Sd Card Power Consumption

[Kaze0110]

This is the first thing that I've seen that has dual SD slots, and will also be in my pocket without a cover for those slots, meaning that there's now the potential for sand / lint / whatevers in my pocket to get into that open port.

So then it comes to mind that I should fill both slots to alleviate the problem, but I'm wondering which is a better route to go, to get, say, 2x 8Gb cards, so that both are filled, or two get a single 16Gb card, and put a blank "slot holder" sd card just to prevent dirt from getting in.

I don't know which would do better in terms of power consumption, I don't imagine it'd be an awful lot either way, I'm just curious which would be better from a technical standpoint, as I've never read any info on whether a larger storage capacity card pulls a higher electrical draw than a smaller one.

 

[smr]

As far as I know, SD cards only consume power when they're being accessed.

 

[lulzfish]

I don't think you'll be able to notice a difference.

if there is a difference, anyway, it will be almost nothing next to the power the CPU and display are already using to work with whatever data is stored on those cards.

 

[dflemstr]

As far as I know, SD cards only consume power when they're being accessed.

Flame me if I'm wrong ( ), but afaik it's only the SD controller that actually consumes any power, and that consumption is almost constant; the electricity required to flash the SD cards is almost nihil, and reading a SD card consumes even less power. You won't notice any power consumption difference between 2 dummy cards and 2 real SD cards, at least practically.
(Or you will, if 5 extra seconds of pattery time are really important to you )

 

[Kaze0110]

I just like to run my things as optimized as possible, and if omitting the card from the board will cause it to stop sending power to that slot, then I just saved the battery that much more for something that I can actually use, instead of it going nowhere.

 

[Tor]

On the other hand there are differences in power consumption between SD card manufacturers. There have been threads about this on the Nokia tablet forums. Some cards are much better than others in this respect, sorry I can't remember many facts from there but e.g a-data was reported to suck more than patriot. In general the well-known, more expensive cards are better though IIRC.

With the cards I've been using in my devices (Kingston cards mostly) there doesn't seem to be any particular problems though. The cards are always in and doesn't seem to create any problems w.r.t. battery time. Well, at least since I stopped the Nokia program which regularly scanned the cards for media files.. that one could do lot of damage.

 

[Svartalf]

I don't know which would do better in terms of power consumption, I don't imagine it'd be an awful lot either way, I'm just curious which would be better from a technical standpoint, as I've never read any info on whether a larger storage capacity card pulls a higher electrical draw than a smaller one.

All things being equal, the power drain from an 8 versus a 16 should be close to identical from parts from the same vendor. They draw next to no power when not being accessed, so that's no big deal. However, if you have 2 8's in there and use them simultaneously, you'll end up with double the consumption over just the 16- obviously. If you're not using them at the same time, the 8's will be close enough to a 16 to not matter.

So, it's more of a six of one, half dozen of another. If you've got a dummy card and have a budget for the 16, getting a good 16 would be the way I'd go. If you've got a couple of 8's and don't expect to use them at the same time, it's going to be a non-cost answer. Oh, and RAID 0'ing the things won't speed things up in this case (No hardware RAID to speed things up with- if there was, I'd be telling people to go DO that... ) so that shouldn't be a consideration.

 

[ledow]

CODE
http://www.opticsplanet.net/silicon-power-ultima-45x-128mb-secure-digital-card.html


suggests that power consumption is the low to mid mA range unless idle. Given that the cards work on 3.3 or 5V, you can do the maths to work out the power (0.2W in the worst case?). Idle isn't really worth working out, so you'll probably not notice the SD card or not, but active-read or -write is likely to hit battery life a little.

That said, it's an old card and newer SD's might do better. I was just going for worst-case.

 

[typs lik dis]

What power do eye-fi's cards feed off of?

 

[Chip]

What power do eye-fi's cards feed off of?
They feed off of the power that is always there. A regular SD card uses no power (or as close to no power as makes no difference) when it's not in use, whereas a SDIO card is using the power all the time whenever it's function (wifi in the case of the Eye-fi) is turned on.

 

[Kramy]

On the other hand there are differences in power consumption between SD card manufacturers. There have been threads about this on the Nokia tablet forums. Some cards are much better than others in this respect, sorry I can't remember many facts from there but e.g a-data was reported to suck more than patriot. In general the well-known, more expensive cards are better though IIRC.

A-Data cards also have higher read/write speeds than Patriot Signature SD cards.

Didn't one of the devs say the LCD was a really low power LED backlit one? It's supposed to max somewhere around a watt, and the CPU is also maxing somewhere around a watt? Or did I get that wrong?

Seems to me 0.2 watts is very high, when stacked against 2 watts. Having an extra SD card could cost 5% battery life.

Okay, not quite, but you get the idea. Just because the numbers are low doesn't mean they should be discounted - it's all about the ratios.