Blue View - New Batteries

Our house batteries have given it up. We had three 100ah deep discharge batteries that supplied all our non-engine electrical needs, like the fridge, lights, coffee maker, and phone and tablet chargers. When new, they could handle all those loads for three cloudy, off-the-grid days, and much longer if those days were sunny enough to generate a full dose of solar energy.

On this trip, however, we soon discovered that even when fully charged, they couldn’t even brew our morning pot of coffee without dropping down to 10.5 volts, causing the inverter to shut down. This was disappointing, not only because we got short shrift on our coffee, but because they were just fourteen months old… just a couple months past their warranty expiration.

We don’t seem to have much luck with batteries in our vans. We went through two sets on our previous van, Blue, and now this is the second set on Blanche - not counting the batteries she came with which were dead when we bought her. None of them lasted much longer than their warranty period. It’s not like we abused them… we never let them dip below 50% depth of discharge, tried to keep them fully charged, and equalized them periodically. Excessive heat is tough on batteries, though, and I suspect that the Las Vegas temperatures probably contributed to their less than stellar performance.

Between our eighteen years aboard Nine of Cups and our five years traveling in vans, we’ve tried almost every battery chemistry available; flooded, sealed lead-acid, gel and absorbed glass mat (AGM). We had the best experience with AGMs. Our last set of Lifeline AGMs on Cups lasted us seven years, far exceeding any of our others.

The only battery type we hadn’t tried was lithium ion. In their early years they were too finicky and dangerous. Charge or discharge too fast, overcharge them, or charge them when it was too hot or cold and catastrophic things happened, like burning your boat to the waterline. Modern Li-Ion batteries all contain sophisticated battery monitoring systems (BMS), however, that completely shut them off if the conditions become dangerous. The BMS also uses smart technology to prolong the battery life. It detects over or under charged cells and automatically equalizes them, for example. Many are even Bluetooth enabled, and can talk to your smartphone. Your batteries can tell you their state of charge, let you know what the charging or load current is or send notifications that warn if your batteries are nearing a dangerous state or are getting low on charge. Amazing, even to a geek like me.

Li-Ion batteries also have a number of advantages over the other chemistries. They weigh about half as much as the others, and can be mounted in any orientation. Li-Ion batteries can be charged faster than lead based battery types, and can be routinely discharged to 20% of capacity (most traditional batteries shouldn’t be discharged to less than 50% of full capacity. This, in theory, means that since you can use 80% of a Li-Ion battery’s capacity versus 50% of an AGM’s capacity, you need fewer batteries to net the same useable battery capacity).

They also have some disadvantages, though… they can’t be charged if the temperature drops below freezing or rises above about 130 degrees F, or used at all below 0 degrees F or above about 135 degrees F.  Car manufacturers cope with these issues by heating or cooling their battery packs to keep them within a limited temperature range - not something we’d be able to manage in our boat or van.

The biggest drawback to Li-Ion batteries, however, was the cost… typically 3 to 8 times the cost of traditional batteries. The flooded batteries I’ve been using cost ~$150 each and come with a full, one year replacement warranty, while the equivalent Li-Ion batteries cost $950. Buying the latter doesn’t make economic sense, even taking into account its three year warranty and higher usable capacity.

That last drawback is quickly disappearing, however… the cost of Li-Ion batteries has already come down significantly. Renogy, a company that I’ve been buying batteries, solar panels, inverters and chargers from for many years, has knocked about a third off their Li-Ion batteries since I last looked about fifteen months ago. Those batteries that used to cost $950 now retail for $650.

But wait - it gets better. Home Depot, which carries the Renogy brand, just put them on sale for $470! HD gives veterans another 10% discount, and since we were in Oregon where there’s no sales tax, our final price would be $846 for two, 100ah Li-Ion batteries. Even if they only lasted for the three year warranty period, it still made economic sense. We ordered two, and had them shipped to an Oregon store we’d be passing by in a few days.

Physically, they were identical to the old batteries, so swapping them out was easy. It took just over two hours from the time I carried them out of the Warrenton, Oregon Home Depot to packing up my tools and carrying the recyclable old batteries back in. I did the entire job in the HD parking lot.

So far, they’ve worked just fine. I love the Bluetooth app that allows me to check on their status whenever I want - which is several times a day, BTW (even if Marcie does begin to roll her eyes a bit when I show her how well the batteries are doing for the fourth or fifth time of a day).

That still leaves the issue of having the batteries shut down when it’s too cold or too hot. We’ve come up with solutions to the temperature issues as well, however… let’s not go to cold places, or if we do, let’s use our new diesel heater to keep the interior livable for us as well as the batteries. And when it’s 118 degrees in Las Vegas? How about we drive to Alaska?

Stay tuned for next week’s scintillating Blue View, whatever it turns out to be…