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May 10, 2015 21:38:45 GMT
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Ok long story. I worked away for three months at the start of the year and the wifes espace blew its turbo. Hence, it sat unused for about 7 weeks. It had a brand new big heavy duty diesel battery on it which worked fine.
I went out and bought a man size charger from halfords and put it on charge for a good 8 hours, checking it every now and again with a multimeter. starting at 10v eventually it got to 12.4 volts (still plugged into the wall/ charger) so I took it off. it's not an automatic charger so I took it off charge. It immediately went back down to 10.8.
Now, should I leave it charging all day until it reads 14v the same as what an alternator would push in? The manual for the battery says it should never exceed 14.4v. The little indicator window on the battery reads green for ok, which I presume is an indication of the water inside. is a good 24hr charge required?
I'm always paranoid of overcharging it or it going pop.
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sparkyt
Posted a lot
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Posts: 1,767
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May 10, 2015 21:59:34 GMT
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It can't really go pop the battery draws current from a charger which has a current limiting device in side like a resistor or an inductor .
When the battery is full of charge you will see the current dial drop to almost 0 . If your chargers has a dial indictator ?
The time it takes is a open question . Dependant on your batt size or amp/hours and the size of the charger .
your batt will have about 1.8v to 2v per cell with 6 cells to make a battery
10.8v to 12.8 v is normally all you can get from a 6 cell battery
The car has a 14.8v zener diode in side the alternator with holds the battery at about this voltage while the engine is running
With a car battery is more to do with the size of the Plates in the cell that can supply you with current or cold cranking amps
If the go faulty the tend to buckle and tutch each other wich shorts them out and the do not hold current .
Do you have a dial indicator on your charger . If it starts off on ten Amps
and falls over time to zero amps your battery could be ok . If it holds just 10v after a charge you may have just one faulty cell . .
Can you see the ends of the battery buckle out ?
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Last Edit: May 10, 2015 22:00:42 GMT by sparkyt
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May 10, 2015 22:20:37 GMT
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Thanka for the reply, it's only six months old and unfortunately a maintenance free job, so no plates to see. I'll check the ampage with a multimeter as I'm not sure it has one on it.
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bortaf
Posted a lot
Posts: 4,549
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May 11, 2015 11:55:12 GMT
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Does the charger have a fast/slow charge option? i allways give batterys 24Hr slow charge then a good couple of hours rest before i test them with a drop tester.
The green bubble in the window is an indication that the battery acid is ok not that it will hold a charge if as said the plates are warped.
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R.I.P photobucket
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taurus
Posted a lot
Posts: 1,084
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May 11, 2015 15:25:48 GMT
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I was taught that a heavily discharged battery won't take any amps out of a normal battery charger. I used to get quite a few batteries from old ladies cars that had sat all winter in the garage - the batteries all read below 12v and wouldn't take a charge. They'd been told they needed to buy a new battery.
What I used to do was to use a 400Ma gell cell charger to 'prime' the battery, leave it on for a few hours to bring the voltage back to 12v, then it goes onto the main charger to put the charge into it. After charging the battery usually reads around 13v and should hold that for quite a long time. Once the battery was charged I took it off the main charger and if it wasn't going to be used for a long time left it on the 400Ma one.
I resurrected many batteries that garages had declared useless that way.
I now use one of those intelligent chargers that basically does the same thing, ie a very small priming charge, then the bulk charge, then a maintenance charge.
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sparkyt
Posted a lot
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Posts: 1,767
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May 11, 2015 16:00:28 GMT
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I've been told you can drop a battery onto grass that's flat from about 3 ft high . .
This will shock the Plates inside then they take a charge
I've not tried this
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May 11, 2015 16:49:22 GMT
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What charger was used? if it's an intelligent one then it may well have just clicked off or something.
If there was a genuine 4A/8A charge going into it for 8 hours to get it to where it is, then it's knackered.
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May 11, 2015 17:14:13 GMT
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Dropping back to 10.8v after charging usually means it has a dead cell, you might get it to recover with EDTA or a desulphator but to be honest I would just take it back at 6 months old and get a new one.
I've got a 12v power supply from an old PC that I use as a charger for really dead batteries that the 'smart' charger refuses to charge.
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Last Edit: May 11, 2015 17:25:33 GMT by dodgerover
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I've been told you can drop a battery onto grass that's flat from about 3 ft high . . This will shock the Plates inside then they take a charge I've not tried this Is that what's known as voltage dropper? lol Seriously though dropping a plastic cased battery isn't a good idea. |
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Hi, I think the idea of that is that it disturbs the sediment in the bottom. The surface comes off the plates and settles in the bottom, it builds up until it shorts the plates out, it works temporarily but is not a long term solution (excuse pun).
When I worked at the bus company, far too many years ago, the electrician sometimes used to empty the acid out, then he used a hose to wash out all the sediment, refilled with fresh acid and charged it up.
Colin
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sparkyt
Posted a lot
selling stuff
Posts: 1,767
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May 13, 2015 10:13:30 GMT
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I've been told you can drop a battery onto grass that's flat from about 3 ft high . . This will shock the Plates inside then they take a charge I've not tried this Is that what's known as voltage dropper? lol Seriously though dropping a plastic cased battery isn't a good idea. I did say I'd not tried it . . |
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Last Edit: May 13, 2015 10:14:55 GMT by sparkyt
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bortaf
Posted a lot
Posts: 4,549
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May 13, 2015 20:39:36 GMT
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If i get a battery too dead for the charger to charge i connect a good battery with jump leads and charge the pair for an hour then remove the 2nd charged battery and leave the first dead one to finish off  |
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R.I.P photobucket
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sparkyt
Posted a lot
selling stuff
Posts: 1,767
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Jump start it ... . Into life .. . Good tip
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May 14, 2015 10:25:56 GMT
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Sorry to hijack this thread kind of, I'm wondering the opposite of the initial question so... how long does it take for them to run out? I accidentally parked up and left my lights on (I must have knocked the light stalk when I got out) from 8 this morning until 11, probably a silly question but I've no idea how long they last Edit: Seen the response below, thanks Colin  |
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Last Edit: May 14, 2015 12:06:04 GMT by Deleted
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May 14, 2015 11:22:44 GMT
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Sorry to hijack this thread kind of, I'm wondering the opposite of the initial question so... how long does it take for them to run out? I accidentally parked up and left my lights on (I must have knocked the light stalk when I got out) from 8 this morning until 11, probably a silly question but I've no idea how long they last Hi, It depends on what size the battery is, Amp/Hr. How many lights were on, Amps. What the condition of the battery is, Fully or partly charged. How long for. Here's a link to explain better than I could. - all-about-lead-acid-batteries.capnfatz.com/all-about-lead-acid-batteries/lead-acid-battery-fundamentals/what-are-amp-hours/ Colin |
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May 15, 2015 17:43:50 GMT
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"how long does it take for them to run out?" Depends on the power that's being used - I recently fitted LED bulbs (very bright but they used very little power) to my sidelights, so I could leave them on for ages without draining the battery. Also fitted a cheapo "lights on" alarm, so if you get out of the car when the lights are on it squeals. Simple but effective! For general use and reviving "dead" batteries, I have a Optimate battery charger, It works out what's needed and automatically tries to "jump start" the battery (using short burst up to 24V !) if it's dead. It works more often than not on "scrap" batteries |
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Porsche
West Midlands
Kev from B'ham.
Posts: 4,725 
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May 15, 2015 18:33:27 GMT
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The battery eye checks the specific gravity of one battery cell. Green usally indicates that the battery state-of-charge is above 57 percent. Black usally means it still needs charging. Clear means that the acid in that cell is too low. Check electrolyte level and refill with distilled water. Note that this is only for the cell that it is fitted to.
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May 16, 2015 11:23:55 GMT
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It can't really go pop the battery draws current from a charger which has a current limiting device in side like a resistor or an inductor . unless the plates have suffered irreversible sulfation, in which case the charger thinks the battery is stone cold dead and puts all its effort into it. the plates distort, the battery swells like a melon and you walk into the garage the next day wondering what that smell of rotten eggs is |
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