A very lucky car battery escape

[Leo Enticknap]

Just to prove what a profligate spender I am, my one and only Black Friday purchase this year was a new car battery. The previous one had done 27 months and 59,203 miles, I had noticed that it was no longer reading more than about 12.5 (even after a long drive), and 2 to 2.5 years is about the lifespan of a car battery in this part of the world.

I have a 750 mile road trip on Monday, and was wondering about whether to swap the batteries now, or wait until next weekend when I get back. Three things tipped me to doing it now: son in bed, wife in the shower, and nothing much to do for an hour, and looking at Crapple Weather on my phone and finding out that the overnight temperatures where I will be for most of next week (El Paso, TX) are forecast to dip into the low 20s, which would likely kill a declining battery.

So I did the swapout just now. This is what I found when I disassembled the positive terminal assembly:

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I cleaned up the terminal piece with steel wool and sprayed terminal protector liberally when installing the replacement, and all is good (though when I get back, I'm going to the Honda dealership to get a replacement for that terminal piece, just to be on the safe side). But if I'd decided not to do the swapout this evening, I suspect that there is a significant chance that a night in frosty conditions could have broken that connection. Relieved that I dealt with that in a garage in California at 65 degrees, rather than a hotel parking lot in El Paso at 25.

[Marcel Birgelen]

This amount of oxidation is an indication the thing must have become very hot, most likely due to an already pretty bad connection.

With all those electronic thingamabobs in your modern car, the battery is more important than ever, not just to start the car, but even to just keep things running. I had a shiny Mercedes recently with a dead battery and getting into the car is already a mission of its own...

I remember driving an old diesel delivery van while the belt fell out of it, but didn't immediately register what happened (actually, I only noticed a very silent bang). Since there was no apparent effect on the vehicle, I just kept on driving. Later I noticed the blower and radio to become more and more faint, yet the thing kept on driving along without a real hitch for at least 250 kilometers (or about 150 miles for all your strange folks out there :P) to my end destination.

On the other hand, I remember driving a standard petrol rental where the generator died while driving on a freeway and I barely made it to the next service stop just a few kilometers (miles, but about 1.6 times less of them) down the road.

[Leo Enticknap]

...most likely due to an already pretty bad connection.

It was so tightly attached to the terminal post on the battery that after loosening the clamping bolt (not easy - needed a breaker bar with the socket on the end, plus a hammer), I needed a 3ft (91cm) crowbar to get it off!

What I suspect is more likely is that that there is a plastic cover over that entire terminal assembly. That is why I didn't spot the corrosion while it was still mild. I'm guessing that the plastic cover trapped heat inside the assembly over the 27 months that battery has been in use.

What tipped me off to a problem was that in the last month or two, it's taken 3-4 turns to start the engine, whereas previously it had always caught by the second. That's a sign of a battery in terminal (excuse the pun) decline, which was what prompted me to buy a new one. The end of the clamp nut protrudes from the plastic cover, which is what I'd always attached the positive lead of my battery tester to periodically, and the charger when I occasionally charged it in the garage (e.g. if the car had sat unused for a few days). So I'd never had a reason to remove that plastic cover over the positive terminal assembly until Saturday evening, and then had the shock of my life when I finally did!

Oh, and the replacement piece of the terminal assembly was $86 - just the piece in the photo above! Still, Honda are by no means the only ones to price gouge on parts, as we well know in our business.

[Kenneth Wuepper]

When a single cell is failing even slightly, there are some very startling indications.

When one cell of a friend's battery was weak, the backup camera failed to operate. Thinking it would be something electronic, he took it to the dealer. They replaced the battery and the problem was fixed.

Strange things these are indeed.

[Paul Finn]

Because background electronics and some memory are always ON in modern vehicles, it is best to provide substitute power to the electrical system during the time the battery is disconnected for exchange. This could be another small 12 volt battery or even a plug-in 12 volt dc wall wart power supply with 1-2 ampere capacity. Remember the positive battery cable terminal will be "hot" to the chassis when disconnected, so be sure it does not touch anything until it is reconnected to the new battery. This vehicle operation will be similar in the procedure details of replacing batteries in Barco DCPs.

Paul Finn

[Marcel Birgelen]

Well, most car manufacturers will build vehicles that survive a limited time without a working main battery either by implementing some backup batteries or by writing some essential stuff to non-volatile memory. Some of the bigger challenges though, are often simple things like how to access your car if you depend on stuff like keyless entry. While most manufacturers have their set of procedures, they aren't always entirely clear and straight forward.

Reviving a dead Tesla, for example, is a procedure like starting a cold nuclear power plant...

[Paul Finn]

Well, my eight year old Dodge Grand Caravan battery needed replacement. Against my better judgement and remembering the advice from Marcel, I did not apply a keep-alive 12volts to the electrical system while the new battery was installed. The heater/AC processor did not like being without power. Now whenever there has been no electrical system activity (everything off) for a few minutes and something is operated, the heater/AC controls are inoperative until the processor checks all the control positions, air damper vane motor positions and everything else it has to know to operate. While this is going on, about 90 seconds, the rear window defroster light is blinking telling me the system is disabled. It happens no matter what system electrical activity is initiated: door unlocked, accessory (radio) turned on, even just turning on a single dome light, whether momentary or not. Once the process starts, it completes itself regardless of the trigger, until there is a lapse again of any electrical system activity. Of course, the dealer can use the magic tool for around $100 to correct the condition.

This may be unique to this series of heater/AC controls. I don't know. My point of this information again is always supply a keep-alive 12volts to the automobile vehicle electrical system when replacing the battery.

Paul Finn

[Leo Enticknap]

After that discovery in November 2020, I replaced the battery out of an abundance of caution and the undesirability of a breakdown during a long road trip. Yesterday evening, prompted by the resurrection of this thread, I tested it. The battery was specified at 440 CCA when new: my tester is showing 198 with a full charge (12.8 V) and a REPLACE BATTERY indication on the display, after only 22 months of use (though a lot of miles - it has been 53,207 miles since that battery was installed). It is still capable of starting the engine, but I'm going to try to get a warranty replacement - it shouldn't have declined so much in so short a time.