What Is Killing Our Batteries?!

At the end of July 2018, we decided to take the new rig out for a trial run of boondocking. It was a bit of a last minute decision, and seeing that it was smack dab in the middle of summer… campgrounds that could fit us were difficult to come by. The friends we were going with were bringing their tent and wanted to be near water for fishing with their kiddos. Cascara campground at Fall Creek Reservoir ended up being the place.

Sunset view from the lakebed just out from the dock across from our campsite.

Somewhere, I read that the campground could only accommodate trailers up to 40 feet. I can’t find that indication now, but at the time, I wasn’t sure if that meant the trailer itself, or the combination of the truck and trailer, so I called to double check. Turned out there was plenty of room to fit us, but it was all first come first served and while it hadn’t filled up the past few weekends, there was no telling what would happen for that weekend.

The campground is only an hour from our RV homebase. As you enter the campground, you can hang a left for the south loop or proceed straight forward toward the lake and then take a right for the north loop. By chance, we turned left and picked spot #23. It was partially shaded and plenty long to fit our rig and leave parking for our friends. The north loop seemed to be the original campground space and is heavily shaded. Looking at the map, I’m glad we headed to the newer side because I wasn’t confident we could make all of the curves on the other end.

Camping was $19 nightly, with a $7 fee for an extra vehicle. Our friends have 3 kids, so with all of their tent camping equipment, they had to bring two cars. The sites only allow for one extra vehicle and the ranger was not willing to budge on that, or let them park overnight in the boat launch area nearby. Instead, they had to park out on the shoulder of the road leading to the campground. The shoulder was wide enough for them to park completely off the road and there wasn’t much traffic, so all ended well.

Scott was concerned about the campground being first come first served and our space needs being a bit on the specific side. From the beginning, he was pushing for us to leave after work on Thursday night to increase our chances of getting a spot. We both had to work on Friday, but from Scott’s perspective, it didn’t matter if he drove into the office from our RV homebase or from out in the boonies. For me, it was a bit of a different story. I needed adequate cell service to attend meetings as well as act as a hotspot for my laptop’s internet connection.

He arrived home on Thursday a bit flustered from the day and adamant about taking advantage of the fact that our house has wheels and we could get out of dodge on a moment’s notice. We packed up the house and made it to the campground shortly before sunset with the plan that I would check the cell strength as soon as we got there to pick which work plan I would need to roll with the next day.

The options were -

1. Work from the rig, but I would need some way to charge the laptop as it typically did not last even half a day of work on its battery alone. This could be either in the form of a cigarette lighter inverter or a true generator that could power the whole rig.

2. Go back to get my car so that I could work from it from wherever the nearest acceptable cell connection was. The inverter would still be required for this option.

3. Plan to work from the office. The office was under construction, so it was going to be tricky to find a desk that I could work from with essentially zero notice.

The cell service was even better than our normal RV space in Harrisburg, so I planned to work from the rig. Unfortunately, the rig doesn’t have a 12V cigarette lighter plug (it has USB ports instead), so the small inverter was out of the question. We had been planning on getting a Honda 2200w Inverter Generator for our travels, so we decided to go ahead and get it that weekend to allow me to charge the laptop (the logic seems a bit out there, but I promise, it made sense). Home Depot had the model we wanted in stock, and we were determined to purchase it from there because we could use our credit card points toward a gift card to help offset some of the expense.

On Friday morning, we headed into town at 6:00 AM so that we would have enough time to purchase the generator and some gas, try it out in the parking lot so I would know what I was doing when I got back to the rig alone, drop Scott off at work, and for me to return to the rig before my 8:30 AM meeting. Despite the time crunch and general messing with karma, the morning tasks were accomplished flawlessly. Upon returning to the rig, I was able to use the generator without issue to connect to the rig, allowing me to use any of the outlets in the rig to charge the laptop. I ran the generator just long enough to charge the laptop, and figured I would turn the generator back on again as needed.

A little after noon, I was in need of more power, so I fired up the generator. As soon as I connected the rig’s power cord, the generator died. I couldn’t figure out what was wrong as it had worked without issue just a few hours prior. I called both Scott and my dad for troubleshooting assistance. Unfortunately, both were busy with work and couldn’t help me at that exact moment. This was the first of several power related frustrations of the weekend and I can look back on it now and say that I didn’t handle any of it very well. Rather, I was quite demanding that resolution of my issue take priority. 

Scott was the genius that figured out what was causing the issue. In the morning, the air temperature was low enough that we didn’t need any A/C or fan running in the rig. Side note- neither of these would work on the batteries alone (12v DC power) or if an inverter had been installed (changing the 12v DC battery power to 120 AC house power). When we left for the campground, we forgot to turn the thermostat off. When I was attempting to connect the rig to the generator in the afternoon, the air temperature had risen enough that the thermostat was attempting to run the A/C, which was too much for the generator to handle, causing it to die. I turned the thermostat off and voila! I was back in business.

Our friends arrived Friday afternoon while I was in town picking Scott up from work. They pitched their tent in the back corner of the site where there was some shade from the trees. While we fixed and ate dinner, we ran the generator because we noticed on the little LED battery status indicator lights that we were a bit low. A few hours later, we killed the generator and checked the indicator lights and saw that the batteries appeared to be topped off. After putting the kids to bed, the adults hung out in our trailer playing Cards Against Humanity. It all made for a fantastic end to the work week. 

The next morning, we woke up to find the battery indicator lights reading 11.2V (the light levels are “Low”, “11.2V”, “11.7V”, and “12.3V” for full, so this in itself is a bit misleading). For those that don’t know - a 12V battery shouldn’t be run down past about 12.3-12.2V before recharging. I will do a separate post that dives into batteries in greater detail as I just spent a good chunk of my time over the past week getting really nerdy trying to gain an understanding (and overcome my frustrations) with 12V battery systems. For now though, all that matters is that:

1. When we went to bed the night before, we believed the batteries to be fully charged, and

2. Because we didn’t have an inverter installed, the only things consuming power were the fridge (which would be on the lower end because it was set to run on propane) and lights (which obviously weren’t running while we slept).  

I was shocked! What could possibly be draining our batteries overnight?!? Throughout the day, I spent time googling, discussing with my Dad, and discussing with Scott and our friend (both of whom are electricians), but I wasn’t getting anywhere. The only thing I could say for certain - the stupid little LED indicator lights were NOT helpful! 

Batteries, and power in general, involve three units of measurement (there are others, but at the moment, this is all I need to focus on): Volts, Amps, Watts. The LED indicator shows the voltage of the batteries. But! When I use an appliance, I’m using Amps/Hour, or Amp Hours (Ah). The two 12V batteries installed on the rig were rated for 150-ish Ah each (for a total of 300 Ah), but really that is only 150 Ah because you shouldn’t use more than 50% of the battery capacity between charging.

In my googling, I found an article that listed out the average amps/hour for various 12V RV appliances. The fridge, when running on propane, would use about 2 amps/hour and lights would be less than 1 amp/hour. My perspective was that because the LED lights indicated the batteries were fully charged the night before, I had 150 total Ah available to me... how did I use all of them, when the only appliances/fixtures I was running totaled a whopping 3 amps/hour (at most that would have been 36Ah consumed, assuming that the fridge and lights were running constantly for 12 hours). The math just didn’t make sense.

Luckily, we had two extra 12V batteries with us (a set that my Dad had given us to incorporate with our existing two as a larger battery bank at some point), so on Saturday morning, we swapped the batteries out giving us a fresh 150 Ah to work with. Once we pulled the old batteries off, we used Scott’s multimeter and found the batteries were down to something like 3.5V. (Remember, they shouldn’t go below 12.2V). They were dead... and boy do I mean dead! I don’t know if a battery can even be salvaged after that!

Figuring that we were back in the clear with the new batteries, we headed off to Winberry State Recreation Site for the kids to do some fishing. The dogs had a good time wading in the water and the kids learned a lesson in why fishing is called fishing, and not catching. They were good sports about it though. As much as I tried not to, all day, I was mentally consumed with trying to figure out what was killing our batteries. 

When we returned to the campsite a few hours later, we fired up the generator because after a few short hours, the new batteries were showing they needed charging. What?!? I was stumped, and getting really annoyed that the stupid little LED lights were only giving minimal information, and it wasn’t enough for me to figure out the culprit!  

A bit more googling returned that as a 12V battery is charged, the actual voltage will read higher than it truly is, and it takes several hours once you remove the charging source for the real voltage to display. You have to wait for a residual charge to disappear. So, a way to back yourself into how long you would need to run the charging source (in this case the generator) to recharge the batteries, is to figure out how many amps are pushed out to the batteries by the onboard converter, and use that in combination with the Ah you have consumed, plus 20% for the inefficiencies of charging batteries. I tore apart the basement storage and used my phone camera to get a look at the model of our converter. It’s a WFCO 8955 and handles 55 Amps, but not all of that would be going to the batteries. I estimated that only 10 Amps would be going to the batteries at any given time, so if we were to recharge the full 150 Ah capacity of the batteries, we would need to run the generator for 18 hours (150/10x1.2). There was no way for us to run the generator long enough during the day to fully recharge our batteries. 

Wesley enjoying some time chasing flies and bees.

We ran the generator as late into the night as was reasonable, but still, the next morning our batteries again indicated they were severely depleted. We hurriedly got to work breaking camp to make sure we could still get the slides in and get back to our RV homebase with full hook ups to stop the madness. While breaking camp, we ran the generator to help as much as possible.

As we were backing the truck up to the trailer, I found the trailer brake cable sitting in the bed of the truck. I asked Scott if there was a reason it was disconnected from the trailer and he immediately had a look of dread on his face. He was fearful that the trailer brakes wouldn’t disengage on their own and that we would need to call for assistance to get out of there. Luckily his fear was unnecessary - once the trailer brake pin was reattached, the trailer brakes disengaged on their own. 

We still have yet to figure out exactly how the cable became disconnected. Typically, disconnecting from the truck is my job, but Scott did it that time. We don’t know if he forgot to detach the cable from the truck, or if the cable got caught on something in the truck bed as we drove it out from under the kingpin, but one way or another, the cable stayed with the truck.

Basically, the trailer brake cable operates just like the emergency kill switch clip on a treadmill or a jet-ski. If pulled, it engages the brakes on the trailer, because the trailer thinks it is careening down a hillside. This was not the case, rather it was safely chocked and up on its jacks. On our way home, I again did a bit of googling. Turns out, trailer brakes draw about 15 amps/hour. This was the killer of our batteries! 

All in all, it was a very educational, albeit frustrating, first attempt at boondocking/first outing in our new-new rolling home.