Solar power is something that I have wanted to learn about and put into action for many years. Previously, the entry cost was prohibitive and finding components to suit my needs was seemingly more complex so I have waited until the panels have become cheaper and more efficient. That, combined with a desire to have some sort of backup power in the case of a catastrophic even (like a category 5 hurricane) has pushed me to finally jump into things head-first. This is an article concerning my journey to learn how to setup my own solar panel system, likely off-grid, but with the potential to be tied-in. I plan on exploring (and sharing via this comprehensive article) potential sources for solar panels, batteries, and some options for inverters and charge controllers. It seems one of the biggest costs of a system is the batteries. I had previously thought the panels to be the most expensive but I now know that batteries to actually utilize the energy that you store during the day is of the utmost importance. While ancillary parts of a solar system will be explored and mentioned, I plan on putting a focus on options concerning what kinds, types, and even potential brands to choose. My initial goal is to setup a system to run a mini-split air conditioner to help save some money on cooling. I’ve found an awesome mini split a/c that has a special compressor to make it more amenable to running on solar power (and for a pretty good cost). More on that later! Warning…this is a LONG and involved article/post/journey that will be updated a lot along the way!
It has taken me a considerable amount of time to take the first steps of putting together a solar powered system but I have plunged into things with both feet. As I write this, there is a shipment of around 1,100 Watts of solar panels en route to my house for me to use. I found an outstanding deal on some very good and powerful panels (260 Watts each) on eBay from an awesome seller! The one drawback, however, is shipping. Since the panels are fairly large they must go via freight and not UPS air USPS. I was actually able to get 4 panels for a total of around $500 (with the freight cost being closer to $300). The interesting part is that the freight charge was about the same whether I bought 1 panel or 4 so it seemed best to go bigger because I can always sell a panel or come up with a separate use, if needed. At the time of this writing there are still at least 12 more panels available for a great price via this link (I have no affiliation nor gain anything if you by from them but they were awesome in helping me to setup the freight and it’s a great deal!): https://www.ebay.com/itm/293260378380
Funny note: I actually purchased a 100 Watt kit from Harbor Freight before I found the panels above so I’ve got a mini system up and running for testing and figuring stuff out (UPDATE: 3/2021: I returned the Harbor Freight kit as it is just not a great deal, financially. You can build a better kit for the total price by picking the items on your own). Nonetheless, since I now have the solar panels that I plan on using my main focus is now on batteries. There are SO many options for batteries and so many pros and cons that I will get into a bit later. I have reached out to a couple of smaller battery companies that sell lithium polymer batteries because I would like to complete tests and find the best value for myself and for people that read and follow my articles. A lot of you contact me via email to give your opinion, to ask me for advice, or to give me potential topics to write about and I really appreciate that. It means a lot to me so I’d love to find some good deals for us! Below is the rough outline of the parts of a system and the options for each item. It is not complete yet but I will continue to update this as my adventure progresses.
Let’s break down what you might need for a solar panel system:
Solar panels – Many, many options here. From mono to poly to amorphous cells…there is no dearth of choices
Charge controller – PWM or MPPT are options and the kind you want/need is likely tied to the size of your system and how many amps you are using/bringing in. In this case, I’m trying out 2 systems at the same time…for science!! The first is a 12 Volt system utilizing a Victron 100/20 MPPT. It is proving to be excellent and includes Bluetooth, is made well, and provides some awesome statistics (Watts, Amps, etc). I’ve included a picture below showing an example.
The second charge controller is a MPPT by SolarEpic that I am running at 24 Volts. Since I have less experience with 24v systems (of any kind) I am taking this one a bit slower. UPDATE (3/2021): I had an issue with the SolarEpic MPPT but they were helpful in assisting me and sent me a unit that works.
The Victron shows a lot of good information without any fuss or issue. No odd parameters to be updated or adapters needed for this model…currently running about $160 on Amazon.
There are so many options but the main ones seem to be either sealed lead acid/AGM or LiFePO4 (lithium iron phosphate) batteries. SLA (Sealed Lead Acid) batteries are WAY cheaper to purchase but you can only use circa 50% of the capacity without damaging the battery…what? Yes, that is correct…if you need 100 amp hours of batteries, you need to buy 200 amp hours of SLA batteries or you can just buy a 100 amp hour LiFePO4 battery (as they can be discharged all the way…but you get more cycles of charging and discharging if you discharge to about 10 or 20%). The difference is that the cost literally many times what the SLA batteries run. Talk about a conundrum! On one hand, I want to go with the cheapest type possible…but I am fundamentally opposed to having to purchase literally double the capacity that I need. In addition to being cheaper, SLA batteries are also larger, weigh more, and take up more space.
A counterpoint to that, however, is the fact a 100 Amp Hour SLA battery might cost around $300 or $400 while a 100 AH LiFePO4 battery might run $900 or more. You will need 2 of the SLA batteries but only 1 LiFePO4 batteries. This is something I am currently struggling to decide about but hope to be able to answer soon, concerning what I believe to be best. There are a couple of options that I am looking at currently (if anyone has any other options they feel are good, please feel free to comment or contact me).
So far, I am sending out a few contacts to Vendors/Sellers to determine who I should go with and what the best choice is for not only me but for the large number of people that read this site and contact me with questions/concerns/feedback. I feel a great deal of responsibility to try to find the best economical and quality options for all concerned. Something that I would like to highlight is the possibility for a Do It Yourself solution for batteries. There are some companies that provide new/used/refurbished batteries for great prices with even better service that merit a significant part of the battery discussion. While DIY can be intimidating, you can also get a ridiculous value with a custom battery to suit your needs. I am in the process of finding out if a company might want to sponsor a battery for this article and maybe (hopefully?) they might be able to provide a discount code for my intelligent/awesome/amazing readers.
Wires – Still learning options but will update. UPDATE (3/2021): I have learned that you should not go cheap on the wires that attach the batteries to the charge controller and/or the solar panels. It is safer, more efficient, and the correct decision. You also need to make sure to purchase some fuses or circuit breakers (this is the better option than buying and replacing a bunch of blown fuses).
Power inverter or tie-in inverter (changes DC to AC power
Place to store batteries
Stay tuned for more! I’m still on this journey but will hopefully have some more good deals on parts and a good basic outline for a potential system to help either save money or use power off the grid!