All about Solar Panels

Hey guys, i've been looking into learning what i can about solar and their efficiency. Will be using the power when offroading/camping, but the main focus reason is because i want to use them to power a smaller camper when off grid. I'll be doing a lot of traveling for work coming up and like the idea of not having to worry about being hooked up at a campground every single night for power.

I'm not a wiz at wiring, power consumption, etc. but have learned more the last 3-4 weeks then i've ever known about volts, amps, watts, conversions, and what accessories use what power. I recently purchased 2 fold out 100w (Rockpals) fold out solar panels because i like the idea of also being able to move the panels quick, easily, and being able to use them for multiple solutions without having them mounted.

However, i've realized that the fold outs are not as efficient when it comes to the price and the output, most of them put out less wattage then the cost of the more stationary ones. For those who use or have experience with solar panels, what are your thoughts of your setups to recharge your battery stations? I've been thinking a minimum of 400w's of solar input would be what i need. Maybe 200-300w stationary, then having the couple of fold out 100w ones to be able to use with the camper or to be able to pack on a weekend fourwheeling/camping trips.

 

Cool beans getting into the solar. I made the jump last summer and it's awesome.

I've only got a 100W panel, and as you know you never really get more than 60-70% out of a panel. Totally not a problem for keeping everything topped off on a sunny day. Even on a cloudy day, making ~20-30W, it keeps the fridge running no problem. 400W seems like a lot. Like, a lot.

Here's the full write-up of my setup, by all means, ask questions:

AdventureTaco - turbodb's build and adventures - Infinite Free Power | Page 175 | Tacoma World

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Thanks for the reply Turbo! The 400w would be for more of a camper setup. I'd be living in the camper while i travel for work so it would be running lights, TV, internet, laptops, etc. inside. a 150w computer or TV running for 3-4 hours a day will probably take at least 400w to keep the batteries topped off.

As far as the camping side of it, 200w should be plenty of power like you said for those weekend trips and keeping a fridge or power pack topped off.

What 100w panel do you have and do you know how many watts you average getting out of it?

 

One of the main concerns should be your charge controller’s voltage capacity... if you have read about series vs parallel. ie Jackery’s max voltage input is 30v but most 100w panels (like renogy’s) output 18v making any type of series wiring basically a non-starter. Two panels in parallel is nbd, four is doable, over that & youre pushing it. Look up a wiring chart for gauge needed vs current & distance.... don’t want 2 gauge wire running around all over the place. Overpanelling generally is not a terrible idea for winter travel. Also note if you are traveling you can also set up a way to charge from the vehicle alternator to top off between stops (ie inverter plugged into cigarette lighter or a fancier dual battery system).

for sizing... only you know the extent of your setup (ie there are people running 1000w of solar with induction cooktops & radiant electric floors) but a 240wh battery (20ah at 12v, pretty small) without any input will run a dometic fridge (60w but runs 10m/hr so 10w/hr for 24hr = 240wh). With input from a 100w solar panel you charge in 3-5 hours from dead. And with pass-through charging you actually end up basically not using the battery during the day. So it really only ends up using the battery overnight.

 

Right. I have a small battery box that i built from scratch. It has 3 12v 16ah batteries inside for 12v 48ah of power. I use it when camping, but just recharge it when i get home from the weekend. Usually just run small things off of it such as LED lights, air mattress, charge phone, etc. For something like that, i feel like 100w panel would hold charge on it and keep a fridge going for the weekend.

The solar generators i've been looking at (Bluetti) have pass through charging, which would be a must in using it for a camper circumstance. I'm thinking the 100w solar panel would probably be beneficial for my weekend needs instead of the 2 100w fold out ones, and then maybe just doing 400w or so on the roof stationary. I like the idea of portable ones better than stationary, but the efficiency of stationary seem to be a higher wattage for the cost.

 

Fwiw I really want someone to fab these brackets:

https://youtu.be/Skfy0jSoerU

because like you said, fixed panels are best value for $. But flexibles are somewhat necessary if you want to use blank curved space (ie hood, Thule box). And the fold outs.... idk I haven’t found a place they fit in w/ my use cases (esp at the cost).

 

Gotcha. A setup where you're working would definitely need more power.

I've got some generic panel from Amazon, and you can see the wattage I get out of it over a few hour period in the graph I posted in my write-up. Full day of sun yields ~500Wh. I had lots of learning in that post, so I'd recommend reading through it, but here were the solar-specific bits of my setup:

• Solar panel - TP-solar 100W Foldable Solar Panel Charger Kit.
• Charge controller - Victron SmartSolar MPPT 100/20 Solar Charge Controller w/Bluetooth

 

For sure!. Will check it out. I've looked at tons of videos and information so i'd love to look at a non biased outlook about some info. When pricing everything setting up (Solar, Charge Controller, Inverter, Batteries) most of these solar generator boxes that are coming out are almost cheaper than building your own setup.

 

that’s basically the conclusion I came to this year. Until battle born drops price substantially, if you need a “standard” size system the Jackery/Bluetti systems are fantastic value for $. If you need something custom (ie very large capacity or inverter) or plan on using shore power mostly is the only time they make less sense. Fwiw HOBOTECH on YouTube is a fantastic resource for these questions too.

 

Ive watched HOBOTECH so much i'm over watching him lol. Really though, he's tested it all. My basic concern is most of it with portable fold out panels is probably not the best for higher wattage. I like the concept of fold and sit out over stationary but for the price per wattage, it isn't the greatest. I'm thinking 400w, with maybe the 2000w Bluetti, will probably run a camper for my needs. 400-500w coming in during the day bypass would probably hold a decent charge for every day usage.

 

Tested the 2 100 watt fold out panels i just purchased, was getting 25.1 volts at 7amps from them, so 175 watts from them. Was pretty stoked about them having such a high efficiency. However i don't believe i'm really going to need that many watts with a fold out panel, so for the price i think i'm going to just keep 1 100w one for camping and purchase a few mountable ones to throw on a roof for the cost. Was surprised at how quick they were charging in direct sunlight though.

 

I think one of my first questions would be what type of battery(ies) are you using for your camper set-up? I use two Trojan 6v deep cycle flooded batteries together for my teardrop, and a 100w folding solar panel, with 30ft. Of 8 awg wire. I have no problem being out for a week at a time with that combo, and keeping charged my 12v fridge, ceiling fan when needed, LED lights, and charging ports for phone. If I absolutely had to I could hook back up to the truck and charge the batteries that way as well, ‘tho I’ve never felt the need.

 

For camping, i have 3 12v 16ah wired in a pelican style case. My buddy works for GE and they are batteries they replace in the mobile xray units. They're a type of acid battery i'm pretty sure. Not lithium. I just use that for regular camping.

For a camper, i'm probably going to pick up a 2000w portable solar generator, which seems like the easiest and around the same price as buying a lithium battery, inverter, controller, wiring, etc.

 

Although old, seems like a good place for some questions...

I have the BLUETTI EB3A. This works well for our weekend camping trips to power fans, cell phones, gopro and kids tablets. In addition, I have a small portable solar panel for devices and a anker backup charger.

I am looking to add a solar panel to the Prinsu roof rack. I have a nice space between my water tank and my pelican case for a solar panel. Renogy 100w seems to be the best for my budget, fit, and use with the BLUETTI for weekend camping.

• Is a charge controller necessary or can I just buy the panel, adapter cable and plug right into the BLUETTI ?
• Can these panels be ganged together if I decide to purchase more in the future ?
• I like the idea of a removable panel, or some kind of hinge for rotating the panel with the sun. Like the youtube video above.

Below are some links to what I have been looking at...

$109 Renogy Solar Panel 100 Watt 12 Volt, High-Efficiency Monocrystalline PV Module Power Charger for RV Marine Rooftop Farm Battery and Other Off-Grid Applications, RNG-100D-SS, Single 100W

https://www.amazon.com/Renogy-Monoc...mzn1.fos.18ed3cb5-28d5-4975-8bc7-93deae8f9840

$108 Renogy 100W 12V Solar Panel Starter Kit, 100 Watt Monocrystalline Solar Panel, 30A LCD PWM Charger Controller, Adaptor Kit, Tray Cables, Z Brackets for RV, Camper, and Other Off Grid Applications

https://www.amazon.com/Renogy-Monoc...&qid=1680092931&sprefix=Renogy,aps,157&sr=8-5

https://www.amazon.com/Renogy-Commu...qid=1680092931&sprefix=Renogy,aps,157&sr=8-15

 

Check the max input for solar on the Bluetti. Over paneling isn't a bad thing but if it only accepts a certain amount of solar, no use in putting way more into it. If you have the same panels they should be able to use as many renogy together. Most panels will allow that. Some fold out panels don't allow parallel linking.

You can plug the panels straight into the Bluetti, it has a built in solar charge controller so no need for another charge controller.

 

Step 1 is to add up up Amp HRs for all devices you intend to run, i.e how many amps for how many hrs.
Step 2 is to determine your usage environment - summer, winter, trees, etc. Estimate time of actual sun exposure.
Step 3 make assumptions about actual solar production vs rated based on step 2. I'd use a 30% as a catch all. Desert people I'd use 50%. This will give your daily Amp HR amount of recharge.
Step 4 determine battery size in amp hrs based on all of the above.
Depending on you trip lengths, you don't need to be able to fully recharge the system daily.
Size accordingly.
If you are in a tough solar environment Consider adding a DC-DC charger that can utilize either solar or your tucks alternator as need be.

 

I'm not sure I really get the argument on wattage for the cost. Spec to Spec, sure, but being able to adjust the panels easily throughout the day to follow the sun makes a MASSIVE difference in how much solar you are bringing in. I MIGHT move my truck once a day to help follow the sun, but if the camper is on the ground for an extended trip that's not really feasible. But my little 100 watt foldable panel, moving it regularly (sometimes even hourly), easily brings in as much or more wattage over the day than my fixed 170 watt panel.

Now, I don't know the current price difference on portable vs stationary, but unless the stationary are 1/2 the price, the watt/$$ might not be what you think it is.


On a separate note, I have been running a Bluetti AC200Max for a lil short of a year now. I went with that one over the older AC200P since the max allowed for expansion batteries (that i'll probably never buy, lol). I had dual AGM house batteries, solar controller, fuse panel, 12v plugs galore, and a big ol' Noco dual bank charger all put together in my previous setup. Was looking into doing a battleborn/victron setup for the camper, but once I priced it all out the Bluetti was so much cheaper and in a smaller form factor I just couldn't see building my own.

 

I agree. Fold outs are usually double the price. Usually around $200ish for 100w. If you watch them, you can swing one for $140+ on a deal. However, I'm like you, I'm always adjusting my 2 panels to directly face the sun. Goes from 80-115ish watts to 160-185w. Making a huge difference instead of having one mounted.

 

Thank you for the reply.