I am not prepared to panic, not yet anyway.

I have left the gate camera battery alone, other than monitoring it, for 10 days. Love the Shelly. More on that someday. Anyway, 11 days, technically. Today isn’t over, but 10 nights for sure.

You may need to click on that image to see the detail, but there is a pretty much linear decline in the “peak” nightly discharge. Overnight December 9-10, it discharged to 12.65 volts before a sunny day recharged it to 13.5 volts. Every night, it would discharge a little lower, then a sunny day would bring it back to 13.5 volts. December 13 was cloudy for much of the day, so we didn’t get a 13.5 volt peak, but the 14th and 15th were sunny enough. The 17th was dreary and today, the 18th has been sunny thus far.

However, each night, the battery discharges a little lower. 12.65 volts the first night, then 12.53, then 12.46. Each night lower until last night, 12.03 volts.

Here’s the rub. I don’t know if this is just a normal decline after the sorta mega charge from the AC powered smart charger and it’s just slowly settling back after that, or if it’s a symptom of a problem and I just happen to have a big enough battery to help make it take a long time to show up.

I do have an apples to pears example to compare with. I put the Triplett logger on the gate opener battery for week or so.

First, I love the sharp little peaks that (probably) show gate usage. If I get ambitious before this gets posted, you’ll never see this sentence, and will instead see my evidence that the little jabs in the opener chart correspond with gate operations. Or maybe because I just like this paragraph I’ll leave it anyway. You’re not the boss of me!

See, I told ya.

Dec 16 gate activity:

I am not sure what causes the positive spikes. There is nothing obvious in the gate camera at those times.

The two battery deployments are exactly the same thing except that the gate opener has an unknown but likely minimal charge control built in instead of a purpose designed solar charger controller, it has a small lawn tractor battery instead of a large deep cycle battery, it’s only a 10 watt solar panel instead of a 100 watt panel and the load is almost nothing most of the time instead of a camera, a WiFi AP and a Shelly UNI running 24/7. Both batteries are black plastic, made by the lowest bidder, so there’s that…

Since the data from both logging sources are available in CSV format, I thought I would try to match up the charts in a spreadsheet, but there are significant enough differences between the data sets, due mostly to the delta method employed by the Shelly UNI, that it is not trivial to match them up. The Triplett has even time between samples, the Shelly samples only when a significant enough change occurs. I am certain I *can* match up the data, but I’m not sure it’s worth the effort.

Even so, one can kinda look at the data and, even if I can’t easily share a spiffy visualization, I can report that the opener battery bottoms out at 12.67 volts consistently, give or take a couple of 100ths, each night in the logged data, unlike the big battery with the big panel, that seems to progressively lose ground every night.

Then again, maybe 10 nights isn’t enough to know the bottom of the pattern yet.

And who knows what spring and summer, with the sun higher in the sky will bring.

Too many variables.

My last post was last Friday. This is Monday. The gate battery had an exciting weekend.

Late Saturday morning, I finally got the official Renogy Solar Panel Mount Brackets deployed.

It is adjusted approximately to the theoretically ideal angle, which somewhat understandably matches the latitude of the location, in this case 33-ish degrees. That doesn’t account for the few degrees off level where it is thrown on the ground, but its more of a rule of thumb anyway. Longer term, I think I will attach it more firmly to the ground than with the gravity afforded single cinder block cap. Also, the cabling is still far from safe from any mowing implements.

For the rest of Saturday, we did unrelated stuff. Sunday, however, I set up our usual fence Christmas decorations, which is modest, but enjoyable. Lighting on the fence and gates, plus a couple of inflatable elfy dachshunds.

One nice side effect of these decorations is that I run a extension cord from the house all the way out to the gate, so for a couple of months, I have mains power available at the gate. So, once I had the basic power distribution in place, put my smart charger on the gate battery and left it.

I deploy a Home Assistant controllable switched outlet for these decorations, along with automations to turn them on a sunset and off at 2:00AM. Since I wanted to leave the charger running, I disabled the automation to turn off the decorations.

Leaving the charger on overnight definitely had the desired effect.

There is a lot going on here. Click on the image below for details.

Of a mildly entertaining nature, the outlet switch I run these lights on reports power use. Right now, with just the lights and the dachshunds, it is drawing a little less that 200 watts. Interestingly, it varies quite a bit, between 170 to 192 watts. I suspect some variation from wind affecting the inflatables, but I would have to care enough to investigate to know for sure. However, while the smart charger was connected, it ramped up to 420 watts peak around 10PM, then back down to baseline 180ish by 5AM or so, including a decided bump down at 5:20AM that corresponds with a bump down in Gate Battery voltage, which I presume to be the Battery Full mark notated above.

Of a even more mildly entertaining nature, when I installed the Shelly UNI on Friday morning, I apparently knocked one of the Triplett clips off the battery terminals and didn’t notice it until Saturday when I was attaching the mounts to the solar panel. The two logs are otherwise very close, within their respective limitations.

Since I now have essentially live logging on the gate battery, I redeployed the Triplett onto the gate opener battery, which is a separate thing. The Mighty Mule gate controller has its own small solar panel, probably 12-15 watts, to maintain it’s rather modest requirements. The opener draws nearly nothing until called upon to open and close the gate, which doesn’t happen very many times per day, often not at all some days. Upon connecting it, it was reading 12.89 volts, so it’s probably pretty healthy. I will try to leave that logger on there for several days to see what that battery does.

Speaking of gate opener, this is what I will probably connect one of my Shelly UNI outputs to, to be able to open the gate from Home Assistant.

I need to nail down the behavior of these outputs. It sounds like I can have it momentarily close with a button push, but the verbiage is not stupid clear 🙂

Ok, I still have my legs, but I am kind of obsessed with this battery thing.

It has been about a week since my last confes… post.

Some of this post will go back and forth, time-wise. I am more interested in covering each subject rather than rigorously maintaining a timeline.

The plan was to leave the new 100 watt solar panel in place as long as possible to see if it can catch up charging the new battery. Unfortunately, the weather saw through my ruse and has conspired to be cloudy and sometimes rainy, limiting the solar flux.

By Tuesday, I decided to help the battery along by connecting a mains powered battery charger, using a 800-ish watt-hour power bank. I knew it would not last all day, but I also knew it would be a powerful boost for the battery.

Wednesday morning, I pulled the voltage logger history, then put it right back on to continue logging.

There were a few key moments in the data:

When the battery voltage dropped to 11.3 volts by about 11:45PM, the charge controller shed the load, resulting in a small voltage boost. Interestingly, it did not restore the load until 5:45PM Monday, well after the peak battery voltage well over 12 volts.

By 11:45PM Monday night, it had again shed load, but it seems important that it shed load at 11.11 volts. This is, to a lead acid battery, significantly lower voltage than the 11.3 volts where load was shed the night before. Very curious.

Around 8:00AM, we actually had a sunny day the solar panel began adding a sharp rise to the battery voltage.

At 8:56, I connected the external charger. The screen display on the power box estimated 3 hours of runtime, but it was wrong. The box was depleted at just over an hour and a half. Since I had set an alarm to check on it in three hours, it was well shut down by the time I checked it. I pulled the charger off and put the power box in the garage to recharge it, but I left the logger in place until Wednesday morning.

When I reconnected the panel on Tuesday, I was smart enough to take my 2nd string cheapy meter up there to see what the open circuit voltage was on the solar panel, which was 23.9 volts. Ironically, I kind of noticed at that time that the charge controller and the voltage logger were slightly different and I remembered the voltage logger as being about 1 volt lower than the charge controller. However, with a meter in my hand, I did not think to check it and compare at that time. Typical.

Early Thursday evening, I took my good meter out there and compared the three readings. They were all close enough to not really matter, though the charge controller reads the lowest by 0.2 volts, possibly a significant number when dealing with lead acid chemistry.

The coolest development is something I have wanted for a long time, a way to monitor the voltage remotely. I had mentioned using an ESP-Home device, which would be inexpensive and pretty easy to build, plus I have already made a few similar devices and likely have everything I might need on hand.

Then again, I discovered that Shelly makes an affordable device that does what I need right out of the box.

For my purposes, it is a WiFi device that talks to Home Assistant using MQTT, runs on 9-28 volts DC and can measure 1-30 volts DC.

It also has two digital inputs, a pulse counter input, two digital outputs that can drive 300ma, and it can operate a variety of one-wire devices, such as temperature and humidity sensors. I see a Home Assistant gate opener in my future. I only wish one unit could monitor two voltages so that I could almost monitor the gate opener battery without deploying a second unit.

It was almost trivial to get it working. This is not really a tutorial, but… I put the Shelly app on my phone and give it Bluetooth permissions. I powered the UNI with a 12V battery pack that I use for various things. The app found the UNI device immediately. I configured it to join my IoT WLAN, then browsed to it to set it up.

First, I set up MQTT. All I had to provide was the IP and MQTT port of my Home Assistant and it pretty much immediately showed up in devices.

I noticed that there was no voltage sensor showing. To enable that, I had to go to Peripherals in the UNI setup menu, click the + button to add a peripheral and add Voltmeter. There are several useful settings, such as a friendly name, measurement range and some custom math and units that can be applied to the measurement before it is reported. For example, you might measure 4 volts, but 4 volts from a strain gauge might mean 9 pounds of grain left in a hopper, so you can do some math and report 9 pounds instead of 4 volts. You can also set up automations from within the UNI device itself

“Delta Threshold” is worth spending a little time on. The Triplett logger takes a voltage reading once every configurable time period. The longer the duration between samples, the longer you can collect data before the memory fills up. The Shelly UNI instead watches the voltage and only reports when the voltage changes a certain amount. The minimum and default is 0.1 volts. This makes for a much more efficient use of database space, but a blockier uglier graph.

Everything else was just minor tweaking of Home Assistant stuff.

I left it connected to the battery pack overnight.

It was several hours between 0.1V drops, from 12.14, to 12.03, to 11.92 volts.

This morning, I added a little more wiring and connected it to the gate battery. We’ve had a reasonably sunny day.

It’s only one day, and the first semi-sunny day in several, but I am disappointed in how rapidly the battery voltage is dropping. Of course, it didn’t peak very high, so that could be a factor as well.

I am thinking of running a cord out there and running the charger for 3-4 days to put a real solid charge on this battery so that the solar can really do just maintenance charging.

It is now Saturday morning and rather than add a whole post just for this, I though I would append to this one.

I took the 30 minutes or so that it took to build and attach the mounting brackets to the panel.

This is set to the reasonably ideal angle for a panel that is the same as the location’s latitude, 33ish degrees in this case, measured imprecisely with a speed square during assembly and using the holes that came closest to that imprecise measurement.

It is a cloudy day and it was a foggy morning, so I can’t expect a lot of energy today. I did find the little dip from the removal of the panel during construction of the brackets a little chuckleworthy.