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IllIlIlllIll
EliteData
Premium
join:2003-07-06
Hampton Bays, NY
kudos:7

Xfmer vs SMPS

My old school days seem to have changed from what i used know to what is now.
After some thorough testing, i believe the 12V 70A SMPS is a winner.
Not just for price and weight either.
Whats your opinion ? What would you get if you needed a 12V supply ?

12V 70A Xfmer
12V 70A SMPS
--
Suffolk County NY Police Feed - »www.scpdny.com
PS3 Gaming Feed - »www.livestream.com/elitedata

TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel
Yeah, these days an SMPS is the obvious choice for any high-power regulated power supply application.

That linear Astron weights an absolute ton, wastes a lot of power, and is only rated for 57A continuous though my experience with these Astron units is that at their rated continuous load, they get HOT enough to be a concern. The passive heatsinking on them just isn't sufficient.

That being said, SMPS can have their own problems. A poorly designed SMPS can produce RFI which can be a nightmare if you're using it to power radio equipment. Also, cheap SMPS may be underrated and not capable of the continuous load they are rated at.

So my suggestion is to thoroughly research the SMPS and company before buying. A good quality SMPS should produce negligible RFI, be capable of easily supporting its rated load, and will be much smaller, lighter, and much more efficient.

A good source of quality SMPS for a decent price, believe it or not, is eBay, where you can find used commercial/industrial grade SMPS from well-known brands such as Astec/Emerson, Lambda, Vicor, and others. The only downside is that most such power supplies have quite noisy fans, although they are designed to be operated in high ambient temperature environments, so you can usually safely replace the fan with a slightly quieter one.

I myself have a 12V 50A Astec MVP series I got for about $50. It has excellent RFI filtering, rock solid line/load regulation, and can run at 100% load for an indefinite amount of time.


IllIlIlllIll
EliteData
Premium
join:2003-07-06
Hampton Bays, NY
kudos:7
said by TheMG:

Yeah, these days an SMPS is the obvious choice for any high-power regulated power supply application.

That linear Astron weights an absolute ton, wastes a lot of power, and is only rated for 57A continuous though my experience with these Astron units is that at their rated continuous load, they get HOT enough to be a concern. The passive heatsinking on them just isn't sufficient.

That being said, SMPS can have their own problems. A poorly designed SMPS can produce RFI which can be a nightmare if you're using it to power radio equipment. Also, cheap SMPS may be underrated and not capable of the continuous load they are rated at.

So my suggestion is to thoroughly research the SMPS and company before buying. A good quality SMPS should produce negligible RFI, be capable of easily supporting its rated load, and will be much smaller, lighter, and much more efficient.

A good source of quality SMPS for a decent price, believe it or not, is eBay, where you can find used commercial/industrial grade SMPS from well-known brands such as Astec/Emerson, Lambda, Vicor, and others. The only downside is that most such power supplies have quite noisy fans, although they are designed to be operated in high ambient temperature environments, so you can usually safely replace the fan with a slightly quieter one.

I myself have a 12V 50A Astec MVP series I got for about $50. It has excellent RFI filtering, rock solid line/load regulation, and can run at 100% load for an indefinite amount of time.

thanks for that information.
i figured it would come down to reliability & RFI noise.
i noticed that operating the Astron at 40A continuous, it got heated alot, heatsink and xfmer, while the SMPS at 40A just got warm.
the SMPS had very little variance in VDC when switching from different levels of current load while the xfmer had more VDC variance.
i purchased the 70A SMPS as a replacement for the 50A 12VDC xfmer in a large tow trailer (Sunline) and "burn" tested it (without the battery) with every 12 volt device operating (except the heat, the fridge operates on 110VAC or LP gas) drawing approximately 40A continuous for about 2 hours and the SMPS was just warm with the fan operating very low (thermally controlled).
not having done research prior to purchase, this seems to be a reliable and decent unit.
using a small battery operated am/fm radio and tuning around the AM band, i didnt detect any major RFI except when placing the radio very close to the SMPS although the RFI may be @ a different freq.
all in all, seems to be a good choice.
i may end up purchasing the 90A version to replace the 70A Astron for my hobby stuff.
--
Suffolk County NY Police Feed - »www.scpdny.com
PS3 Gaming Feed - »www.livestream.com/elitedata

TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel
Ah, so you already have both units.

If you don't mind (and assuming there are no "warranty void if removed" stickers, would you be able to take the cover off on that SMPS and snap some pictures of the insides? The presence or absence of certain components and the component choices can be an indicator of how much thought went into the design and quality of the unit.

If it looks decent I might pick one up and put it through its paces testing it for regulation, ripple, RFI, etc. That's actually a very good price for a 70A 12V SMPS assuming it is reliable and doesn't spew out RFI all over the place.

public

join:2002-01-19
Santa Clara, CA

1 edit
said by TheMG:

If it looks decent I might pick one up and put it through its paces testing it for regulation, ripple, RFI, etc. That's actually a very good price for a 70A 12V SMPS assuming it is reliable and doesn't spew out RFI all over the place.

Cheap ones often skip a pfc stage, use native chinese parts, and operate power parts at high Tj, even though the unit feels cool.
i have a number of XPpower 12V 50A units with share input, for high power arrays.
»www.xppower.com/orderPriceList2.···&lang=EN
These are $70.

TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel
said by public:

i have a number of XPpower 12V 50A units with share input, for high power arrays.
»www.xppower.com/orderPriceList2.···&lang=EN
These are $70.

That seems almost too good to be true. It's almost like the Astec units that I have, and those are around $800 new!!! Is that $70 retail/small qty pricing or a special contract/bulk pricing?

Where do you buy them from? It doesn't looks like you can simply order them straight from their website...

public

join:2002-01-19
Santa Clara, CA
said by TheMG:

Where do you buy them from? It doesn't looks like you can simply order them straight from their website...

It is excess inventory, which may or may not be repeated. Mfg warranty may be honored, but is not guaranteed. It is a small lot, so unit pricing applies. If you want some, order quickly.

TheMG
Premium
join:2007-09-04
Canada
kudos:3
Reviews:
·NorthWest Tel
said by public:

said by TheMG:

Where do you buy them from? It doesn't looks like you can simply order them straight from their website...

It is excess inventory, which may or may not be repeated. Mfg warranty may be honored, but is not guaranteed. It is a small lot, so unit pricing applies. If you want some, order quickly.

That still doesn't tell me where you ordered them? Manufacturer's website? Some other site?