Toyota's Plug-in Prius tackles the Green Hell.

Staff Car Report: Hybrids. Eventually the worst of all worlds?

There’s an argument that some automakers seem keen on: the hybrid is the best of all worlds. A car that can be electric for your (short) daily commute and petrol (or diesel) for those longer journeys. An automobile that can meet your every perceivable need. The perceived need for flexibility is, I suppose, the reason that I bought a big-ish four-seater over a teeny tiny car when I first needed something other than my beloved 1969 Morris Minor. And whilst that 1970s Vauxhall Viva proved to be a disaster of 1970’s sized proportions, I still do that same calculation when deciding on any modern car and tend towards the ‘4 people plus luggage’ answer.

To return to the subject at hand, a hybrid, they say, is a vehicle which is flexible. It’s efficient and multifunctional. But it’s also amazingly complex and, as was amply demonstrated by my 2005 Toyota Prius a few days ago, it is also prone to the vagaries of both EVs and traditional petrol vehicles. I’m aware that the hybrid battery pack in the Prius is not quite as good as a brand new one; with 144k miles on the clock, that’s to be expected. But it’s within what I consider acceptable limits.

Unfortunately, ageing doesn’t just affect the EV components. In this case, it was the dinky little 12V battery, which it turns out was as old as the car, that gave up the ghost.

Prius battery date code

Period charm from the 2005 battery

It’s been cold here. Not really, really cold. But on a couple of nights the outside thermostat’s dropped to 1°C, and on the trips I’ve taken out there’ve been a few days where the jaunty little ice snowflake’s not disappeared from the dash for the entire journey. So it wasn’t really surprising that after nearly a decade in service the battery in the Prius was a little bit frail. Lead acid batteries, as they age and sulphate, get pernickety about their treatment, and standing them outside at 1°C tends to kill them if they’re on the edge. Indeed, in a traditional petrol vehicle it’s recommended that the battery is changed every few years to ensure that you don’t encounter the rather distressing situation of getting in and finding a deceased battery. I suspect the same statement is made on the Prius, but I doubt many owners remember to do it. Hell, some owners forget to top up the oil…

Of course, as a driver of vehicles that are not top of the posh automobile tree, I’ve encountered the entertaining ‘click…[pause]…oh’ scenario more than a few times. Most notoriously, I had a 1982 VW Golf that would occasionally, and for no apparent reason, drain the battery overnight. And after many years’ service, the Minor’s battery has been known to flake out too. The moment of discovering a dead battery is never a fun one. Despite that, and the development of shiny new LiIon jump-start battery packs, I don’t actually have a jump-start pack kicking around. So it was that, having attempted to turn the Prius on and been met with a distressing beeping noise, no centre console screen and an array of warning lights, I found myself jogging back through to the garage and then wandering around cursing for a little while before finding an old, spare battery and the bag with the jump leads in.

Jumpstarting a Prius

This is not the recommended method of jump-starting a Prius

Thankfully, because the Prius actually just uses the 12V circuit to turn on all the cunning electronics, my puny Morris Minor jump leads (circa 1970) and the last-charged-about-8-months-ago battery were able to provide more than enough current to get the Prius going.

But it did lead me to thinking about the fact that, at the end of the day, an aging hybrid is left with all the weaknesses of both the ICE and the EV. Whilst EVs have a delightful mechanical simplicity, their electrical systems are the stuff of an electronics engineer’s dreams. High voltage components and complex circuits marry with general purpose computers tasked with the complexities of managing systems vastly more advanced than most ICE vehicles possess. Similarly, modern ICE vehicles are a cornucopia of mechanical, electronic and electromechanical systems, all tethered together to provide the experience of reliability and low maintenance that modern owners require. To keep things ticking over, cars of the ’60s and ’70s required frequent fettling. A tweak here and a touch there, keeping everything just right. They demand it, and if it’s not provided, they rapidly become the stuff of nightmares.

As cars progressed in complexity through the ’80s and ’90s, reliability went up, but the ability to repair them and keep them going without replacing large, complex parts – that capability all but disappeared. And then we have the modern ICE vehicle; change the oil and it does the rest. More or less. Until it doesn’t. At which point all the fettling in the world won’t fix it.

And so I ponder the fate of these hybrids as they age. The best and worst of both worlds, perhaps. The Gen 1 Prius is known to have episodes of transmission failure and, whilst repairs are possible, they’re certainly not simple. Nor is it the stuff of the standard back-street garage’s normal workload. Even as a longstanding shadetree mechanic I baulk at the thought of whipping out the Prius’s motor for the kinds of repair required.

Perhaps I’m unduly negative, and modern mechanics will be completely unphased by the problems exhibited by an aging hybrid fleet. But perhaps not, and those of us with these less shiny hybrids will continue to cower in fear at the sight of the dreaded master warning light.

Master warning light on on a 2005 Prius

There glows the master warning light. A symbol to alarm the Prius owner.


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  • vdiv

    Uhm, all modern EVs have a 12V lead-acid battery that will wreak havoc when it goes bad, just like in any ICE car with a regular starter motor. Vampire draws on the Model S? Check. Erratic behavior in the Leaf and Volt? Check. Cheap lead-acid batteries are one of the reasons why people mistrust EVs, they think the propulsion battery is as flaky and unreliable.nnnThe solution? Better auxiliary batteries and better management system. Add the voltage and current gauges back to the dashboard so that the driver has visibility as to what is happening with the battery. On plugins assure that the car can trickle-charge the aux battery when plugged, even when the propulsion battery is fully charged.

    • Michael Thwaite

      vdiv, On my Roadster, the lead-acid motorcycle pack is located in the wheel well just ahead of the front wheel, what a miserable existence! Needless to say, it lasts about two to three years so, the replacement this time around was a super lightweight Li-iON replacement and, apart from shaving a few mS of the 0-60 time, it’s promised to be much tougher than the standard unit. Let’s see.nnnBut, I digress, the Roadster has a neat trick. When the motorcycle pack goes flat, which it does if you leave the lights on, two squeezes on the electronic door handle and the main DC-DC converter fires up and the car comes back to life powered from the traction pack. Of course, no good deed goes un-punished. This means the main traction pack is always active so, leave the car for a year or so and the main pack is dead.nnnOn balance, I like the Roadster design, it’s saved my bacon a couple of times and, I know enough about EVs to know that you leave them plugged in so don’t suffer the ultimate flat battery problem.

      • vdiv

        Oh, I know where this is headed, manual crank generators (gulp!) Well, how about the modern version, a roof-mounted solar panel (for cars that have roofs anyway)? 🙂

        • Michael Thwaite

          A starting handle on the front 🙂

  • Greg

    we need to see good series hybrids – 100% capable EV, just with a self contained engine for special occasions. The i3 is the only contender as far as I know. nnAfter 12 years, perhaps owners can throw out the generator and put in the latest in battery packs. nnI agree most hybrids rely on both aspects – a weak electric motor and weak petrol engine together performing better and saying on gasoline. Short future to these bad ideas.

    • vdiv

      Both the Fisker Karma and the VIA Trux are serial plugin hybrids. Whether they meet the qualification of “good” is a different story. The reason why the Volt went with a dual-motor/parallel hybrid mode is the 10 to 15% improved efficiency at high speed, low torque demand. If the point is to reduce the use of gasoline then that compromise is “good” as long as it does not increase the transaxle complexity and weight too much.

  • Yann

    I am wondering what this article tries to demonstrate. That 12V batteries die in hybrids like they die in standard ICEs? Well, yes (is it worth writing an article about this?). But this post shows a quite different title, one which would please anti-hybrids and Prius haters in their Hummers (or EVs ?).nI drive an 8 year old Prius 2, and all I had to change on it was indeed the 12V battery (once), and the car actually warned me well in advance. Oh, I also had to change the brakes… after 85,000 miles (and they could have gone another 10,000 at least thanks to electric regen). MOT is bright green every time, and servicing is minimal (around u00a3200 a year on average). Hey standard ICEs, beat that.nnMy ageing Prius doesn’t consume more than on its first day, since the battery managing system keeps it charged between 20% and 80% of its capacity, making sure it lasts “forever” (did I mention the whole hybrid system, including the battery, was guaranteed 8 years by Toyota?). nnOn a Prius, there is no gearbox, clutch or timebelt (it’s a robust chain), which are indeed the chores of standard ageing ICEs, and are very expensive to change. Kate should know that, if she is such a car geek.nThe petrol engine itself in the Prius is very reliable and that car has become the preferred car for French taxi drivers, despite the fact the incentives are much greater for diesels in France. That is a sign of real-world experience, real “staff car report”.

  • Irony : My wife’s Mercedes GLK failed to start due to 12V battery failure. She took my Smart Electric Drive from me and wouldn’t give it back till she “trusted that gas car” again. Of course, that lasted more than a week, which made me wonder, as it was very cold those mornings, and the Smart ED is far faster to warm up!nnMeanwhile, much of the rest of the planet fears and doubts EV’s.

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