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Aldi 12V Battery Charger Repair - where to start ?

Shaky

Mar 4, 2022
15
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Mar 4, 2022
Messages
15
Just wondering.......is it worth trying to figure out what's gone in the battery ? Surely the actual cells will still be OK ?

Just thinking out loud :D
 

Martaine2005

May 12, 2015
4,293
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May 12, 2015
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4,293
Hi, curry was one of my best restaurant style curries ever. I got the base gravy and tomato bases spiced perfectly. Even the onion Bhajis were superb.
Back to your problem. The batteries won’t be dead, there is a frowned upon trick that you didn’t hear from me. (Use a good battery and connect a wire from negative to negative of bad battery. Do the same with the positive of one battery. quickly touch the other positive. Do this a couple of times. There may be a small spark initially. That should work to trick the circuit. If not, repeat but leave both connected for 20 seconds or so). This works for my tool batteries and I will never admit to telling you! You do so at your own risk..
Now, your transistor. Did it have a plastic insulating shim between it and the heat sink?.
I say this because short circuits normally blow the fuse and at least we know we’re dealing with a short.
I’m sorry to say that now, you’ll have to re-check all the first tests of components. Won’t take long, and is good to build experience along with patience! Keep me updated.

Martin
 

Shaky

Mar 4, 2022
15
Joined
Mar 4, 2022
Messages
15
Curry sounded good ;). Just finished my lamb roast myself - lol. I've done that battery trick a while ago with some nicads, I didn't realise it still applied with lions. I'll give it a go with the remaining good battery and report back.

I will say though that I stripped the control pcb off one of the battery packs and tested the cell voltages. All three of the Samsung 18650 cells tested just over or just under 1V and my (admittedly lacking) knowledge says that if they're under 2.5V they need chucking. I haven't done anything with the last one the charger took out so I'll see if your trick works with that one - fingers crossed :p.

Re: the charger, I think I it is beyond salvation now coz I did notice another SMD component near the mosfet had blown. I checked continuity and one side of it was in contact with the mains voltage so no wonder it blew - lol.
 

Martaine2005

May 12, 2015
4,293
Joined
May 12, 2015
Messages
4,293
I think an experienced member here could help you in no time. I can help to a degree but SMPS for me are quite complex individuals. It depends on you. I don’t let much beat me and refer to this forum if it does. But remember, you have the circuit in your hands, we have photos and text.
We rely on you to give us all the information.
Don’t bin it, wait until another member chimes in.


Martin
 

Shaky

Mar 4, 2022
15
Joined
Mar 4, 2022
Messages
15
Well I've got nowt to lose Martin so I don't mind having a go at 'owt. Re the battery packs, did "that" trick ;) and it appeared to work as each cell suddenly showed just about 3V and connected, just over 9.5V. Put the controller back in cct however and same problem as before. Interestingly enough, when I measure the full pack with my dmm, it instantly shows about 10V but quickly drops to about 5.5-6V and holds there. Using my old Analogue BT tester, it shows nothing, even on the 5V scale so I'm guessing that will be down to internal resistances between the meters ?

Atm I'm using my Parkside Dremel-type tool charger on the remaining good battery so at least I've got summat to use, if a bit slow. The duff battery packs just refuse point-blank to charge but I might try to rig up summat on a bit of veroboard (sp?) to see if I can use the good controller out-board so to speak and allow the other batteries to charge.

I'm actually enjoying faffing about with this, shows what a sad life I lead :D:D
 

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