HeadAmp Pico Power: Pre-Order Thread
Mar 20, 2013 at 3:40 AM Post #571 of 730

cooperpwc

Headphoneus Supremus
Joined
Nov 20, 2006
Posts
6,805
Likes
538
Quote:
Lithium do have some advantages over Ni-MH as well as some disadvantages.
 
...really I just want to make a good purchase and get the most out of my Pico Power.

 
 
Off the top of my memory, Justin, referring to the 9.6 volt lithium ions, said that he would not want to go much higher, i.e. that is pushing the envelope. He also said that the power cut-off circuit cuts in at 6 volts. 
 
Generally anything outputting in the 7 to 9 volt range is going to work fine. From there you are not going to get a definitive answer as to the best choice. As you said, there advantages and disadvantages.
 
Mar 20, 2013 at 5:06 AM Post #572 of 730

Husq2100

New Head-Fier
Joined
Feb 7, 2013
Posts
44
Likes
10
Quote:
 
 
Off the top of my memory, Justin, referring to the 9.6 volt lithium ions, said that he would not want to go much higher, i.e. that is pushing the envelope. He also said that the power cut-off circuit cuts in at 6 volts. 
 
Generally anything outputting in the 7 to 9 volt range is going to work fine. From there you are not going to get a definitive answer as to the best choice. As you said, there advantages and disadvantages.

Thanks for your reply cooperpwc,
 
Here is one of Justins comments regarding lithium:
 
"that would depend how they're charged but most will do 8.4V. 8.2V a little less common. the nominal voltage is 7.4V and they'll spend most of their life around this range, before quickly dropping to 6V and then being shut-off by internal protection circuitry."
 
Im reading this as the internal protection circuity is in the battery (which I belive all Lithium rechargeables have to have or they are very easily killed)
 
I guess I cant explain very well what im thinking regarding the actual peak voltage of a "9v"  Lithium (being that a single cell is 3.6v) Given that he said 7.4v is their nominal voltage, Im thinking a Ni-Mh made from 1.2v cells may be able to have a higher nominal voltage without being to high when fully charged.....but could be very wrong..
 
but maybe 7.4v is fine and no advantage in more volts, but an advantage in the amp hours of the lithium.????
 
Mar 20, 2013 at 9:39 AM Post #573 of 730

Hi Rez

100+ Head-Fier
Joined
Oct 16, 2012
Posts
209
Likes
51
Quote:
Sorry for asking some actual tech and when I was given the dont worry about it rather than an actual tech answer, I asked again.  Seems you know all the answers, so if your going to waste your time posting that I am wasting time, how about adding the tech.......
 

Voltage measurements for the PowerEx Imedion 8.4V 250 mAh - actual use.  Fully charged:  11V,  after 4-5 hours of use:  9V,  Pico Power light off after 12 - 14 hours of use.  NIMH batteries stay relatively close to their specified voltage through most of their discharge cycle.  Follow the links to see typical discharge cycles.  NIMH could be a better choice than alkaline as it operates at a more consistent voltage throughout it's discharge cycle than alkaline.  NIMH also appears to operate at a more consistent voltage than Lithium, but the difference is fairly insignificant.
 
NIMH:
 
http://www.google.com/search?q=nimh+battery+voltage+curve&hl=en&safe=off&client=safari&rls=en&tbm=isch&tbo=u&source=univ&sa=X&ei=bLVJUZqRNsqayQH3z4GwBg&ved=0CD8QsAQ&biw=1361&bih=916#imgrc=82PYrM-QXG65MM%3A%3BpRzhJcfk0khQlM%3Bhttp%253A%252F%252Ftangentsoft.net%252Faudio%252Fpimeta2%252Fbitmaps%252Fnimh-9v-discharge.png%3Bhttp%253A%252F%252Ftangentsoft.net%252Faudio%252Fpimeta2%252Fps.html%3B833%3B381
 
NIMH vs Alkaline:
 
http://www.google.com/imgres?imgurl=http://www.stefanv.com/electronics/using_nimh/nimh_vs_alkaline.gif&imgrefurl=http://www.stefanv.com/electronics/using_nimh.html&h=360&w=480&sz=5&tbnid=VdRJBOHteSKFHM:&tbnh=91&tbnw=121&prev=/search%3Fq%3Dalkaline%2Bbattery%2Bdischarge%2Bcurve%26tbm%3Disch%26tbo%3Du&zoom=1&q=alkaline+battery+discharge+curve&usg=__CKjCsuAtf6ZEv-FI0_iby5D35z0=&docid=zRRLidL16QG8aM&sa=X&ei=NLhJUa76MdPlyAGetYGQBQ&ved=0CEgQ9QEwBA&dur=91
 
Lithium:
 
http://www.google.com/search?hl=en&safe=off&client=safari&rls=en&tbm=isch&source=univ&sa=X&ei=ablJUaOGKcnJyQHHj4HwDA&ved=0CDAQsAQ&biw=1361&bih=932&q=lithium%20ion%20battery%20discharge%20curve#imgrc=dQcLQHMvKlYmPM%3A%3BM6nDBBPJoplA_M%3Bhttp%253A%252F%252Fwww.lenrek.net%252Fexperiments%252Fnokia%252Fdischarge.2002-11-09.png%3Bhttp%253A%252F%252Fwww.lenrek.net%252Fexperiments%252Fnokia%252F%3B640%3B480
 
Mar 20, 2013 at 2:26 PM Post #577 of 730

bcwang

500+ Head-Fier
Joined
Feb 28, 2003
Posts
799
Likes
37
The powerex imedion 8.4v should have a max voltage of 10.08v open circuit fully charged
The powerex imedion 9.6v should have a max voltage of 11.52v open circuit fully charged
Any li-ion 9v size should have a max voltage of 8.4v open circuit fully charged
 
Justin did mention it's safe with 11.52v per battery when I previously asked, and I assume that is the highest voltage you'll get out of any 9v sized battery.  So it sounds like anything would be safe as long as Justin's comment is accurate. 
 
 
Mar 20, 2013 at 10:30 PM Post #578 of 730

Mediahound

Headphoneus Supremus
Joined
Jul 22, 2009
Posts
4,081
Likes
1,559
Location
USA
I'm now running these rechargeables and charger.
 
They seem to work fine. I'm not sure how long they last compared to other rechargeables however they were priced well, so worth it to me:
 
http://amzn.to/15tbRq9
 
http://amzn.to/WF97oX
 

 
Mar 20, 2013 at 11:00 PM Post #579 of 730

MilesDavis2

100+ Head-Fier
Joined
Mar 31, 2011
Posts
339
Likes
25
Thats good pricing, Phototristan. I am using Powerex 9V and a 4 bank charger by Powerex too. This way, when I change the pair, there's a new set thats freshly charged. Got mine from thomas Distributing. Check them out. They also have the Imedion low discharge variety.
 
Mar 21, 2013 at 5:15 AM Post #580 of 730

feliks

New Head-Fier
Joined
Nov 2, 2008
Posts
42
Likes
0
Quote:
11 volts was measured from the battery immediately after charge using a volt meter.

 
Maybe the difference is due to the fact that your test occurred on the brand new batteries, and it over time will drop to average index - 8.4V
 
Ok
smile.gif

 
Mar 21, 2013 at 5:49 AM Post #581 of 730

Husq2100

New Head-Fier
Joined
Feb 7, 2013
Posts
44
Likes
10
Excellent info guys, I appreciate the time given. And yes some more questions. Is voltage the important factor? Will the lower voltage lithium be noticable sound wise compared to the higher Ni-MH? The advantages I like about Lithium are you dont have to fully drain them before charging. You dont have to fully charge them. They have double the amp hrs. And if looked after store well. Im thinking for my use of the Pico Power, sometimes daily, sometimes not. If im not sure of the charge in the battery I can just put them on charge for a bit then go.
 
cheers
Serg
 

Users who are viewing this thread

Top