Recommendation for best size portable solar panel

aquadgolf13 · December 2025

Hi, owner of a 2023 Tab 400 with factory 185w roof solar. Planning to swap out the 100ah battle born with a 230-320ah battery. I'm considering a 300-350w portable solar panel either Renogy or Zoupw with the new N cells. Any recommendations for best size portable panel for charging, setup, storing, etc?

pthomas745 · December 2025

Back in the Old Days of lead acid batteries, the general rule of thumb was to match the wattage of the panel to the amp hour rating of the battery setup. This worked, because not too many owners were consuming a large amount of amp hours. If you only used 40 amp hours from your 80 amp hour battery in 24 hours, a 100 watt panel could potentially replace that 40 amp hours in under 8 hours of daylight. (There are lots of factors, of course). The 185 watts of solar on a 400 matched up fairly well with the 135 amp hours of "usable" power from the 225 amp hour lead acid setup.

Your 230 amp hour battery now gives you about 200 amp hours of usable power. The question would be: how much more power do you think you will wind up using? Do you have plans to use 80-100 amp hours a day? Or, is your amp hour usage going to remain about the same as what you have been using before? 300 amp hours of portable panel, on paper, could produce 24 amps an hour under "perfect" conditions. If you did happen to use 80-100 amp hours, you would replace that amount (again, under optimum conditions) in 4-5 hours. (And, this doesn't even add in the existing 185 watts on the roof of the trailer).

This isn't the "old days", especially with the prices of the panels much less expensive than they used to be. Both the Renogy and Zoupw seem to be good deals. I see some of the Dokio panels selling 300 watt setups for less than 200 bucks.

You really can't go wrong with that type of setup.

AnOldUR · December 2025

Similar to what @pthomas745 said, I've heard that in the past the minimum is to have the same wattage solar as your usable battery's amp hour capacity. IMO that's still generally true, but as you increase your battery Ah's, that 1:1 ratio becomes less important and your camping style has more of an impact. With extra battery capacity, recouping your daily usage from solar is more important than battery size. That's something that's a little different for everyone.

For us, having enough battery capacity to go a week (or more) with limited solar availability was important. Next was to have enough solar to recoup our daily power usage (up to 50Ah per day) even with poor solar conditions. To meet that, we move up to a 400W Renogy suitcase. We also have rooftop solar, but don't count on it since we try to park in the shade.

We've also carried a little 25lb, 700W propane generator for emergency charging, but have been bringing it less and less since its lack of use makes it hard to justify. Worst case, we have to hit a spot with an electric hookup every week or two.

Horigan · December 2025

We've been happy with our Renogy 200W portable panel. It has a small folded size and fits nicely in the under bed storage area on our 2019 400.
https://www.renogy.com/collections/portable-solar-panels/products/renogy-e-flex-200w-portable-solar-panel

ChrisFix · December 2025

I have the 350W Zoupw and it is really well built and comes with all the cables you'll probably want to have. Works great and is a good compromise between capacity and physical size. It isn't small to be sure, but is still easy to store, carry and setup.
You may already know this, but you will need a solar charge controller with this setup.

donmontalvo · December 2025

For my Jeep (JLUR), I run with a Rich Solar MEGA 200 Portable Briefcase Solar Panel (RS-X200B). It is a little on the heavy side since it uses tempered glass panels. It is connected to a Renogy DCC30S 12V 30A Dual Input DC-DC On-Board Battery Charger with MPPT (RBC30D1S) in the Jeep. It charges the Renogy 12V 100Ah LiFePO4 (RBT100LFP12SH-US) off grid battery in the Jeep. Here in Quartzsite, AZ, it is Winter so the sun is a little low, but the above combo easily keeps the LiFePO4 battery topped off. The DC to DC charges the battery from solar when camping, or from the Jeep's heavy duty 240A alternator (part of the towing package) while driving.

For my T@B 320S BBC, I run with a Renogy 220W Lightweight Portable Solar Panel Suitcase (RSP220LSC-US). It is connected to a Victron SmartSolar MPPT 100/30 that I installed in the Nautilus compartment's SAE port on the camper. It keeps my two Battle Born 12V 100Ah LiFePO4 batteries (a BB10012H and a BBGC2H set up in parallel) topped off easily on sunny or partially sunny days.

I didn't mention the 380W flexible panel on the camper's roof, since the OP asked about portable panels. I used to hang a 100W flexible panel under the roof rack, but that was before I bought the second solar suitcase. I might use it later if I buy a battery pack later on.

A couple RVers here at Quartzsite, AZ have a Renogy 400W suitcase. They're huge but the RVers say they're incredible, but harder to store than the 220W suitcase.

I schlep a Champion 2500W gas generator that I only use when there are stretches of rainy days and the batteries need charging, or when the temp goes into the high 80s and I need to run the Air8 air conditioning (which I set up with a SoftStart RV (the hard wired model). I keep a 5G fuel can attached to my Jeep spare tire, so good for five days of generator running.

Image: https://us.v-cdn.net/5021717/uploads/editor/ne/17rwuqizygpl.jpeg

aquadgolf13 · December 2025

Quite the setup, Don! Thank you all for the replies. Very helpful. I just pulled the trigger on a Zoupw 350 watt panel for $289 after a coupon code based on your assessment, Chris. I like the good compromise between capacity & size.

I installed a Victron smart shunt last year, so I plan to pair the Zoupw with a Victron 100/30 monitor both solar panels & battery in one place.

Recommendation for best size portable solar panel

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