Antigravity’s new LiFePO4 batteries

One morning in the early 1990s, when I was still leading sea kayaking tours in Mexico, I found myself stranded on a remote beach at the end of a tour with a suddenly dead Sears Die-Hard battery in my FJ40 (this was before I’d ever heard of a dual-battery system). Rather embarrassed, I got a jump start from a client, sent everyone home ahead of me, then drove the entire way back to Tucson, towing a trailer full of kayaks, without turning off the engine. (It took some doing to convince the U.S. customs people I wasn’t just preparing to do a runner after I was pulled into the inspection lane. In an FJ40 pulling a trailer? They could have caught me on foot.)

Not the best place for battery failure.

The battery was well within its pro-rated warranty period, so once home I got a new one for around half price. But that really wasn’t the point, was it? If I’d sent everyone home before discovering the dead battery, I would have had a very long walk to the nearest fishing village—I certainly couldn’t have push-started an FJ40 solo in beach sand. I was also aware of other circumstances I’d been in that could have been as bad or worse if a battery had failed. My experience with Die-Hards—then the much-hyped premier battery on the market—was that they lasted an average of two years before failing, usually abruptly. 

There had to be a better way. I did some research (remember when that took actual effort?), which led me to news of a recently available type of über SLA (sealed lead acid) battery called a “gel cell” or AGM (for absorbed glass matt). A company called Optima made them, and the one that suited my FJ40 was around $130 special order—an outrageous price when a Die-Hard went for $55. I winced and ordered one anyway, and that first red-top Optima lasted six years before—very politely—showing signs of weakening. Thus, not only did it prove less expensive in the long run, it saved me at least two battery failures that could have happened anywhere. The AGM battery (I switched to Odyssey later on) became my standard battery configuration—as did a dual-battery system.

Twenty five years later there is a new über battery on the market, with a price as startlingly higher than a typical AGM as that Optima was higher than the Die-Hard. Does the lithium iron phosphate, or LiFePO4, battery represent as much of a leap as the AGM did? Can an overlander on a modest budget justify spending $800 or more for a single battery?

I’d like to find the answer—for myself as well as readers who might be contemplating the upgrade. So I’ll be installing a new dual-battery system in our Land Cruiser Troop Carrier, using one of  Antigravity’s new DC-100-VI deep-cycle LiFePO4 batteries, along with one of their already introduced LiFePO4 starting batteries.

Not your father’s car battery . . .

I’ve been a fan of Antigravity’s products since their pioneering, pocket-sized Micro-Start jump-starting unit, which I embraced very early on and with which I’ve astonished more stranded motorists than I can count, including dozens at several Overland Expos who immediately headed for the Antigravity booth to buy their own. I also astonished, and rather horrified, Scott Schafer, the founder of the company, when I called to tell him that Tim Scully and I had successfully daisy-chained three Micro-Starts and performed an excellent field weld. That function was definitely not within his original design goals—yet we still have all three of those units and they still work perfectly.

NOT recommended!

Given that history, I have every expectation that Antigravity’s LiFePO4 automotive batteries will display similar quality. But I had to promise Scott I wouldn’t try welding with them.

So what’s all the fuss about LiFePO4 technology?

Most articles covering lithium batteries (to use the convenient shorthand) immediately mention the weight savings. And that aspect is impressive—The 100-amp-hour deep-cycle battery Antigravity sent me weighs 30.5 pounds; an equivalent Odyssey AGM unit weighs 69.5. Switching to a dual-battery system employing both starting and deep-cycle lithium units will, in our case for example, completely offset the weight of our 60-liter National Luna fridge-freezer. With a case of beer inside.

Thus there is an obvious advantage in energy density to the lithium battery. However, it’s even greater than the weight difference implies.

Consider a deep-cycle AGM battery and a deep-cycle LiFePO4 battery, each rated at 100 amp hours. While that seems equivalent on the surface, in delivery it is not. As soon as a draw is placed on an AGM battery, its voltage begins to drop in a more or less linear fashion. Once that voltage drops below 10.5 or so, a 12V appliance such as a fridge will shut itself off. At that point the battery retains nearly 50 percent of its theoretical energy, but it is unavailable to a 12V appliance because the voltage is too low.

By contrast, the energy delivery of a LiFePO4 battery is a nearly flat line that remains above 12 volts until the unit is almost fully discharged, at which point it drops off rather rapidly. Thus you get far more actual available power from a lithium battery than you would from an “equivalent” AGM.

But that’s not all. A LiFePO4 battery is also capable of accepting a charge at three to four times the rate of an AGM battery. A typical AGM in a vehicle can take as long as 10 hours to recover from a completely discharged state. A LiFePO4 battery can be recharged completely in four. And while an AGM battery typically can withstand around 300 such discharges, a lithium battery can withstand around 2,000—which brings up the last comparison: lifespan and amortized cost.

Currently a high-quality LiFePO4 battery costs two and a half to three times as much as a high-quality AGM battery from a manufacturer such as Odyssey. However, it appears likely the lithium battery will outlast the AGM battery by about the same factor—if not more. Thus over time the LiFePO4 battery should recoup its cost—and that doesn’t count the hassle of having two or three AGM batteries fail in that time. On an amp-hour basis, there’s no comparison—the LiFePO4 delivers far more energy over its lifespan.

(This obviously assumes that you keep your vehicle for a long time, or that you swap the lithium batteries from old truck to new truck, and say, “Get your own!” to the buyer of the old one.)

There are other advantages. For example, the Antigravity lithium starting battery has a built-in wireless jump-start feature. Leave the lights on or in some other way run down the battery, and it will shut itself down while retaining sufficient starting power to start the vehicle. Just tap a button on a wireless key fob to activate it; you don’t even need to open the hood. (You can also hit the button on the battery itself.)

So . . . end of argument? Not quite.

The bête noire of the LiFePO4 battery is temperature, or rather temperature extremes. Most lithium automotive batteries, including the Antigravity unit, can be used (i.e. discharged) at temperatures down to -20ºC (-4ºF). However, they cannot be charged at temperatures lower than about 0ºC (32ºF). The Cliff’s Notes reason for this is that, when recharging at temperatures above 0ºC, the lithium ions are absorbed by the porous graphite that comprises the anode—the negative side of the battery. Below this, the lithium instead begins sticking to the outside of the graphite, a process called lithium plating. This not only reduces efficiency but can permanently damage the battery.

Keep in mind that these critical numbers represent the internal temperature of the battery, not the ambient air temperature. As the outside temperature drops, the internal battery temperature will lag significantly. A night that drops to freezing or even several degrees below is unlikely to chill the internals to critical level—and we never charge batteries at night anyway. Also, drawing power from the battery—even for efficient LED camper lights—raises its internal temperature somewhat.

Fortunately, each Antigravity battery incorporates a sophisticated battery management system (BMS), which prevents charging when the temperature drops too low. So you don’t have to worry about damaging the battery; however, this aspect might be important if you camp for long periods in persistently below-freezing weather. Antigravity is also preparing to introduce a LiFePO4 battery with an automatic internal heat source that runs off the battery itself, as some other manufacturers have done. We don’t feel the need for this in our application—for Roseann, the words “snow” and “camping” never appear in the same sentence.

(As usual, clever owners who adopted LiFePO4 technology ahead of the rest of us have figured out their own hacks to deal with the low-temperature issue. Some have combined a simple temperature-controlled switch such as this with an inexpensive 12V heating film like this.)

(Another parenthetical aside: While researching all this I came across an article detailing the efforts of NASA scientists to extend the low-temperature parameters of lithium batteries—of obvious importance when sending them into space. The article noted that engineers had significantly extended these parameters by using an electrolyte formation of—ready?—1.O MLiPF6EC+DEC+DMC+EMC (1:1:1:2 v/v) and 1.O M LiPF6 EC+DEC+DMC+EMC (1:1:1:3 v/v). If they’d only called me I would have suggested that in the first place.) 

Very high temperatures can also affect LiFePO4 performance. The listed upper limit for discharging the Antigravity deep-cycle battery is 55ºC (131ºF). For this reason, some owners install their lithium “house” batteries inside the vehicle or camper rather than in the engine compartment. This has the doubled effect of keeping the battery warmer on cold nights, especially if any kind of heat source is used in the camper for the comfort of occupants.

I’ve decided to take a slightly bolder approach, partially as an experiment to see the effects of different installations. Our Troopy has the stock dual-battery tray in the engine compartment, and  I plan to mount both batteries there and monitor the temperature extremes they experience, using (in part) Racetech stick-on temperature strips, which record the high temperatures reached on the surface to which they’re attached. 

The other part? That will be courtesy the built-in Bluetooth connectivity of each battery, which will enable me to monitor, through my iPhone:

• Battery voltage

• Current/amps going in or out

• Watt output

• State of charge percentage (SOC)

• Interior temperature

• Individual cell voltage

• Number of cycles the battery has experienced
  
  
  

In addition to that internal temperature readout, the state of charge in percent will be especially helpful—given the LiFePO4’s characteristic of maintaining flat voltage delivery, it’s difficult if not impossible to ascertain the state of charge by voltage alone, as on an AGM battery.

Our Troopy’s battery tray is in the back right corner of the engine compartment, looking from the front of the vehicle. The 1HZ diesel’s exhaust manifold is on the opposite side of the engine, which will help mitigate heat gain. I also plan to have fabricated a metal heat shield that will block the inside faces of the batteries, to help even more. I’ll add some sort of heat barrier to the sheet metal as well. In a few months the southern Arizona summer should give us some solid data on the effects on both batteries; then we can re-evaluate their placement.

I’m going to take the opportunity to replace the existing cables and terminals with new ones, and clean up the rather tangled routing resulting from adding on the winch, driving lamps, and National Luna isolator.

There is one other cost factor to consider when considering a LiFePO4 battery. As I mentioned, a lithium battery has a very different charging profile from an AGM battery. Thus, for the deep-cycle unit I’m installing in the Troop Carrier, I’ll need to swap the existing DC-DC charger, designed for AGM batteries, for one that includes a setting for lithium batteries and is suitable for routing and managing both alternator and solar power to the Antigravity battery. Such units can run from about $300 to $400. This is pretty much a one-time outlay, but it still needs to be factored into the initial investment. 

I’ll be doing regular updates here as soon as the starting battery arrives.

Anti-Gravity Batteries' Battery Tracker

I’m not much of a mobile phone person—in fact I hate the things and would happily revert to a black Bakelite dial phone in a little nook in the hallway. But such is no longer the way of the world.

One bright spot of the new world is the availability of apps, which tend to be far more useful than the average actual phone call. I have the Star Walk astronomy guide—which is pure magic—and a bird guide that not only has descriptions and photos but will play the bird’s song for you. Brilliant. Motion-X GPS of course, and several practical tools such as inclinometers and an OBDII reader.

But way too many apps seem to exist just because they can. I recently got an otherwise excellent LED flashlight to review, the programming of which is accomplished with an app. Seriously? I need to clutter my phone with another program just to tell my flashlight whether to come on bright or dim when I push the button? Absurd.

Thus—even though I’ve been a fan of Anti-Gravity Batteries and their superb Micro-Start since the beginning—I wasn’t sure about their Battery Tracker, which is also paired with an app. Nevertheless I decided to give it a try.

The Battery Tracker is designed to let you monitor battery status via a smart phone. Okay, let’s see how it works.

Well, it works about as simply as one could imagine. Use your smart phone to scan the squiggly square thing on the package. (Roseann chimes in: “Uh, that’s called a QR Code, Mr. Gates.”). And bink, there’s the (free) app. Hook the wires on the tracker to the positive and negative terminals of the battery, and you’re done. The phone pops up with the voltage. I was disappointed the tracker didn’t come with a penny’s worth of double-sided tape to adhere it to the battery, but we had some.

Okay, battery voltage. Wirelessly. I can check it from the living room. I still wasn’t really getting it, so I kept reading the instructions. Aha: you can set the tracker to send you an alert if your battery’s voltage drops into the danger zone. That’s cool. It will also run a cranking test and a charging test to confirm adequate starting power in the battery and adequate charge from the alternator. Definitely a smart thing to do before a major trip.

And yet. I still wasn’t quite fully sold on it for my own use.

Finally I realized the problem. There was nothing wrong with the product; I was just using it on the wrong battery. I swapped it from the starting battery to the auxiliary.

Suddenly it was brilliant.

Our auxiliary batteries are the ones that are working all the time, to run fridges, lights, chargers, and inverters. Some of us install voltmeters in the system to monitor them, but you need to get up from the Kermit chair and go look at it, leaving your campmates ample time to steal your drink and gorge on the snacks. Others of us simply guess how long we can go without charging until the low-voltage cutout on the fridge kicks in. Now a simple glance at the phone will tell you if it’s time to re-orient the solar panels or go for a drive. And the tracker can alert you before the beer gets warm.

But that’s not all. The tracker can give you a 31-day record of charge condition. This would be perfect when setting up an auxiliary battery system, especially with solar input. You can determine if the all-important float voltage is being reached every day—critical to long battery life.

At $36 the Battery Tracker is reasonably priced, and could be used to significantly extend the life of your auxiliary (or main) battery, saving its cost several times over.

Anti-Gravity Batteries is here.

Nitecore charger

One of the few downsides of modern digital cameras is the need for frequent battery charging. My first pro-level camera, a (film, of course) Canon F1 built with the ruggedness of a 747’s Black Box, had a battery to operate the light meter, but would function quite happily without it; you just had to remember the classic “Sunny 16” rule for exposure. 

Not so these days: No battery, no camera. Even the ascetic’s choice, manual-focus rangefinder Leica M10 is digitized and thus dead without power. 

One upside is, modern lithium/ion batteries boast tremendous charge density for their weight. Another—important for travelers—is that virtually all chargers for those batteries are muti-voltage and will operate happily on either 120 or 240 VAC current. Unfortunately, while the countries of the world managed to confine their mains single-phase voltage supply to those two choices, the variety of plugs necessary to access that voltage is bewildering. And if, like me, you are absent-minded enough to leave not one, but two adapters firmly inserted in sockets on a single trip across Africa, you could find yourself critically short on charging capabilities. Trust me that finding a U.S. to Botswana or Namibia adapter in Botswana or Namibia is a near-futile quest.

Fortunately there is a backup power source right there in the notebook computer you take to download and store those photos: the USB port. Which brings me to the Nitecore charger.

The Nitecore, which is available in numerous configurations to accept most camera batteries, plugs into the USB port of your notebook computer, which means it is way less likely to be left behind. That would be enough for me to click “buy now” right there, but the Nitecore also incorporates a digital readout that tells you the overall health of the battery, its current state of charge, rate of charge, and voltage. Brilliant. 

I used the Nitecore on a recent trip to Mexico in our Tacoma and Four Wheel Camper, which highlighted another advantage: Since we currently have only a single-outlet 12VDC to 120VAC inverter in the truck, I was able to charge both computer and camera batteries at once. And I found the state-of-charge feature useful: At one point I was unsure of the capacity left in one of my BP-DC12 1200mAh batteries before a long hike. So I plugged it into the Nitecore, which informed me it was at 980 mAh—plenty to go on with just a single spare.

The Nitecore has a very short cord, which enables it to fold away in the back of the unit. And as you can see from the lead photo, the unit itself is significantly smaller than either my factory Lumix or Leica chargers. Given the extra functions included, that’s remarkable. Bravo Nitecore. 

Highly recommended, even if you’re not absent-minded.

Battery decluttering

Even in a vehicle as electrically antediluvian as a 1973 FJ40, connections to the battery can get out of hand with the addition of just a few accessories. For many years, I’ve used battery terminals incorporating a threaded vertical post to secure positive and negative cables and wires, both for basic functions (starter, etc.) and accessories such as the 2-gauge cables powering the Warn 8274 winch, and the 10-gauge connection to the auxiliary driving lights. 

But over time the connections have been stacking up—there’s now a separate cable to charge the auxiliary battery, and another for the ARB compressor.  Even with the installation of an Optima yellow-top battery with redundant side terminals, it was beginning to look cluttered, and probably doing nothing to maintain adequate current flow.

So I ordered a pair of Pico 0810PT “Military style” (their words) terminals from Amazon. Nothing fancy—no gold plating or built-in digital voltmeter—but substantial, and the horizontal bolt not only doubles the available connections but is far more secure than the wing nut on the old terminals. At $10 for the pair it was a bargain for a significant improvement in my wiring. 

P3 Solar—power an iPhone or an Expo

Even the most back-to-basics overland trips rely heavily on electronic equipment these days. Last fall I bicycled the length of Israel—about as back-to-basics as you can get short of walking—yet I still carried an iPhone to log the route and an iPad for taking notes.

Most of the time I was far from wilderness, but I planned to spend time in the Negev Desert, and also just wanted to be as independent as possible from the usual juggling act with outlets in hotel rooms. So I borrowed a Dynamo solar power pack kit from P3 Solar.

The Dynamo kit comprised a folding 20-watt PV panel, a 16,800 mAh lithium-ion battery pack, connectors for various devices, a set of alligator clips to jump an auto battery, and both 12VDC and AC units to recharge the battery from other sources if needed. 

The P3 panel soaking up early morning Negev Desert sun.

I originally intended to see if I could secure the open PV panel to the tops of my panniers behind me to get constant charge, but quickly realized that, since 90 percent of my route was trending southward, I’d be shading the panel most of the time. So I was mostly restricted to laying it out in the morning and evening to charge the power pack.

I needn’t have worried. The pack retained enough juice to keep the iPhone navigating and recording all day, and regained full charge easily with just a few hours of exposure. I rode all the way from the Lebanon border to the Red Sea praying I’d come across a motorist with a dead battery, so I could whip the P3 pack out of my handlebar pack and jump his car, but alas, Israelis apparently maintain their vehicles well despite being among the planet’s worst drivers.

The Dynamo kit nestled securely under my tent between the rear panniers.

With connectors pared down to only those I needed, the P3 kit with power pack added just 2.3 pounds to my load (I could have reduced that further if I'd left the case at home). Perfectly manageable on a bicycle, it would be virtually unnoticeable on a motorcycle. The kit is now called the Dynamo Plus and incorporates a 25-watt panel, so recharging devices will be even quicker. 

P3 Solar offers an array of products up to an impressive 200-watt rollable panel—available with a folding mount to secure and angle it properly—that will power a fully equipped overland vehicle campsite, fridge included. We used a pair of them along with two of P3’s Dynamo AC600 battery/sine-wave inverter pack to run the entire Overland Expo headquarters at the Biltmore last year, including lights, computers, and a printer. Check out the entire line here.

Energy independence . . . for your overland vehicle

This will come as a shock to many of you, but it is actually possible to camp without electricity. 

Reliable visual records from the Middle Ages (1950—1985) clearly show families surviving—even, at times, apparently enjoying themselves—in campsites lit only by white gas or propane lanterns, retrieving food from insulated boxes cooled only with ice, and engaging in such non-electrically dependent activities as fishing, swimming, climbing trees, and reading books manufactured in the ancient Gutenberg manner, on paper. (A few disputed images even purport to show family members talking to each other.)

Of course it’s easy to idealize scenes in vintage Kodachrome transparencies. What isn’t so apparent are the tragic effects of those primitive times: respiratory problems from second-hand kerosene smoke, salmonellosis caused by eating chicken stored at above-optimal temperatures, blindness brought on after repeated attempts to read Field and Stream by the light of a candle lantern (not to mention the devastating tent fires also associated with open flames), ugly cases of fratricide sparked when siblings were forced to interact directly with each other. (“Where’s Timmy?” “I don’t know, mommy. Maybe a bear ate him.”)

We can thank the advances of civilization—the Cree, the Engel, the earbud—for the blessedly longer median life expectancies now enjoyed by overland travelers. But LED lanterns, 12V fridges, and the myriad of electronic entertainment and communication devices now virtually grafted to our persons—they all require electrical power. Those of us who’ve moved even farther upmarket with such things as truck-mounted campers need yet more, for water pumps, vent fans, heater blowers . . . although personally I’ll draw my line of sympathy this side of anyone who wants to power a flatscreen TV in the wilderness.

An auxiliary deep-cycle battery has become nearly standard equipment for a well-sorted overland vehicle, and with good reason. It keeps the starting battery free for its critical duty, and serves as a starting backup as well if connected with a selectable isolator such as the National Luna (although the advent of the brilliant Micro-Start and similar products has made this function nearly redundant). With a battery monitor it’s easy to keep track of usage and voltage.

However, depending on load (especially that fridge), you can run down even a high-quality Group 34 AGM battery in anything from six or seven days to less than one. If you’re on the move day to day, it’s likely your engine’s alternator will be more than adequate to bring the voltage back up to an ideal float level of 13.4 volts or so. But what if you’ve found the perfect beach or forest campsite and don’t want to move for a week, or two? Idling the engine is a notoriously poor (slow) way to recharge a battery, irrespective of the fact that you’re pointlessly burning fuel, causing pollution, and spoiling your ideal campsite with noise. You need a different power source—and the finest one you could ask for is a mere 93 million miles away.

For years auxiliary photovoltaic (PV) solar panels for vehicles fell into two broad categories and capabilities: You either had a permanently mounted rigid unit or units of decent (50 to 200 watts) output installed on the roof with brackets, or you made do with much smaller flexible PV panels which clipped directly to your battery and could be laid out on either the hood, roof, or ground. The former, while sometimes capable of maintaining auxiliary battery voltage nearly indefinitely, were bulky and heavy, and created serious overhead hazards for tree limbs, etc. The latter were rarely if ever capable of doing more than delaying the necessity for running the engine.

That’s all changing. Roseann and I now have two 100-watt semi-rigid PV panels on the roof of our Four Wheel Camper; attached directly to the roof via stout adhesive backing, they create essentially no windage or clearance issues, and over many trips have proven to keep our auxiliary fully topped up to run the camper’s fridge, (LED) lights, vent fan, and water pressure pump, and recharge capabilities for our extensive array of journalist-oriented electronic devices and cameras.

And now it’s possible to get that same level of input with a completely portable kit displayed by P3Solar at the Overland Expo. Their 200-watt flexible panel weighs barely five pounds, and rolls into a 35-inch by 5-inch tube. While it obviously takes more time to set up than a permanently mounted panel, you can use it on different vehicles, and if you want to park in the shade you can run the panel out into the sun (although since the panel is equipped with bypass diodes it handles partial shade quite well). Your roof is also now free for bicycle or kayak racks, or a roof tent.

The P3Solar panel connects with standard 2-pin SAE plug. You could run that through alligator clips and simply hook it up directly to your battery, but with that much input you’d need to monitor the system very carefully to avoid exceeding maximum voltage. Much better to run it through an MPPT (maximum power point tracking) charge controller, which will optimize the unit’s 24-volt output. A standard charge controller will work as well, but will pull the voltage down a bit and thus not exploit the panel’s full output.

The panel can be deployed by laying it flat on the ground; however, the company also offers a clever folding aluminum frame that positions the panel at a more optimum angle for those in latitudes above the tropics. It expands accordion-like in about five seconds and snaps into place; the panel then attaches to it securely with Velcro. The frame can be (that is, should be) staked to the ground with included stakes that are stouter than anything I’ve ever seen included with a family sized tent. Impressive. Thus anchored the assembly shrugged off a 20mph breeze out at our desert camp; Wally Stoss at P3Solar assures me it’s been tested at over twice that. The EZ-out kit include a larger diameter bag and a rigid tube to separate the panel and frame, and the whole kit is still under 20 pounds. 

On a very warm (95ºF) summer morning with the sun still low, I recorded a bit over 100 watts out of the panel mounted on the frame. Since PV output is lower in high temperatures, and obviously lower when the sun isn’t directly overhead—and since most PV panels never see their theoretical maximum—this is astounding performance. Most fridges draw in the neighborhood of three amps (36 watts at 12volts—and of course only intermittently), so I was already well ahead of that. 

It’s clear the P3Solar panel would give most overland vehicles complete electrical independence—and then some—for as long as you wanted to stay and enjoy that beach. I’m curious what the output of this panel will be in colder temperatures with the sun overhead. Imagine selling your excess electricity to fellow campers . . .

P3Solar is here.