A Game-Changer for Off-Grid Battery Storage

The lead-acid battery bank consisted of 24-2V batteries. All photos: N.R. Mallery

N.R. Mallery

As Bob Dylan wrote, “The times they are a changin’…”. The change is now. Battery storage, on or off the grid today has produced a real game-changer. And my off-the-grid experience proves it.

In the beginning, I wanted to “go solar” so much that I made a lot of changes to my lifestyle. To be able to go solar at a time when solar PVs were over $10 per watt of output capacity, I actually learned how to cut my electric use from 20kWh per day to 3.5kWh per day. I wanted a battery bank sized to keep me powered for three to five days of cloudy weather. With a year of research, I was able to make a 3.8kW solar system work with a suitably sized lead-acid battery bank. There was also a backup propane generator for when necessary. The bottom line is, I have done it with minimal fossil fuels usage since 2002. Life was great for a few years while the batteries were new.

My system was originally designed by groSolar, back in the days when they designed and installed off-grid solar. They designed it to produce enough electricity to last me three to five days or longer. You may wonder how this is possible with such a small system, but we will cover that in another story. Suffice it to say for now that I do live a normal lifestyle, complete with electric refrigerator, microwave, dishwasher, vacuum cleaner, laundry, jacuzzi tub, computers, and two robotic lawn mowers. I also have an electric bicycle. And there is electricity to spare.

The new RELiON LiFePO4 battery bank consists of 3-200 Ah batteries.

In the fifteen years since that system was put together, we have gone through battery banks. I tried different battery sizes. Originally, we had a bank of eight six-volt batteries. When those needed to be replaced, we went to four 12V batteries. The last lead-acid battery bank consisted of twenty-four 2V batteries. The power was always 48V. On average, these battery banks had to be replaced after five years.

The batteries had to be housed indoors to keep them from freezing, in a well-sealed and protected box. When they are charging, the batteries get hot, which is regulated by the charge controllers, but they give off fumes that need to be vented.

Last year, after fifteen years of living off the grid, with winter approaching, my batteries were failing once more. In fact, they were failing miserably, and the generator was coming on daily. This was not acceptable to me, because I strive to live as free of fossil fuels as possible. So, in fifteen years I have already paid for three battery banks, which means the lead-acid batteries were only lasting five years. The last battery bank was $7,000, at cost. Pablo Fleischmann of Green Energy Options, in Keene, NH, confirmed that a lead-acid battery bank nowadays costs about $8,000.

As publisher of Green Energy Times, you might think that it would be a simple thing for me to choose which battery to buy. Well, it wasn’t. My attempts proved to be very discouraging. Some lithium battery options would only work with new solar systems and components. Many are not really suited for the demands of off-grid living. Many of the alternatives to lead-acid batteries had things I questioned, and many vendors never even bothered to return my calls. One company with a promising battery technology went bankrupt. I was getting to the point of thinking I would have to get yet another lead-acid system.

It took me months of research online and calling to find the battery option that was right for me. But when I finally found the right one, was it ever right! I expect my new batteries may last the rest of my life. In fact, my granddaughter, Makenzie, might inherit them when I’m no longer around.

The table compares the total cost of ownership of RELiON’s RB100, a 12V 100 Ah LiFePO4 battery, to three equivalent size off-the-shelf lead-acid battery technologies. Using measured lifetimes taken from the manufacturer’s published specifications of each battery, the analysis shows that the RB100 costs at least 51% less over life than even the most cost-effective lead-acid battery

I bought three 200-Ah RELiON LiFePO₄ batteries. While their cost seemed high at first, it turns out they will save a lot of money because of longevity, efficiency, reliability, and no need to buy propane for the generator. My generator has not been on since my new batteries were installed last fall. This is a game-changer, especially when you live off-grid. We just went through a tough, cloudy winter!

Howie Michael of Suncatcher Solar installed the new RELiON LiFePO4 batteries, simply making some setting changes to the existing inverter and charge controllers

The new lithium batteries store the energy from my 15-year-old 3.8kW solar array. The solar system connects to the original components: a Xantrex SW4048 inverter and two OutBack MX-60-MPPT charge controllers.

Since the RELiON lithium batteries were installed, I no longer go into conservation mode at night or after a number of consecutive cloudy days. I don’t hesitate to use electricity at night time. I don’t worry too much about the lights being on, using the microwave, or washing laundry. I even use my hair dryer at night.

Most off-grid homes today run with 48 volts systems. The generator is programmed to come on when the battery voltage goes down to about 47 volts. Since the batteries were installed, I have never seen the voltage go below 52.3 volts. I have been thinking, “Why is it that the voltage isn’t dropping?” Part of the answer is that, unlike lead-acid batteries with which you can only use 50% of their storage capacity, the RELiON batteries can be discharged 100%. (You really want to take them down only 98% because the whole system would shut down, but you would not harm the batteries if that happened. Full discharge would destroy lead-acid batteries).

I have not yet seen a need to charge these batteries with the (dreaded) propane generator, but they could be charged just a bit with no harm to the batteries. This also is not true of my former batteries.

There are a number of other benefits of the RELiON batteries. They have no maintenance, such as keeping battery cells full and checking electrolyte levels. They need no equalizing, which would be done every few months with lead-acid batteries. They emit no fumes, so there is no need to vent them. Lead-acid battery discharge cycles are measured in hundreds, not thousands. RELiON batteries are rated to go through 7,200 charge-discharge cycles or longer. For most households, there is one cycle per day, which means these batteries should go for at least twenty years. (I suspect they will keep going much, much longer.)

The old battery box is now a cabinet with shelves and holds older copies of G.E.T.

To sum it up, RELiON LiFePO₄ batteries offer significant advantages over other types. They are long-lasting, efficient, and take up much less space, making them much lighter.

Please note the size of my last battery system in the photos and compare it with the new system. What do you do with an empty battery box of this size? You stand it on end, put shelves in it, and store your past editions of Green Energy Times, of course! I don’t believe in waste, after all.

The lithium chemical used in these LiFePO₄ batteries is different from what is used in many other types. It is safer, more reliable, and has no danger that they will heat up too much. They have no cobalt, which is used in many of the other lithium batteries and much of which is mined using child labor.

If you are on the grid, the RELiON batteries are even a better choice so that you can be assured that you will have power when the grid goes down. As the climate crisis continues, this will become a necessity.

This information about the batteries is based on what I know from experience. I was not paid to say these things. I felt a need to share my story and positive experience with our readers. It is a product that I have a need to speak up for and recommend. It really has been a game changer for me. I hope that it will be helpful to you, the reader, if you are thinkng or needing to invest in new batteries.

Being able to store electricity made from renewable energy is a must if we expect to be able to replace dirty, polluting fossil fuels. Don’t just take my word for it, check them out for yourself. A video of a recent RELiON webinar, Lithium batteries 101, explains the basics: https://youtu.be/oA20aPBOUrk.

Learn more at the RELiON website: relionbattery.com. For knowledgeable answers to questions, I suggest you contact Craig Quentin, a great tech guy. He knows what he is talking about. His email is: cquentin@relionbattery.com. Tell him or anyone you speak to that I sent you!

RELiON is located in Rock Hill, South Carolina. Call them at 844.385.9840. You will get your questions answered!