NIMH batteries - slightly OT

Martin,
Tom Moore who is a test engineer for medical and military battery
packs wrote recently on a RC web site that the chief reason NiMh false
peak is the wrong charge rate. They should be charged at close to 1C
or the peak may not be detected. He also mentions that they should
never be left on trickle charge for an extended time and that trickle
charge as a regular charging method will eventually destroy them.

I have had good luck with Sanyo Eneloops 2000 mAh.

John

On Sun, 12 Apr 2009 17:31:06 -0700, jbourlandmd wrote:

Martin,
Tom Moore who is a test engineer for medical and military battery packs
wrote recently on a RC web site that the chief reason NiMh false peak is
the wrong charge rate. They should be charged at close to 1C or the
peak may not be detected.

That's worth knowing. Thanks. Do you know how he is detecting the peak
(i.e. voltage or involution)?

I've just upped the rate to 1C charge (2.4A) and 0.2C (0.5A) discharge on
the Prodigy II and am running a couple of cycles.

He also mentions that they should never be
left on trickle charge for an extended time and that trickle charge as a
regular charging method will eventually destroy them.

Noted with thanks.

I have had good luck with Sanyo Eneloops 2000 mAh.

Looks like I need to get a set. I did a search and found a lot of good
experiences being reported. What charge conditions are you using for them?


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

Mr. Moore did not mention any specifics on how he detects peak.

I am using a very basic one stage peak charger similar to your Prodigy
II. I charge my Eneloops at 2A. Peak is not adjustable.

John* * * |

On Mon, 13 Apr 2009 07:50:26 -0700, jbourlandmd wrote:

Mr. Moore did not mention any specifics on how he detects peak.

I am using a very basic one stage peak charger similar to your Prodigy
II. I charge my Eneloops at 2A. Peak is not adjustable.

Looks like I just wasted my money on the Ansmann batteries, then, and
need to get a set of eneloops.

On last overnight discharge on the UBA III+ the Ansmanns managed 500 mAh,
but today (2.5 amp charge, 0.5A discharge on the Prodigy II) they would
only show a bit under 400 mAh capacity. Junk. NOT recommended. Avoid them.

Thanks for your data and advice.


--
martin@ | Martin Gregorie
gregorie. | Essex, UK
org |

On Apr 13, 11:46*am, Martin Gregorie
wrote:
On Mon, 13 Apr 2009 07:50:26 -0700, jbourlandmd wrote:
Mr. Moore did not mention any specifics on how he detects peak.

I am using a very basic one stage peak charger similar to your Prodigy
II. *I charge my Eneloops at 2A. *Peak is not adjustable.

Looks like I just wasted my money on the Ansmann batteries, then, and
need to get a set of eneloops.

On last overnight discharge on the UBA III+ the Ansmanns managed 500 mAh,
but today (2.5 amp charge, 0.5A discharge on the Prodigy II) they would
only show a bit under 400 mAh capacity. Junk. NOT recommended. Avoid them..

Thanks for your data and advice.

--
martin@ * | Martin Gregorie
gregorie. | Essex, UK
org * * * |

AFAIK, Enelopes only real advantage is that they have a longer shelf
life due to new separator technology. But for that reason alone they
are good for cameras.

In my RC addiction, I often use what many of my fellow modelers would
call "garbage" $1 per nimh batteries made in China from Ebay. I
regularly see 1800-1900 mah from a 2000 mah rated pack charged on a
Triton. Not bad. I use the same batteries in a 10 cell (12 volt)
portable sailplane VHF radio with great results (12+ hours rx time). I
fly them in very expensive carbon fiber full house models using six
digital servos in DS applications down to 15F with no problems. So far
I have used 24 of these cells and have not had one dead cell or
problem in two years use. I cannot say the same for name brand cells.
YMMV.

I typically charge at 0.5 to 1C for small AA and AAA batteries like
these. Zapped sub-C traction batteries were charged at 2C plus.

I wonder about your chargers. The standard Triton 2 is a super charger
for the money and pretty much standard equipment over here. If you do
go that route, avoid the "jr" version as it has some limitations on
amperage (5A) and lipo cell count (4S).

/Adam