Battery Project - Part 1

Monday - Now starts the planning process for the battery installation. Since the battery bay is an uninsulated compartment, I will be building an insulated box for them. 

The bottom of the battery bay is sturdy metal and Home Depot has 1” rigid insulation in 2’x2’ pieces. I think that’ll work for the bottom of the box. A piece of 1/2” plywood will distribute the load onto the foam. The box itself will simply be 1/2” plywood with 1/2” insulation inside with the same construction for the top. 

I’ve identified most of the cables shown in the first picture and I want to relocate a couple of them that will be hard to access once the box is in place. The large, cylindrical relay on the right will be removed and replaced with a DC-DC charger. This relay is energized when the engine is running to allow the engine alternator to charge the coach batteries. The alternator is rated at 160amps and the DC-DC charger will limit the current to 40amps. The internal resistance of LiFePO4 batteries is very low and it will max out the alternator (burning it out) and possibly exceed the max charge rate of the batteries (70 amps each). The other purpose of the relay is to “jump” the chassis batteries in case they are dead. 

Wednesday - The batteries arrived already, three days before they promised. I checked the voltage on them and they are both partially charged. The batteries also have Bluetooth built into the BMS (Battery Management System) so I can see the individual cell voltages and the internal temperature. This is an unexpected feature. The next screenshot shows how the battery shows up on the phone screen.

At the top of the screen is the SOC (State of Charge) but it won't reflect reality until after a couple of complete charges. There is a switch for heating but I didn’t get that option. At the bottom are the individual cell voltages. Pretty cool! 

The first task was removing the old batteries and wiring them back up to the RV so we still have 12V functionality. Another RVer here in the park loaned me a set of jumper cables so I could temporarily power the RV off of the old batteries. The battery bay has a lot of rust on the bottom where the flooded lead acid batteries were sitting so I'm going to paint the floor before starting to build the battery box. The rust is just on the surface and the Rustoleum paint that I already have says to just remove the loose rust and clean with soap and water. This afternoon, picked up a drill mounted wire brush and used that do get rid of as much of the surface rust as I can. Tomorrow, paint. 

Another Potential Issue

Friday - An observation that I made yesterday evening after getting an alert from the Victron battery monitor yesterday morning. The alert was for battery voltage dropping below 12VDC on the morning of Nov 24. 

This chart indicates that 12VDC is around 50% charge which is about as low as you want to go when using lead acid batteries. At this point, we had only used about 120AH of the 420AH of capacity. This is the capacity when the batteries were still new. 

I adjusted the battery capacity on the battery monitor to only 210AH, turned off the charging function on the inverter, and we’ll keep an eye on it. The batteries are still working and we do have a generator so it’s not anything critical. Especially since we don’t dry camp a lot.

In the middle of the afternoon, I’m trying to figure out what is drawing 228watts. The refrigerator plus fans are drawing about 80-100watts. The inverter is off and the basement fridge is on shore power. Maybe the two fans are drawing about 80 watts between the pair. All more than I thought. 

Saturday - Early this morning, I checked the SOC (state of charge) and the battery voltage and adjusted the battery bank capacity to match what I was seeing. The battery voltage was still around 12.25VDC so I raised the capacity to 265AH. This raised the SOC to 62% which matches the chart shown above.

I think that our batteries were discharged to almost zero when it was in the shop. Initially, I had the batteries disconnected but the shop needed them on to operate the slides and steps. They were left on for weeks while waiting for parts and when I picked the RV up, the coach batteries were almost completely dead. We may be replacing batteries next month as we won't be able to make it through the night if we need to use the furnace.

A morning project was making this little steering wheel table from wood left over from other projects. The steering wheel is tilted up right now. Some people like driving it the RV with the wheel almost horizontal as it gives them more leverage. I prefer it down at a more familiar angle. 

Sunday - It’s looking like we will be ordering some batteries in the near future. Even without using the propane furnace, our batteries are already dipping down to 60%. 

I’m pretty convinced to get two of the 206AH, 12V SOK batteries without the internal heaters and BT. They are slightly larger and a couple of inches taller than the each of the four existing 6V golf cart batteries. They have a maximum continuous discharge rate of 100amps each so if we upgrade to a 3K inverter, we will need to add a 3rd battery. I am planning to install them in a homemade insulated box in the battery compartment. I can make my own silicone heat pad temperature control with a small WiFi enabled microprocessor. 

I need to also order a DC-DC charger for engine charging. The existing cables are adequate but I’ll need some jumper cables to allow me to remove the existing batteries from the compartment and still have the coach powered up. 

The old Magnum inverter/charger doesn’t have a LiFePO4 charge profile but the solar charge controller does. The Magnum can charge the batteries to ~80% SOC and the solar can top them off if needed. I had originally thought that I needed to change out the inverter/charger first but this should work fine. 

Happy Thanksgiving!

Thursday - Turkey day! I have a turkey breast in the sous vide, dressing in the convection oven, gravy simmering on the stove, whole berry cranberry sauce and a pumpkin pie in the refrigerator. We will be sharing Thanksgiving dinner with Lynne and Jerry in a couple of hours. 

Later - Dinner was wonderful! Everything turned out great and the company was great. After resting from the post-thanksgiving doldrums, I headed to the jacuzzi. It was around 8pm or so. Much later than usual but it felt fantastic with the air temperature in the low 50s (°F).

No RV Projects

Sunday - No RV projects today for a change. This afternoon, we joined Jerry & Lynne, and Kathy & Mike at Borderlands Brewing Company. The live music and the great company made for a great afternoon. 

Monday - I finally started a non-RV project late last night and didn't finish it until this morning. My Macbook Pro is a 2016 model with 16GB of memory and a 1TB internal drive. It is a 3.3GHz dual-core I7 so as far as performance goes, it's more than adequate for what I do. But, it is considered by Apple to be too old to automatically upgrade the operating system. I followed instructions I found online to upgrade it to the latest OS, macOS 13.01 aka Ventura. It took quite a while but finally finished this morning. I could barely read the screen as the default resolution was set so high. The text on the screen was tiny. I found the post-install patches which corrected the screen resolution and all seems to be working properly. Given that I only seem to use the laptop for Zoom, Discord, email, and web browsing, my needs are pretty minimal. 

I led one of the afternoon test sessions. That would be the normal use for the laptop. Even though it's only a 13" screen, it's still better to try to participate using the phone. No problems at all with any of the applications or tethering with the iPhone.

Tuesday - Scattered clouds today during the morning test session. But still nice enough to sit outside. We are testing a full-time RVer currently in Livingston, TX. 

I then walked to Sprouts to pick up some vegetable stock to brine the turkey breast overnight. I cut off the meaty portions and have the rest in a small stock pot for broth for both the dressing and gravy. Tomorrow afternoon, it’ll get vacuum sealed and put in the sous vide. Later today, I'll make the cranberry sauce now that whole cranberries are available. I enjoy cooking for the holidays...

Wednesday - This morning, Kathy took us to Catalina State Park to do a bit of hiking. The first one was a loop trail through a small valley. Lots of saguaro and views of the nearby hills. No wildlife but lots of sand. 

The fall colors are still out here in Arizona. The leaves are still changing and hadn’t fallen yet. There were still lots of burned areas from the 2020 brush fire. 

And, the required selfie from the trail. 

Even More Minor Projects

Thursday - I picked up an assortment of cable clamps at the all-too-close Home Depot. The rubber and metal one was used on the first panel as it held the 10AWG solar wire snugly. The wire insulation is rated for outdoor use in sunshine. 

Further down, I used ½ nylon clamps where the wire passed between the panels. I also used these nylon squares with VHB tape and are used with zip ties. I used them where the wires run across the roof. The VHB tape used isn’t the high-strength version and the squares didn’t stand up to rain unless they are covered with Dicor to protect the VHB.

Other than that, not much going on. No test sessions today as no one signed up.

Friday - Two test sessions today plus I started another small project. The 12V portable refrigerator/freezer is in one of the full width basement storage bays. Currently, the 12V supply is one of the storage bay lights. The light power runs throughout the basement area so the portable unit sees only around 11.2V due to resistive loses from the long wiring run and small gauge wires. 

Saturday - Today, I ran a short run from the new distribution panel to an Anderson Power Pole distribution block within the storage bay. In addition, I installed a 110VAC duplex outlet. I can run the portable refrigerator/freezer off either one. 

Finishing Projects

Monday - Another cool night. And, I don’t think the high temperature was above 70°F. I finally got around to washing the Jeep. It was getting pretty dirty plus the tree was shedding leaves on it. I also went up on the roof of the RV and checked the solar panel. The VHB tape seems to be solid except one corner has a small gap. It seems that the roof isn’t completely flat. Tomorrow, I’ll unscrew that mount from the panel and try and replace the tape and remount the plastic bracket so there isn’t a gap by elongating the holes in the bracket. 

Tuesday - Today, I adjusted the solar panel mounting bracket that wasn’t making good contact with the roof. I also added five screws where the brackets lined up with the metal roof joists. I still need to pick up some wire clamps to prevent the wires from moving around with the wind. The Dicor self-leveling sealant is just to help protect the VHB tape. Before we leave here in January, I’ll check the panels again. If I add more panels, I think I will use aluminum unistrut instead of these plastic brackets. 

Not a “project” but dinner was kimchi fried rice. The Blackstone does a fantastic job. 

Staying up really late (for me) waiting to see if Artemis 1 launches on SLS. While I’m waiting, I decided to make another batch of furikake Chex mix. The last batch was a hit. 

Wednesday - I went to Great Clips for my quarterly haircut. I got a coupon that made it ~40%. A good enough deal. We went to Blackrock Brewers, a small microbrewery in a commercial area near here, with Lynne and Jerry. They had a blackberry sour that was pretty good. Afterwards, we went to In-N-Out for dinner. There is always a huge line at the drive-up so I was expecting it to be crowded. It wasn’t too bad inside. 

Another Project

Thursday - My next project arrived today. Another solar panel. The older panels are 210watt, 12V panels but they are no longer made. This is a 215watt, 12V panel that I will install in series with the other three. The current rating is similar (Isc=9.85amps @22.4V vs Isc=10.83 @20.72V) or close enough. With the low sun angle, I’m not getting anywhere near 200 watts from my non-tilting panels. 

A quick test verified that the panel works. Voc=25.1V, Isc=9.85amps with the panel aimed roughly towards the sun. With it lying flat on the ground, Isc was around 6.8amps which is about what I am seeing from the other panels. The high temperature over the weekend is over 70°F so that’ll be ideal for the Sikaflex to set. Though I’m toying with using the high strength 3M tape to see how well it bonds. When I installed the other panels, there was only a few days before we would be traveling. Possibly not enough time for the tape to bond.

I’m still thrilled with the performance of the JC Refrigeration unit. An improvement would be two compressors so the freezer could have its own controller. 

Friday - A slow start this morning as the temperature was in the mid-40s. After the early test session, I started working on the solar panel. I cleaned the plastic mounting brackets and the roof and used some high strength VHB double sided tape. 

I mounted this panel near the front to avoid shading from the front A/C unit. I still need to dress up the wires. The tape seems to stick really well but if you pull up on the panel, the fiberglass roof just lifts up. So some screws will be needed. 

There is still some room for additional panels though this is the limit of this charge controller. Another one will be needed if additional panels are installed. 

Saturday - I think the forecast for last night was in the upper 30s (°F). I turned the battery charging off last night to allow the batteries to discharge overnight. By morning, they were down to 83%. By 10:30 this morning, they were back up to 100%. The extra panel makes a difference. The three panels were just keeping up with demand and trickling several amps into the batteries.

Well, 350watts is more than I was seeing before. Or less than half the theoretical max for the panels. 

Sunday - A quiet, non-activity day. No projects. Picked up some groceries including some Thanksgiving food. We haven’t really decided what to do but I’m picked up a turkey breast, fresh cranberries, and some dressing ingredients (sausage, water chestnuts, bread, onions, celery). I’ll add some Chinese sausage, dried mushrooms, olives, pecans, and may some wild rice. In other words, it’s time to clean out the pantry. 

Tucson, AZ

Sunday - We are back to 80°F for the afternoon high so back to the pool. Not much going on today. I did get the first coat of paint on the last of the refrigerator trim. It needs to dry overnight before a final light sanding and the second coat. 

The furikake Chex mix turned out pretty good. Basically, replace the Worcestershire sauce with soy sauce, and instead of salt, add a whole bunch of furikake which is a mixture of seaweed, sesame seeds, and dried mackerel all crumbled up and sold as a condiment for rice. It’s addictive… BTW, I didn’t add pretzels but did add dry roasted peanuts. The don’t take up as much volume. 

Monday - On the way back from Bridget’s appointment, we stopped at Costco. No big, major purchases but some of my favorite ramen bowls and other “bulk-ish” groceries such as olive oil and those wonderful Costco hot dogs.

Tuesday - We went out to a park west of town for a Pima county moon rise walk. There were only about six of us including the leader. We went for a short walk with a lot of explanation of why there is a full moon and some other facts about the dark sky program.

We watched the moon rise with saguaros in the foreground. The phone camera isn’t good enough to see the silhouette of the saguaro. The hills block the city lights from Tucson and streetlights are required to have covers to block the upper side of the fixtures. 

Once the moon was up, there was plenty of light to cast distinct shadows and walk along the trail. Not quite as well as night x-country skiing under a full moon. The snow would make it seem very bright even more than the light sand of the desert. 

No Title…

Wednesday - I’m still impressed with how well this is working. The spikes are when the doors are opened and it seems to recover quickly. Since the only temperature sensor is in the refrigerator, putting something warm-ish in there will cause the freezer temperature to drop. 

I participated in the morning test session. He was prepared and passed easily. Those are always enjoyable. I needed one more trim piece for the bottom of the refrigerator. I picked up a 1”x2”x 4’ piece of poplar and it didn’t have a barcode. The cashier just picked a random entry from their product menu and asked if that price sounded reasonable. It was very reasonable. I stopped at the wood shop and ripped it down to 5/8” and test fit it. I need to rip it 5/8” in the other dimension tomorrow then prime and paint. 

Thursday - I went to the wood shop this morning and ripped the trim to 11/16” then ran it through the drum sander for the last 1/16”. Now, I need warm weather to return so I can prime and paint the piece. 

My Amazon order arrived with 2x30’ of UV resistant 10AWG solar cable, and one PVC panel mount. I ordered one more 200watt panel to add to the existing three for a theoretical total of 800 watts. I am limited by the 100volt limit of the charge controller. With the panels all in series, the Vmpp voltage is 84volts. One more panel would push it over 100volts. The maximum current is still 9.3amps so the 10AWG cable is still adequate. Now, I just need the panel. 

Friday - A cooking day plus I participated in a couple of test sessions. It was too cold to do any painting. In fact, I dug out the electric space heater for the bedroom. The heat pump did great keeping the rest of the rig warm.

Saturday - It warmed up today after a couple nights of lows in the upper 30s (°F). It warmed up enough to prime the last bit of trim and I’ll do a couple of coats of paint. This bit of trim is on the lower front of the refrigerator so it really needs to be well protected from water as the area will get wet whenever the freezer is defrosted. 

Another cooking day. I wanted to try furikake Chex mix. It came out pretty tasty with the addition of soy sauce and furikake. I also picked up some collard greens that needed to be cooked. Last week, we picked up some cauliflower from the food surplus truck here at the RV park. 

More Minor Projects

Sunday - I finally got the additional trim installed around the refrigerator. It took me a while to get the wooden pieces painted (several coats of satin black). I fastened it with stainless pan head screws. I think it turned out all right. I just need to screw the refrigerator into the wooden frame in the front plus a couple of screws in the back. 

I also picked up and installed felt glide feet on the swivel rocker. The rocker is bolted into the slide but the base also rests on the main floor. I found some that can be adjusted as the thickness of the support is a little off.

Monday - Today’s Amazon delivery was a replacement LED light strip for the awning. The old one had some broken wires and solder joints so green was completely missing as was about a third of the length. The new strip was 5m long, IP65 rated somewhat waterproof but not submersible, and came with 3M outdoor double sided tape. Plus a small bag of mechanical fasteners. I didn’t use the controller or IR remote as the old controller supports Bluetooth. 

I also re-installed the refrigerator vent fans. These are thermostatically controlled with the sensor mounted above the coils behind the refrigerator. They blow air into the compartment. The propane line is still here as the Blackstone griddle is plugged in. 

You might remember that I am running HomeAssistant on a Raspberry Pi with a half dozen ESP8266 and ESP32 microcontrollers. The ESP32 software needed to be uninstalled and reinstalled in order to upgrade to the current version. Kind of a lame process. But they fixed a bug that I ran into around the beginning of the summer. The upgrade required a recompile of the firmware for all of the microcontrollers which took over an hour. 

Tuesday - Started the day with coffee and donut in the clubhouse. Being the beginning of the month, there have been a lot of new arrivals. I participated in the afternoon test session then spent the late afternoon across the street at what they call AA or “attitude adjustment”. More commonly referred to as happy hour…