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Battery charger monitor

steamthief

Jul 11, 2013
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Hi, I have a 12v lead-acid battery charger which has a 6-LED charge-progress display. I think I accidentally touched the + & - terminals together when live, & seem to have blown the circuit running the LED display. Has anyone any idea what sort of circuit would be required to monitor charge levels of a battery charger, as outlined above
Thanks
 

john monks

Mar 9, 2012
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What is the make and model of the battery charger?
It's hard for me to think that any 12v lead-acid battery charger would be damage by temporarily shorting the leads together. If you just bought it maybe you should return it.
 

steamthief

Jul 11, 2013
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12v Charger type

It's a Streetwise Master Charger Model SWBCH12 Hav had it for a few years
 

john monks

Mar 9, 2012
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Sorry but I can't find the schematic but from my experience most of these kind of voltage level detectors employ at least 1 IC
 

KrisBlueNZ

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Nov 28, 2011
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Does the LED display show the battery terminal voltage or simply the timed progress through the charge cycle?

Take it apart and take some photos of the board that drives the LEDs. Or if the LEDs are on the main board, take some photos of that.

What are the symptoms? I guess the LEDs don't illuminate. Does the charger charge batteries at all?
 

steamthief

Jul 11, 2013
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The 6 LEDs are connected to the mall circuit board, each one having a transistor & a bank of relays & some capacitors & diosdes around them.Since playing with it to get photos, on power up again, now both the <min> & <max> LEDs are lit.
The cahrger is delivering a 14+ volt supploy (heavy charge) to the battery, but the LEDs don't seem to be changing
 

KrisBlueNZ

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I guess you mean LM358P?

This is a very common dual op-amp that should be available from most electronic component shops for less than a quid. Or you can order it from Farnell / Element 14 or RS Components.

You can just replace it on suspicion, or take some photos of all the boards and we can try to help you fault-find it. Do you have a multimeter?
 

steamthief

Jul 11, 2013
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Multimeter

Hi, yes, I do have a multimeter (2 in fact), also a signal generator, (though I don't know how to use this)

I also have photos of the component side & the track-detail side, but this message system will not let me attach them.

Thanks
 

steamthief

Jul 11, 2013
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Yes, I have 2 multimeters, and a signal generator (which I don't know how to use!) I also have a photo of each side of the board, but can't seem to find a way to upload them into this message system
Thanks for info so far.
 

steamthief

Jul 11, 2013
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Sorry for duplicate messgae - first one didn't show up on the post board, so I thought it hadn't got through!
 

KrisBlueNZ

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You can upload the photos to a photo hosting web site and put links in your post.

Or you can upload them to the Electronics Point forum, as long as each picture is smaller than about 100 kilobytes. Click "Go Advanced", and click the paper clip icon. Browse and select the pictures, and click Upload. When they've uploaded, click Close at the bottom of the dialog box. They will appear as thumbnails in your post.
 

steamthief

Jul 11, 2013
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error

Sorry to be a nuisance, but that's the problem- in Go Advanced, the paperclip icon is not active, all the <open link> options are greyed-out & inactive.
 

KrisBlueNZ

Sadly passed away in 2015
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Ah, that's probably because you've only posted nine messages so far. The forums are set up so that you don't get certain privileges for a while.
 

(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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They all tell me it's an invalid album. Perhaps you have them marled as private?
 

KrisBlueNZ

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We'll need to know about the connections to the board.

There's a red and a black wire at the top, and at least three red wires at the bottom. Are there any other wires?

What do those wires connect to?

Measure the voltage between the red and black wires at the top.
 
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