NIMH TX pack

[Keith Black]

I know nothing about the Alpha charger, but I do know that the peak
detection on NiMh batteries is more sensitive than that of NiCad batteries,
this is why a charger designed specifically for NiCad batteries will
sometimes get NiMh batteries very hot. Basically the charger will continue
charging when the battery has already reached peak. This isn't particularly
good for the battery, and I personally wouldn't want that hot battery inside
my TX or Plane, not to mention the serious negative consequences that occur
if the battery is damaged by overheating.

Another way that batteries get too hot is by charging them with too high of
a current. The electric guys really abuse these batteries and will charge
them with very high loads, but when doing so they will put them in a cooling
tube to keep the heat down. I don't know if I believe them, but I'm told
that as log as they keep the batteries cool they can use the higher
currents.

I have charged NiMh batteries on a charger made for NiCads with hit and miss
success, but this was done on my electric plane batteries where the BEC will
shut the motor off and I'd know when the battery was low. In our glow planes
if the battery prematurely discharges in the air our method of finding out
is not as graceful.

The last set of NiMh batteries I bought the manufacture specifically stated
to only peak charge with charges that have peak detection for NiMh. They
said that using a NiCad peak detection charger could damage the batteries.

BTW, everything I stated above only applies to peak charging. It is safe to
trickle charge NiMh batteries with chargers such as the Accu-Cycle plus even
though the Accu-Cycle plus was designed for NiCads.

Keith Black


----- Original Message ----- 
From: "Verne Koester" <verne at twmi.rr.com>
To: <discussion at nsrca.org>
Sent: Thursday, October 09, 2003 6:25 PM
Subject: Re: NIMH TX pack


> Wayne,
> Yes, they do get warm, even when properly charged. However, with the
Alpha,
> they get hot. I'm not sure how hot they would've gotten because I shut
down
> the charger when the pack went from warm to hot. The Alpha is the Cadillac
> of Nicad chargers, at least by my experience. I think it would need some
> tweaking by the designer to be suitable for Nimh.
>
> Verne
>
>
> ----- Original Message -----
> From: "Wayne Galligan" <wgalligan at goodsonacura.com>
> To: <discussion at nsrca.org>
> Sent: Thursday, October 09, 2003 5:44 PM
> Subject: Re: NIMH TX pack
>
>
> > Verne,
> >
> > I have noticed that NiMh battery will get a little warmer at similar
> charge
> > rates when compared to a NiCad's.  I believe it has something to do with
> the
> > higher resistance in these types of cells.  But mine have never gotten
too
> > hot even at 1C.  That's why a I stick to the .5C charge rate to keep
temps
> > lower.  I charge mine with the SuperNova and I also use the Hangar 9
> Double
> > Vision field charger that charges at 750mil rate.  I have no experience
> with
> > the Alpha but I thought it was supposed to be the Caddilac of chargers.
> >
> > Wayne G.
> >
> > ----- Original Message -----
> > From: "Verne Koester" <verne at twmi.rr.com>
> > To: <discussion at nsrca.org>
> > Sent: Thursday, October 09, 2003 4:37 PM
> > Subject: Re: NIMH TX pack
> >
> >
> > > Derek,
> > > I went to the Litco site and read all of their instructions on using
the
> > > Alpha on NIMH packs and followed those instructions to the letter on
my
> > > 2000mah NIMH Tx pack. The pack got much hotter than I felt it should
and
> I
> > > shut it down before it was finished. After checking with more
> experienced
> > > guys who had been using NIMH including feeling the temp of their packs
> at
> > > peak charge, I came to the conclusion that  the Alpha isn't suited to
> NIMH
> > > batteries. I bought a GP Titan charger and it works great. This isn't
> > meant
> > > to slight the Alpha in any way since I've been using it on Nicads with
> > great
> > > success for years. However, my experience indicates it isn't he best
> > choice
> > > for NIMH.
> > >
> > > Verne
> > >
> > >
> > > ----- Original Message -----
> > > From: "Derek Koopowitz" <derekkoopowitz at earthlink.net>
> > > To: <discussion at nsrca.org>
> > > Sent: Thursday, October 09, 2003 4:54 PM
> > > Subject: NIMH TX pack
> > >
> > >
> > > > I just ordered a new (replacement) TX NimH battery pack from
Cermark.
> > It
> > > is a 1650mah pack.  I've never had a NimH pack before so I'd like to
> find
> > > out from the experts out there if there is anything I need to do
> > differently
> > > than a standard NiCad pack.  Can I use my Alpha 4 to charge it?  I do
> have
> > a
> > > Dymond charger that I can use and I know that it does support NimH but
> I'd
> > > prefer to use the Alpha 4 because of its AC/DC versatility.
> > > >
> > > >
> > > > Thanks.
> > > >
> > > >
> > > > =====================================
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> > >
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> > >
> > >
> >
> >
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> >
>
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