Renewable Energy Rabbit Hole II
“Electricity can transform people’s lives, not just economically but also socially.” - Piyush Goyal
Welcome to my second renewable energy article. This is part 2 of an article I wrote last July that people have found quite helpful. I do hope you find this useful too. Prior to getting my initial solar inverter setup, I did a lot of reading, and question asking and I did learn a lot. It’s been over a year since then and what I can say is that I have learnt more.
In the last article I mentioned these above, things I felt I would like to do in the future. I am glad to say I have achieved them and it feels really nice. With a steady electricity supply, I could see the need or chance to have the smart home I always wanted to live in. While it was cost-intensive getting those smart switches and plugs, the comfort they now offer is something I do not take for granted.
I got a Raspberry Pi Model 4B and I run an amazing open source home automation platform called Home Assistant on it. It’s the perfect platform for tinkerers and DIY enthusiasts and I highly recommend it. Thanks to it and some tinkering, I was able to extract data from my SRNE inverter and display it inside my Home Assistant instance. The thread I linked should give you an idea of how to replicate it.
Why do I consider energy monitoring important? Well ”In God we trust. All others must bring data.” Without data, you can’t make informed decisions and the remaining part of this would be talking about how the data helped me decide what to do. I was using a 3kva 24v SRNE Inverter with a 4kWh lithium battery and a 2.2kw panel array. My inverter’s MPPT has a max PV current of 1400w and since I started monitoring using my DIY data logger, I didn’t get past that. I did so about 1440w on some rare days but that was it.
Looking at my setup, you would notice it’s something I would call Sapasolar (do not sue me The Law) because it was just a minimal build that works and it did work well thanks to me turning into an energy watchdog. This setup was deployed in a four-bedroom apartment with a good number of humans. The max load I did was 1,556.12w which is less than 52% of the full inverter’s capacity. As much as I did an energy audit prior to the start of the project, I didn’t end up sticking with just what I added. I added the pumping machine and washing machine at home because why not? I just made sure it was used during optimal periods.
On a good sunny day, the setup was able to carry us for 24 hours, remember I was somehow strict with power usage. However on some days, the sun was very poor, and I needed about 3 hours of grid/generator power supply to keep things running for 24 hours. On some days, I turn off the power output from the inverter and let it charge just the battery so it can be used at night. For context, my area is on Band D and the power supply can be really bad. In fact I have turned to a mockery before my mutuals on Twitter, thanks to PHEDC. On the week when they work well (bringing light at night), I don’t bother turning on the generator. Despite them being bad, most of the time, I could go a full month without having to turn on the generator and this drastically reduced fuel expenses. All thanks to my Sapasolar setup. Data shows I generated 1,441.6kWh in a year (the inverter registry saves the data) of using it, which is 3.95kWh per day, which isn’t bad for it.
However, I knew my setup wasn’t going to be able to make me have electricity 24/7 without relying on the grid or generator. So my first thought was to increase my battery bank. Now, most people would say starting a project at the beginning part of the year (February) is crazy. This is after the Detty December period and most times, it is when you try to recover from such expenses. Luckily? for me, I had some money saved up and I decided to solve my electricity problem once and for all. Like I said, my first plan was to increase my battery bank. To me, it would give me enough runway for days when there was no grid and PV generation was poor. I planned to get more packs from who I got my previous one but things happened and he wasn’t available. In looking for an alternative, I was directed to buy directly from a company called Shenzhen Deriy New Energy Technology in China.
After reaching out to the contact person for Nigeria, Selina Li, I paid for three 24v 280ah (7.1kWh) batteries. This would have brought my total 24v battery bank to 25.4kWh (inclusive of the 4kWh in use). After some days and thinking, I decided if I was spending this much, it was better to move to a 48v system. Now while I could charge from the grid and fill it up on a 24v system, it wouldn’t be possible with my current MPPT of 1400w to charge those batteries up to half. I would need to get more than one external charge controller, which means more wires, complexity and expenses. So it was much better to move to a 48v system as I could easily see inverters that do as much as 4,800w. This was before I knew of dual MPPT inverters, trust me, they are beautiful.
After much consideration, I decided to buy the SRNE HYP4850S100-H, which has 100A of PV charging current and 5,500w PV power in February. Then I told Selina to change my order from three 24v 280ah (7.1kWh) batteries to two 48v 280ah (14.3kWh) batteries and paid the remaining balance for the order. I was informed the batteries would take 3-4 months to arrive and I patiently waited for them till they arrived in late June. In the course of waiting, I discovered some inverters came with dual MPPTs. I instantly fell in love with them and I wanted one because it just made sense cost, form and functionality-wise. I wanted the 6kw SRNE HESP but the authorised distributors I knew didn’t have it in stock and I didn’t want to get it more expensive and still not enjoy a good warranty support.
Then I stumbled on the 6kw Growatt SPF 6000ES Plus which is also a dual MPPT inverter although 1,000w PV less. I decided to sell the SRNE HYP I got previously, at a loss (the price got cheaper after I bought it), and I added money to it and purchased the Growatt. Funny how when I wanted to get it, it became somehow scarce and I didn’t want to risk waiting for the SRNE HESP and buying at a more expensive price, so I bought the Growatt. However, the Growatt became available cheaper at some other good distributors. It was as if I kept buying the top when it came to an inverter, lol. I also decided to get 7 x 665w Canadian Solar panels to max out one of the MPPT PV strings while using the older 4 x 550w Jinko panels on the other string.
Also in that one year of knowing more, I stumbled on a lot of messages about solar inverter protection. Truly ignorance is bliss, as I started spending money to make sure that everything was done as professionally as possible. I did the work of sourcing the materials and I contracted a better company (Twinskenny on Nairaland, Twitter, Telegram)to install the new one. The former one used their fancy website to attract me but they didn’t do a great job and I haven’t benefited from customer service from them. I pretty much troubleshoot my system myself, when the need arises, which is very rare though. The new people I used were quite friendly and they were open to my input to give me what I wanted to taste. Also, we were able to jerry-rig a pair of bus bars into a “NEPA” metre case to make a suitable bus bar case for the setup.
I will try my best to write down the things and prices I got for my upgrade. I may have forgotten some things though. Also, I reused the SPDs and MCBs from my former setup. I only had to buy an extra SPD and MCB for the other MPPT string, then I changed the 63A DC Schneider electric MCB I had.
Using $1/₦1650.
Materials
48v 280ah (14.3kWh) Deriy lithium battery - $1,359.5 x 2 = $2,719 (₦4,486,350)
Growatt SPF 6000ES Plus - ₦1,029,000 (Sygnite)
Canadian Solar panel 665w - ₦182,875 x 7 = ₦1,280,125 (Techland Solar)
FEEO 250A DC MCCB - ₦93,000 x 2 = ₦186,000 (Talk with Oga Solar)
FEEO 24-way plastic box - ₦30,000 (Talk with Oga Solar)
FEEO 20A DC MCB - ₦16,000 (Talk with Oga Solar)
FEEO DC SPD 600VDC - $22.68 (₦37,422) Aliexpress (it’s cheaper if you can get it in Nigeria)
Double core PV wire 6mm² - ₦4,500 x 18 metres = ₦81,0000 (Okija market)
Flexible silicone 50mm² - ₦7,000 x 8 metres = ₦56,000 (Okija market)
Single core 6mm² - ₦1,900 x 15 metres = ₦28,500 (Okija market)
Single core 16mm² - ₦3,000 x 15 metres = ₦57,000 (Okija market)
Industrial busbar - ₦17,000 x 3 = ₦51,000 (Okija market)
Plastic metre case - ₦15,000 (Okija market)
Total cost - ₦7,353,397 (excludes installation and miscellaneous costs that kept popping up)
Disclaimer: I do not bear the risk for any of your transactions with any vendor
Honestly, it wasn’t easy finishing up this project which I started in February. At one point, miscellaneous expenses kept popping up and I was considering selling one of the batteries so I could escape sapa. However, I decided to continue and said even if I was broke now, it wouldn’t last forever. I have been away for a long while (and also monitoring while away) but they haven't had a reason to turn on the generator. I am broke (send gigs) but I am happy that I do not have electricity as a problem in this big 2024.
Now this article might serve as a guide for an average family house that wants to go off-grid (or not fully reliant on the grid), however, I would ask that you start by doing your energy audit first, as energy consumption differs depending on a lot of factors.
Thanks for reading, do well to join the Nigeria Solar DIY community (the community now has a good number of more interesting topics) on telegram and also share the article if you found it educational.
