Let's anthromorphize a bit, and think of lead batteries as living creatures.
- They need exercise. It's good for them. You get the longest life when they are worked to about 50% of their
capacity at moderate loads. After they've been loafing for weeks, you'll notice a distinct improvement just
from giving them moderate exercise.
- But don't work 'em 'til they drop! If you drive an EV until it barely moves, the batteries are having a near-death
experience. This is outright battricide, a leading cause of early battery death.
- They need to be be fed regularly -- that is, charged. Feed them as soon as possible after a workout; they don't like to
sit around starving after use. Batteries left sitting for days in an undercharged state develop a condition called sulfation.
- Don't overfeed them, or they get fat, have cumulative health problems, and die early. Chronic overcharging
is another major cause of early battery death.
- Don't underfeed them, or they can starve to death. Chronic underfeeding also leads to a weak, sickly battery and, again,
an early death.
- Batteries can hibernate, like bears -- that is, sit unused for months without needing to be fed. You don't need to put
them on a "trickle charger." Just be sure to feed them occasionally so they stay near full charge.
- They need fresh, clean water occasionally. Sealed batteries (gel and AGM) have a built-in watering system, but
flooded batteries don't. Be sure to check water levels, and fill with distilled water as needed. As with any animal, dirty
water will poison them!
- They need to be kept at reasonable temperatures, ones you would find comfortable. Not too hot, and not too cold.
Lead batteries are cold-blooded, like lizards. The lower the temperature, the slower they get. Likewise, they can't
sweat, so high temperatures cook 'em to death.
- Batteries are stoic creatures. They won't whine when they're hungry, or cry when you hurt them. But you can check
their state of health with a physical exam. The vet uses a stethoscope and a thermometer -- you use a voltmeter, ammeter,
and hydrometer.
- There are different breeds of batteries, each with its own good and bad points. Flooded batteries are slow plodding
workhorses, but are long-lived. AGMs are racehorses, fast and powerful, but shorter-lived. Using the wrong breed
of battery for the application, or having unrealistic expectations, leads to disappointing results.
- Just as with living things, sometimes it's the luck of the draw. You'll have identical batteries in the same vehicle and,
for no obvious reason, some will die young, while some seem to live forever.
A little detective work to fix the problems, and then some tender loving care, will go a long way toward getting the
longest life possible for your EV's batteries.
The usual reason you see used EV ads that say "needs batteries" is that the previous owner treated the batteries
cruelly or carelessly. Whether by ignorance or laziness, he or she violated some or all of the above guidelines. But unlike
your dog or your horse or your brother, batteries are easily replaceable. "Needs batteries"
usually means you can buy the EV cheaply.
