On being discharged — 15 Comments

  1. Batteries can be fickle things. I once had a 3 year guarantee Exide battery fail 2 weeks outside the warranty period – and it happened while I was driving! The car started perfectly, and I drove to a nearby town. On returning to it an hour later nothing, not even enough to bring the panel lights on. Fortunately someone gave me a jump start and I drove back carefully, so as to avoid stalling, or letting the engine revs get too low, knowing that the alternator was doing all the work. That damn battery was still dead when I got home. I figured that one of the internal links between each cell must have broken.

    • My story is identical to your except that when I got home I had a fully charged battery again [after 1 mile?]. I have had dud batteries in the past – I think I got through two or three in the Fiesta and the symptoms are identical: a good battery that suddenly dies, but in my case it rises from the dead and acts perfectly normally for many months again.

  2. You can get small jump starters these days not much bigger than your phone, handy for throwing in the glovebox for emergency use. The one I have has no problem starting a 3.8l V6 engine, the car spends a lot of time not being used so invariably when I jump in it the battery is flat. (Mine came with a lighter plug as well so you can charge it up with the car, once started !!!)

    • Yesterday I took a trip to Halford and gout myself a jump start kit. I asked the lad if it was mains charged. He assured me it was, but in fact he was wrong – it’s USB charged which is great. As you say – I can charge it while driving off the USB port on the dash. Like yours it can happily reside in the glove compartment when it’s not charging itself [or charging up my mobile!].

  3. That generation of Dacias have a known fault with the ignition switch, it can continue to turn the starter-motor long after the engine has fired up. Worst case, it can burn out the starter-motor (which is a knuckle-scraping bugger to replace if the car has air-con).
    It may be that your randomly ‘flat’ battery can be traced to that problem area – could be worth a chat with the local dealer (then get an independent auto-electrician to fix it at a more sensible price).

    • Interesting [and not very cheerful]. The starter motor is an obvious contender [and I do have air-con] so I’ll mention it when it next gets a service in a couple of months. I don’t think it’s the specific problem you mention though as the battery wouldn’t charge that quickly then?

  4. A flat battery won’t fully charge in an hour using a home charger or from a 1 mile run. So if it was ‘lively’ that quickly I don’t think it was actually discharged. Assuming it’s not the starter motor and the battery was really dead (did you try the lights?) I suspect you have an internal fault in the battery or an intermittent connection (possibly the engine earth strap) elsewhere. Intermittent faults can be a right pain.

    • The fact that the battery was so lively after the one hour did seem to point to a non-battery problem. The bloke in Halfords did a test on it and it’s showing something like 85% efficiency which he reckoned is fine for its age. It does seem to be a non-battery problem but why then does a jump-start or a quick charge fix things? It’s a mystery.

  5. Doesn’t sound like a duff battery to me, Disconnect everything put some copper grease on the fittings and reassemble.

    Buy one of those cheap solar panels to keep it topped up if you use it infrequently. I found that it keeps the battery topped up and ready to go even after months between uses.

    • That solar panel sounds like a good idea. Pity I didn’t see this before I went to Halfords!

  6. You can test the battery and charging system easily if you have a multimeter, but you will also need an extra pair of hands. Put the multimeter (on say a 20V DC setting) leads on the battery terminals, then turn the car over. If the voltage drops much below 10V then your battery is knackered. Once going, you should see 14 to 14.5 volts if your alternator is working properly

    • I used to have several multimeters but they have all vanished over the years [probably buried under junk in the garage]. I’ll leave that test to my mechanic next time he does a service.

  7. Whenever i have a battery issue the old one goes straight out, i’m off to work around 3.30am when on shift, can’t be pissing about jump starting at that time in the morn.
    Also if the battery tray is large enough, i get the Diesel version battery or the highest capacity AH/CCA that will fit in the tray, you won’t believe how fast the engine will whizz over when the battery has half as much again CCA’s.

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