Hello. I considering to retrofit 500w r7s t3 halogen floodlights.  Are the r7s LED lamps any good for retrofitting halogen floodlights? The reason why I want to use LED is because re-lamping the halogen lamps 15 feet in the air is kind of a pain. Normally I wouldn't go with LED, but I'd like to know if these r7s LEDs are any good or not.

What wattage are you talking about? Last time the linear halogen retrofit was discussed, light output was just a joke, compared to a real lamp.

For instance a 30w LED. Are they any good at all?

I looked into 500w LED retrofits a few years ago for the lights I had at work . Nothing I found was even half as bright as the halogen ! I did buy one of the LED work lights a few years ago that is as bright as the halogen floods :  https://www.lighting-gallery.net/gallery/displayimage.php?album=5209&pos=26&pid=161339

For instance a 30w LED. Are they any good at all?

I doubt reliable temperature control is possible for 30W LED retrofit lamp in RX7 volume. So either they are lying about the power and it will be dim, or it certainly will run very hot and do not last long.

Good 500W halogen is probably around 15 lm/W, so ~7500lumens. To be as bright, an average 120lm/W retrofit should be about 63W, not realistic.

If you are ready to replace your entire floodlights to LED ones, okay, the choice is enormous. Cheaper ones are just the boards with LEDs, no optical control, so are glare bombs. Also cheaper floodlights just use current-limiting diodes for ballasting, no proper power supplies, so they flicker wildly.
 

I think r7s double-ended CMH is an option as they seem reasonably priced. I have plenty of 150w and 100w PSMH ballasts. As for LED, I think there is really no LED that can fit in an r7s form factor and be as bright as a 500w halogen.

Yeah MH lamp is a good option but look carefully if it will fit. There are two RX7 sizes with slightly different lengths for MH, RX7s and RX7s-24 , 70 and 150W respectively. And the ends of MH lamp are wider and sometimes do not fit well into halogen lampholders. Also, in theory, MH lampholders should have better voltage ratings to withstand ignitor pulses.

I remember doing this many many years ago, may be in the beginning of 2000s or even earlier, when first MH lamps started to appear. I got my first lamp, quartz Radium 70W MH. I did not have nor a suitable luminaire for it nor a suitable ballast and ignitor. So I got a cheap 500W floodlight, was lucky as the lamp fit well, also emulated 70W ballast with two 40W fluorescent chokes (a bit of underdrive, about -10%) and tried to create a working ignitor (tough) using old Soviet SCRs and diy transformer

   

The MH conversion would make sense, but only in case the lantern is used for long ON time per start and if we were in the 2000's. But not 2023, when all HIDs are about to leave the market (even being banned at many places around the world).

40..60W of LEDs is practically impossible to cool within anything similar to the linear halogen format. Or it will be one of the crazy creations that "fits the Rx7 and emits similar amount of light" (well, lets assume the later is true), but optically were anything similar to that linear light source the halogen lanterns are designed for. Regardless if it were the CFLs, or today the LEDs.
If it fits optically, it will be in the 1000lm ballpark if really a good one, not the 7500lm the halogen had.

So really the only options today are either keep using the halogens (you may go to the 280W IRC type - that is supposed to be equivalent to the "classic" 500W halogen), or really replace the whole fixture for some decent LED type.

To get better reliability, you may buy one step higher power rating that you need (e.g. a 15klm one), but replace the LED driver for a lower power one (same LED voltage range, but lower current), or if the original used two equal sections (2x7500lm) with two drivers, you connect both sections in parallel and feed from a single driver. Is may cost a bit extra, but you get quite a boost in reliability (the LEDs use to operate at the edge to get the required lifetime, lowering the LED loading extends their life significantly, as well as it increases their efficacy a bit too), yet with common parts.

Well, very fortunate for us, no one is physically able to 'cancel' a MH lamp and its ballast once you have them in you hands. Whatever 'bans' or 'obsolescences' are invented. Unlike modern cloud crap that goes dead if the parent company gets belly up. So getting a hefty box of spares solves all the problems You can continue to use your favorite lamps while you are still happy with the color and efficacy, whatever they said...

Yeah that's the advantage of HID, if you're concerned about long term use for a small installation, just buy a spare case of lamps and a couple ballasts and they should last a pretty long while. A lot of IOT lighting is rendered useless once the parent company goes under or if they decided to pull support for the service.

Well, very fortunate for us, no one is physically able to 'cancel' a MH lamp and its ballast once you have them in you hands. Whatever 'bans' or 'obsolescences' are invented. Unlike modern cloud crap that goes dead if the parent company gets belly up. So getting a hefty box of spares solves all the problems You can continue to use your favorite lamps while you are still happy with the color and efficacy, whatever they said...

Yeah smart lighting is useless if the software is isn't supported. I wonder if Phillips Hue may become obsolete at some point in time.