The joy of a good starter battery is second to none, as far as your car is concerned. You get into a vehicle, and on the first crank, the motor comes alive, without any hesitation. You decide to attend a party and, without any fear, turn yourself into a DJ using the car’s speakers as your equipment. Or, you’re stranded in a place and decide to use your headlights for an extended period of time, without the engine running, all without fear that the motor will crank down, right after.
These are luxuries you’ll hardly view as such, especially if you’ve never been cursed with a bad starter battery that made it its sole purpose in life to thoroughly frustrate you.
The fun part?
Getting a good starter battery begins with the purchase itself, even before your use patterns emerge. Buy a good one, and you’ll enjoy it for years to come. Buy something without thought, and you’ll regret it sooner, rather than later.
So, how do you buy a good starter battery that will serve you, in the most luxurious manner, in the years to come?
It turns out, you only need a multimeter (and an understanding of how to use it in testing a battery’s resistance to charge).
Article Outline
A Short Story (Featuring Battery Testers)
If you’ve been following my work here for any length of time, you may have concluded that I’m stuck in the past, riddled with fond nostalgia. For instance, I recently argued that newer cars aren’t generally better than older ones, and my Honda Super Cub, despite being 30 years old, beats many new bikes.
This is far from the true position, especially when it comes to vehicle tech and diagnostic equipment.
Right up until recently, you needed to know how to use a multimeter, or hope the stars aligned perfectly when you chose a starter battery. If these did not hold, you were simply toast.
However, now, you only need a battery tester, hook it to your car’s battery, and enter the values. That done, the state of the starter battery would be displayed for you, usually, in mere seconds.
My best option for this is the Ancel BA101 battery tester, and I’ve voted it the best car battery tester you can buy right now.
There’s a little challenge, however: what if you don’t have a battery tester, don’t intend to own one, or simply don’t trust them?
This is where things get interesting, and this is where a good, old, cheap multimeter features.
How to Buy a Good Starter Battery with a Multimeter
To test a starter battery before buying with the intent of purchasing the best one possible, you need to focus on one metric of the starter battery: its resistance (to charge), measured in Ohms.
0-5 ohms
A lead-acid starter battery with an internal resistance to charge reading of 5 ohms (or less) is excellent and will last the longest when put into use. Generally, here, the lower the figure, the better the starter battery is overall.
Thus, a unit that has a resistance reading of 1 ohm (if you’re super lucky) will generally be better than another with, for instance, 2.5 ohms (all other things being equal).
5-10 ohms
From 5-10 ohms, the starter battery will serve, but it has started getting weak (generally). Under load, such a battery will falter, after a while, but typically, for the sole sake of starting your vehicle, this should be fine (if only for the interim).
Above 10 ohms
If, for any reason, the internal resistance to charge of a starter battery you’re interested in buying reads more than 10 ohms, you should leave that battery alone, even if you believe it could be the last starter battery left in the entire world.
The reason? Simple.
At over 10 ohms, the starter battery is already gone, and even if it manages to start your vehicle, a slight drop in temperature will make it painfully obvious that you chose a battery that was already compromised.
Summary: Are Battery Testers No Longer Needed To Buy Good Starter Batteries?
To buy a good starter battery (and keep tabs on when it’s right to replace it to avoid being stranded), you absolutely need a battery tester.
The reason?
Battery testers go over and above what the general-purpose multimeters achieve and point you in the right direction, even if you don’t know what you’re doing. They also take the extra step, thanks to several metrics tested (beyond resistance), to counsel you when it’s time to change your starter battery.
A multimeter won’t afford you these luxuries. If you’re looking for a badass battery tester, I highly recommend the Ancel BA 101. It’s what I use myself, and I’ve never had cause to miss bigger, complicated, or more expensive models.
However, if you’re simply looking to get the best starter battery off the shelf and want a unit that sulfation hasn’t yet dealt with, you’re great going the multimeter route and saving some bucks, assuming you already have the unit at home.
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Throttle Lan
DIY Mechanic and Freelance Auto Writer