Linear Power Supply for Hard Drives

[wushuliu]

I just realized that 2.5" hard drives only need 5v power (or most of them anyway) as opposed to the multiple voltages of 3.5". So I'm thinking of whipping up a simple linear power supply for both my main drive and music drive. I found cheap sata adapters and molex connectors on Amazon, so this should be easy peasy.

Anyone have any thoughts on how worthwhile this might be?

[randytsuch]

Or get two lifepo4 batteries, wire in series, drain them down with a power resistor until they are below 5 volts. This might take a while. They "bounce" back, so if you drain them to 4.8v, and disconnect the resistor, they may be over 5V a little while later, which is why I drain below 5v.

Connect them to a 5v linear supply to keep them charged. I use whatever is handy, including 3 terminal regulators.

Use this as your hdd "power supply".

Randy

[wushuliu]

Or get two lifepo4 batteries, wire in series, drain them down with a power resistor until they are below 5 volts. This might take a while. They "bounce" back, so if you drain them to 4.8v, and disconnect the resistor, they may be over 5V a little while later, which is why I drain below 5v.

Connect them to a 5v linear supply to keep them charged. I use whatever is handy, including 3 terminal regulators.

Use this as your hdd "power supply".

Randy

Interesting. Do you have them charging individually or at either end of the series wiring?

In any case I just bought an industrial linear supply for $30. 5v/12A. Opting for convenience in this case.

[nige2000]

Or get two lifepo4 batteries, wire in series, drain them down with a power resistor until they are below 5 volts. This might take a while. They "bounce" back, so if you drain them to 4.8v, and disconnect the resistor, they may be over 5V a little while later, which is why I drain below 5v.

Connect them to a 5v linear supply to keep them charged. I use whatever is handy, including 3 terminal regulators.

Use this as your hdd "power supply".

Randy

Interesting. Do you have them charging individually or at either end of the series wiring?

you can do either in series charging or charge individually with two 2.5v ps from two separate transformer secondary windings which is a more bulletproof method

In any case I just bought an industrial linear supply for $30. 5v/12A. Opting for convenience in this case.

with computers we did lots of tests
ssd better than hdd
lifepo4 better than linear (unless for a paul hynes supply)
with linear, separate supplies (separate windings) for as many different devices as possible shown to be beneficial, maybe it was less cross-contamination?

anyway two cells in series discharged to 5v will provide an excellent test
there is likely some form of ssd that runs off 3.3v out there

car bulbs are great for discharging cells

[randytsuch]

I'm lazy, so charge two batteries in series, but Nige is correct that two 2.5V chargers is the better way to do it.

And it's easy enough to add batteries to the supply you already bought.

Randy

[jrling]

I'm lazy, so charge two batteries in series, but Nige is correct that two 2.5V chargers is the better way to do it.

And it's easy enough to add batteries to the supply you already bought.

Randy

I am even lazier!

I run my embedded Intel Bay Trail mobo, which only requires one 12V supply, off 4 A123 26650s in series being charged by a 12V linear PSU in series. [Having discharged them all to 3.0V].
You will be told by 'those who know' that you will find the four cells will get out of balance with different voltages, but I have tested that and my four do not. Worst case is that you may need to balance them up once in a while but I never have needed to do so.

Also to my pleasant surprise, I found no difference in SQ running the PC on just battery power (for a short while) and with the mains powered float charger connected to the batteries.

Jonathan

[wushuliu]

Hm, how about something like this? Just so darn convenient.

http://www.batteryspace.com/lifepo41865 ... witch.aspx

[randytsuch]

This is the recommended lifepo4 battery manufacturer and type:
http://www.batteryspace.com/A123-System ... 0-mAh.aspx

Notice the 50A rate, which I think is a key to why they work so well.

Having said that, I've been using clones, but have some "real" ones to try.

You can get with tabs, or you can buy holders
http://www.batteryspace.com/Battery-hol ... -Wire.aspx

I haven't used the holders myself, but looks like they would work fine.

Randy

[nige2000]

Hm, how about something like this? Just so darn convenient.

http://www.batteryspace.com/lifepo41865 ... witch.aspx

yea its the battery management pcb in those that negate some- most of the benefit of using lifepo4

just to convenient to be audiophile i guess

[wushuliu]

Hm, how about something like this? Just so darn convenient.

http://www.batteryspace.com/lifepo41865 ... witch.aspx

yea its the battery management pcb in those that negate some- most of the benefit of using lifepo4

just to convenient to be audiophile i guess

Ok, bought some more A123 22650s. Going to try them out with my TPA amp first. I have the bench supply hooked
up to the hard drives, sounds better than sata but with a very slight high frequency hash on some tracks.