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#1
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
The brother-in-law has an old car that he wanted to take to the breakers
yard and asked if I could charge the battery. It had been stood for several months without starting so was flatter than a witches tit. I measured the voltage at the terminals and it read 1.6volts. I said it may be too far knackered but would give it a try. I have 2 battery chargers, one is a new 3 phase charger from Lidl and the other a donkeys years old basic 6amp charger with switchable 6 or 12 volts. I tried to charge using the new 3 phase charger but it would not even come out of standby mode. I then tried the old 6amp charger and when I switched it on the needle on the amp meter started to rise & rise and went completely off the scale. It was only connected for a few moments and when I measured the battery voltage it now read over 13v so I disconnected the old charger and reconnected the new 3 phase charger and it now went into charge mode and was fully charged about 15 hours later. I think this has damaged the old charger as when I now try and connect the charger leads to a battery it causes a short with loads of sparks (this is before the charger is switched on). If I switch on the charger without the leads connected the charger makes a clicking sound as though it's continually cutting on & off. I'm guessing that trying to charge a battery so flat has forced more current from the charger than it was designed to give? Before I take a look inside (or bin the thing) I just wondered if anyone had an idea what might have gone kaput. |
#2
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
Before I take a look inside (or bin the thing) I just
wondered if anyone had an idea what might have gone kaput. I guess you old charger contains nothing more than a big transformer and a bridge rectifier. The rectifier contains 4 diodes to convert the AC from the transformer to the DC for the battery. If one of the diodes goes short circuit then you will get the effect you are seeing. If you really want to resurrect the charger you could probably replace the old bridge rectifier with a new one from Maplins for couple of quid (AR84F looks suitable). But as modern cars and batteries are more susceptible to mistreatment I would be tempted to just get rid of it. Chris |
#3
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
"redwood" wrote in message ... The brother-in-law has an old car that he wanted to take to the breakers yard and asked if I could charge the battery. It had been stood for several months without starting so was flatter than a witches tit. I measured the voltage at the terminals and it read 1.6volts. I said it may be too far knackered but would give it a try. I have 2 battery chargers, one is a new 3 phase charger from Lidl and the other a donkeys years old basic 6amp charger with switchable 6 or 12 volts. I tried to charge using the new 3 phase charger but it would not even come out of standby mode. I then tried the old 6amp charger and when I switched it on the needle on the amp meter started to rise & rise and went completely off the scale. It was only connected for a few moments and when I measured the battery voltage it now read over 13v so I disconnected the old charger and reconnected the new 3 phase charger and it now went into charge mode and was fully charged about 15 hours later. I think this has damaged the old charger as when I now try and connect the charger leads to a battery it causes a short with loads of sparks (this is before the charger is switched on). If I switch on the charger without the leads connected the charger makes a clicking sound as though it's continually cutting on & off. I'm guessing that trying to charge a battery so flat has forced more current from the charger than it was designed to give? Before I take a look inside (or bin the thing) I just wondered if anyone had an idea what might have gone kaput. Older battery chargers are usually very basic, generally consisting of a mains transformer, rectifier, ammeter, and a fuse... I'd guess by the sound of it that the rectifier has gone short circuit. |
#4
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
"Chris" wrote in message
... Before I take a look inside (or bin the thing) I just wondered if anyone had an idea what might have gone kaput. I guess you old charger contains nothing more than a big transformer and a bridge rectifier. The rectifier contains 4 diodes to convert the AC from the transformer to the DC for the battery. If one of the diodes goes short circuit then you will get the effect you are seeing. If you really want to resurrect the charger you could probably replace the old bridge rectifier with a new one from Maplins for couple of quid (AR84F looks suitable). But as modern cars and batteries are more susceptible to mistreatment I would be tempted to just get rid of it. Thanks for the quick replies. I have now taken the back off and yes it does look very basic inside. I can see the rectifier which has 4 connectors and a hole in the middle screwed into a thin sheet of metal (or is that a heatshield). It has writing on the rectifier which says; S4VB 10 (Hole) 84 I'm guessing that the 10 refers to 10amp (84 could be the year?). I've looked at the Maplin code for AR84F and that is 25A. Would it cause any problems using a higher amp or is it best to keep with a 10A? Cheers. |
#5
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
On Fri, 01 Dec 2006 20:15:54 -0000, redwood wrote:
"Chris" wrote in message ... Before I take a look inside (or bin the thing) I just wondered if anyone had an idea what might have gone kaput. I guess you old charger contains nothing more than a big transformer and a bridge rectifier. The rectifier contains 4 diodes to convert the AC from the transformer to the DC for the battery. If one of the diodes goes short circuit then you will get the effect you are seeing. If you really want to resurrect the charger you could probably replace the old bridge rectifier with a new one from Maplins for couple of quid (AR84F looks suitable). But as modern cars and batteries are more susceptible to mistreatment I would be tempted to just get rid of it. Thanks for the quick replies. I have now taken the back off and yes it does look very basic inside. I can see the rectifier which has 4 connectors and a hole in the middle screwed into a thin sheet of metal (or is that a heatshield). It has writing on the rectifier which says; S4VB 10 (Hole) 84 I'm guessing that the 10 refers to 10amp (84 could be the year?). I've looked at the Maplin code for AR84F and that is 25A. Would it cause any problems using a higher amp or is it best to keep with a 10A? Cheers. Nope, that'll be fine. |
#6
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
redwood wrote:
connectors and a hole in the middle screwed into a thin sheet of metal (or is that a heatshield). That wil be a heat*sink* - deisnged to help cool the rectifier. You will need to fit something similar to the replacement part. I'm guessing that the 10 refers to 10amp (84 could be the year?). I've looked at the Maplin code for AR84F and that is 25A. Would it cause any problems using a higher amp or is it best to keep with a 10A? Cheers. Bigger (in this application) will be fine. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
#7
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
In article ,
"redwood" writes: Thanks for the quick replies. I have now taken the back off and yes it does look very basic inside. I can see the rectifier which has 4 connectors and a hole in the middle screwed into a thin sheet of metal (or is that a heatshield). It has writing on the rectifier which says; S4VB 10 (Hole) 84 I'm guessing that the 10 refers to 10amp (84 could be the year?). I've looked at the Maplin code for AR84F and that is 25A. Would it cause any problems using a higher amp or is it best to keep with a 10A? Cheers. S4VB is a 4A bridge rectifier, and the 10 means 100V working. A 10A or higher (50V or higher) bridge rectifier will be fine. (A 4A bridge rectifier was obviously inadiquate.) I would also get some heat sink compound to smear between the new rectifier and the heatsink. -- Andrew Gabriel |
#8
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
"Andrew Gabriel" wrote in message
S4VB is a 4A bridge rectifier, and the 10 means 100V working. A 10A or higher (50V or higher) bridge rectifier will be fine. (A 4A bridge rectifier was obviously inadiquate.) I would also get some heat sink compound to smear between the new rectifier and the heatsink. Got the rectifier from my local Maplins and is now fitted. It's twice the size of the original with bigger spade connectors so had to replace the ends of the 4 wires. It was a bit confusing knowing which way round the - wires go as the only markings on the new rectifier only displayed on one side showing the AC & +. Going round in a clockwise direction, if the 1st terminal is AC+, the 2nd terminal is DC+, I connected the 3rd terminal to AC-, and the 4th terminal to DC- I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. |
#9
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
On Sat, 02 Dec 2006 15:20:13 -0000, redwood wrote:
"Andrew Gabriel" wrote in message S4VB is a 4A bridge rectifier, and the 10 means 100V working. A 10A or higher (50V or higher) bridge rectifier will be fine. (A 4A bridge rectifier was obviously inadiquate.) I would also get some heat sink compound to smear between the new rectifier and the heatsink. Got the rectifier from my local Maplins and is now fitted. It's twice the size of the original with bigger spade connectors so had to replace the ends of the 4 wires. It was a bit confusing knowing which way round the - wires go as the only markings on the new rectifier only displayed on one side showing the AC & +. Going round in a clockwise direction, if the 1st terminal is AC+, the 2nd terminal is DC+, I connected the 3rd terminal to AC-, and the 4th terminal to DC- That should be right. I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. |
#10
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
"Duncan Wood" wrote in message newsp.tjxupjhyyuobwl@lucy... On Sat, 02 Dec 2006 15:20:13 -0000, redwood wrote: "Andrew Gabriel" wrote in message S4VB is a 4A bridge rectifier, and the 10 means 100V working. A 10A or higher (50V or higher) bridge rectifier will be fine. (A 4A bridge rectifier was obviously inadiquate.) I would also get some heat sink compound to smear between the new rectifier and the heatsink. Got the rectifier from my local Maplins and is now fitted. It's twice the size of the original with bigger spade connectors so had to replace the ends of the 4 wires. It was a bit confusing knowing which way round the - wires go as the only markings on the new rectifier only displayed on one side showing the AC & +. Going round in a clockwise direction, if the 1st terminal is AC+, the 2nd terminal is DC+, I connected the 3rd terminal to AC-, and the 4th terminal to DC- That should be right. I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Is your meter reasonably accurate? These voltage readings seem rather low. Sylvain. |
#11
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
"Sylvain VAN DER WALDE" wrote in message
I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Is your meter reasonably accurate? These voltage readings seem rather low. I think the battery charger voltage increases when connected to a battery, I will check it out tomorrow. cheers. |
#12
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
"redwood" wrote in message ... "Andrew Gabriel" wrote in message S4VB is a 4A bridge rectifier, and the 10 means 100V working. A 10A or higher (50V or higher) bridge rectifier will be fine. (A 4A bridge rectifier was obviously inadiquate.) I would also get some heat sink compound to smear between the new rectifier and the heatsink. Got the rectifier from my local Maplins and is now fitted. It's twice the size of the original with bigger spade connectors so had to replace the ends of the 4 wires. It was a bit confusing knowing which way round the - wires go as the only markings on the new rectifier only displayed on one side showing the AC & +. Going round in a clockwise direction, if the 1st terminal is AC+, the 2nd terminal is DC+, I connected the 3rd terminal to AC-, and the 4th terminal to DC- I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Most bridge rectifier are usually marked: ~ ~ (ac in) + - (dc out). |
#13
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
"Ivan" wrote in message
. uk... "redwood" wrote in message Got the rectifier from my local Maplins and is now fitted. It's twice the size of the original with bigger spade connectors so had to replace the ends of the 4 wires. It was a bit confusing knowing which way round the - wires go as the only markings on the new rectifier only displayed on one side showing the AC & +. Going round in a clockwise direction, if the 1st terminal is AC+, the 2nd terminal is DC+, I connected the 3rd terminal to AC-, and the 4th terminal to DC- Most bridge rectifier are usually marked: ~ ~ (ac in) + - (dc out). Looked all round using a magnifying glass but the only marks I could find were on one edge similar to this pic http://www.kpsec.freeuk.com/photos/rapid/brect5.jpg |
#14
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
In article ,
"Ivan" writes: Most bridge rectifier are usually marked: ~ ~ (ac in) + - (dc out). IME, only the +ve is normally marked on the square ones. The -ve will be diagonally opposite, and the others are the AC (doesn't matter which way around). -- Andrew Gabriel |
#15
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
"redwood" wrote in message ... "Ivan" wrote in message . uk... "redwood" wrote in message Got the rectifier from my local Maplins and is now fitted. It's twice the size of the original with bigger spade connectors so had to replace the ends of the 4 wires. It was a bit confusing knowing which way round the - wires go as the only markings on the new rectifier only displayed on one side showing the AC & +. Going round in a clockwise direction, if the 1st terminal is AC+, the 2nd terminal is DC+, I connected the 3rd terminal to AC-, and the 4th terminal to DC- Most bridge rectifier are usually marked: ~ ~ (ac in) + - (dc out). Looked all round using a magnifying glass but the only marks I could find were on one edge similar to this pic http://www.kpsec.freeuk.com/photos/rapid/brect5.jpg Are the other two terminals on the other side of the rectifier similarly marked AC & - ? ....if so then it's simply a matter of the mains transformer connecting to the two terminals marked AC and the ones marked + & - eventually finding their way to the respective battery terminals. |
#16
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
On 2006-12-02, redwood wrote:
"Ivan" wrote in message . uk... "redwood" wrote in message Got the rectifier from my local Maplins and is now fitted. It's twice the size of the original with bigger spade connectors so had to replace the ends of the 4 wires. It was a bit confusing knowing which way round the - wires go as the only markings on the new rectifier only displayed on one side showing the AC & +. Going round in a clockwise direction, if the 1st terminal is AC+, the 2nd terminal is DC+, I connected the 3rd terminal to AC-, and the 4th terminal to DC- Most bridge rectifier are usually marked: ~ ~ (ac in) + - (dc out). Looked all round using a magnifying glass but the only marks I could find were on one edge similar to this pic http://www.kpsec.freeuk.com/photos/rapid/brect5.jpg The terminal marked AC is one AC connection, the other AC connection goes to the corner diagonally opposite. The terminal marked "+" is the DC+, the terminal opposite that is DC-. -- David Taylor |
#17
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Battery charger shorts out?
On Sat, 02 Dec 2006 17:43:42 -0000, Sylvain VAN DER WALDE
wrote: "Duncan Wood" wrote in message newsp.tjxupjhyyuobwl@lucy... On Sat, 02 Dec 2006 15:20:13 -0000, redwood wrote: "Andrew Gabriel" wrote in message S4VB is a 4A bridge rectifier, and the 10 means 100V working. A 10A or higher (50V or higher) bridge rectifier will be fine. (A 4A bridge rectifier was obviously inadiquate.) I would also get some heat sink compound to smear between the new rectifier and the heatsink. Got the rectifier from my local Maplins and is now fitted. It's twice the size of the original with bigger spade connectors so had to replace the ends of the 4 wires. It was a bit confusing knowing which way round the - wires go as the only markings on the new rectifier only displayed on one side showing the AC & +. Going round in a clockwise direction, if the 1st terminal is AC+, the 2nd terminal is DC+, I connected the 3rd terminal to AC-, and the 4th terminal to DC- That should be right. I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Is your meter reasonably accurate? These voltage readings seem rather low. Sylvain. If there's no battery connected it'll be trying to measure a non-dc waveform, how it does this will give a somewhat arbitrary result. |
#18
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
"redwood" wrote in message ... "Sylvain VAN DER WALDE" wrote in message I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Is your meter reasonably accurate? These voltage readings seem rather low. I think the battery charger voltage increases when connected to a battery, I will check it out tomorrow. cheers. I'm afraid not. With an unregulated supply, the voltage will drop when connected to a load. It would be interesting to know what the transformer voltage (AC) is with the rectifier disconnected. Those people more knowledgeable than myself should be able to work out the expected DC voltages (2 diodes in series dropping 1.5 VDC each ?). This would also check whether the rectifier is correctly connected. Sylvain. |
#19
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
In article ,
redwood wrote: "Sylvain VAN DER WALDE" wrote in message I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Is your meter reasonably accurate? These voltage readings seem rather low. I think the battery charger voltage increases when connected to a battery, That would be a clever trick. ;-) Unless there is some form of electronics regulating the output the open circuit voltage should be very much higher than that. Have you measured the AC voltage direct across the transformer - ie the input to the rectifier? I will check it out tomorrow. cheers. -- *Laugh alone and the world thinks you're an idiot. Dave Plowman London SW To e-mail, change noise into sound. |
#20
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Battery charger shorts out?
"Dave Plowman (News)" wrote in message ... In article , redwood wrote: "Sylvain VAN DER WALDE" wrote in message I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Is your meter reasonably accurate? These voltage readings seem rather low. I think the battery charger voltage increases when connected to a battery, That would be a clever trick. ;-) Unless there is some form of electronics regulating the output the open circuit voltage should be very much higher than that. Have you measured the AC voltage direct across the transformer - ie the input to the rectifier? I seem to recall my cheap n nasty charger puts out around 12v when not connected to a battery, but I've seen it reach 17v when charging a failing battery after 12 hours or so. Which I don't think was good for the battery but at least it was an old and tired one. I'm thinking about Heath Robinsoning something using an old 240v AC motor and spare alternator now... |
#21
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Battery charger shorts out?
In message , Stuffed
writes That would be a clever trick. ;-) Unless there is some form of electronics regulating the output the open circuit voltage should be very much higher than that. Have you measured the AC voltage direct across the transformer - ie the input to the rectifier? I seem to recall my cheap n nasty charger puts out around 12v when not connected to a battery, but I've seen it reach 17v when charging a failing battery after 12 hours or so. Which I don't think was good for the battery but at least it was an old and tired one. What was the shape of the 12.06V though? The DVM was probably struggling to realise it was DC, try putting a large-ish electrolytic cap' across it to smooth it out and measure again. -- Bill |
#22
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
On 2006-12-03, Sylvain VAN DER WALDE wrote:
"redwood" wrote in message ... "Sylvain VAN DER WALDE" wrote in message I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Is your meter reasonably accurate? These voltage readings seem rather low. I think the battery charger voltage increases when connected to a battery, I will check it out tomorrow. cheers. I'm afraid not. With an unregulated supply, the voltage will drop when connected to a load. It would be interesting to know what the transformer voltage (AC) is with the rectifier disconnected. Those people more knowledgeable than myself should be able to work out the expected DC voltages (2 diodes in series dropping 1.5 VDC each ?). This would also check whether the rectifier is correctly connected. Without smoothing capacitors (or a battery) it's not DC, though, it's full-wave rectified AC... -- David Taylor |
#23
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
"David Taylor" wrote in message ... On 2006-12-03, Sylvain VAN DER WALDE wrote: "redwood" wrote in message ... "Sylvain VAN DER WALDE" wrote in message I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Is your meter reasonably accurate? These voltage readings seem rather low. I think the battery charger voltage increases when connected to a battery, I will check it out tomorrow. cheers. I'm afraid not. With an unregulated supply, the voltage will drop when connected to a load. It would be interesting to know what the transformer voltage (AC) is with the rectifier disconnected. Those people more knowledgeable than myself should be able to work out the expected DC voltages (2 diodes in series dropping 1.5 VDC each ?). This would also check whether the rectifier is correctly connected. Without smoothing capacitors (or a battery) it's not DC, though, it's full-wave rectified AC... Hmm! I haven't seen a battery charger with a reservoir capacitor, a smoothing capacitor, a choke, or series resistor; yet such chargers are DC _in practice_, if not in theory. Thanks for reminding me about capacitors; in a conventional power supply they would raise the output voltage (not applicable in a basic battery charger). Sylvain. -- David Taylor |
#24
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Battery charger shorts out?
On Sun, 03 Dec 2006 11:03:32 -0000, Dave Plowman (News)
wrote: In article , redwood wrote: "Sylvain VAN DER WALDE" wrote in message I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Is your meter reasonably accurate? These voltage readings seem rather low. I think the battery charger voltage increases when connected to a battery, That would be a clever trick. ;-) Unless there is some form of electronics regulating the output the open circuit voltage should be very much higher than that. Have you measured the AC voltage direct across the transformer - ie the input to the rectifier? I will check it out tomorrow. cheers. The DC voltage will rise when you attach a battery, as it will if you attached a cap, in the former to the battery terminal voltage, in the latter case to the peak voltage of the waveform. |
#25
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Battery charger shorts out?
On Sun, 03 Dec 2006 14:42:40 -0000, Sylvain VAN DER WALDE
wrote: "David Taylor" wrote in message ... On 2006-12-03, Sylvain VAN DER WALDE wrote: "redwood" wrote in message ... "Sylvain VAN DER WALDE" wrote in message I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Is your meter reasonably accurate? These voltage readings seem rather low. I think the battery charger voltage increases when connected to a battery, I will check it out tomorrow. cheers. I'm afraid not. With an unregulated supply, the voltage will drop when connected to a load. It would be interesting to know what the transformer voltage (AC) is with the rectifier disconnected. Those people more knowledgeable than myself should be able to work out the expected DC voltages (2 diodes in series dropping 1.5 VDC each ?). This would also check whether the rectifier is correctly connected. Without smoothing capacitors (or a battery) it's not DC, though, it's full-wave rectified AC... Hmm! I haven't seen a battery charger with a reservoir capacitor, a smoothing capacitor, a choke, or series resistor; yet such chargers are DC _in practice_, if not in theory. Thanks for reminding me about capacitors; in a conventional power supply they would raise the output voltage (not applicable in a basic battery charger). Sylvain. -- David Taylor They're not DC in practice, in pratice they supply a pulsed DC charge, hence why they're all rated at RMS. Wheras the rate of charge is the average current, which will be lower. Marketing :-) |
#26
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Battery charger shorts out?
In article ,
Sylvain VAN DER WALDE wrote: Without smoothing capacitors (or a battery) it's not DC, though, it's full-wave rectified AC... Hmm! I haven't seen a battery charger with a reservoir capacitor, a smoothing capacitor, a choke, or series resistor; yet such chargers are DC _in practice_, if not in theory. Thanks for reminding me about capacitors; in a conventional power supply they would raise the output voltage (not applicable in a basic battery charger). The battery acts as a vast capacitor, though. -- *If you ate pasta and anti-pasta, would you still be hungry? Dave Plowman London SW To e-mail, change noise into sound. |
#27
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Battery charger shorts out?
On Dec 1, 8:15 pm, "redwood" wrote: "Chris" wrote in ... Before I take a look inside (or bin the thing) I just wondered if anyone had an idea what might have gone kaput. I guess you old charger contains nothing more than a big transformer and a bridge rectifier. The rectifier contains 4 diodes to convert the AC from the transformer to the DC for the battery. If one of the diodes goes short circuit then you will get the effect you are seeing. If you really want to resurrect the charger you could probably replace the old bridge rectifier with a new one from Maplins for couple of quid (AR84F looks suitable). But as modern cars and batteries are more susceptible to mistreatment I would be tempted to just get rid of it.Thanks for the quick replies. I have now taken the back off and yes it does look very basic inside. I can see the rectifier which has 4 connectors and a hole in the middle screwed into a thin sheet of metal (or is that a heatshield). It has writing on the rectifier which says; S4VB 10 (Hole) 84 I'm guessing that the 10 refers to 10amp (84 could be the year?). I've More likely week 10 1984 MBQ |
#28
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
redwood wrote: "Andrew Gabriel" wrote in message S4VB is a 4A bridge rectifier, and the 10 means 100V working. A 10A or higher (50V or higher) bridge rectifier will be fine. (A 4A bridge rectifier was obviously inadiquate.) I would also get some heat sink compound to smear between the new rectifier and the heatsink. Got the rectifier from my local Maplins and is now fitted. It's twice the size of the original with bigger spade connectors so had to replace the ends of the 4 wires. It was a bit confusing knowing which way round the - wires go as the only markings on the new rectifier only displayed on one side showing the AC & +. Going round in a clockwise direction, if the 1st terminal is AC+, the 2nd terminal is DC+, I connected the 3rd terminal to AC-, and the 4th terminal to DC- I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Don't buy anything from Maplins. My broadband started to go slow and my ISP said I needed a new filter. Maplins said I needed new cable. I bought new cable but the broadband speeded up again - must have been BT. So I took the cable back. But because it had been machine packed there is no way I would return it "in the same condition". The cable WAS "in the same condition". But the idiots said the packing had to be the same -- impossible! If they want to get things back "correctly" they should use packing it is possible to pack. Every other company I've taken anything back to, in living memory has accepted it back with full refund. Except Maplins. Don't even think of shopping with them. |
#29
Posted to uk.d-i-y,uk.rec.cars.maintenance
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Battery charger shorts out?
On Mon, 4 Dec 2006 16:07:33 UTC, "Paul" wrote:
(snip) Every other company I've taken anything back to, in living memory has accepted it back with full refund. Except Maplins. Don't even think of shopping with them. Yes, you said that. -- The information contained in this post is copyright the poster, and specifically may not be published in, or used by Avenue Supplies, http://avenuesupplies.co.uk |
#30
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
Paul wrote:
redwood wrote: "Andrew Gabriel" wrote in message S4VB is a 4A bridge rectifier, and the 10 means 100V working. A 10A or higher (50V or higher) bridge rectifier will be fine. (A 4A bridge rectifier was obviously inadiquate.) I would also get some heat sink compound to smear between the new rectifier and the heatsink. Got the rectifier from my local Maplins and is now fitted. It's twice the size of the original with bigger spade connectors so had to replace the ends of the 4 wires. It was a bit confusing knowing which way round the - wires go as the only markings on the new rectifier only displayed on one side showing the AC & +. Going round in a clockwise direction, if the 1st terminal is AC+, the 2nd terminal is DC+, I connected the 3rd terminal to AC-, and the 4th terminal to DC- I've not yet tried it connected to a battery but it now powers on without clicking and connecting a DVM to the croc clips shows around 12.06v or 6.02 on the 6 volt setting. I shall give it a test on a battery tomorrow. Don't buy anything from Maplins. My broadband started to go slow and my ISP said I needed a new filter. Maplins said I needed new cable. I bought new cable but the broadband speeded up again - must have been BT. So I took the cable back. But because it had been machine packed there is no way I would return it "in the same condition". The cable WAS "in the same condition". But the idiots said the packing had to be the same -- impossible! If they want to get things back "correctly" they should use packing it is possible to pack. Every other company I've taken anything back to, in living memory has accepted it back with full refund. Except Maplins. Don't even think of shopping with them. the goods had been used so they could not be sold on again as new they coud not offer a warranty on the product and in law if the goods are not faulty then thier is no reason why they should ecept them back -- |
#31
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
In message om, Paul
writes Every other company I've taken anything back to, in living memory has accepted it back with full refund. Except Maplins. Don't even think of shopping with them. That's the trouble with dealing with toy shops manned by kids. -- Bill |
#32
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
In article om,
Paul wrote: Don't buy anything from Maplins. You've just said that... -- *Sticks and stones may break my bones but whips and chains excite me* Dave Plowman London SW To e-mail, change noise into sound. |
#33
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
In article ,
Bill wrote: That's the trouble with dealing with toy shops manned by kids. You expect a Maplin shop assistant to be an expert on every product sold by them? -- *Who is this General Failure chap anyway - and why is he reading my HD? * Dave Plowman London SW To e-mail, change noise into sound. |
#34
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
In message , "Dave Plowman (News)"
writes In article , Bill wrote: That's the trouble with dealing with toy shops manned by kids. You expect a Maplin shop assistant to be an expert on every product sold by them? Not in the slightest, but I would expect them to know that for you to prove a cable was unsuitable for the purpose that you bought it for that you had to remove it from the packaging. I have seen a number of items like this in Maplins in taped or stapled packets so presumably some of their stores will accept them back. The only Maplins that I had any confidence in was in Milton Keynes where one member of staff, Marian, seemed to have a good working knowledge of most of their range and if not knew who or where to ask. Unfortunately she seems to have left. -- Bill |
#35
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
In message , "Dave Plowman (News)"
writes In article om, Paul wrote: Don't buy anything from Maplins. You've just said that... He does seem to have a downer on Maplins at the moment, a couple of similar posts have appeared elsewhere today. -- Bill |
#36
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
In article ,
Bill wrote: In message , "Dave Plowman (News)" writes In article , Bill wrote: That's the trouble with dealing with toy shops manned by kids. You expect a Maplin shop assistant to be an expert on every product sold by them? Not in the slightest, but I would expect them to know that for you to prove a cable was unsuitable for the purpose that you bought it for that you had to remove it from the packaging. Eh? It's labelled with what it is. And in clear wrapping. I have seen a number of items like this in Maplins in taped or stapled packets so presumably some of their stores will accept them back. And are you happy to buy such secondhand goods? Or go for a new one further back on the rack? The only Maplins that I had any confidence in was in Milton Keynes where one member of staff, Marian, seemed to have a good working knowledge of most of their range and if not knew who or where to ask. Unfortunately she seems to have left. Probably fed up with rude 'know it all' customers. ;-) It's a job I certainly wouldn't fancy. Although at least the MK branch has a better stock than most. -- *I have a degree in liberal arts -- do you want fries with that Dave Plowman London SW To e-mail, change noise into sound. |
#37
Posted to uk.rec.cars.maintenance,uk.d-i-y
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Battery charger shorts out?
In message , "Dave Plowman (News)"
writes Eh? It's labelled with what it is. And in clear wrapping. Hang on this wasn't my argument in the first place, I believe that Pauls point was that they wouldn't consider the return in anyway, OK it was not faulty so they did not have to accept it but it has been known in way of customer relations for them to do so in the past. I have seen a number of items like this in Maplins in taped or stapled packets so presumably some of their stores will accept them back. And are you happy to buy such secondhand goods? Or go for a new one further back on the rack? In the case of a lead would it really matter? The only Maplins that I had any confidence in was in Milton Keynes where one member of staff, Marian, seemed to have a good working knowledge of most of their range and if not knew who or where to ask. Unfortunately she seems to have left. Probably fed up with rude 'know it all' customers. ;-) You know the population of MK well then!!!!! ;-) (I'm not from MK, thank God) t's a job I certainly wouldn't fancy. Although at least the MK branch has a better stock than most. It's turning into a Tandy rapidly though, although it did get me out of a hole a while back when I needed 50+ 5K6 resistors in a hurry i.e. I had the buses queuing up to have RT installed and they had fitted switch mode 24V 12V convertors with an over active shut down circuit that tripped as soon as it saw the radio attached. Personally I prefer to buy from RS and Farnell, even Canford! But then I'm not normally paying the bill. -- Bill |
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