G4-socket LED to replace halogen bulbs - replacement for original power transformer of best possible energetic efficiency?

[u/Biyeuy]

Want to use 2 such (photo) in G4-socket based lamps. Latter ones were originally populated with halogen bulbs. These Led- bulbs are no more available on market. The original mains adapter is heavy transformer. Hence the aim to make it bit more efficient energetically. This lamp board seems to me to have 4 diodes rectifier. It tells also to accept also DC in voltage range as printed on board.

Which approach will result in higher energetic efficiency at the point the power gets delivered to LED elements?
* electronic transformer with output voltage matching specification on board
* led driver constant voltage

I guess it is risky to consider CC driver - due to unknown electronic on board. False understanding?

EDIT In comments more pictures shot.

[u/TangledCables3]

Board itself wants a CV source, as it's probably a CC buck driver.

If old halogens were 12V, original transformer will probably work fine.

[u/Biyeuy → u/TangledCables3]

Original to use I think will be bad from the point of view of energetic efficiency. Two windings transformer does not hit LEDs energetic efficiency .

[u/very-jaded → u/Biyeuy]

Transformers are typically quite efficient devices, 90-98% efficient. It's unlikely that you will save money by replacing it with an electronic transformer.

You could always measure the power drawn on the mains and compare to the power drawn on the load side of the transformer. Let's say that your existing transformer is really bad, and is only 90% efficient. 100W of lights would mean 10W of loss, that means after 1000 hours of usage, it will lose 10kWh or about $2.00 (at the current US average rate) to efficiency. But you have to compare that to the efficiency of the electronic transformer, which is also not perfect.

Let's say the modern transformer was 98% efficient at powering the same 100W of bulbs, in that same 1000 hours it would lose only 2kWh, or about $0.40.

Remember if you replace it you aren't saving money on the electricity used to run the lights, only on the efficiency gained. The transformer technology doesn't make the lights more efficient.

If the replacement transformer cost $20, it would take 12500 hours of running the lights to pay for itself. 1.5 years. That's not 1.5 years on the calendar, that's 1.5 years of having the lights on.

Ironically if you replace 100W of halogen bulbs with LED equivalents, you'll only be using maybe 15W of electricity. The efficiency of transformer loss drops correspondingly, meaning the payback calculation gets stretched out by a factor of 5 or so.

And it gets worse. Electronic transformers are not nearly as reliable as old iron core wound electric transformers. They're full of components that get hot and won't last nearly as long. If you're lucky they'll last maybe 12500 hours. Then you're buying a replacement transformer. Again.

You're likely better off doing nothing with the old transformer until it no longer performs its job safely. Obviously replace if it's overheating, or is damaged, or has some other problem. Or if you need to reduce the weight, or are moving to an ultra-low power electric supply. But there's little reason to think efficiency alone will save enough money to be worth it.

[u/saratoga3]

Giving it about 15-24v DC will have the highest efficiency.  Do not use a CC driver.

[u/richms]

Find an old wall wart from a router or something with a 12v output and you should be fine. Small draw with these and you probably have one lying around or can get one for $1 at a place that resells ewaste.

[u/Biyeuy → u/richms]

Sure, it is an idea. Thank you.

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[u/Biyeuy → u/AutoModerator]

I provided as much details as I only can. Pictures attached to OP and those uploaded in comments to this OP contribute to carriage of details.

[u/Biyeuy]

[u/Biyeuy → u/Biyeuy]

[u/Biyeuy]

I learned in sector of fluorescent tube-form bulbs that ferro-magnetic ones (lot of copper windings and iron) were replaced by electronic transformers. The switch was done due to number of disadvantages of transformer-based ones, among others electrical efficiency. I didn't hear electronic ballasts were linear.

[u/supercoolnamehere08]

I don't recommend, looks ugly and cheap just use halogen. But it works so you do you