NiZn Batteries

[Dennis Hoyle]

I saw this article today and thought these batteries sounded interesting. Has anyone tried them yet?

 

http://www.engadget.com/2009/11/09/powergenix-nizn-rechargeable-aa-batteries-finally-some-cells-w/

 

Dennis Hoyle

WMSS

[Jack Womack]

I wonder about chargers for them in packs of 4 or 8 cells... Might be
interesting.

[A. B. Lyles]

Well....you will need a voltage source that will create an electromotive
force that is greater than the resistance of the cells you are trying to
force electrons into. NiZn ??
A.B.

[George Joy]

The Sirius Charge line of chargers should work fine on them. I'll have to
get some and see what their charge curves look like.
George

At 01:36 PM 11/11/2009 -0800, you wrote:
>
>I wonder about chargers for them in packs of 4 or 8 cells... Might be
>interesting.
>
>
>>

Smooth Landings
George

[Dennis Hoyle]

Thanks George, please let us know what you find out.

Dennis

[George Joy]

Dennis and all,
I received a set of these NiZi batteries on Friday. I ran one
charge/discharge cycle on them, in a plastic spring holder, 4 cells. The
charge curve looked similar to that of the NiCd and NiMH, but had funny
"glitches" in the middle. I suspected that it was due to the poor
connections of the plastic holder, so I soldered up a pack of 4 cells and
ran the tests again.
This time the charge curve looked exactly like the NiCd and NiMH
cells. The only difference was the voltage. These cells have a full voltage
of over 8 volts, YES that is 4 cells!
They are rated at 2500 mAh capacity "WRONG" So far the best I can get
from these cells at a 500 mA discharge rate is 1555 mAh. My first
thought is that they needed to be Formed, the batteries came in at voltages
that were not near each other, so I did.
After the forming charge I ran the tests again, but still I have not
been able to get the capacity above 1600 mAh.
I will cycle them several more times to see if they will produce any
more capacity.
My conclusion so far is that they are rated just like the NiMH cells,
way ocver rated. The good side is that they will be great with 2.4 gHz
systems on only 4 cells!
Smooth Landings
George

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Smooth Landings
George

[Jack Womack]

Thanks, AB... I needed that... 8^)

Jack

[Alberto]

Hi guys:

This is the way to go now (in the near future):

http://www.hobbyclub.com/product_info.php?products_id=989&osCsid=acaeb525955d7da2d860ca900a66fd53

Technology is moving so fast that it's difficult to keep up,

regards,

Alberto
www.hobbyclub.com

----- Original Message -----
From: "Jack Womack" <schre...@yahoo.com>
To: "RCSE" <rc...@googlegroups.com>
Sent: Wednesday, November 18, 2009 4:11 PM
Subject: [RCSE] Re: NiZn Batteries

> Thanks, AB... I needed that... 8^)
>
> Jack
>

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[Simon Van Leeuwen]

Good info George, maybe you can try at 1A and see how badly they drop off...

simon

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[Jim Porter]

They are rated at 2500 mAh capacity "WRONG" So far the best I can get from these cells at a 500 mA discharge rate is 1555 mAh.     My first thought is that they needed to be Formed, the batteries came in at voltages that were not near each other, so I did. 

After the forming charge I ran the tests again, but still I have not been able to get the capacity above 1600 mAh.   I will cycle them several more times to see if they will produce any more capacity.

My conclusion so far is that they are rated just like the NiMH cells, way over rated. The good side is that they will be great with 2.4 gHz systems on only 4 cells!

 

The mistake here is that the cells are NOT rated in milliamp hours but in milliWATT hours.  If you take George's capacity of 1555 mah times the average voltage of slightly over 1.6 volts you get their stated 2500 milliwatt hours. 

 

Still, it's a cheap marketing trick that many will miss.

 

Porter

[Dennis Hoyle]

Thank you George, very good information and interesting results. I'll
watch for your final results.

Dennis

Sent from my iPhone

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[fnnwizard]

I agree with Alberto on the use of LiFe's for sailplane Rx power. It's a
perfect match. There is nothing more simple and reliable. Less solder joints
(3), extremely stable, almost zero self-discharge, plenty of current
delivering capcity, no need for regulator if your electronics can handle it,
last a real 1000 cycles at rated DOD.

Btw, I have heard that the 2.4g Airtronics receivers are not to be used with
anything over 6.6v. Is that so? Can someone comment on this? It would seem a
step backwards if this was the case.

Stuck in Chicago where its rainy and cold.
TL

-----Original Message-----
From: Alberto [mailto:hobb...@earthlink.net]
Sent: Wednesday, November 18, 2009 6:25 PM
To: rc...@googlegroups.com
Subject: Re: [RCSE] Re: NiZn Batteries

[Alberto]

TL

Hope the weather improves on that nice part of the Country.

Airtronics technician said:
6.6V might be a bit high . The one that I would recommend is a 6.1V

rgds,

[Daryl Perkins]

Woah kids... From the horses mouth (Mike Greenshields - Airtronics/Global)

"The fHss3 10 ch receiver works great on Li fe or a123 2 cell packs

Unregulated! No problem

Another great choice for very stable cells are Sanyo eneloop packs. They are
just like nimh but they hold their charge in storage for very long periods
of time. They were specifically designed for this purpose."

When I asked him about the other receivers, here was his response:

"The fhss1 equipment is not designed for higher voltage. In fact it is
designed to be safe with lower voltage. So the receiver computer works down
to 1.9v and can actually be run on a single lipo!

So some of the hand launch flyers are running the fhss1 7ch receiver which
is small and light with a single lipo and 94091 servos. Mike Fox is running
this combo

The 10 ch receiver will work down to 2.5v or so with no problem although we
do not recommend using this with 1 cell."

Enjoy your day!!!

D

[Bruce Twining]

Daryl,

How would you feel about using Airtronics 94761Z servos with the 2s LiFe
pack, no regulator? Thanks.

Bruce Twining

[Daryl Perkins]

Wouldn't bother me a bit. I'm running the SD10G with the 10 channel
receivers, 761's all the way around, on 5 cell packs right now. I'm also
running an 8 channel receiver in a 2M Sprite, 5 cell pack, with almost all
761's.

[fnnwizard]

I've used 2 cell A123's with 761's for a while now and they are rock solid
throughout. No issues at all. I've written a few times before that a good
5cell nimh pack will have the same starting voltage than the 2 A123's once
everything is powered up. The A123's peak at 7.2-7.3v, but depending on your
charge rate and leads the battery end may show only 7.1v which will quickly
settle to ~6.8v once a light load is put on the battery.

If you run a HD JR switch with the 22g leads, 6 digital servos, then the rx
sees right around 6.6-6.7v as soon as everything is turned on.

Attached is a graph of voltage and current during an easy launch of an
Aspire 3.7 using 2 A123's and all Atx 761's.

Here's more info on RCG for those interested in A123's for use in
sailplanes. http://www.rcgroups.com/forums/showthread.php?t=996241 the graph
is also in that thread in case the attachment doesn't work here.

I know I probably sound like a broken record by now touting the A123's for
our use, but I truly believe they are the best there is out there right now
if your electronics can operate with 5c Nimh.

And no, I am not a share holder in AONE :).

Tuan

-----Original Message-----
From: Bruce Twining [mailto:bgtw...@gmail.com]

[Bruce Twining]

Thanks Tuan and Daryl.

Bruce

[AMA...@aol.com]

I've been using Hyperion brand LiFePO4 batteries lately. I've got them in a 5 meter ASW28 (2100 mAh packs, 2 in parallel) and a Sprite (850 mAh pack) and both are fine so far, knock wood. No regulators, JR rx's, and various types of servos. Same chemistry and voltage as A123, but more sizes available.

 

If I can make them work and Daryl can make them work it may not be rocket science (sorry D)

 

Bubba.

[George Joy]

Jim,
     You are right again  :-)  I missed that, the small print IS important! That should teach me to put on the glasses too!!
George

Smooth Landings

George

[Jim Porter]

Hello George,

 

Don't feel bad, I too missed it the first time around.  Then I got to wondering how they got so much is so little a package and looked things over a little more closely.  Pretty chintzy way of presenting the 'facts'.

 

Still this chemistry has some potential (pun intended).  I am, however, a bit concerned on the recommended charge protocol.  And I found nothing to indicate the effects of overcharging the cells.  I've charged mine by limiting the input mah and watching the voltage as I have nothing that lets me set the end charge voltage as recommended.

 

Oh for the days of NiCads where nearly anything would work and the cells protested hardly at all.

 

Porter

[George Joy]

Jim,
     I didn't look for a charge protocol, I just put it on the data acquisition system and recorded the charge voltage curve. it matches the NiCd/NiMH. The only difference I can see is the voltage.
     The Sirius charge algorythum(Spelling?) works perfectly on them. The charge times and the discharge capacity have been consistant.
     Next week I'll start discharging them at 1 Amp to see what effect the increase in current has on them. They say on them "high drain" Whatever that means to them?
    Then I'll start charging them at 2C and see what that does.
Smooth Landings
George

Smooth Landings

George

[AMA...@aol.com]

In a message dated 11/19/2009 10:37:52 P.M. Central Standard Time, airp...@mchsi.com writes:

Oh for the days of NiCads where nearly anything would work and the cells protested hardly at all.

 

Porter

Amen Brother

Bubba

[Zbigniew]

Hi there!
I have been flying A123 set up since 2006 exclusively
This is a best chemistry so far
I have not encountered any failure from over voltage yet
Just do not short them - they will melt anything
I was thinking to install "over current" fuses in servo lines in case
servo shorts out stuck

I made some writing about it late in 2006 and A123 cells keep their promises

http://mysite.verizon.net/vze2qbfc/id25.html


By the way
I got 2 X Astro "Blinky A123" balancers to go
One is brand new in the bag
one is used
Those are up to 6 cell balancers
any takers?

I use big balancers now

regards
ZM