On our West 2018 trip we spent 96 nights on the road. We visited friends and family for a bit over a week. Of all the other nights on the road, we had shore power the first week crossing the South, and never plugged in the rest of the trip.
On our first tour in our van (and the previous tour in our Subaru) we had a Yeti cooler to keep stuff chilled. We bought ice as needed. If you pack a Yeti well, and don't open it too often, stuff will stay cold for days, up to a week. If you are using it to keep the food that you're eating every day cold, taking food out, putting food back in, grabbing a beer out of it, its efficiency is compromised, and we found ourselves buying a bag of ice pretty much every day. Which turns out to be anywhere from $2 to $7.
So we convinced ourselves that it made sense to buy an ARB cooler. It is rugged and efficient, and runs on either DC or AC current. We had a solar panel and a house battery installed to power it, and charge our phones and Kindles. We had low needs, still evolving from our tent camping heritage.
The original solar panel failed first, and it was replaced by a Renogy panel and controller, which worked far more efficiently (and with the Bluetooth module, could be tracked from my phone). and provided enough power for the ARB and more. Soon Sharon was plugging her NutriBullet in each morning to make smoothies. We were also tapping the house battery for inflating our Stand Up Paddleboards. We usually wanted to paddle in the morning, and the house battery was often down to 50% after a night of keeping food cool, so we missed a couple of opportunities.
(We don't have a generator. We spent too many nights tent camping, listening to someone else's generator humming away all night, making a mockery of our outdoor experience. We aren't ready to disturb nearby tent folk if we can find a viable alternative.)
(We could have also started the Sprinter, and with the engine running, power the air pump from the started battery. For a while I didn't want to do this for fear of harming the starter battery, but I've come to realize I was just being over cautious, and it wouldn't worked just fine. Just don't tell Sharon.)
As the Summer trip went on, and cloudy days interspersed intruded occasionally, it took longer to recharge the house battery from the solar panel. The ARB is sensitive to the DC coming from the battery, and takes less power as the battery is depleted. The good news is that it's kinder on the battery, the bad news is that the fridge temp creeps up. So we found ourselves buying ice a few times to keep the food chilled. And the AGM battery kept seeming more and more lame.
So we decided to upgrade! More battery, more solar, more charging.
First off, we figured our AGM battery was pretty much dead. Deep cycle lead acid batteries really don't like discharging more than 50% of their rated power. Pushing them decreases the number of cycles in their lifespan. If you're kind and don't abuse a lead acid, you can hope for maybe 500 power cycles before replacement time comes. We abused ours, and it was dropping to 50% and below from a nominally full charge far faster than it used to.
Rather than simply buy a replacement lead acid AGM, we decided to upgrade to Lithium. The Lithium Iron Phosphate batteries are quite stable (no fires or toxic gas discharge), and they can be discharged to 20% without long term harm, and they have an Order of Magnitude more cycles in them. The minor drawback is that they're about 4-5x more expensive. The problem my research found was finding quality lithium batteries. It seemed most come from China, and quality assurance is an issue. And who wants to pay big dollars for something, only to have it fail with some internal fault a few months down the line?
My research led me to call Batteries Distributors SE, a . Simon proved to be a wealth of information. The phone conversation led to a visit and the eventual purchase of two Relion LiFePO4 batteries to replace the single AGM. And instead of a box under the van, the two batteries sit inside the van in a space that used to hold tools I never used.
Batteries Distributors SE also provided us with a Victron Energy Battery Monitor with a Bluetooth module so I can view details about the batteries from their phone app. The information from the monitor gives me real-time information about the current Voltage, the net Current and Power (positive or negative Amperes and Watts, depending on how much Sun and how much load), the number of Consumed Amp hours, and the Time Remaining based on the current load. Between this and the Renogy app, I have more metrics on our electricity than I know what to do with. It is a joy to monitor how much power is coming off our roof, and how much power is being consumed inside Ernie.
With the two 100Ah Relion batteries, we now have more than 3x the usable power we had last summer (50% of 100Ah is 50Ah, vs. 80% of 200Ah is 160Ah). The next steps are to upgrade the power generation. We have room on the roof for another solar panel, and we could tap into the Sprinter alternator for some power.
Pictures of the new batteries are at https://photos.app.goo.gl/KrfqRtuG2BKnC3Sp8
