Why are LED streetlight drivers usually having such low output voltage?

Why do all offtheshelf LED streetlight drivers have output voltages limited to below 60V?
This is very inconvenient and often means that one has to put the LEDs in parallel.
There is no requirement to have a SELV circuit at the top of a lamp post, so why the output voltage limitation?

Eg Meanwell HLG series LED streetlight driver….
https://www.meanwell.com/Upload/PDF/HLG-100/HLG-100-SPEC.PDF

If you have low current, maybe ELG series is better suited for your needs

Thankyou @Volker
Ive emailed Meanwwell about the " ELG-1200-C1050-DA " LED driver, as the datasheet doesnt fully explain its operation as below.

ELG-1200-C1050-DA " LED driver datasheet
https://www.meanwell.com/Upload/PDF/ELG-100-C/ELG-100-C-SPEC.PDF

As usual though, i doubt Meanwell will reply, i find no manufacturers do.

Please could you advise on the following technical points about the " ELG-1200-C1050-DA " LED driver....?
1...On 2nd page of datasheet it says "constant current region" is 48-95V....does that mean it is impossible to drive a LED load that has voltage less than 48V?
2.....On 2nd Page of datasheet it says that "Current Adj Range" is 525-1050mA. Does this mean that we can't adjust the current to less than 525mA?
3....Please can you recomend a DALI power supply that can be used with this power supply?
4....Please advise if the unit has electrolytic capacitors in it?
5......How much current can the DALI terminals sink? (as you know, DALI transmission is by pulling the DALI bus down with eg a transistor)

treez said:

1...On 2nd page of datasheet it says "constant current region" is 48-95V....does that mean it is impossible to drive a LED load that has voltage less than 48V?

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Yes, you would then use other ELG model with less power than this 100W model. ELG-100 is 100W nominal power.
There's also a 75W model: https://www.meanwell.com/webapp/product/search.aspx?prod=ELG-75-C

treez said:

2.....On 2nd Page of datasheet it says that "Current Adj Range" is 525-1050mA. Does this mean that we can't adjust the current to less than 525mA?

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Yes, the ...1050 is for 1050mA current. There are other models for other constant current values.

I can't comment on the other questions. DALI-wise, I think that's pretty much standardized.

Thankyou Volker, wow......that is pretty shocking that a LED driver can't be dimmed down significantly in that way...i mean, dimming down is a major way that a LED driver can save energy............say a streetlight at 3am in the morning would be wanted to operate at just 10% of the full power level, because few people are around at 3am.

You missed that these devices are usally dimmed by PWM rather than current reduction. If you go to page 4 of the data sheet, you'll find a detailed description of the dimming options.

Please could you advise on the following technical points...

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Many questions are answered in the datasheet. E.g. current adjustment is 50 - 100% for the A type, others have dimming down to 8% like the DALI version. Output voltage range is 2:1 for all ELG-C models, there's a large choice with different current/voltage rating available. Review the full Meanwell LED catalog.

The datasheet clearly states that the power supply transits to hick-up mode below 50% output voltage. I presume that's for rated output current setting. Designing a lighting application with less than 50% of rated output voltage (and respectively utilizing less than 50% rated power) doesn't seem reasonable.

All Meanwell switchers that I have ever seen are built with electrolytic caps. I would be rather surprised if ELG-C series isn't.

Like Volker I would expect standard DALI interface parameters with ELG-C.

The datasheet clearly states that the power supply transits to hick-up mode below 50% output voltage. I presume that's for rated output current setting. Designing a lighting application with less than 50% of rated output voltage (and respectively utilizing less than 50% rated power) doesn't seem reasonable.

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Thanks, I take it that you mean it would be tricky to design for say 10-100% of rated vout and still deliver full rated power at all those voltage levels. –Because we have designed an offline dimmable LED driver which can drive LEDs at any string voltage from 3V up to 80V….however, we can only do this at full power from 55V to 80V……going below that we have to dim down, but we can still easily do it. One problem is that our driver goes into CCM at low vout and the switching losses get large, so we have a look-up table in the micro and make it dim down to keep the driver in DCM at all vout levels.
I noted that the ELG-1200-C1050-DA driver seems to do PWM dimming. If it does then that suggests a downstream PWM stage after the stage that switches the post-PFC bus….so that sounds inefficient….but of course could just be a Buck where the fet is left permanently on when its not being used to do pwm dimming.

I also note in the datasheet that they say the driver lifetime is 50,000 hrs. If its using a longest life electrolytic (eg 3000 hrs at 105degc), then that would be 48000 hrs at 65degc….and so they must be keeping the internal ambient less than 65degc…that’s very good going for a totally enclosed unit, even if it is made of metal. It seems a bit far-fetched.

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I must admit i think the datasheet is quite unclear, particularly when you think that most people buying an off-the-shelf driver wont necessarily have much electronics qualifications or experience. OK, now seen where it says that can DALI dim down to 8%..and it appears to be in steps of 8% above that

treez said:

Thanks, I take it that you mean it would be tricky to design for say 10-100% of rated vout and still deliver full rated power at all those voltage levels.

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Do you understand the meaning of constant current LED driver? If you have constant current operation and reduce voltage, how can that ever be constant power?

treez said:

I noted that the ELG-1200-C1050-DA driver seems to do PWM dimming. If it does then that suggests a downstream PWM stage after the stage that switches the post-PFC bus….so that sounds inefficient….

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Not at all, PWM is widely used in LED dimming and rather efficient.

I'm not sure about the dimming method in this CC driver, if it's PWM or current reduction. So my post above might have been misleading regarding PWM. I know many people use Meanwell constant voltage supplies (HLG series) followed by external PWM dimming control.

Efficiency figures in the data sheet.

treez said:

I must admit i think the datasheet is quite unclear, particularly when you think that most people buying an off-the-shelf driver wont necessarily have much electronics qualifications or experience.

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I'm in another forum where they use Meanwell extensively (almost exclusively) for LED lighting, and you are the first and only person so far who complained about the data sheets.

treez said:

and it appears to be in steps of 8% above that

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What??? Have you ever used DALI?

thanks, yes we made a constant current led driver...and we can control the current into any led load attached, from 3v to 80v.....just that below 55v, this cannot be done at full power (60w).
Thanks, i see the DALI is starting from 8% and going upwards.

My impression is that from 525ma to 1050ma, its constant current (analog dimming)...below that and its pwm dimming of presumably the 525ma current.....quite a sizeable current to be switching on and off with pwm.
Wish they had stated the pwm dimming frequency...flicker and all that.

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thanks i appreciate that pwm dimming is efficient....but cascading a pwm stage below an upstream stage is not so efficient....the cascade bringing inefficiency

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Its a shame Meanwell and others' led streetlight drivers (outdoor led drivers) can't be searched on google so that the full range available on the entire market can be seen.
Googling "Buy led streetlight driver" reveals pretty much nothing.
Digikey dont categorise "led streetlight drivers"...or "outdoor led drivers"

I am not in the streetlighting business, but it seems that TCI also have some products:
https://win.tcisaronno.com/downloads/?IDnode=3488&field=docs