For Boondocking: What is better more solar panels or more battery storage?

CampsiteGal · April 5

I want to add to my 12v system but where should I focus my attention and money? Collection or Storage? I have a 2022 T@b 400 BD I call the T@bacabana.

I have an external solar port that came originally from Nucamp that ties into the battery. Adding a suitcase solar array 100w or even 200w would give me more energy input to compensate for the PNW tall trees and overcast/rainy days. I would also have to check on the fuse amp and think I need a separate controller for it and get a 10' max cable.

I also want a battery monitor and I'm looking at the Victron BMV-712 bundled with a shunt; or maybe a smart shunt (700 or higher?). $$-$$$

For batteries I have the standard for 2022, 2 AGM 6 volt batteries with a Victron controller. The 2022 supposedly has a lithium switch that makes converting simple. Someday I want to upgrade to lithium batteries. $$$$

More solar means I can use the inverter more too plus keep the frig cold and crank up the fan during the day and use the lights at night.

I've been checking out the forums but does anyone know a good resource on configuring for a tab solar expansion so everything plays happily together?

Everyone in the forum seems to be finding solutions that work with their model and year but it can be confusing and contra indicative for someone new to 12V systems.

DM159 · April 5

We have upgraded our '22 TAB400 this past winter to LiTime LiFEPO4 230Ah battery to replace the 2 AGM batteries. The single LiFEPO4 battery is the same size as the 2 AGMs and is much lighter. The WFCO WF8955LiS (switchable to LIFEPO4 battery) converter is excellent at keeping the battery charged using shore power and the roof mounter solar panel. I have added another MPPT 75/15 solar controller for our 200 watt solar suitcase. Also we added a BMV712 Smart battery monitor to the mix. Also added a Micro-Air 364 Easy Start to the A/C. We are very satisfied with our power system as is.

webers3 · April 5

Solar recharges the batteries but does not provide the main power so your statement "More solar means I can use the inverter more too plus keep the frig cold and crank up the fan during the day and use the lights at night." makes a wrong assumption. More battery capacity is better than more solar capacity. Imagine you are boondocking 3-4 days without any sun, your batteries will be depleted very quickly. I would chose storage over collection

pthomas745 · April 5

If your AGM batteries are healthy, and have been getting you through with just the stock solar panels, improving your solar setup would be the most cost effective. Try the new panels with your current setup and see how much that improves things.

There are many lighter weight panel setups that go up to 200 watts which will work. With the Dual 6V setup, you have about 135 amp hours available. If/When you do upgrade to a 200 amp hour Lithium setup, that 200 watt portable solar, with the panels on the roof, will be more than adequate to keep that setup running.

The shunt should be included with the new panels. The shunt is a quantum leap in battery monitoring. It will let you see clearly how much power you actually have....and how much you have actually used. You may find your dual AGM's have been working much better for you than you suspect. And, when you eventually replace the AGM's for lithiums, the shunt will be even more useful.

You will need a solar setup with its own controller. If you add a shunt to the mix, the new controller does not have to be another Victron. The current controller and the new shunt will be able to monitor the information coming into the batteries.

Many owners have done this sort of upgrade. The lithium batteries do not have to be overly spendy. There are many 200 ah lithium options that do a great job, such as the LiTime batteries mentioned by DM159. Many owners have bought the LiTime, the SOK, etc. Look over the Will Prowse recommendations. Skim through some of his battery reviews on YouTube.

https://www.mobile-solarpower.com/lithium-batteries.html

bergger · April 6

I agree with @pthomas745. Focus on solar. Add a solar suitcase to what you currently have. No need spend the money on new batteries and ditch the 6v agms now if they are still in good condition. I have an early production 2021 400 with the dual 6v batteries and after 4 years the batteries are still going strong. I did add the Victron smart shunt at the factory and it's been great. I really recommend adding that. It really lets you monitor your electrical usage. I can literally tell which lights in the trailer use more power. Hint, hint, the accent strip lights use way more power than the over head lights.

We have the stock 163 watt roof solar and if we are parked in the shade I will plug in either a 100 watt panel or add the second one for 200 watts. Never had a problem keeping the batteries topped off even with using the inverter to run the coffee pot in the morning. We do have the 3 way fridge that runs on propane so I'm sure that helps us a lot with our power consumption.

So if I were you I'd keep the batteries you currently have, you can change to lithium when their life finally runs out, add the victron smart shunt, and get a solar suitcase. I would either get a 200 watt suitcase or a 100 watt panel that has the ability to add a second 100 watt if needed. The suitcase needs it's own controller. You can also have a cable longer than 10 feet for the suitcase. But check with the specs of the suitcase. I have a 16 foot cable and will plan on getting a second 16 foot to my kit this summer. This is allowed in the specs of what I have. I already had two 100 watt jackery panels so I simply added a goal zero controller to them. A self contained suitcase is certainly a cleaner set up than what I have. However I really like having he ability to just hook up a single 100 watt panel or both of them. The panels are super lightweight and easy to carry around.

Hammick · April 6

My advice is to use Victron equipment. It's worth the premium. We have a TAB 400 with the Lithium upgrade package. The external solar port is connected to a Victron 75/10 charge controller. That controller can't even handle 200w of solar. I will be upgrading it to a Victron 150/35 Charge Controller. This will allow me to use up to 600 watts of suitcase panels in series and not change any of the wiring. I'll be able to have over 50' of wire to the panels with only a 1% drop in voltage. The rooftop solar is 185w to a Victron 75/15 charge controller and I'll be keeping that as is.

I already have two Yargo YP100 suitcase panels and will get two more to start with. The 150/35 will allow me to use up to 6 of those in series. In my opinion having the panels in series is the only way to go if starting from scratch. You will need much larger wire if you put them in parallel.

subkron · April 6

In my 2022 400 I added a 100W renogy suitcase along with a victron controller and the shunt. The dual AGMs for us work out fine and using the suitcase is great. Once the AGM start aging I will switch over to Li but at this point it really makes no sense for use. We also have the 3-way and always have that on propane. Our biggest draw are 2 cpaps which knock done the AGMs to about 80% nightly but usually are recharged quickly in the morning. During overcast days/wooded sites I am more diligent about aligning the suitcase and we have dropped to 65% remaining a couple of times. I think it is more of where you camp, what you want to deal with and when, not if, you will need to switch to Li.

MarkAl · April 6

Also in PNW and camp mostly in trees/mountains/clouds. I have 300 watts available (1roof, 2 remote) but so rarely in good continuous sun that the panels rarely replace the lost charge from my 2 6V LdA batteries. Camping in the winter here, forget it the sun if visible is rarely above the surrounding mtns. As a few above have mentioned if your camping style has the batteries below 45-50% much you need higher capacity. I also have only the Victron shunt which is fine as I don't care seeing the battery state except once AM & PM. I will update to at least 200AH Lithium but my original batteries are still good and will wait. Also the Lithium will allow much faster charging to 100% as the Lead-Acid for longevity require slower topping off.

In our area suggest going with the shunt 1st, then a remote panel option, then update batteries when needed to what you find you need or 2nd after the shunt if you need more capacity. Remember whatever capacity you have unless sufficient for the trip can't be counted on to recharge if you are in low light most of the time. BUT with Lithium it will be faster than Lead acid. If going for longer than 3 days or expect sun I bring the remote panels - they strap to the carrier on the T@B & I pull them down if needed.

Camping on the east side and open areas I'm always amazed that I don't have to worry especially when I crank up the remote panels.

Denny16 · April 6

I second Mark. Start with what you have, add an external suitcase Solar panel, and get the Victron BMV-712 bundled with a shunt, or the Smat Shunt which uses your phone app for the display. We added the BMV-712 with its own display for convenience to monitor battery level.

The Victron unit already in your trailer is for the roof top solar, and is the solar controller, not a battery monitor per se. So adding the 712 gives you full 12-VDC battery monitoring, and the Victron app can tell you not only the battery voltage, but is current rate of use and how long you have power left for at that rate of use.

As for the battery bank it is 200-amps, and should provide enough power for a long weekend. We went three and a half days and three nights with the TaB400 rooftop solar, and had more than enough power. The TaB was parked under a small shade tree, so panels did not get full sun, and still had the 200-amp AGM charged by lunch time. We had the 12-VDC fridge running all the time, used lights at night, some radio for music and news, and the Alde at night (gas/mode but still uses 12VDC to,run circulation pumps and control system/display panel.

Get out and go camping, see how long your setup will work for, and go from there!

We planned on replacing the AGM with Lithium when it quits working, but since it is not brok (yet) why fix it. The Victron 712 monitor was the best 12VDC power system upgrade, so start there.
cheers

CampsiteGal · April 6

These comments are so helpful! Thank you for sharing your experience and expertise.

elbolillo · April 6

@CampsiteGal what kind of solar charger is the solar port on your Tab connected to? Knowing that would help you determine the size of panels that can be connected to it. I like the standard smart shunt from Victron without the display. I monitor the batteries along with my inverter and two solar charger via Bluetooth on my phone. We had the BMV-712 on our previous Tab 320, however with our new 400 I don’t miss having the physical display.

Like many have already commented, I would start with an external panel first to supplement your rooftop solar. You may find that is all you need to keep the batteries topped off. Work from there taking into consideration your style of camping and your specific needs.

Denny16 · April 6

@elbolillo The TaB400 external solar connector is not connected t9 a solar charger/controller. It is connected directly to the battery. Some installs had an inline fuse, most did not. You need a Solar Suitcase type setup that has its own controller. I bought a second Victron Controller to put between the external connector and the battery, so I could use standard portable panels (no controller) that I had.

Cheers

elbolillo · April 7

@Denny16 Thanks for the clarification. I guess if I would have read a bit more closely I would have seen that @CampsiteGal mentioned that it was connected directly to the battery. 😞

Hammick · April 7

Denny16 said:

@elbolillo The TaB400 external solar connector is not connected t9 a solar charger/controller. It is connected directly to the battery. Some installs had an inline fuse, most did not. You need a Solar Suitcase type setup that has its own controller. I bought a second Victron Controller to put between the external connector and the battery, so I could use standard portable panels (no controller) that I had.
Cheers

Depends on the year. Our '23 with the Lithium package has a 75/10 inline between the solar port and the batteries. Not sure what NuCamp was doing in 2022. I know they quit connecting directly to the batteries because some people assumed there was a CC and trashing their AGM batteries.

subkron · April 7

In my '22 the solar port goes directly to the battery. I placed another Victron controller behind the drawer under (3-way) fridge and mounted it adjacent to the Victron for the rooftop.

Denny16 · April 8

Hammick, thanks for the update on the newer lithium package TaB models, good to know. I was referring to the older, pre lithium battery package units, that had the external solar port directly wired to the battery, 2018-2022, as that is what the discussion was covering.
cheers

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