Max sata power connections per cable?

[NecroFlex]

So first off i know the saying ''Molex to Sata lose all your data'' but i have a good idea which molex to sata adaptors to look for to know they won't catch fire...well won't have as much chance as an actual sata connector on a PSU.

 

With that out of the way, i've seen molex to 5xsata on the internet and i want to know if all 5 can be used? I heard that usually it's a limit of 3 sata connections per cable since the 4th one doesn't get enough power and was wondering if that applies to the adaptors aswell? IIRC molex can in theory provide up to 140w of power, one HDD uses around 5-10w of power when in use, so is it then possible to use all 5 of the sata power connectors on the molex/sata adaptor or will it still fall into the ''max 3'' category?

 

This is the adaptor in question.

http://prntscr.com/la3nf0

 

Aliexpress ofc. But in general the wires aren't ''molded'' into the plastic so they aren't as likely to cause fires as the actual PSU sata connectors, since they are similar in design.

 

Thoughts? If it's bad i have a ton of PSUs i can solder off the SATA cables and attach them to the plastic molex part and then to the actual molex connector, just wondered if this adaptor would be fine enough?

[Jurrunio]

each SATA connector allows up to 4.5A on each of the 3 voltages (of which you'll skil the 3.3V because molex doesnt have one).

[Mira Yurizaki]

The only worry about getting cheap cables or whatever is the wire thickness. If the wire is too thin for the amperage it's expected to carry, that's what will cause it to go down in flames, nothing more.

[mariushm]

The main limitation is the fact that you have only one wire that carries 12v and 5v on a strand of molex connectors coming from the power supply.

There is also a limit on how much current the individual metal contacts inside those modular connectors can safely transfer. In the case of most common modular connectors that look like the pci-e connectors, each metal contact is rated for 9A of current.

 

An AWG18 wire can safely carry around 10-12A of current. It has a resistance of ~ 21 ohm per km, so around 0.021 ohm per meter.

An AWG16 wire can safely carry around 15-18A of current.  It has a resistance of ~ 13 ohm per km, so around 0.013 ohm per meter.

 

If you have a SATA connector at the end of 50cm of cable with AWG18 wires, then you have 1 meter of cable between the device plugged into that SATA connector and the power supply so at 10A of current going to devices, there will be V = I x R = 10A x 0.021 ohm = 0.2v drop on just the cables alone. So imagine that your SSD sees 4.8v instead of 5v. Your SSD would probably still work, but below around 4.75v all bets are off.

 

If you have longer strands and more than 10A of current, the voltage drop on the wires will only increase - and we're not even including the resistance of contacts in the SATA connector AND the molex connector AND the modular connector on the power supply - typically wherever two connector mate, there's around 0.01 ohm of resistance.

 

If the power supply is not modular, then depending on AWG gauge, assume you can go up to around 12-15A per pair of cables.

If the power supply is modular, the modular connector on the power supply has one pair of wires which carry 5v and one pair which carries 12v to the strand with molex connectors. If you want to stay strictly within the standards, you have 9A x 5v = 45w on 5v and 9A x 12v = 108w on 12v , where 9A is the limit of the individual contacts in the modular connectors.

Regardless of how many molex connectors are on that chain coming from the psu, you should not exceed these limits.

The contacts inside each individual molex connector are rated for 5A of current - basically there's enough friction between the male and female part in molex connectors, enough separation, the resistance of the contacts and all that... the standard says you should not exceed 5A per voltage. In practice, you can probably go a bit higher if the connector is "healthy" (not loose, wiggling around, good contact) but you risk overheating the connector and melting the plastic shroud.

 

The SATA connectors are designed with 3 contacts per voltage, and each of these tiny contacts are rated for 1.5A maximum current, so you could say that you have a maximum current of 4.5A of current for each voltage on the SATA connector. In real world, the SATA connectors are of various levels of quality and imho one should never draw more than around 3A per voltage on a connector.

 

So assuming you have a molex ---->[sata]---->[sata]----->[sata]---->[sata] like in the picture you link to. 

 

Your power budget is:

1. 5v x 5A = 25w on 5v

2. 12v x 5A = 60w on 12v  ( limitations of the individual connector)

 

3. ~ 12A per voltage, limitation of the thickness of wire between the molex connector and the sata connectors, so

3a. 5v x 12A = 60w on 5v

3b. 12v x 12A = 144w on 12v (but this is not possible due to 4. )

 

4. 9A per contact in the modular connector on the cable at the other end of the molex connector, which limits your maximum current for the strand of SATA connectors to

4b. 5v x 9A = 45w on 5v

4c. 12v x 9A = 108w on 12v

 

So without any modifications to that cable in the picture, ALL devices you plug in SATA connectors should not consume more than 25w on 5v and 60w on 12v.

This is not a problem with mechanical hard drives, as they typically consume around 1A on 5v and around 0.8A on 12v , so 4 such devices will easily fit within this budget.

However, SSD drives don't use 12v, they mostly use 5v and some could use up to 5-10w (2A) of current from 5v when writing data to Flash memory - all the other time, reading and idling, they typically consume less than 1-2w (0.1...0.3A)

Basically, if you have 4 SSDs on that chain and you write data for long periods of time on all 4 (let's say you have a RAID 5) then you may exceed the 25w limit in your budget but it's extremely unlikely to happen.

 

So what you can do to increase these limits if you want to?

The easiest would be to ADD a molex connector. You now have 10A on 5v and 10A on 12v ... that's the easiest hack you can do.

 

 

 

[macmus]

I have a question regarding adding 6 Fans for TT controller. 

 

https://www.thermaltake.com/Cooler/Cooling_Accessory_/Fan_Controller/C_00003143/TT_Sync_Controller_TT_Premium_Edition/Design.htm

 

I want to use new Ring Trio fans but 6 of them for my build. On the page I see:

 

*The max. rated current of the SATA port is 5A (±5%) . To avoid causing damage to the port, the TT Sync Controller is allowed to be connected with:
1. Up to 4 Riing Trio fans while adding other PLUS series products.
or.
2. Up to 5 Riing Trio fans without connecting other PLUS series products.

 

What will happen if I use 6 of them ?

[mariushm]

Short term? Nothing.

Long term?

Depending on the quality of the SATA connector, the contacts inside the connector may overheat and the plastic housing of the connector could melt and then you'd get poor contact with that SATA connector and fans would randomly start and stop running

Worse case scenario, the housing could become so soft from heat that the contacts inside could move around and the 5v and ground contacts or 12v and ground contacts could touch and then you get a short circuit and power supply will either detect it and shut down or the short circuit could cause so much heat to be produced that the insulation on the sata cables starts melting down and maybe even produce flames.

 

The trio fans says they're rated for 12v 0.1 A and 5v 1.03A ... the 5v i assume it's for the rgb leds. If those RGB leds really do consume 1A from 5v all the time (which seems a bit much to me) then I personally wouldn't connect more than 4 such fans on a SATA strip ... the SATA connector is actually rated for 4.5A and the quality varies substantially between manufacturers.

[macmus]

This is what they saying on the page... The problem is there is no way to daisy chain this controller...

 

I have corsair HX1000i platinium power supply for this build, so PS is good quality. I'm more woried about the controller itself, since it going to pass more Amperage I don't want it to go into flames  

 

I assume this 1A is only when it's using max RPM and max brightness right ? I don't think those 6 FANs will be working on max RPM anyway maybe 50-70% all the time. The issue maybe only with lighting ?

 

 

[mariushm]

The fan itself works on 12v, and the power consumption there is little, they say 0.1A  ... so 6 fans would only consume 0.6A  out of the 4.5A (or slightly more) available in the SATA connector on the 12v contacts.

Your problem is the consumption on 5v, which is separate from the 12v consumption and which is probably used by the RGB leds alone.  I would suspect the fan could consume up to 1A at maximum brightness, with all leds set to white, since you need all red, green and blue leds turned on to produce white.

If you don't keep the brightness to the maximum and don't use full white for long periods of time (let's say more than 5-10 continuous seconds within 30s-1m ) then the power consumption on 5v would probably much smaller than 1A, and that would make it safe to use 5 or 6 fans. 

 

The power supply quality doesn't matter... the connectors are pretty much all the same and the SATA connectors are kinda poorly designed, they were thinking more with the idea of making them thin and reusable for laptops, not with good contact , high current, good separation between voltages in mind. It's not a connector designed for high currents.

You can have a cheapo 30$ psu or a 200$ psu and the SATA connector themselves will still only be able to transfer 4.5A or slightly more per voltage... only differences may be one connector may be plated with gold or not, or wires may be crimped or molded inside connector etc..