That makes good sense - my wife didn’t know when she bought it, but I was doing all the “extra” research, like how not to jump other cars from the PHEV, and other emergency situations, and that’s how I found out. My wife is actually better “hands on” on almost any technical task, but I’m the one who does pre-emptive research. IE “read the manual”!
My mother used to watch the home shopping channels. So one year, my Christmas present was a little box for jump starting a car. I’ve used it a couple of times over the years, most recently after being out of town for over a month earlier this year.
My last 20 years of German ICE cars have all had the battery in the trunk. My late wife’s earlier (mid 1980s) Audi had the battery under the passenger seat. Something about German safety regs require the battery to be kept away from the engine.
My various trunk batteries have fit into a well sized exactly for that model of battery. There is no way to fit a different sized battery in there.
Anyhow, to jump such a car, there are dedicate positive and negative jumper connection points in the engine compartment. If you screwed up and connected a jumper cable and another car directly to the battery in the trunk you’d probably do a lot of damage.
There is, no kidding, a small explosive charge built into one of the battery cables that will instantly sever it under various accident or electrical malfunction scenarios. The cable alone sells for a few hundred dollars. If you tried to do a jump connected directly to your car’s dead battery the computers will read that situation as a severe electrical problem and fire the explosive severance unit. Oops.
I’m trying to remember the last time I’ve had to jump start one of my daily (or more-or-less daily) drivers. In recent years I’ve tended to have an extra car sitting around and often the batteries will die in one of those due to infrequent use, but that’s expected. I suppose I really should invest in a trickle charger.
In my daily drivers… I honestly can’t remember the last time I had to jump one. I keep jumper cables in the back of all my cars but they pretty much go unused. I’ve toyed with the idea of getting one of those jump starter battery packs but my concern is that the battery pack will slowly discharge as it sits in the glove box for months on end without getting used. Should that happen, the battery pack would be useless and therefore just a waste of money.
To answer the OP, my habit has been to replace car batteries when they die. However, getting stranded sucks mightily so I’ve been considering changing them out on a regular schedule as part of normal preventative maintenance. My wife’s GMC Terrain is a 2014 model, bought by us 4 years ago this summer with only 29K miles on the clock and it still is using the battery that was in it when we bought it. I should probably change it out this summer as I haven’t a clue how old it is.
Protip: when buying a new battery write the date you bought it on the top with an industrial-grade Sharpie. Three years down the road you likely won’t remember exactly when it was purchased, so note it on the battery itself. Then take the receipt and put it a small Ziplock snack baggie and duct tape it to the side of the battery. Some batteries have warranties and a receipt is needed to make a claim. Or stick the receipt in an envelope and put it in the glove box.
I had a 1990 Mercedes 300E sedan that had the battery – a damn HUGE thing – in the engine compartment.
I have the same experience of substantially never needing to give or receive a jump with modern cars. Last time I did that it was because I’d left an OBD dongle plugged in, and unbeknownst to me that left many of the car’s computers in a live state even though the car was off, the doors locked, and the cockpit & instrument cluster dark. Drained the battery stone dead in 24 hours. Oops.
I did buy one of those jump start battery packs from Amazon awhile ago. Pulled it out 3 or 4 years later to inspect it. Discovered it was a) dead, and b) swelling :eek:. This is a Li-ion battery pack stored in a duffle in the trunk of my car. Had it lit off it most likely would have destroyed the car. Since I park in a dense parking garage it might well have triggered a chain reaction multi-car fire.
Bought a new one, and now have a periodic reminder in my tasks to pull it out and recharge it. From its first full charge after I got it I inspected it after 3 months and it was still at 100%. So I’ve bumped my inspection interval out to 6 months and that hasn’t come up yet. But when it does I’ll bring it upstairs and check the state of charge and if necessary plug it into the USB thing to charge. I’ll eventually home in on an inspection and recharge interval that is as long as possible but no longer.
Similarly, I have a 3 month reminder set on Alexa to go through and recharge all my various electronics not in normal use (flashlights, emergency weather radio/lights, car based battery powered pump, big-ass home backup powerbank for other emergencies, etc.). Slightly different than checking my various emergency kits and rotating out batteries every other year or so, but same sort of thing.
My car is now 10 years old. The battery compartment is longer than the battery, and there is a clip in the bottom of the battery compartment to keep the battery firm.
They make Beetle-specific batteries that have a plastic cover over the positive terminal to prevent the terminal from contacting the seat springs and making the VW “hot seat”.
My Beetle just has a regular battery and a rubber insulating mat that covers it to prevent shorting to the seat.
My floor pan is also intact but this Beetle was completely restored a few years ago. Who knows what condition the pans were in before that.
BMW’s have some special contacts under the hood that you’re supposed to use to jump. If it’s jumped directly at the battery, there’s the potential for frying the electronics. I have personal experience with that. I jumped my BMW at the battery and fried my transmission control module. When researching the problem, I found out that jumping the battery bypasses the electrical voltage regulator and allows excessive voltage to reach the computer units.
With modern cars being basically computers, I wouldn’t recommend jumping it unless you know how to jump that specific car. In the past I’d jump strangers cars to be nice, but not any more. I don’t want to fry their car and I don’t want anything to happen to my car. If possible, the safest thing is to remove the battery and charge it on its own.
Not that I’m recommending this, but I follow the old “replace battery when it’s obviously getting weaker and is past a reasonable life expectancy” method. I figure if it’s going to fail to the point of being unable to start the car, it’s most likely to happen at home after it’s been sitting for a few days or more, where I have access to a Li-ion booster pack. I suppose I could carry it around with me (it’s powerful but very small) but I’d rather not subject it to temperature extremes.
My car has two states: everything works, and, everything works except nothing happens when you turn the starter key.
My guess is that it’s got a starter relay that is the first thing to not work.
What has worked for me – and again, not a recommendation, just an observation – is to start to worry when cranking speed starts to become slower than normal. There are several signs of a healthy battery, one of which is the ability to turn the engine over rapidly even after it’s been sitting for as long as a week. But this may not be a reliable method in some fancier, newer cars.
It’s not a fancier, newer car – it’s a base model 10 year old, widely recognized as having a really poor engine (but that’s mostly due to the use of plastic). But unlike 40-50 years, ago, it always starts immediately (until it doesn’t), and I never have to listen to it turning over before it catches. Although there are many things wrong with it, and many cheap design decisions, it won’t turn over unless there is enough power to spin the engine and get a good spark.
While battery size has gone down in cars the AMPERAGE has gone up. This is done by putting more plates in the battery and spacing them closer together. The problem with that is there is none of the traditional warning we use to get. The engine would turn over slower when it was dying. Now it’s often an all or nothing scenario. I had a modern battery start like it was brand new and completely self destructed in mid start. Gone.
I just replaced a battery a month ago and I could tell it was going because the voltage kept dropping over a short time frame.
That may be true for some battery types, which may be required in some cars. All I can say is that observation of cranking performance, taking into account how long the car has been sitting and the ambient temperature, is still a useful guide for me, though I certainly don’t claim it’s reliable in all cases.
But I’ve experienced total battery failure only twice in my long driving career. Once was a long time ago – at least 20 years ago – and was due to a defective battery that was replaced under warranty. The other was about a year ago that didn’t appear to be a battery problem, but rather an intermittent alternator problem that allowed the battery to go completely flat after sitting unused for about a week, which also damaged the battery.
That was a weird one. The interior lights wouldn’t even produce a faint glow, and there was no clicking from the starter motor – everything was just 100% dead. Both the alternator and the battery were replaced and it’s been fine ever since.
Our cars were bought used while in southern states. When I replaced the batteries, I bought the optional larger battery (described in the ‘cold weather’ package). They fit, barely, in the existing battery pan/box. The price wasn’t substantially more.