My battery charger seems to be faulty - cutting out as soon as it is plugged in, with a flash coming regularly every couple of seconds (from a fuse-like bulb located on top of the coil (cover off)). It's a good enough charger when it's working, with boost/fast start as well as trickle; it also has an automatic cut-out to prevent over-charging. With the cover off, there does not seem to be any obvious short. Any ideas?
Long distance diagnosis of this sort is impossible without greater information ... What make/model is the charger? When was the last time you used it and "knew" it to work? Why do you have the top off and what leads you to think its faulty? Is not the battery screwed perhaps, leading to the charger shutting down due to overcurrent?
It's a "GUNSON's Rapid Start Heavy Duty Starting Charger suitable for all 12v Lead/Acid batteries Start: 47A RMS 30A DC @ 9v (10-15 secs) Boost: 26A RMS 17A DC @ 12v (10 minutes) Fast: 15A RMS 10A DC @ 12v (continuous)
Recommended minimum battery capacity: 30Ah. Full overload protection, Reverse polarity protection. Thermal cut-out protection."
I last used it at Christmas to quick start my car battery; it worked fine. My son put it on an old (12v) battery he had been using for an electric fence for his chickens (does not need full 12 volts). He noted it flashing a making a pulsing clicking sound. I then tried it on a working forklift battery with the same result. I took the top off to check for any obvious shorting or dampness. I have never noticed it flashing prior to this. Needless to say, I can't find the instructions anywhere.
post the circuit diagram for us, get ready with the multimeter, and we'll see if we can take you through it.
NT
I repaired one of these last month ( friend who lives on a barge ! )
Inside at the front is a printed circuit board with a large relay underneath it, yes ? towards one corner ( same side as the start/boost switch towards rear of pcb ) there is a small 10uF 25v electrolytic capacitor which will be dried up and open circuit. This causes the relay to quickly pulse on/off instead of coming on until the battery reaches a high enough voltage. Also the green 12v bulb on the front panel which is lit all the time a battery is connected had gone ( spare xmas tree bulb fitted fine ).
Sorry, I've no circuit diagram but I've posted some photos here:
Regards
seconds
Certainly brought a smile to my face
Glad to hear it NT, which is more than can be said for my son's chickens - they got a visit from the fox last night - left nothing but a few feathers! I'd be grateful for any suggestions (about the charger, not the fox!). I have the technology (ie multimeter) but not the knowledge (self-evident!).
Regards
fox!).
Well I made it, but I guess I wasnt clear enough.
Otherwise youre outta luck.
NT
Hi,
Does it cut out even when no battery is connected?
If so switch off and try disconnecting one of the wires from the secondary (non mains) side of the transformer that go to the black box on the heatsink.
Then does it still cut out?
If so it's likely to be a short in the transformer which is probably not worth replacing, if not it's likely to be the black box (bridge rectifier) on the heatsink which should be fairly cheap and easy to replace.
cheers, Pete.
Thanks Pete,
It does cut out when no battery is connected but doesn't when I disconnect either wire going to the black box from the transformer. So, hopefully, a new bridge rectifier will solve my problem. Is this the sort of thing I can get at Maplins - I've had a look but none has the same markings as mine: AC BR354 A 38 I'd be grateful for any pointers on this one. Many thanks for your help thus far.
Regards, Brian
Any 10A 40V or better bridge rectifier will work.
Often found on e-bay.
Looks like a 'BR354' is a 35A 400V spec:
Maplins do a 'KBPC3504' which has the same spec, for £1.29:
Looking at a data sheet it's the same size with the same type terminals too:
When fitting the new one be sure the AC terminals marked '~' are connected to either lead from the transformer, and the DC terminals '+'/'-' are connected to the appropriate outputs of the charger.
If you take the old one off and measure the resistance each way across adjacent terminals, you should find that 3 of the 4 diodes only show resistance one way, but one doesn't show resistance either way which proves it's defective.
cheers, Pete.
Pete,
Spot on in every respect. You're a real Sherlock! Many thanks and best wishes,
Brian
replying to wb, john O. wrote: I have same problem. there is a short cct across croc clips which shorts the battery out. instantly the leads current is enough to operate the bi-metalic cut-out. which then flips in and out. Think the output rectifier is fauly, (only half wave?) but can find no diagram to replace it.
Try a functional user interface:
A circuit diagram would help, or even a clear pic of the circuit board.
NT
original posted on February 15, 2005, 12:55 am
I think he might have bought a new one by now.
How do you get the date?
Try using a computer made in the current century. If you can afford one.
He posted it about 2 hours ago.
NT
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