Challenge of the Day: from halogen transformer to battery charger

It's silly challenge of the day time. I'm wondering if discarded halogen lamp SMPSU transformers could become car battery chargers.

Thoughts so far.... The main question is what can these units be counted on to protect themselves against. Overcurrent & short are the main questions. They will come across these IRL when driving halogens. How would they respond if the output were bridge rectified and fed straight to a battery?

Slow diodes on a high frequency output, how will that work?

I know it sounds like a daft idea, but not entirely. I might have a use for a lot of them if they survive, stay safe and function somewhat. I'm not considering adding any smarts.

NT

Reply to
tabbypurr
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It depends.

Rick C.

Reply to
gnuarm.deletethisbit

I've concluded that the only way is to try them. They should be protected against overload & short, but making sure would be needed. Also would need to check they can tolerate the unexpected nature of the load.

NT

Reply to
tabbypurr

gen lamp SMPSU transformers could become car battery chargers.

emselves against. Overcurrent & short are the main questions. They will com e across these IRL when driving halogens.

raight to a battery?

se for a lot of them if they survive, stay safe and function somewhat. I'm not considering adding any smarts.

against overload & short, but making sure would be needed. Also would need to check they can tolerate the unexpected nature of the load.

How is it that you think they will do a good job of charging the battery? I'd be more worried about that. It is easy enough to add a current limit t o the output, but to make a PSU into a battery charger is about the same as starting from scratch. Do you know the voltage output? You said you want ed to charge a car battery. I guess that won't be too hard to do, but it i s still a bit of work in terms of added circuitry.

Rick C.

Reply to
gnuarm.deletethisbit

logen lamp SMPSU transformers could become car battery chargers.

themselves against. Overcurrent & short are the main questions. They will c ome across these IRL when driving halogens.

straight to a battery?

use for a lot of them if they survive, stay safe and function somewhat. I' m not considering adding any smarts.

ed against overload & short, but making sure would be needed. Also would ne ed to check they can tolerate the unexpected nature of the load.

I'd be more worried about that. It is easy enough to add a current limit to the output, but to make a PSU into a battery charger is about the same as starting from scratch. Do you know the voltage output? You said you wa nted to charge a car battery. I guess that won't be too hard to do, but it is still a bit of work in terms of added circuitry.

It's sod all work, add a BR & fuse & it's done. I didn't say it'd be a good charger, it won't, but it will do the job if the psu can cope with the bat tery's interest in current. That 'if' is the big question, not from a safet y pov but continuing to function rather than shutting down. Soon I'll try a couple & see.

The output is 11.5v ac, but the waveform is so far unknown. That will have a significant effect on things. Frequency is high, how diodes will react to that is also not yet known.

NT

Reply to
tabbypurr

od charger, it won't, but it will do the job if the psu can cope with the b attery's interest in current. That 'if' is the big question, not from a saf ety pov but continuing to function rather than shutting down. Soon I'll try a couple & see.

e a significant effect on things. Frequency is high, how diodes will react to that is also not yet known.

** Typial output ( burst pattern ) waveform is shown at 1:34 into this U-tu be.

At 1:40 the HF switching wave is shown.

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Although specified at 11.5V rms output, the max output will be significantl y higher - maybe 15 to 18 volts peak, more than compensating the diode dro ps in an external bridge.

You may need to use fast diodes too.

.... Phil

Reply to
Phil Allison

good charger, it won't, but it will do the job if the psu can cope with the battery's interest in current. That 'if' is the big question, not from a s afety pov but continuing to function rather than shutting down. Soon I'll t ry a couple & see.

ave a significant effect on things. Frequency is high, how diodes will reac t to that is also not yet known.

tube.

tly higher - maybe 15 to 18 volts peak, more than compensating the diode d rops in an external bridge.

that's quite informative, thanks. With a near square wave output that's only going to be 11.5 or 12v peak tho ugh. Not enough.

NT

Reply to
tabbypurr

a good charger, it won't, but it will do the job if the psu can cope with t he battery's interest in current. That 'if' is the big question, not from a safety pov but continuing to function rather than shutting down. Soon I'll try a couple & see.

have a significant effect on things. Frequency is high, how diodes will re act to that is also not yet known.

U-tube.

antly higher - maybe 15 to 18 volts peak, more than compensating the diode drops in an external bridge.

** More informative than you think.

** You have misunderstood the scope traces.

The nominal 11.5V output consists of a high frequency, rectangular wave 100 % MODULATED at double supply frequency - because the AC supply to the oscil lator is rectified but NOT filtered !!.

The first scope trace shows just one supply cycle with oscillation stating at about half supply voltage, rising to a maximum at supply peak and then f alling until oscillation stops. The amplitude variations are smoothed out b y the thermal inertia of the halogen lamp filament.

The peak value is much higher than 11.5V and will be enough to charge a 12V car battery - same a using a conventional transformer and bridge rectifier does.

.... Phil

Reply to
Phil Allison

e a good charger, it won't, but it will do the job if the psu can cope with the battery's interest in current. That 'if' is the big question, not from a safety pov but continuing to function rather than shutting down. Soon I' ll try a couple & see.

ll have a significant effect on things. Frequency is high, how diodes will react to that is also not yet known.

s U-tube.

icantly higher - maybe 15 to 18 volts peak, more than compensating the dio de drops in an external bridge.

00% MODULATED at double supply frequency - because the AC supply to the osc illator is rectified but NOT filtered !!.

g at about half supply voltage, rising to a maximum at supply peak and then falling until oscillation stops. The amplitude variations are smoothed out by the thermal inertia of the halogen lamp filament.

2V car battery - same a using a conventional transformer and bridge rectifi er does.

yes, I hadn't thought that through for some reason. That makes life easier. 11.5x1.414= 16.26v. -2v for diode drops makes about 14.2v peak loaded, n ot bad for a dumb lead acid charger.

NT

Reply to
tabbypurr

cted against overload & short, but making sure would be needed. Also would need to check they can tolerate the unexpected nature of the load.

y? I'd be more worried about that. It is easy enough to add a current lim it to the output, but to make a PSU into a battery charger is about the sam e as starting from scratch. Do you know the voltage output? You said you wanted to charge a car battery. I guess that won't be too hard to do, but it is still a bit of work in terms of added circuitry.

od charger, it won't, but it will do the job if the psu can cope with the b attery's interest in current. That 'if' is the big question, not from a saf ety pov but continuing to function rather than shutting down. Soon I'll try a couple & see.

Can't say, I have no idea what a BR is. But if your charger doesn't do a p roper job of charging a battery it is pretty pointless and can actually dam age the battery, so worse than just poor.

e a significant effect on things. Frequency is high, how diodes will react to that is also not yet known.

AC??? So when you say transformer, you mean a thing with coils and a metal core? The industry calls all devices for powering lighting transformers o r ballasts even if they are constant voltage power supplies or similar. I thought you referred to it as a SMPS but I don't get why it would be AC and a SMPS.

Rick C.

Reply to
gnuarm.deletethisbit

tected against overload & short, but making sure would be needed. Also woul d need to check they can tolerate the unexpected nature of the load.

ery? I'd be more worried about that. It is easy enough to add a current l imit to the output, but to make a PSU into a battery charger is about the s ame as starting from scratch. Do you know the voltage output? You said yo u wanted to charge a car battery. I guess that won't be too hard to do, bu t it is still a bit of work in terms of added circuitry.

good charger, it won't, but it will do the job if the psu can cope with the battery's interest in current. That 'if' is the big question, not from a s afety pov but continuing to function rather than shutting down. Soon I'll t ry a couple & see.

proper job of charging a battery it is pretty pointless and can actually d amage the battery, so worse than just poor.

ave a significant effect on things. Frequency is high, how diodes will reac t to that is also not yet known.

al core? The industry calls all devices for powering lighting transformers or ballasts even if they are constant voltage power supplies or similar. I thought you referred to it as a SMPS but I don't get why it would be AC a nd a SMPS.

saves a rectifier and the lamp doesn't care

Reply to
Lasse Langwadt Christensen

tected against overload & short, but making sure would be needed. Also woul d need to check they can tolerate the unexpected nature of the load.

ery? I'd be more worried about that. It is easy enough to add a current l imit to the output, but to make a PSU into a battery charger is about the s ame as starting from scratch. Do you know the voltage output? You said yo u wanted to charge a car battery. I guess that won't be too hard to do, bu t it is still a bit of work in terms of added circuitry.

good charger, it won't, but it will do the job if the psu can cope with the battery's interest in current. That 'if' is the big question, not from a s afety pov but continuing to function rather than shutting down. Soon I'll t ry a couple & see.

proper job of charging a battery it is pretty pointless and can actually d amage the battery, so worse than just poor.

its functionality is as wanted.

ave a significant effect on things. Frequency is high, how diodes will reac t to that is also not yet known.

al core? The industry calls all devices for powering lighting transformers or ballasts even if they are constant voltage power supplies or similar. I thought you referred to it as a SMPS but I don't get why it would be AC a nd a SMPS.

I'm not clear why you're confused. Halogen lighting transformers are widesp read & well known SMPSUs with ac output. Phil posted enough info for anyone to understand them.

NT

Reply to
tabbypurr

A battery is not a halogen lamp. Your 'challenge' is dumb.

Reply to
bloggs.fredbloggs.fred

lol. I accept that you've no awareness what the point of it is.

Reply to
tabbypurr

rotected against overload & short, but making sure would be needed. Also wo uld need to check they can tolerate the unexpected nature of the load.

ttery? I'd be more worried about that. It is easy enough to add a current limit to the output, but to make a PSU into a battery charger is about the same as starting from scratch. Do you know the voltage output? You said you wanted to charge a car battery. I guess that won't be too hard to do, but it is still a bit of work in terms of added circuitry.

a good charger, it won't, but it will do the job if the psu can cope with t he battery's interest in current. That 'if' is the big question, not from a safety pov but continuing to function rather than shutting down. Soon I'll try a couple & see.

a proper job of charging a battery it is pretty pointless and can actually damage the battery, so worse than just poor.

Huh? It's functionality is not the same as a battery charger, not even clo se.

So you don't know what a BR is either?

have a significant effect on things. Frequency is high, how diodes will re act to that is also not yet known.

etal core? The industry calls all devices for powering lighting transforme rs or ballasts even if they are constant voltage power supplies or similar. I thought you referred to it as a SMPS but I don't get why it would be AC and a SMPS.

spread & well known SMPSUs with ac output. Phil posted enough info for anyo ne to understand them.

Yeah, I hadn't seen that when I posted. I guess I was thinking of the LED PSUs that they call transformers or ballasts. It makes sense an incandesce nt supply would output AC.

Rick C.

Reply to
gnuarm.deletethisbit

:

e:

protected against overload & short, but making sure would be needed. Also would need to check they can tolerate the unexpected nature of the load.

battery? I'd be more worried about that. It is easy enough to add a curre nt limit to the output, but to make a PSU into a battery charger is about t he same as starting from scratch. Do you know the voltage output? You sai d you wanted to charge a car battery. I guess that won't be too hard to do , but it is still a bit of work in terms of added circuitry.

e a good charger, it won't, but it will do the job if the psu can cope with the battery's interest in current. That 'if' is the big question, not from a safety pov but continuing to function rather than shutting down. Soon I' ll try a couple & see.

do a proper job of charging a battery it is pretty pointless and can actual ly damage the battery, so worse than just poor.

lose.

it's identical

it's you that doesn't know what one is, remember? I mentioned using one, so presumably, at least if you're at all sensible, I do. If you don't understand what a BR is when it's the only thing that takes ac and charges a battery with it then you're either not an EE or are a silly troll.

NT

Reply to
tabbypurr

te:

ote:

be protected against overload & short, but making sure would be needed. Als o would need to check they can tolerate the unexpected nature of the load.

e battery? I'd be more worried about that. It is easy enough to add a cur rent limit to the output, but to make a PSU into a battery charger is about the same as starting from scratch. Do you know the voltage output? You s aid you wanted to charge a car battery. I guess that won't be too hard to do, but it is still a bit of work in terms of added circuitry.

be a good charger, it won't, but it will do the job if the psu can cope wi th the battery's interest in current. That 'if' is the big question, not fr om a safety pov but continuing to function rather than shutting down. Soon I'll try a couple & see.

t do a proper job of charging a battery it is pretty pointless and can actu ally damage the battery, so worse than just poor.

close.

so presumably, at least if you're at all sensible, I do.

ac and charges a battery with it then you're either not an EE or are a sill y troll.

I'm not going to argue silly word games with you. If you know what a BR is and would like to share, then please do. Otherwise there is no point havi ng a discussion with you. I never said I didn't "understand" a BR, I said I don't know what it is. What does BR stand for? EAOWSA - Engineers are o bsessed with silly abbreviations.

Rick C.

Reply to
gnuarm.deletethisbit

:

rote:

d be protected against overload & short, but making sure would be needed. A lso would need to check they can tolerate the unexpected nature of the load .

the battery? I'd be more worried about that. It is easy enough to add a c urrent limit to the output, but to make a PSU into a battery charger is abo ut the same as starting from scratch. Do you know the voltage output? You said you wanted to charge a car battery. I guess that won't be too hard t o do, but it is still a bit of work in terms of added circuitry.

'd be a good charger, it won't, but it will do the job if the psu can cope with the battery's interest in current. That 'if' is the big question, not from a safety pov but continuing to function rather than shutting down. Soo n I'll try a couple & see.

n't do a proper job of charging a battery it is pretty pointless and can ac tually damage the battery, so worse than just poor.

en close.

, so presumably, at least if you're at all sensible, I do.

s ac and charges a battery with it then you're either not an EE or are a si lly troll.

is and would like to share, then please do. Otherwise there is no point ha ving a discussion with you. I never said I didn't "understand" a BR, I sai d I don't know what it is. What does BR stand for? EAOWSA - Engineers are obsessed with silly abbreviations.

bridge rectifier. It turns ac into dc. The charger wouldn't work without a rectifier of some sort.

NT

Reply to
tabbypurr

te:

uld be protected against overload & short, but making sure would be needed. Also would need to check they can tolerate the unexpected nature of the lo ad.

g the battery? I'd be more worried about that. It is easy enough to add a current limit to the output, but to make a PSU into a battery charger is a bout the same as starting from scratch. Do you know the voltage output? Y ou said you wanted to charge a car battery. I guess that won't be too hard to do, but it is still a bit of work in terms of added circuitry.

it'd be a good charger, it won't, but it will do the job if the psu can cop e with the battery's interest in current. That 'if' is the big question, no t from a safety pov but continuing to function rather than shutting down. S oon I'll try a couple & see.

esn't do a proper job of charging a battery it is pretty pointless and can actually damage the battery, so worse than just poor.

even close.

ne, so presumably, at least if you're at all sensible, I do.

kes ac and charges a battery with it then you're either not an EE or are a silly troll.

R is and would like to share, then please do. Otherwise there is no point having a discussion with you. I never said I didn't "understand" a BR, I s aid I don't know what it is. What does BR stand for? EAOWSA - Engineers a re obsessed with silly abbreviations.

a rectifier of some sort.

That's all you needed to do, use words instead of abbreviating every simple term.

Rick C.

Reply to
gnuarm.deletethisbit

:

rote:

hould be protected against overload & short, but making sure would be neede d. Also would need to check they can tolerate the unexpected nature of the load.

ing the battery? I'd be more worried about that. It is easy enough to add a current limit to the output, but to make a PSU into a battery charger is about the same as starting from scratch. Do you know the voltage output? You said you wanted to charge a car battery. I guess that won't be too ha rd to do, but it is still a bit of work in terms of added circuitry.

y it'd be a good charger, it won't, but it will do the job if the psu can c ope with the battery's interest in current. That 'if' is the big question, not from a safety pov but continuing to function rather than shutting down. Soon I'll try a couple & see.

doesn't do a proper job of charging a battery it is pretty pointless and ca n actually damage the battery, so worse than just poor.

t even close.

one, so presumably, at least if you're at all sensible, I do.

takes ac and charges a battery with it then you're either not an EE or are a silly troll.

BR is and would like to share, then please do. Otherwise there is no poin t having a discussion with you. I never said I didn't "understand" a BR, I said I don't know what it is. What does BR stand for? EAOWSA - Engineers are obsessed with silly abbreviations.

t a rectifier of some sort.

le term.

I've not met an EE before that didn't know what a BR was.

NT

Reply to
tabbypurr

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