Lithium automotive batteries have long been heralded — and desired — by the racing community for their ultra-light weight relative to traditional lead-acid batteries, but did you know the advantages go well beyond their airy mass?
Longer-lasting? Check. Safer? Check. Five-fold faster recharging times? Also check.
Fred Bartoli is a veteran of the sportsman drag racing ranks — he also owns and operates Altronics Inc., which in addition to a wide range of performance electronics, also manufactures lithium racing batteries to power those essential tools inside a racecar. Altronics’ Powerlite series of batteries, which feature optional built-in battery management systems (BMS), are capable of providing the cranking power and output for even the most demanding of drag racing vehicles.
We picked Bartoli’s brain on all things lithium, and the conversation, it turns out, is about much more than weight. In fact, it is all of the pros of lithium cells themselves, along with the BMS, that ultimately lead to the feather-weight. And for those reading this who find themselves compelled to invest in a Powerlite lithium battery at its conclusion, weight may not even be the primary deciding factor.
Let’s start with the basic premise: a lithium car battery is effectively a box packed with rows of lithium cells, grouped in individual banks in series and parallel. The cells use a form of lithium — there are a wide range of lithium chemistries, from lithium-iron phosphate and lithium-cobalt to lithium-manganese, and so on — all of which are much lighter in mass than lead acid or alkaline. Thus, the reason why a lithium battery is so light.
“We’re using a high-quality type of cell that is made to put out the type of power we’re using it for. When you use one of these cells that is not made to put out that kind of power, there’s a concern that things can start to go wrong. You’re putting out 10 times as much current as the thing was designed for. – Fred Bartoli, Altronics Inc.
Internally, while the individual cells are sized similar to something like an Energizer D battery off the store shelf, they don’t weigh anywhere near the same. A “D” size battery is quite hefty, actually, and you can imagine a whole box full of them. The difference is the liquid mass of the lithium and that more energy can be drawn from an equal volume of lead. As an example, with a 40 amp/hr, 12-volt battery that puts out 800 cranking amps, a lead-acid battery would need 40-pounds of lead compared to just 10-pounds of lithium.
A 12-volt Powerlite battery weighs between 5.5 and 8-pounds, while a 16-volt ranges from 7-9.25-pounds.
Altronics uses a brand called A123, a popular form of Lithium Iron Phosphate cell originally developed by the U.S. government that’s roughly the size of a “D” lead-acid battery. This A123 (a LiFePo4 Lithium Iron Phosphate type) is considered among the highest quality and safest of cells. Chiefly among its advantages is that it’s designed to put out considerable pulse discharge current; others are designed to put out power over a longer period, but without a lot of current. There are, as Bartoli explains, two different types of cells: energy and power. Bartoli chose the A123, a power cell, because he wants a lot of cranking power to turn a high-compression engine over. A solar backup system, as an example, is more begetting of an “energy” type cell.
To further explain LiFePo4 cells in science-y terms, they have a nominal voltage of 3.2-volts, therefore a Powerlite 16-volt battery is 5 by 3.2-volts, equaling 16-volt nominal. The peak voltage of a Powerlite is 18.2-volts, but is advertised as a 16-volt, not 18. Lithium-Colbalt or Lithium-Manganese have a 3.7 nominal voltage, so 4 by 3.7-volts equals 14.8-volts nominal and 16.9-volts peak. A “12-volt” lead-acid battery has a 12.6 volt nominal charge and 13.2 peak.
“We’re using a high-quality type of cell that is made to put out the type of power we’re using it for,” Bartoli says. “When you use one of these cells that is not made to put out that kind of power, there’s a concern that things can start to go wrong. You’re putting out 10 times as much current as the thing was designed for.”
Bartoli says other types of cells, more in line with an “energy” type cell, are not made to do what they’re being used for, and other brands on the market are using such cells.
All lithium batteries have what is known as a “C” rating, which is indicative of how much current can be discharged for a certain length of time. A typical lithium battery has a 2 amp/hr rating, which is a 10C rating, meaning it can pull 10 times the amp/hr rating of the battery, or 20 amps for roughly 10-seconds. Using that formula, a 50C rated battery can pull 100 amps for 10-seconds. This rating is generally an indicator of what the cell can be used for.
“Any battery that’s used as a starting battery needs to be able to put out a lot of current for a short duration,” Bartoli notes, adding that Altronics’ A123 cells have a very high 50C rating, while some exist on the market as low as 10C.
The chemical make-up of the cell, the overall design of the cell and the layering inside, dictates the C-rating. Altronics uses 1/2-inch solid copper bus bars that connect to a fully welded battery pack with 5/16-inch bolts.
A lesser-current battery will, for a time, serve its purpose, but a cell doing what it is not designed to do will create heat, will expand and contract, and fail, either catastrophically, or a gradual degradation.
Bartoli notes that other brands often choose a 10C cell rather than 50C because of cost — A123 cells retail for about $25 per amp/hr, compared to around $7 per amp/hr for a lesser quality cell, or about three times less in raw cell cost.
“In a lithium battery, as you’re pushing this cell that’s not designed to put out this much current, you’re causing fatigue inside the cell, both structurally and chemically, and you’re breaking down the interior of that cell, the insulation, and you can cause short circuits and things that can go wrong. And that can be catastrophic — it can cause what’s known as thermal runaway, which is when the cell starts self-heating. It internally shorts-out. It literally eats itself, and once this chemical reaction starts, it can’t stop until it consumes itself and it keeps going faster and faster,” Bartoli explains.
This can, as Bartoli goes on to add, in a worst-case scenario, result in a fire, if they build up enough heat internally. And they have done so.
One of the primary concerns of the consumer is that lithium batteries are prone to catching fire, which as Bartoli reiterated, is entirely true, when not using a battery containing cells designed for the use…in this case, drag racing and engine cranking.
As a side note regarding lithium batteries in general, Bartoli explains that lithium-ion battery fires can be put out with a standard Class ABC fire extinguisher.
“In a racing situation, typically in a accident, any fire from fuel or oil is brought under control by on-track safety personal in a short amount of time. It would be unlikely that any fire in this circumstance would allow a battery pack to get hot enough from the fire to cause the pack to self-ignite, but if it did the standard fire extinguisher would be able to put it out.”
These individual banks of cells in a lithium battery have to be controlled separately, because each group has different characteristics. No matter how closely you try to match them together, Bartoli says you’ll always have a weaker and stronger group in a lithium battery.
“Over time, if you have nothing in the battery to monitor and regulate the charging and discharging of these groups of cells, they get out of balance — the weaker one naturally isn’t going to charge up as much, the stronger one is going to charge more, and so on. And every time you cycle the battery, that offset gets worse and worse, and it keeps going until one cell gets severely overcharged and one undercharged and you knock out a group of cells. Now that battery goes down to a 9-volt battery,” he explains.
This is where Altronics’ BMS, costly as it may seem at the outset, is worth its weight in gold as a long-term investment for your vehicle.
“Over time, without any intervention, they’re going to go bad. What most manufacturers do — and we even still make a battery like this — you just have what’s called a balancer on the battery that tries to eat up the extra charge to even the banks of cells out. But it’s just a passive device, so it turns on and off, but it has nothing controlling it. It works well for a while, and it depends how bad the battery goes out of balance. It can only overcome so much, and how the user cares for the battery will dictate how well it works over time,” Bartoli shares.
A BMS is a small computer that controls the battery — it stops a cell from being over-charged, from being under-charged, keeps it balanced, and prevents a short-circuit. With an Altronics BMS, you can leave your battery on the charger all week (intentionally or unintentionally), or even all winter long, and it will effectively manage the battery to sustain the charge of the cells over the long-term from going out of balance.
With a BMS, a lithium batteries’ cycle-life, or how many times it can be charged and discharged and keep so much of its capacity, is around 2,000 cycles, compared to 200-300 of a lead-acid battery, when instituting best care practices.
In a lithium battery, as you’re pushing this cell that’s not designed to put out this much current, you’re causing fatigue inside the cell, both structurally and chemically, and you’re breaking down the interior of that cell, the insulation, and you can cause short circuits and things that can go wrong. – Fred Bartoli, Altronics Inc.
This highlights the cost-benefit analysis for the consumer: a lithium battery costs more up front, but can exceed the life of a lead-acid battery ten-fold, and demands far less supervision by the user, if a BMS is used.
Bartoli says that, in theory, if you care for a lithium battery without a BMS to the nth degree year-round, you could get just as long of a cycle-life out of it as one with a BMS. But again, that requires continual care and attention, making the BMS upgrade a valuable one.
It should be noted, speaking to the value of a BMS, is that draining a lithium battery completely will, in Bartoli’s words, “most likely damage or destroy it,” adding, “when a lithium cell gets below a certain point, depending on the chemical makeup of the battery, it damages the internals and either causes complete failure or a significant loss in capacity.”
Altronics’ BMS senses a percentage of drain and shuts down so as to stay above the threshold of incurring damage. It’s worth noting here that in order to retain the warranty, an Altronics battery must be fully charged at least once every four months.
To the point, charging time on a lithium battery is generally around five times quicker than a comparable lead-acid battery, depending on the charger used. Bartoli, who campaigns an NHRA Super Stock car, explained it as a worst-case scenario in drag racing, as they have to be driven to the lanes, restarted several times to get through the lanes, be weighed, and have the fuel checked, resulting in an average of seven start-up’s per run — despite that, on a hot day with the fans running, Bartoli’s 25-amp charger fully recharges his battery in about 40 minutes.
While Bartoli highlights weight and recharge time as the two key benefits of lithium batteries, in that order, there’s another point he says is often overlooked: lithium batteries maintain a very stable output voltage.
“A lead battery, as you take charge out of the battery, as you deplete charge out of it from use, the voltage falls off in a linear fashion — in other words, as you’re pulling current, your voltage is continually dropping as you consume the battery,” he explains. “You start out with 16-volts, you start the car up and you’re idling, you’re probably at 15.8-volts, and by the time you get to the end of the run you’re down at maybe 14.8. A lithium battery, however, has very little voltage drop out of it as you consume it — you may start at 15.5 and only get down to 15.3-15.4, so everything in your vehicle is running more consistently.”
As you can see, the advantages stem well beyond the weight of a lithium battery, although that remains a primary factory in many racers’ buying decisions, particularly those in heads-up eliminators with weight restrictions where every pound matters. But if you need cranking power you can rely on start after start, no matter the application, Altronics’ high-current batteries can get it done safely, reliably, and with quick charging times, get you back to the lanes in the late rounds. And with the right care, it will continue to do so for years to come, making that initial investment all the more valuable over time.
To learn more about Altronics’ lithium batteries, including specific product information on the various options in 12- and 16-volt offerings, visit altronicsinc.com.