buy one of these first. It manages everything I need to maximize solar energy collection and storage. It charges the battery in four stages, optimizing the battery's energy storage potential. It automatically detects flooded lithium, SLA, and gel batteries.