Electrical dimwit!
Discussion
Hi Peeps..As most of you know im not electrikery blessed and TBH it goes straight over my head..(Not literally..Well i suppose static does..)..Anyway i went out to Delilah this morning, Got in..powered the windows down..False of habit im affraid..Turned the key and nothing..No ignition light..No noise..Nothing..So i asked a neighbour to give me a jump start..Nothing...Let it sit for a min..Nothing..Then it started snowing..So i covered her up but had to leave the windows down..Ten minutes later it stopped snowing so i got him to take his battery off and put it on mine..Sure enough the windows could be powered up and i had an ignition light..He has borrowed me a slow trickle charger (6amp) to charge the battery..I wanted to test the battery to see if there was any life in it so i got out my NEW digital multimeter out of its box that someone kindly sent me...Brushed the dust off..And then just stared at it..My neighbour then plugged in the leads and tested the battery..It seemed that the battery was dropping a digit every second..He said my battery is fooked..When he left i stared at the multimeter some more and then thought..Aaahhh..Better check the instructions..I found that he had put the leads in the wrong ports..+ instead of - he had also switched it to DCA..20m?..Im sure the instructions say DCV?..This is were i go all jellified... 
...Here is a pic..(I know) of my multi thingy and i wondered if someone would be so kind as to explain what i need to set it to to test my battery and what i should see on the display..(Other than my face staring back at me)..
Thanks in advance for the auto-electrical advanced forum based course..
..Im still trying to learn...Honest...cheers...Ziga
...Here is a pic..(I know) of my multi thingy and i wondered if someone would be so kind as to explain what i need to set it to to test my battery and what i should see on the display..(Other than my face staring back at me)..Thanks in advance for the auto-electrical advanced forum based course..
..Im still trying to learn...Honest...cheers...Ziga
Cheers for that chaps..I think it is totally flat..Its a WestCo MX5 Battery and has absorbed glass mat technology..(Not wet gel)..What ever that is?...It needs a low amp 2-3amp trickle charger over 3-5 days...So will the 6amp charger be ok?..what should i see on the multimeter screen after say two hours?..Cheers...Ziga
Actually just checked it with that setting ian and it say's 8.57...Is that 8 volt?..Cheers
Actually just checked it with that setting ian and it say's 8.57...Is that 8 volt?..Cheers
Edited by mrzigazaga on Sunday 31st March 18:07
Danny Hoffman said:
Don't use the 6 amp charger.
The voltage reading is pretty irrelevant whilst charging and can only give you any indication of the battery condition once it's fully charged.
Just un-plugged it...But now im stuck!..I dont have a spare battery and they are 100 sobs new..Yes the correct charger is cheaper but it takes 3-5 days of charging.."Feck it"..The voltage reading is pretty irrelevant whilst charging and can only give you any indication of the battery condition once it's fully charged.
If you've started charging with the 6 amp charger you might have damaged it anyway (if it's going to get damaged) so might be worth risking it.
Also you could connect a headlamp/spotlamp bulb to the battery whilst charging it with your 6 amp charger, this will take more than half the current and protect the battery
Also you could connect a headlamp/spotlamp bulb to the battery whilst charging it with your 6 amp charger, this will take more than half the current and protect the battery
Well you could use the 6A charger if you could keep the current down to 2A. How to do this?
You have your multimeter handy and it's got a 10A setting. So what you need to do is set up the multimeter first... plug the black into COM and the red into the top 10ADC socket. Turn the switch around to the red 10A setting.
Now connect your charger - black to negative, red to the multimeter red and black multimeter to the battery +, but only dab onto the battery for a few seconds. If you get 6A or above what you need to do is stick some resistance in series. You will need about one ohm to half an ohm... What do you have around the house that you could use.... or in the car... try a big reel of wire if you have one. An alternative could be - instead of putting the charger directly onto battery -ve, connect it to an earth far away from the battery such as the rear of the chassis. If you can find a place that gives you the 2A approx then that will do.
You have your multimeter handy and it's got a 10A setting. So what you need to do is set up the multimeter first... plug the black into COM and the red into the top 10ADC socket. Turn the switch around to the red 10A setting.
Now connect your charger - black to negative, red to the multimeter red and black multimeter to the battery +, but only dab onto the battery for a few seconds. If you get 6A or above what you need to do is stick some resistance in series. You will need about one ohm to half an ohm... What do you have around the house that you could use.... or in the car... try a big reel of wire if you have one. An alternative could be - instead of putting the charger directly onto battery -ve, connect it to an earth far away from the battery such as the rear of the chassis. If you can find a place that gives you the 2A approx then that will do.
Danny Hoffman said:
Also you could connect a headlamp/spotlamp bulb to the battery whilst charging it with your 6 amp charger, this will take more than half the current and protect the battery
Cheers for that but i dont have either and knowing my luck i have probably damaged the battery...>> You have your multimeter handy and it's got a 10A setting. So what you need to do is set up the multimeter first... plug the black into COM and the red into the top 10ADC socket. Turn the switch around to the red 10A setting.
Forgot the warning though - DO MAKE SURE you move the multimeter lead back to the middle port AND select the 20V setting before you re-check the battery voltage. Or else you'll get a big spark!!!
Forgot the warning though - DO MAKE SURE you move the multimeter lead back to the middle port AND select the 20V setting before you re-check the battery voltage. Or else you'll get a big spark!!!
Zig,
Cold is the bitter enemy of batteries, pretty much all rechargeable types suffer in the cold.
Connecting a testmeter set to 20A (20 amps) across the battery should pretty much MELT the testmeter with a good battery - the insulation on the wires would burn of in a few secs, as you should have about 400 Amps going throught them !! Always leave your testmeter wired for voltage, it's safer !!
If you had the charger connected the wrong way round for any lenght of time (like more than a minute or two) it might damage the battery, but probably OK - if ti gets charged too fast, the same applies, if you found the problem quickly, should be OK.
Try taking it in the house and warming it up - classic lead-acid batteries can come back to life after 30 mins by the radiator !!
Don't know about gel batteries for sure, but lead acid ones should NEVER drop below about 10 volts, and should read around 13.5 or more immediately after charging, if it's lower than that, then you probably have a faulty cell, and a new battery is the only answer.... I think gel ones are the same or pretty close.
Cold is the bitter enemy of batteries, pretty much all rechargeable types suffer in the cold.
Connecting a testmeter set to 20A (20 amps) across the battery should pretty much MELT the testmeter with a good battery - the insulation on the wires would burn of in a few secs, as you should have about 400 Amps going throught them !! Always leave your testmeter wired for voltage, it's safer !!
If you had the charger connected the wrong way round for any lenght of time (like more than a minute or two) it might damage the battery, but probably OK - if ti gets charged too fast, the same applies, if you found the problem quickly, should be OK.
Try taking it in the house and warming it up - classic lead-acid batteries can come back to life after 30 mins by the radiator !!
Don't know about gel batteries for sure, but lead acid ones should NEVER drop below about 10 volts, and should read around 13.5 or more immediately after charging, if it's lower than that, then you probably have a faulty cell, and a new battery is the only answer.... I think gel ones are the same or pretty close.
Edited by RCK974X on Sunday 31st March 20:16
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..........................Cheers for the help peeps...Unfortunately this is what happens when i read it...I have decided to use the 6amp charger and have tested the battery with the multimeter every hour using the setting as first advised and it has gone from 8.57 to 9.04 in an hour..What is this figure please?..Amps or watts....Sorry for all the "Der" questions but im slowly getting my head around it..I think...Cheers...
...ZigaThe reading you are getting will be Volts. When fully charged, this should be around 13V or 13.5V.
While this might be an indication of it the battery is charged or not, its not much use to tell you the health of the battery. A quickish way to test this is, once the battery is back on the car, check the voltage with everything off, then flick on the headlights and fan, now check the voltage, hopefully somewhere around 12V, and an indication that the battery may be OK. Of however at this point the voltage has dropped significantly (down to 10V or less), then its probably new battery time...
This is because the reading you take with nothing connected to the battery are with no load. Once you start to add some load to it, then if the battery can't supply enough current, then the voltage will drop.
While this might be an indication of it the battery is charged or not, its not much use to tell you the health of the battery. A quickish way to test this is, once the battery is back on the car, check the voltage with everything off, then flick on the headlights and fan, now check the voltage, hopefully somewhere around 12V, and an indication that the battery may be OK. Of however at this point the voltage has dropped significantly (down to 10V or less), then its probably new battery time...
This is because the reading you take with nothing connected to the battery are with no load. Once you start to add some load to it, then if the battery can't supply enough current, then the voltage will drop.
Adam..That is it with it connected!!....(Didnt want to admit that at first but it seems ok)...
Thanks for that also jon..Its starting to make sense..So if the battery is charging at the rate it is now..1Hr = 0.47v then it should take 6-7 more hours to charge fully...Or near to...
Thanks for that also jon..Its starting to make sense..So if the battery is charging at the rate it is now..1Hr = 0.47v then it should take 6-7 more hours to charge fully...Or near to...
Edited by mrzigazaga on Sunday 31st March 21:17
That seems a bit low then - the battery is still sucking the life out of the charger.
I wouldn't leave it connected to this rapid charger for extended periods or you will knacker the battery.
I don't think this sort of battery is suited to the application - if it can only accept 2-3A then surely it will get knackered by the alternator which can output 40+A??
I wouldn't leave it connected to this rapid charger for extended periods or you will knacker the battery.
I don't think this sort of battery is suited to the application - if it can only accept 2-3A then surely it will get knackered by the alternator which can output 40+A??
Thing is it 470 cca apparently and is normally fine..I havent had any battery problems since i bought this battery..I think i may of knocked the interior light on, The car has been covered for two days so its enough to flatten the bettery i should imagine...There might of been enough life left in it just before i lowered the windows to crank or at least show me a dull ignition light..These type of batteries need a trickle charge to charge them but like you say when the alternator is charging its supplying more than that...I think the last time i had someone check the volts going into the battery i recall it being something like 13.6...And as i say normally i have a very healthy starter..Especially cold start..
6-7 hours is a good guess, though it is more based upon current that the voltage. Using an example, if you had a 40AH (Amp Hour - i.e. capacity) battery, and hooked it up to a 6 amp charger, you would expect it to take around 6.6 Hours to fully charge (Capacity/charge current - 40/6), however in the real world, there are going to be some losses (heat in the wires and the battery getting warm), so realistically 8-9 hours would be expected.
As to what charger to use, my knowledge is based more on Nimh/Nimh and Lithium Polymer batteries, but some of the principals are the same, and relate to lead acid batteries (though how that translates to the gel batteries I'm not too sure). The easiest way to damage your battery is to have too high a voltage when charging, for example using a 12v charger for an AA battery, this is not good (pretty similar really to plugging a 12V bulb into a 240V light socket..). With a lead acid battery that is very flat (or deep discharged, less than 8v with no load) then if you were to connect it to a 12V charger that could supply limitless current, then the battery would take as much current as it could initially, and as the battery charged, you would see this current tail off. What some chargers (e.g. trickle chargers) do is limit the current available to the battery to avoid this big gulp to start with, as repeatedly doing this from a deep discharge state can lead to problems (liquids in the battery boil, battery dries out etc..) and shorten the life of the battery significantly.
An alternator may be capable of supplying 40A, but this does not mean the battery is actually going to draw this, likewise with a charger, just because it is capable of supplying x amps does not mean anything connected to it will take this many amps. (Think of anything you plug into the mains, the circuit is capable of supplying 13Amps or more, but the thing you plug in only takes what it needs, not the full 13Amps all the time)
With batteries, the handling of the charging leads to maintaining the condition of the battery, and hence its life, as all batteries wear out and become less effective over time. This is why with some battery technologies you end up with chargers that are 2, 3 or 4 stage, they limit the current to start with until the battery gets to a set level, then allow more, then reduce it again, then trickle to maintain a full charge. Any charging is damaging a battery, its just to what extent and how you manage it that makes the difference. In normal use, the battery in your car will not be deeply discharged, so will maintain its own 'trickle' from the alternator. Buying a trickle charger is simply a charger that can only supply a limited current (enough to overcome the losses due to the internal resistance of the battery), and that if you connected it to a deeply discharged battery it would take an absolute age to fully recharge.
As to what charger to use, my knowledge is based more on Nimh/Nimh and Lithium Polymer batteries, but some of the principals are the same, and relate to lead acid batteries (though how that translates to the gel batteries I'm not too sure). The easiest way to damage your battery is to have too high a voltage when charging, for example using a 12v charger for an AA battery, this is not good (pretty similar really to plugging a 12V bulb into a 240V light socket..). With a lead acid battery that is very flat (or deep discharged, less than 8v with no load) then if you were to connect it to a 12V charger that could supply limitless current, then the battery would take as much current as it could initially, and as the battery charged, you would see this current tail off. What some chargers (e.g. trickle chargers) do is limit the current available to the battery to avoid this big gulp to start with, as repeatedly doing this from a deep discharge state can lead to problems (liquids in the battery boil, battery dries out etc..) and shorten the life of the battery significantly.
An alternator may be capable of supplying 40A, but this does not mean the battery is actually going to draw this, likewise with a charger, just because it is capable of supplying x amps does not mean anything connected to it will take this many amps. (Think of anything you plug into the mains, the circuit is capable of supplying 13Amps or more, but the thing you plug in only takes what it needs, not the full 13Amps all the time)
With batteries, the handling of the charging leads to maintaining the condition of the battery, and hence its life, as all batteries wear out and become less effective over time. This is why with some battery technologies you end up with chargers that are 2, 3 or 4 stage, they limit the current to start with until the battery gets to a set level, then allow more, then reduce it again, then trickle to maintain a full charge. Any charging is damaging a battery, its just to what extent and how you manage it that makes the difference. In normal use, the battery in your car will not be deeply discharged, so will maintain its own 'trickle' from the alternator. Buying a trickle charger is simply a charger that can only supply a limited current (enough to overcome the losses due to the internal resistance of the battery), and that if you connected it to a deeply discharged battery it would take an absolute age to fully recharge.
i don't know if it applies to Zig's battery but other gel-type batteries (Sealed Lead-Acid Batteries or SLABS) should only be charged from a constant voltage source, so as they get near fully charged they don't start to outgas. If you let them lose gas (which they will do through a small valve) then you lose water out of the battery which means less capacity, and it you overdo it you can dry out or burst the battery.
I suppose if you regularly monitor it unti it gets to 12V but no more, that will be safe enough, assuming all the cells are charging equally.
I suppose if you regularly monitor it unti it gets to 12V but no more, that will be safe enough, assuming all the cells are charging equally.
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