Tag Archives: battery

photo of the solar system with A new AGM battery

A Solar Upgrade for the Teardrop Trailer

Teardrop Trail: June 4, 2017

In the last few months, I’ve been working on a larger solar system to pump water at the ranch. We live out in the Texas Hill Country and occasionally experience power interruptions, and I wanted to use solar power to improve our emergency preparedness. The experience of designing and building that system led me to rethinking the teardrop solar system.

A New Battery

photo of Cutting a hole for the data display

Cutting a hole for the data display

Two 100-watt solar panels provide enough power to meet our modest camping needs, but I felt the battery could be improved. We were using a marine battery, but it was a compromise between high starter current (which we would never use)  and deep-cycle power for camping use. An Absorbed Glass Mat (AGM) deep-cycle seemed a better match. I ordered an Optima D34M Blue Top that could supply up to 55 Amp/hours of power and fit into the modest available space.

And a way to measure it

photo of The new data display

The new data display

Of course, fully discharging any lead-acid battery will shorten its life and normally one leaves at least a 50% charge. How do you know when you’ve reached 50% remaining power? You can estimate from the battery voltage, but measuring power directly would be best. That led to the second upgrade; a digital energy meter. It shows voltage, current and power, as well as the total power in watt/hours consumed since the last reset. Using the Optima battery as an example, I could use up to 330 watt/hours of power ((55 amp/hours / 2) * 12 volts = 330 watt hours) before it was wise to recharge.

Electric Kettles for Camping?

Finally, we enjoy electric kettles for heating water, and they’re perfect for camping. In many campgrounds, shore power is available and we can heat water for tea, coffee and washing up with ease. Would it be possible to use an electric kettle on solar power?

photo showing solar system With 1000 watt inverter installed

With 1000 watt inverter installed

Researching electric kettles and hot pots I found one model that only used about 1000 watts. A lot of power, but within reach of a not-too-expensive 12-volt to 120-volt inverter. It looked like fun to see if I could make it work, and I ordered an inverter and the necessary wiring to hook it up. Besides; the same inverter could be used to power a Crockpot or Slow-cooker — something we’ve already shown is practical.

The picture tells the story. The new battery, inverter and hot pot were connected and did indeed heat 12 ounces of water to boiling. It used 164 watt/hours of energy as measured by the new digital meter — about half of the available battery storage. Not too practical, but a fun experiment!

photo of the solar panel. It was still there in Perry

There Be Dragons …

Teardrop Trail Log: June 13, 2016

I guess I should be grateful we didn’t have more problems. If you think about it, trailering is an unlikely pastime, wherein one drags a small metal box on wheels at high speed over sometimes nasty, bumpy roads and expects everything to arrive at the same time. Then there’s the summer heat, rain, and wind — all of which can be extreme. Top it off by camping in the woods with open campfires, animal encounters and rutted trails masquerading as roads, and it’s a wonder things go as smoothly as they do. It’s a testament to the essential hopefulness and naïveté of the average camper. Certainly it describes our view of staying in the woods.

photo of Jim Repairing the antenna tube

Repairing the antenna tube

Looking back, I understand our first several trips were usually trouble-free. Perhaps it was payback time. After a day of construction, rain, and detours, I thought we might have taken our lumps. As it turned out, we were just getting started. Day 2 dawned cool and overcast, and wonder of wonders, there was a Starbucks nearby. We went in and ordered, and within minutes I was in possession of the magic elixir. A Mocha. On the way back to the rig, I noticed that the antenna storage tube was askew. One of the supports had broken. Better fix it.

I decided to run our solar beer cooler while we were on the road. The day promised to be sunny, and I would have cold beer while setting up camp. Off we went through Paris, Texas, on our way to Joplin. Easy travel.

photo of Galley outlets

Dropping voltage

Since I was curious how much power we were generating and using with the beer cooler, I checked the voltage monitor every time we stopped. The battery voltage was falling slowly, suggesting the solar panel wasn’t keeping up, but nothing to worry about. Then during one of our stops, I noticed that the battery voltage had dropped by two volts. Not normal behavior. Considering the problem while we drove the next leg of the trip, I realized that one cell in the battery had catastrophically failed. This battery was toast.

We would have to find another. Marilyn got to work with the maps. As she plotted routes and queried the web, I mused on the rotten luck. What were the odds? Batteries don’t normally fail like this. On the other hand, it was over a year old. Maybe the battery maintainer wasn’t very good. Then, she announced her result. There was a Costco in southeast Kansas City, and going there would only take us a few miles out of our way. The camping gods had smiled.

We stopped at Costco, bought a replacement battery, and installed it in the parking lot to recover the core charge. Even so, we arrived at the Jacomo Campground by 7. Plenty of light to set up while Marilyn cooked a delicious dinner. Maybe we had finally paid our karma debt and could sail unconcerned into the adventure!

photo of A New Battery

A New Battery