I’ve been shopping around for an emergency jump starter to carry around in the car. I’ve found jump packs that are roughly a little larger than a cell phone, and produce 1000 amps or more. What is keeping them from being a main car battery?
In: Engineering
If I understand it right, those external power packs can go “UP TO” the said amount. but that is not the standard power output. Sometimes those power packs can only keep that level of power ina few seconds since they power other smaller things like smartphones.
Because lead acid is good at dumping a whole bunch of current really quickly. It’s power density is very low and it hates to be discharged fully… But when it comes to hitting a starter motor with a massive surge of juice to get a stiff engine block moving, a lead acid battery is a pretty cheap way to do it.
What I’ve just described is essential what’s known as the “power” of a battery. It’s not a metric that’s often discussed, usually people are very wrapped up in energy density or cycle life, but for some applications it’s less important how much energy a battery can hold overall, and more important how quickly it can discharge that stored power.
Anyway, you could easily hold the volume of power a typical lead acid battery has in a much smaller space using a lithium battery, but that’s not really what you care about when it comes to starting your car. You care about getting a large amount of current to your starter for a few seconds at an affordable price. For all it’s faults, your standard car battery is just fine for this. Yes, you could spend way more to get a smaller battery under your hood… but why would you?
Latest Answers