GPS NiMH batteries

Ron Hardin

Long ago I reported that my bottom-of-the-line handlebar-mounted eTrex
ran 10 hours on NiMH batteries (from CCrane); that slowly wandered down
to 6 hours as they were recharged over and over, so I replaced them
with new 2200mAh PowerX AA's. These run 15-16 hours on the first
charge anyway (in my two eTrex's, the older one ran 15:15 and the newer
16:00). It may get better before it gets worse, since the first charge
just sort of limbers up the batteries.

The interesting thing is that that's longer most alkalines do.
--
Ron Hardin
rhhardin@mindspring.com

On the internet, nobody knows you're a jerk.

patrick mitchel

Ron, how many cycles did the nimh's take before they become unserviceable .
I understand that nimh will survive a bit longer if they aren't drained
completely before recharging. Frequent topping up's works better. Pat

Ron Hardin

patrick mitchel wrote:
>
> Ron, how many cycles did the nimh's take before they become unserviceable .
> I understand that nimh will survive a bit longer if they aren't drained
> completely before recharging. Frequent topping up's works better. Pat

Gee, I don't know, probably 500 cycles. The GPS turns off before they're
completely drained anyway. They still worked fine, but just held only 6 hours.
They got used winter and summer, so all kinds of awful temperatures.

Draining completely hurts chiefly when a stronger battery starts reverse-charging
a weaker one, and it never gets that far.
--
Ron Hardin
rhhardin@mindspring.com

On the internet, nobody knows you're a jerk.

patrick mitchel

Ron Hardin <rhhardin@mindspring.com> wrote in message
news:408D101A.626C@mindspring.com...
> patrick mitchel wrote:
> >
> > Ron, how many cycles did the nimh's take before they become
unserviceable .
> > I understand that nimh will survive a bit longer if they aren't drained
> > completely before recharging. Frequent topping up's works better. Pat
>
> Gee, I don't know, probably 500 cycles. The GPS turns off before they're
> completely drained anyway. They still worked fine, but just held only 6
hours.
> They got used winter and summer, so all kinds of awful temperatures.
>
> Draining completely hurts chiefly when a stronger battery starts
reverse-charging
> a weaker one, and it never gets that far.
> --
> Ron Hardin
> rhhardin@mindspring.com
>
> On the internet, nobody knows you're a jerk.
One of the things ive heard about the current tech batteries is the limited
# of cycles thay can endure before coming to the point that they're no
longer useful in higher drain apps. I have some old (1979) nicads that are
still doing their duty- wonder if nimhs-let alone lithium ion are gonna do
as well in the #of cycles. Pat

Kyle.B.H

"Ron Hardin" <rhhardin@mindspring.com> wrote in message
news:408D101A.626C@mindspring.com...
> patrick mitchel wrote:
> >
> > Ron, how many cycles did the nimh's take before they become
unserviceable .
> > I understand that nimh will survive a bit longer if they aren't drained
> > completely before recharging. Frequent topping up's works better. Pat
>
> Gee, I don't know, probably 500 cycles. The GPS turns off before they're
> completely drained anyway. They still worked fine, but just held only 6
hours.
> They got used winter and summer, so all kinds of awful temperatures.
>
> Draining completely hurts chiefly when a stronger battery starts
reverse-charging
> a weaker one, and it never gets that far.


I was under the impression from the FAQ here

http://www.alltekpower.com/faq/index.asp?c=4

that NiMH batteries need to be fully cycled several times when you initially
buy them, and after extended storage.

Rick Warner

Ron Hardin <rhhardin@mindspring.com> wrote in message news:<408CBEF5.54EF@mindspring.com>...
> Long ago I reported that my bottom-of-the-line handlebar-mounted eTrex
> ran 10 hours on NiMH batteries (from CCrane); that slowly wandered down
> to 6 hours as they were recharged over and over, so I replaced them
> with new 2200mAh PowerX AA's. These run 15-16 hours on the first
> charge anyway (in my two eTrex's, the older one ran 15:15 and the newer
> 16:00). It may get better before it gets worse, since the first charge
> just sort of limbers up the batteries.
>
> The interesting thing is that that's longer most alkalines do.

You need a better charger. I have two sets of 1800 mah NiMH
batteries that have been in service, nearly daily, for two years. I
use a Maha C204F charger; it has a reconditioning cycle that I run on
each battery pair every 2-3 weeks. No noticable decrease at all in
battery life in the Vista.

- rick

Ron Hardin

Rick Warner wrote:
>
> Ron Hardin <rhhardin@mindspring.com> wrote in message news:<408CBEF5.54EF@mindspring.com>...
> > Long ago I reported that my bottom-of-the-line handlebar-mounted eTrex
> > ran 10 hours on NiMH batteries (from CCrane); that slowly wandered down
> > to 6 hours as they were recharged over and over, so I replaced them
> > with new 2200mAh PowerX AA's. These run 15-16 hours on the first
> > charge anyway (in my two eTrex's, the older one ran 15:15 and the newer
> > 16:00). It may get better before it gets worse, since the first charge
> > just sort of limbers up the batteries.
> >
> > The interesting thing is that that's longer most alkalines do.
>
> You need a better charger. I have two sets of 1800 mah NiMH
> batteries that have been in service, nearly daily, for two years. I
> use a Maha C204F charger; it has a reconditioning cycle that I run on
> each battery pair every 2-3 weeks. No noticable decrease at all in
> battery life in the Vista.
>
> - rick

I used that and the later C401FS (an even better charger - I charge also
8 AAA's every day so have a charger armada available) but I think the CCrane
batteries are much less than 1800mAh, probably 1400 or so, and running at
zero degrees F in the winter has not done them any good.

The reconditioning is for NiCads. The NiMH don't have a memory effect; and
the reconditioning amounts only to discharging them, and mine are discharged
for practical purposes (when the voltage drops, there's very little left).

I think now that reconditioning has been debunked even for NiCads. Anyway the
newer charger doesn't have it any longer, yet is for NiCads too.
--
Ron Hardin
rhhardin@mindspring.com

On the internet, nobody knows you're a jerk.

Bruce Graham

In article <c6iqkb$bo25t$1@ID-155247.news.uni-berlin.de>,
patm317@hotmail.com says...
> Ron, how many cycles did the nimh's take before they become unserviceable .
> I understand that nimh will survive a bit longer if they aren't drained
> completely before recharging. Frequent topping up's works better. Pat
>
>
>
vibration on the bike seems to be an issue also. I read on a motorcyle
gps site some useful tips about GPS batteries.

http://www.cycoactive.com/gps/gps_batteries.html

My NiMh batteries were no longer useable due to premature shut-off and
when I examined them, their terminals were slightly dented and also
corroded, exactly as described.

My GPS use is cycle touring, outback 4WD (high vibration also) and some
MTB touring.

I am about to try their battery taping and contact greasing tips on a
new set of batteries.