Jaroslav Posted January 16, 2009 Share Posted January 16, 2009 Hi all, It's me again with an endless supply of silly questions :-) I've got a battery that seems to be empty: it doesn't turn the starter (but has enough charge to turn on the lights). I can only blame myself for killing it: when I just bought this 110, NA diesel, I kept starting the engine several times a day, but since I couldn't legally drive it (needed to pass the test first), I was never actually recharging the battery. Anyway, one day I discovered that the battery is no good. I put it on my micro-controlled charger for deep cycle marine batteries. The charger blinks its LEDs for a few hours and then declares the charge to be complete. Now, putting the battery back to the vehicle produces the same results - no cranking. I bought a battery tester. When connected to the battery contacts, the tester shows "green", i.e. the voltage level with no load is OK. But once I place the 100A load, the voltage drops to zero! The electrolyte levels and gravity are OK. I had two theories: either the battery is sulfated (has no capacity), or the charger (being a deep cycle one) is not suitable for car batteries, although I really can't see why. So, I borrowed an old unregulated car battery charger. When I connect it to the battery and set it to 10A, I can see the voltage climbing steadily: I didn't have the nerve to watch it cross the 15.8V mark, since I was afraid of frying the battery. Is this battery dead for all intents and purposes? Cheers, /Jaroslav Quote Link to comment Share on other sites More sharing options...
Lars L Posted January 16, 2009 Share Posted January 16, 2009 Since the load tester dropped as soon as you put on the load, yes. One of the battery's cells is gone. New battery is the only way forward IMHO. Quote Link to comment Share on other sites More sharing options...
LandyManLuke Posted January 16, 2009 Share Posted January 16, 2009 Is this battery dead for all intents and purposes? Yes Quote Link to comment Share on other sites More sharing options...
freeagent Posted January 16, 2009 Share Posted January 16, 2009 sounds knackered to me. When you get a new one invest in a trickle charger if the vehicle is to be layed-up for long periods.. Quote Link to comment Share on other sites More sharing options...
patch1 Posted January 16, 2009 Share Posted January 16, 2009 Pass your test and get out on the road and drive but remember its a landrover and not a nova or a clio. Quote Link to comment Share on other sites More sharing options...
santalars Posted January 16, 2009 Share Posted January 16, 2009 I agree that most likely the battery is gone. However. to be sure I would recommend to try to jumpstart it first (use decent size vehicle for that, not polo). This way you can make sure that there is not a fault in the connections before buying a new battery. Quote Link to comment Share on other sites More sharing options...
GBMUD Posted January 16, 2009 Share Posted January 16, 2009 Is this battery dead for all intents and purposes? No. You could still use it to prevent light objects (piles of paper, polytsyrene, Sticky) from being blown away on windy days. Chris Quote Link to comment Share on other sites More sharing options...
Jaroslav Posted January 16, 2009 Author Share Posted January 16, 2009 sounds knackered to me.When you get a new one invest in a trickle charger if the vehicle is to be layed-up for long periods.. Yep, I got myself a solar trickle battery charger (costs $30 around here + tax). /Jaroslav Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted January 17, 2009 Share Posted January 17, 2009 I agree that most likely the battery is gone. However. to be sure I would recommend to try to jumpstart it first (use decent size vehicle for that, not polo). This way you can make sure that there is not a fault in the connections before buying a new battery. I wouldn't do that as the high voltage to try to charge the dead battery may fry your alternator. I remember a Bearmach catalogue where they warned you against fitting a new alternator to a flat battery. In this case the battery has been proved to be a complete dud and should be replaced before doing anything else. You could try to fit the battery from the Polo and try starting on that, though Quote Link to comment Share on other sites More sharing options...
Jaroslav Posted April 21, 2009 Author Share Posted April 21, 2009 I wouldn't do that as the high voltage to try to charge the dead battery may fry your alternator. I remember a Bearmach catalogue where they warned you against fitting a new alternator to a flat battery. No need to jump start anything... got myself a battery tester that shows voltage under a load. The battery was dead indeed. By the way, the solar trickle charger, I mentioned above, almost killed my other battery. I have an old minivan on my driveway; to prevent its battery from discharging I connected it to a trickle charger via a cigarette lighter socket. Trouble is that a couple months later the battery was dead. I think it was because the windshield was covered with snow most of the time. I figured the charger should have protection against draining battery when there is dark (like at night). Go figure. Anyway, I've returned the faulty charger and got myself another one (from another place and at half price). It looks awfully similar to the previous one... probably made in the same factory somewhere in China. I'm testing it in complete darkness on my marine battery now (which shouldn't get damaged when discharged completely); hopefully this one is better. Quote Link to comment Share on other sites More sharing options...
pete3000 Posted April 21, 2009 Share Posted April 21, 2009 Those solar chargers aren't really much good, not the cheapo ones anyway. If you look at the current given out they wont actually charge anything useful, well maybe a few AA cells in 8 hrs. To charge a 80A battery Fast/slow the charge rate is C/10 or /20 or 8A or 4A. The trickle rate once this is done is C/80 or 1A which can be left on almost indefinatley. This means you would need to buy a 12v/12W solar to charge at 1A. The 5W chargers might do at a push. The 1W and 1.8W chargers are a waste of time all they do really is delay the inevitable slightly. The main thing to remember though is the ghost drain (things like your clock/interior lights/radio/alarm) and the natural discharge of your battery. I find the best option is to use a batt disconnect switch to kill everything, and trickle charge every other weekend. RE: charging and capacity I would leave your batt on your computer charger till green. Measure the volts once done and make a note, should be 12.95 ish. Then find a load of some sort pair of 60W driving lights or mains inverter, run for a minute or two then disconnect and record volts again. Repeat this until the volts is down to 11v. If you repeat the test with a good battery of a similar capacity you will see if your battery has any capacity or not. Pete Quote Link to comment Share on other sites More sharing options...
Aragorn Posted April 21, 2009 Share Posted April 21, 2009 Batteries will store charge for a pretty long period of time if there is no load on it. I once scrapped an old car and chucked its battery in the shed as it was pretty new, nearly a year later went to buy a cheap car for my brother and the bloke told me the battery was dead and it wouldnt start, i took that battery from the shed, hooked it up and the car started first time... I'd just take the negative lead off when its parked up with the battery fully charged. Its also not very good for the engine to continually start it and shut it off again. Most engine wear occurs when its cold, and without actually driving it you'll be getting everything inside covered in carbon deposits... Pete: a fully charged healthy 80Ah battery would take quite a few hours of 60W to discharge it enough to drop it to 11v, and if you've drained it enough to only show 11v when unloaded you're risking permanently damaging the cells. A 12v car battery is flat once its unloaded voltage drops below about 12.2v Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted April 21, 2009 Share Posted April 21, 2009 If you want a decent charger I can recommend OptiMate/AccuMate, they will revive sulphated batteries (although yours sounds proper dead) and can be left on permanently. Quote Link to comment Share on other sites More sharing options...
pete3000 Posted April 21, 2009 Share Posted April 21, 2009 Pete: a fully charged healthy 80Ah battery would take quite a few hours of 60W to discharge it enough to drop it to 11v, and if you've drained it enough to only show 11v when unloaded you're risking permanently damaging the cells. A 12v car battery is flat once its unloaded voltage drops below about 12.2v Yeah sorry should have been 12v, 11v would be very, very dead. If the load was applied as mentioned though it should give an idea of capacity, Pair (2x) 60W driving lights or an inverter should pull 10A or more out of battery, Wouldn't take too long to drop a dead battery to 12v. Pete Quote Link to comment Share on other sites More sharing options...
Aragorn Posted April 21, 2009 Share Posted April 21, 2009 if its rated at 80AH it can supply 80amps for an hour, or 10A for 8 hours... But ye if the battery was knackered it would die pretty quickly Quote Link to comment Share on other sites More sharing options...
GL88 Posted April 21, 2009 Share Posted April 21, 2009 Maplin has a solar charger that is over 4A: http://www.maplin.co.uk/Module.aspx?moduleno=115194 Quote Link to comment Share on other sites More sharing options...
pete3000 Posted April 21, 2009 Share Posted April 21, 2009 Maplin has a solar charger that is over 4A: http://www.maplin.co.uk/Module.aspx?moduleno=115194 No, that is 4.8W which is 4.8W/12v = 0.4A or less if you are calculating at 13.8-14.2v 4.8/14.2 Pete Quote Link to comment Share on other sites More sharing options...
Aragorn Posted April 21, 2009 Share Posted April 21, 2009 i really wouldnt bother with these solar chargers, batteries like a reasonably constant charging current/voltage, and thats something a solar cell cannot supply... Quote Link to comment Share on other sites More sharing options...
western Posted April 21, 2009 Share Posted April 21, 2009 I recently bought a CTEK Multi XS 25000 fab bit of kit, ideal for dragging a almost dead battery back to the living world. expensive but then so were my odyssey batteries looks like this Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted April 21, 2009 Share Posted April 21, 2009 I found the flaw with the solar chargers (apart from the fact they're so pathetic) is the indicator LED is connected across them but there is often no reverse diode in the wire, so when it's dark the LED actually runs off your battery and probably takes out as much energy overnight as the thing manages to put in during the day! IMHO there's still nothing of any reasonable value solar-wise to fit to a vehicle, 10 minutes running the engine with a standard alternator kicking out ~50A is going to do far more than an entire day of half a gnat's fart from a solar panel. Quote Link to comment Share on other sites More sharing options...
Jaroslav Posted April 22, 2009 Author Share Posted April 22, 2009 IMHO there's still nothing of any reasonable value solar-wise to fit to a vehicle, 10 minutes running the engine with a standard alternator kicking out ~50A is going to do far more than an entire day of half a gnat's fart from a solar panel. Well, I don't think the solar chargers are supposed to recharge your battery; their goal is to keep a charged battery charged. I read somewhere that any battery will eventually discharge naturally even when there is no load connected. Quote Link to comment Share on other sites More sharing options...
Aragorn Posted April 22, 2009 Share Posted April 22, 2009 if you believe the hype yes, As we've just said though, they're ****e. Yes a battery will discharge over time, however i've already pointed out that a fully charged battery left laying in my shed for a year was still perfectly capable of starting a car without any sort of recharging. If its left standing, remove the negative lead, charge the battery fully with a normal charger and leave it alone. And dont continually start your engine but not drive it, its really not very good for it. A perfect example of this is generator sets, they often test them say once a week, but to test them, they dont start it up and let it idle, they start it up and let it run the building for a few hours, then shut it off. Anything else is just causing pointless wear on the motor. Quote Link to comment Share on other sites More sharing options...
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