Solar for Long Term Boondocking

Solar Panels

As technology changes, it seems inevitable that my power set-up will change. I put off analyzing my power needs and understanding solar and batteries like people put off going to the dentist. It took me 2 years to really determine what kind of set-up I needed for solar in order to sustain long-term boondocking. I think I have found a viable solution, for now. Let me start off with the pros and cons and then I will dive into details of my set-up. I will include some references to my battery and monitoring components as well, since they are related. I am neither an electrician nor a solar expert. Follow any of my advice or example at your own risk.

To read more about my dual GC battery set-up, watch the video.

To read more about my battery monitoring system, read here.

Pros:

  • Moderate cost
  • Lightweight
  • Actionable data analytics
  • Mobile app
  • DIY

Cons:

  • DIY
  • Thicker, 8 guage wire difficult to work with
  • Still have limitations: no a/c, no hairdryer, ect..

Details:

Solar Panel Selection

When Renogy offered flexible solar panels, they became all the rage. Why? They were so much lighter and easier to mount. I never liked the idea of a permanent mount of solar panels on a T@b for four reasons. First, I didn’t like how they looked on the T@b. That is 100% personal preference. Second, it limited where you could park your T@b and charge your batteries. With a permanent install you have to be in the sun. Third, solar technology is still in a faster changing period and I wanted to be able to upgrade my technology in the future without leaving marks on my T@b. Lastly, in general, solar performs better at lower temperatures. Permanently mounting the panels to the T@b can cause het build-up under the panel without proper room to breathe. This can damage your clear coat or paint. I know this last point is true, because I have a 50 watt Renogy flexible panel I use a trickle charge when the T@b is not being used and with just mounting via 2 top suction cups, and have a  small patch where the clear coat has been damaged on my T@b.
However, those flexible panels are light. Some subjective testing I read about indicated that flexible panels may be more prone to wear (pitting) and tear than hard panels and may also not be as efficient as traditional hard panels, but I felt as thought the weight and ease of storage and set-up made the flexible panels worthwhile. However, by the time I reached this decision, Renogy had stopped producing the 100 watt panels. Through some Amazon sleuthing, I discovered that there was a company selling what appeared to be the same panels as Renogy. The good news is that from the time I started looking into these panels until I was ready to buy, the price dropped and this confirmed, to me, that it was worthwhile to go the flexible route.

How Much Solar Do I Need?

This is one of the most commonly asked questions I see on T@b forums and the Facebook groups. The answer is, it depends. It depends on what your power needs are. To determine my power needs, I developed a worksheet to assess my needs. I knew I wanted the ability to be full-time and work from my T@b, so my needs are different than the person who is a weekender or travels for a couple of weeks per year. I highly suggest you read the 2 posts I have written on battery management and power use, here:
I chose 200 watts of solar (2, 100 watt panels) but I chose a solar controller that would give me room to expand, if necessary. After 3 straight weeks of boondocking, 200 watts of solar has been perfect. I am generally back at 100% before noon.

Choosing a Solar Controller

I knew that MPPT controllers were generally considered more efficient than PWM controllers, but what I didn’t realize was that with an MPPT controller, you could run the panels to produce 24 volts and the controller could reduce the charge to your batteries to 12v, maximizing your charge, which is very helpful on cloudy days, because you can charge your panels, faster. I read several articles that promoted both types of controllers and they were far more technical than I am going to go into, here, but that was the deciding factor for me. I chose a controller that exceeded my current needs, to “future proof” my installation and allow room for expansion.

Why Victron?

Victron is not the cheapest on the market, so why did I chose them?
  1. Positive reviews and ratings
  2. Bluetooth/app capability – I can quickly check my battery via the Bluetooth dongle via an app on my phone.
  3. Frequent updates (firmware) – if you cannot update the product, it will be the same in 3 years as the day it was made. Victron updates their product with performance improvements and new functionality
  4. Controller + Monitors – I like the additional monitoring functionality provided by Victron and the amount of actionable data the monitoring provides.
  5. Responsive customer service.
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Victron Connect App

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Victron Connect App

Putting it All Together

Wiring and connectors can be the hidden surprise costs in a solar set-up. Generally, the cables provided by a solar panel manufacturer that are included with a panel, are too short to be useful. Wire is expensive and this is a way for the manufacturer to keep costs down. @JCFaber from the Tab forum made some good recommendations for wiring and quick connectors. I knew I wanted the ability to move the panel away from the T@b so I could park in the shade, but put the panels in the open. I started with 50′ of cable. So far, it has been sufficient. I might need to go longer in the future, but for now, the length has been good. The challenge is that the longer the wire, the greater the loss of power is. If your cable is less than 20′, probably not a big deal, as the loss would be somewhat negligible. However, with a 50′ cable, I knew I had to mitigate the loss, so I went with an 8# wire.  This is very thick and not at all easy to work with in terms of crimping and cutting. I had a good crimping tool to begin with, but even that was stretched by the thickness of the wire. I asked an electrician for tips, and he admitted it was difficult for him, too.
Based on @JCFaber’s recommendation, I chose a trolling motor plug to use as a quick disconnect to connect the panel cable to the T@b tub. The wire then goes to the solar controller, mounted in the original battery box that came with the T@b. I found the MinnKota brand plug and receptacle better than Marinco for working with 8# wire. The Marinco screws stripped easily and had a hard time gripping the wire.
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Trolling motor plug & receptacle

If you use 8# wire, it is essential that you find MC4 connectors that are suitable for 8# wire. I found this pair on Amazon.

Mounting the Panels

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I was originally planning to build a PVC frame for my flexible panels, but right before I bought the supplies it occurred to me that I might be able to use the folding legs I had purchased for me previous, temporary set-up. This mounting set-up has been great, so far, even in high winds.  I put rocks from around the campsite on the legs and in front of the panels to anchor them and they hold strong. I attached the legs to the panels using 3M Heavy Duty, Interlocking Velcro fasteners. This makes the legs and panels easy to separate and reconnect and allows me to lay my panels flat for transport and the real bonus is that it does not really add to the bulk or weight of the set-up. 20160531_080625
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Real Life Usage

So, the proof is in the pudding, right? How does this all work out in real life? So far, it has been great! I have been running the fan almost all day long, using lights liberally, using the TV/Jenson (I Miracast movies and TV from my Android phone and Surface Pro 3 Tablet to the TV with a Microsoft Wireless Display adapter), the pump, Alde, and fridge on LP and have not reduced the battery charge below 95%, yet. My GC batteries provide 225ah capacity, thus allowing me to be more liberal with my power consumption.

Random Tips:

  1. Make sure you can change the settings in your controller to match the specific charging settings recommended by your battery manufacturer. These settings vary by battery.
  2. I personally think the Zamp systems are way overpriced and take advantage of people who want an easy plug and play set-up. That being said, I totally understand why people go that route. The Zamp quick disconnect cable/port is nothing more than the SAE plug that has been around for years. Zamp reverses the polarity in their receptacle. I have used Goal Zero’s 2 pin (SAE) plug with the Zamp port by swapping the pos/neg cables on the battery from the Zamp port. It is misleading for Zamp to market their port as a proprietary quick disconnect when the 2 pin cable has been around for a very long time.
  3. My set-up is not for everyone. Please thoroughly understand your camping style and power needs. Read my 2 posts on battery management linked, above.
  4. If possible, use 12v adapters for electronics whenever possible. they draw less power than an inverter will draw.
  5. I also upgraded my fan to the Fantastic Fan 7359 kit. It offers 10 speeds, is generally much quieter, and more power efficient than the standard one that comes in the T@b. One person reported that it did not fit his T@b. I had no problems. Upgrade at your own risk.
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Closing Thoughts

For most people, the plug and play option is a simple, no thought set-up. I understand that. Sometimes the time and effort put into a DIY or partial DIY set up is not worth it. I have spent countless hours on DIY projects to later decide it would have been better to buy a “plug and play” set-up. I cannot say that this is one of those scenarios. I am really happy with the set-up and unless technology were to dramatically change or my needs change, I see this is my set-up for the foreseeable future.
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