Tag: living off the grid

ExNotes Solar Series: Lithium Batteries

By Joe Gresh

I finally made the leap. My solar system went online in 2018 and except for a few snow days has produced reliable power in all that time. We’ve had around 30 power outages at the grid-tied Carriage House (some 5 minutes, some 5 hours) during the same time span.

The old, lead-acid bank gave great service but it is time to step into the future. I’ll be keeping the best of the old ones for a power source in the green house.

Initially we went with plain old lead-acid batteries because they were a third the cost of lithium batteries. The lead-acids worked well and since they’ve been around hundreds of years it was easy to predict performance and longevity.

The jumper cables are messy but effective.
The old bank was four boxes on two shelves. I never did get around to filling the last box.

The battery bank started small with just 4 batteries and grew with our budget to 12 total. There are two of the original 2018 batteries still functioning and I’ve replaced three batteries that failed. It’s easy to tell a bad lead-acid in a battery bank: it’s the hot one.

I haven’t been religious about topping up the electrolyte so some of the batteries might have failed due to misuse. Regardless, I’m happy with their performance and the lead-acids did me right.

Last year I noticed lithium batteries dropping in price. They ended up costing the same as the cheap Walmart lead-acids I was using. With new tariffs looming I decided to make the switch. I bought one batch in January and another batch in March, depending on whatever sale was on. My cost averaged around $119 per 12-volt, 100-ah battery. I wasn’t brand loyal, whatever was cheapest was fine by me.

With winter approaching and long cold nights of pipe heaters draining storage I built an insulated box to hold the new batteries. Advantages with the lithium are 16 batteries fit on one shelf, weight is half of lead acid, and there’s no need for a sealed battery box as there’s no acid to leak.

Most of this was replaced by copper bars.
Lots of copper buss bars took a couple days to make. Foam on top to prevent shorts in case a chunk of metal lands on the bank.

I also took the opportunity to clean up the installation, getting rid of messy-looking jumper cables and replacing them with solid copper buss bars. With everything on one shelf I eliminated several feet of cabling which can only be good.

Lithium batteries need a bit more charging voltage so I cranked up the solar regulator a 1/2 volt or so. I also reset the inverter charger setting to one more like lithium.

The batteries have sat on the shed floor for 6-8 months so when I connected them up to the solar they sucked a steady diet of 55 amps from the sun.

Theoretically I have 19,000 watts of storage now, more than double the 7200 watts of the old, lead-acid battery bank. In actuality it’s probably 80% of 19,000 watts because you don’t want to drain the batteries flat.

The new box is 1-inch foam skinned with sheet metal. Hopefully it will slow a fire.
All the batteries on one shelf cuts down on cabling. Buss bars make a tidier installation. With no acid fumes connections should stay cleaner. What’s not to like?

Some disadvantages to lithium batteries are they are more affected by cold temperatures (hence the insulated battery box), they are limited to 100-amp output per battery (not a problem as my inverter draws 250-amp max), and I can’t really think of any others.

Time will tell if the lithium batteries last the 10-year claimed life span. I’ve pre-tested each battery’s load capacity and marked the results on top of the battery. I should be able to compare results in the future to see if individual battery performance degrades. All in, I’m happy with the new batteries. Hopefully I’ll have about a 3-day reserve for those snow days.

Oh, and those tariffs? They don’t seem to apply to lithium batteries as you can still get 12-v, 100-ah lithiums for $119 on Amazon.

Join our Facebook ExNotes page!

Never miss an ExNotes blog:

Help us keep the lights on:

Don’t forget: Visit our advertisers!

A Shift In Battery

By Joe Gresh

I was going to do a bunch of stories on my solar power system that powers my shed. I may still do that but this is more of an update on the batteries I use to store the solar power.

Small footprint means more energy density and hotter, more localized fires…

With solar, unless you plan on only having power in the daytime, you’ll need a way to store energy. The traditional way to accomplish this is with lead-acid batteries. I’m a lead-acid fan boy because they are so much cheaper than lithium batteries or a molten salt battery.

I should say, were cheaper…as of late lithium batteries have been dropping in price so much you can now get a 12-volt 100ah lithium battery for the same price as the cheapest Walmart lead-acid, deep cycle battery.

My solar system has been online since 2018 and in those years I’ve had to replace three Walmart batteries. The others are getting a bit long in the tooth, you know? Six years is a good service life for a lead-acid battery. Walking by the battery bank a few days ago I smelled the telltale odor of sulphur. This meant another battery had given up the ghost. It’s usually easy to find the bad battery in a bank. It will be hot to the touch, or in this case the filler caps had blown off. Kind of obvious.

The lithium batteries seem fairly even voltage wise at 100-amp load.

Looking at the average age of my battery bank I decided to bite the bullet and buy a new lithium set up. Getting in just under the tariff wire, so to speak.

My new bank will be 12, 12-volt, 100ah lithiums. Wired in series/parallel to produce a 24-volt, 600 amp hour storage capacity. That’s theoretically 14,400 watts of storage if you could squeeze every bit of juice out of the batteries.

By contrast, the existing 12, 12-volt 100ah battery bank only has 7200 watts of usable storage capacity due to lead -acid batteries dropping voltage below 50% capacity. The same total amount of juice is in the lead-acids but it’s at a voltage too low to operate equipment.

I use an old, analogue battery load tester to establish baseline numbers for future troubleshooting.

In addition, the lithium batteries have a smaller footprint so I’ll be able to rig the new bank on a single shelf instead of two shelves like the set up is now. This will cut down in battery cable length and by extension, voltage drop. Less cable is always good with electricity.

All in, I’ll nearly double my solar storage capacity in less square footage for less money than the old style lead-acids. This seems like a win-win.

Lots of important information that I will ignore is printed on the battery.

Now for the downside. These generic lithium batteries claim a 10-year life span but since the Chinese manufacturer’s keep changing brand names like I change underwear the likelihood of the same battery company being around a decade is slim. And then there’s that small detail of the fires.

Lithium batteries don’t like cold weather so that could be an issue. We do get some 20-degree nights at the ranch. I run pipe heaters at night so maybe that bit of drain will keep the batteries snug and warm.

Ah well, it’s not like lead-acid batteries don’t catch fire or explode occasionally.

I’ve had good luck with my Walmart lead-acids, no complaints, and I’m hoping these lithium replacements hold up at least 6 years. 10 years will be great and if they last look for an exhaustnotes long term review in 2035.

Join our Facebook ExNotes page!

Never miss an ExNotes blog:

Help us keep the lights on:

Don’t forget: Visit our advertisers!

Water Security

As mentioned in a previous ExhaustNotes story titled “Guilt Trip,” our water well at the ranch has become unreliable. In order to quickly bring some stability to the situation we decided to install a storage tank and re-shuffle the way water is delivered to our shack.

After pouring a slab to support the new, 3000-gallon water tank we had the local Tank Guy deliver Big ‘Mo to the ranch. Big ‘Mo cost $2800 delivered to our door and that’s a bit expensive but it seems like everything costs more since the Covid crisis eased up. Home Depot has a 2500-gallon tank that is slightly lighter construction for $2300 plus $80 delivery plus tax so the per gallon price is comparable. Buying local means the Tank Guy will spend his money locally. Anyway, I don’t like the way our local Home Depot stores their tank inventory. They put the tanks on their sides instead of the bottom. This makes it easier to move the tanks with a forklift but I suspect it does the tank no good having all the weight where it’s not designed to go.

The Tank Guy stores his tanks upright, just north of Tularosa in a big field across from the railroad overpass. Our tank showed up securely strapped to a trailer…on its side. But only for the time it took to arrive at the ranch. These tanks look huge but they are rotocast plastic and are not that heavy. The 3000-gallon tank weighs 500 pounds. It took the Tank Guy, the Tank Guy’s wife and me to slide the tank up a ramp I handily screwed together earlier for pouring the tank slab.

I installed two ball valves in the bottom of the tank, one ¾-inch for the output and one ½-inch to fill the tank. Tank filling can be done three ways: by water delivery truck, gravity fed from the upper level shed storage tank, or by pumping well water into the tank. A jumble of shut-off valves can be juggled to pressure feed the house from the well, from Big ‘Mo via a centrifugal pump or by gravity from the upper level storage. I’m into redundancy when it comes to water.

If you live in areas that freeze you’ll want to add a pipe heater and insulate any exposed pipe. The black tank helps keep the water from freezing and when the sun comes out we rarely get days under 40 degrees so water freezing in the tank has not been an issue so far.

I took this re-plumbing opportunity to eliminate the water softener and reduce the size of the very old well pump expansion tank. The water softener periodically runs a flush cycle and being on a fixed water supply we can’t waste water like that. The bladder inside the big expansion tank became porous over the years and water had migrated to the dry side causing rust. Plus it was too damn big. I’m thinking it will make a great stand alone fireplace or smoker.

From Big ‘Mo water is piped through a mesh screen filter, a one-way check valve and into a centrifugal pump that provides 40psi of pressure to a large 5-micron filter and on to the house plumbing. The pump has its own small expansion tank that seems to keep a fairly steady flow of water to the fixtures. You can see the flow increase a bit when the pump cycles but nothing a rough, tough, couple of pioneers like CT and I can’t handle.

Since we’ve moved from hot, humid Florida to a colder climate I’ve learned that PVC plumbing is not ideal in freezing conditions. Going forward I’m trying to use PEX plumbing in all my projects and I’ve been happy with the results so far. PEX uses a more flexible pipe that is crimped onto brass PEX fittings with brass/copper-ish crimp rings. You’ll need a special PEX crimp tool to compress the rings onto the PEX fittings. Once crimped, you can spin PEX pipe on its brass fitting (within reason) without causing a leak. I haven’t had one PEX-related leak yet, even when tight working conditions result in a less than optimal crimp. I wish I could say the same for the PEX-to-threaded-pipe connections. One thing to keep in mind is that PEX pipe is not UV resistant so cover any pipes that will see sunlight.

Like most plumbing systems PEX has to be cut and pipes replaced if you need to change anything. You’ll need a PEX removal tool if you want to reuse the brass PEX fittings and why wouldn’t you want to reuse them? The ability to reuse PEX fittings is a big deal. When is the last time you were able to reuse a glued PVC fitting or soldered copper fitting? The removal tool cuts the crimp ring without cutting into the PEX barb. Once the ring is out of the way you can crimp V-shaped depressions around the bit of PEX stuck on the barb. Crimping the Vee’s causes the PEX pipe circumference to expand and the pipe will slide right of the barb without causing undue stress.

It’s a bad feeling when your well runs dry. All of a sudden your shack becomes unlivable. But by building in a little extra infrastructure we have water security even if it means buying water from our local water delivery service. And I have plans on the table for catching much more rain during the next monsoon season that will nearly eliminate our reliance on bought water.

Do us a solid and click on the popup ads!

Never miss an ExNotes blog:

Guilt Trip

The ExhaustNotes website consumes a lot of content. Berk writes most of it and he’s always up to something interesting. I feel bad that he has to carry the load, but I just don’t have that much to write about. Here in the wilds of New Mexico we spend a lot of time and energy just surviving. Take water, for instance.

Our place has a combination of well water and rainwater. The well supplies the tiny shack we live in and the cistern for rainwater catches ½ of the shed roof runoff. It all worked ok until the well ran dry. Our well is only 85 feet deep and since our land sits at 6000 feet elevation you’ve got to figure the water in the well comes from a trapped source. Maybe there’s a layer of impervious stone or clay at 90 feet. The well was already dug when we bought the place, but the pump was dead.

Colleen and I installed a new pump using the existing piping and we had a reliable supply of water. The well inspector said it was good for 1.5 gallons a minute, which isn’t a lot unless you count the minutes in a day. We have a 40-gallon pressure tank with a pressure switch to turn the pump on and off.

The system worked fine until a month ago when the water stopped flowing. The well was flat out of water. The well guy told me this happens all the time. Maybe someone below me used a lot of water, maybe the well is silted up or maybe wells just go dry after 27 years. To get back in the swim I ran two, 150-foot-long garden hoses to a bib outside of the shack and fed the house from the shed water supply.

We let the well rest for about a week and then tried it. We had water again. Everything was fine until a few days ago when the water ran out again. Obviously, we are going to need a better water supply.

We decided to go with a hybrid, part well water, part rainwater, part purchased water set up. We’re getting a 3000-gallon storage tank that will sit next to the well house. Of course, the new tank will require a concrete slab. During monsoon season I can dump excess water from the shed tank into the lower, 3000-gallon tank. Probably 4 or 5 months of the year we can get by on rain water unless there is a drought.

We’re hoping this will take much of the load off the well and give it a chance to recharge from wherever its water comes from. If we need to we can purchase water. Many homes around here buy water and store it in tanks; they have no well because well drilling is expensive and you pay for the work whether the driller hits water or not. A typical well a few hundred feet deep will run around $30,000. If they hit water the first time.

The new system will require a bit of re-plumbing. Instead of directly feeding the shack the well output will dump into the 3000-gallon storage tank and from there the water will go to a jet type pump to provide pressure to the house. I’m hoping the tank will be a sort of battery to store the well water as I can adjust the well output to a trickle to not outrun the well’s capacity per minute. If we are lucky the slower draw will buy a few more years from our well, if not we may drill another, deeper well.

Using rainwater is way nicer than the mineral-rich stuff we get from the well. Soap makes better suds, sinks and faucets stay cleaner and you don’t get those stalactites of gypsum hanging off the aerators. Bought water comes from a city supply and so has all manner of junk floating around.

Future water infrastructure plans include a second, 2500-gallon tank up at the shed. I lost thousands of gallons this monsoon season due to the single tank being full. It drives me crazy seeing that water spilling onto the ground. Installing another rainwater tank to handle runoff from the Carriage House roof should be good for 3 or 4 thousand gallons during monsoon. One day I will get around to guttering the other half of the shed roof and that should double production from the upper level. If we get enough storage I think we can operate the ranch using just rainwater, giving the old well a much-deserved rest. My job will be to move water from all the different tanks to the main 3000-gallon unit.

And this is why I don’t have much fun stuff to write about lately. Things are falling apart faster than I can fix them. Men were given dominion over the Earth but it’s not an easy task to rule nature. I’m starting to think this ranch living is no country for old men. Maybe one day when we get really old we’ll get a suburban house. I’ll have my own garage door opener or a breakfast nook.

Help us pay for all these tanks, pumps, gutters, and more:  Please click on those popup ads!

Never miss an ExNotes blog: