@nikolajhendel. It lasts only an hour, right? I suspect that, as it is rated 1350 mAH.

@qole when battery goes low, the HD light will flicker between red and green. So I do not have to listen to the click, click, click....

I have tried many battery extenders and laptop batteries and even big big ugly monster battery. Surprise, only the Tekkeon MP 1550 works. and only 2700 mAH batteries work, not even 2500 mAH batteries. And big laptop batteries certainly has enough juice to make drive those tiny palmsize HD. No, it does not work. I guess the make and break is the mA from the USB port. Anyhow, the setup I have seems to be able to run continuously 6+ hrs for every set of 2700 mAH batteries, and will run forever provide you can keep up with a set 4 x batteries very.

4X 2700 mAH seems to be doing the trick for extHD, would it be better for 6X battery or even 8X battery. I truly think so. However, I have NOT come across such thing, i.e, 6x or 8x battery extender with USB output. Anyone?



bun

yep - one hour only.
mAh rating sholdn't really make a difference regarding working with the ext HD. Higher mAh shold only mean that they pack mpre charge = last longer.
Regarding number of batteries, you only need four. They are connected to deliver a 5 v charge.
6 or 8 batteries would give too high a charge.

My old laptop spontaneously rebooted when driving my USB HD! I think the HD drew too much power...

@nikolajhendel:"mAh rating sholdn't really make a difference regarding working with the ext HD. Higher mAh shold only mean that they pack mpre charge = last longer.
Regarding number of batteries, you only need four. They are connected to deliver a 5 v charge.
6 or 8 batteries would give too high a charge"
================================================== ===========

Some yes and some no. There is a threshold to kick start a HD, I think it is called "peak surge" and there is juice to do work, "continuous load". When the threshold is reached, a continuous spinning HD may continual to spin, but once it stops, it will not be able to get up. So, a lower mA battery extender may stopped much earlier than the juice is actually finished.

You probably think ALL USB AC adapter are born equal, right? I do, AC adapter means unlimited juice. Well, I was dead wrong. USB adapter that rated low, I got a couple, one rated 200-300 mA, another 350 mA, are NOT able to drive my HD. The one rated 1A easily drive the HD.

I have a battery inverter, that has 2 outlets. one produces household current, 115V AC and another USB outlet of 5V 350 mA DC. The 115 V outlet can drive a big 3.5 in 750G HD, but the dumb 350 mA USB outlet is NOT able to spin the tiny palmsize HD.

4X battery gives about 5.5V, you are right, they do not have to do anything about the V. For 6X or 8X that would give much higher than 5V one may have to do some 'step down' conversion. But I have eyes on the ampere. I guess an electrical engineer may be better to judge whether that is a good proposal.

@qole:"My old laptop spontaneously rebooted when driving my USB HD! I think the HD drew too much power... "
================================================== =====
I used to think so. In your case, if it made your laptop reboot, the power consumption logic is proabably valid. As I play with battery more, I start to believe, power consumption is only part of the game, threshold rating is also a factor.

bun

bunanson
- I forgot about the peak surge. Not that I have any knowledge about the subject, but there is a "warning" when using the sanyo eneloop that it can damage especially flashes, as the peak surge is so good that the flash can burn out (because the flash gets recharged too fast).

Cool thread!

I'm really glad I'm not the only one doing stuff like this!

One of the first things I did after getting the USB adapters for my N810 was to set up the exact same thing here on my desk to see how it would all work, and of course it all does.
For my brief test I used a battery pack that takes 4 "AA" batteries and has a USB port connected to a hub to pass power to a little 1.8" HD I have in a tiny enclosure.

I have no idea how long the setup would run for, but to me it's not an issue because I would never transport all the stuff anywhere to set up in the field.
It's just too much of a kludge!

As already stated 16GB flash stuff will be hitting (and subsequently price dropping) soon enough.

While I'm truly impressed with all the stuff you can attach to the N810, I'm also impressed by the fact that it really doesn't NEED any of that stuff to be any better than it already is.

Still good to know you can do all this if you want to though.

I've successfully set all of this up (with velcro) on the bus, so this kludge does work in the field...

What brand/$/where you got your 1.8" I am thinking to get one curious to see whether 1.8" is "easier". However, the 1.8" HD USB is getting real close to the flash price. The cheapest I can find is 80G 1.8" for $80 while 32G flash is still running $100.

I also run around with my setup, everything is in a camera bag and works fine.

bun

I wouldn't go the 1.8 way.
I had a 1.8 hd a few years ago, very portable - but slooooow.
But then again, I'm going the flash way - 32gb (and hopefully soon 64gb) usb sticks are enough for me.

I have a little 20GB that I pulled from a demo Magellan GPS unit that was being thrown away.
I think it's the same drive used in older iPods as well.
I simply did a search for the drive and found a place online that carried the special USB enclosure it required due to it's different pin layout.

Also I apologize. I meant toting that stuff simply isn't for me in particular.
As I stated before It most certainly does work, and of course would also do so in the field. I didn't mean to imply otherwise.

Also, my drive is so small comparatively that I'm going to hold out for a class 4 or above 16GB Micro SD when it hits.