Registered: Jul 2001
Location: The Netherlands
Posts: 47

NiMH batteries

Hi all,

I bought myself some NiMH rechargeable batteries (GP) for my Visor de Luxe. However the OS 3.1H3 doesn't support NiMH batteries. Which alternative setting is the best: NiCAd, Rechargeable Alkalines, or just Alkalines? Do I have to (can I) manually change the warning treshold or the critical treshold settings?
Any other tips on this?
Thanks

Registered: Mar 2001
Location: Nebraska- the Good life
Posts: 695

NiCad setting works well- the discharge curves are close enough.

These seem to work the best when you swap them daily. I have 3 pairs- 2 in the charger and 1 in the machine at all times. I color-coded the pairs so I do not just swap out the same pairs.

(for those who do not know, you can change the internal battery meter in your Palm OS device by going to the memo pad (or other text area) and typing in the 'shortcut' stroke- the upsidedown 'Y', then a period, then the number 7- so the sequence is ' tap tap 7'. In Palm 3.1, this rotates you between alkaline, NiCad, and rechargeable alkaline).

Registered: Dec 2000
Location: Elkins Park, Pa
Posts: 577

quote:

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Originally posted by Madkins007
These seem to work the best when you swap them daily. I have 3 pairs- 2 in the charger and 1 in the machine at all times. I color-coded the pairs so I do not just swap out the same pairs.

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__________________
-Bernie

"One word sums up probably the responsibility of any vice president, and that one word is 'to be prepared'.
-Dan Quayle

Registered: Aug 2001
Location: TX
Posts: 80

I have been using NiMH batteries for several months now on my VDx. I use Battery Meter Hack to change the battery type and it works just fine. I usually change the batteries when it drops to 20-30%. I always carry a spare charged set. They generally last 5-7 days. Although when I installed the trial version of Scrabble it seemed to eat the power like mad when I was playing. I'm sure that has nothing to do with the fact that I spent 2 hours playing at one time...

Teri

Registered: Dec 1999
Location: Connecticut USA
Posts: 2682

quote:

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Originally posted by tstarky
I'm sure that has nothing to do with the fact that I spent 2 hours playing at one time...

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Absolutely not!!!

quote:

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Originally posted by ernieba1
Doesn't that dramatically reduce the lifespan of the batteries?

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NiMH batteries don't suffer from a memory effect the way NiCad's do. It is reasonable to use them only partially and then recharge without any long-term ill effects.

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God bless America, my home sweet home...

Registered: Mar 2001
Location: Nebraska- the Good life
Posts: 695

Everything I can find about NiMH batteries reinforces the idea that they should be kept as fully charged as possible for maximum life- which is quite different from the old batteries that developed 'memory' or suffered from other concerns.

Naturally, I do not have to change them daily- but changing the batteries, cleaning the screen, doing a hot sync, and backing up the data is sort of a ritual now!

Registered: Dec 2000
Location: Elkins Park, Pa
Posts: 577

quote:

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Originally posted by MarkEagle
NiMH batteries don't suffer from a memory effect the way NiCad's do. It is reasonable to use them only partially and then recharge without any long-term ill effects.

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__________________
-Bernie

"One word sums up probably the responsibility of any vice president, and that one word is 'to be prepared'.
-Dan Quayle

Registered: Mar 2001
Location: Nebraska- the Good life
Posts: 695

"Up to 1000 recharges" is almost 2.75 years worth at a daily recharge. Considering that few rechargeable batteries of any type last much longer than 3 years, this ain't too shabby!

I work with and on batteries a lot, although more often 12VDC gel-packs. I have a LOT of rechargeable batteries around me- my Visor, 6 power tools with rechargeable packs, my laptop, shaver, safety light, walkie-talkies, electric scooters and wheelchairs, client-owned communication devices and computers, etc.

Keeping all these batteries in good shape is a real pain in the neck- but no matter how hard we try, most of them will only last 1.5-3 years in typical use.

What REALLY drives me whacko is that so many companies disagree on what the best way to charge the batteries is! Does this type develop 'memory'? Should they be allowed to discharge before recharge? Is 'conditioning' helpful?

Even in a specific type of battery- say the wheelchair gel-pack deep cycles, I have a hard time finding two sources that say the same things!

Registered: Feb 2001
Location: Portland, OR
Posts: 6

My experiences with NiMH's

I've been using the Maha MH-C204F rapid recharger and Nexcell 650 mAH batteries in my Visor Deluxe now for about three and a half months.

I usually run the Nexcell's down to 10-20% before recharging, but that's only because I'm lazy. Occasionally, if I'm going to be out hiking and using my Geode GPS unit, I'll stick in a fresh set.

I use Battery Panel by Remo Hofer to make sure the battery's stats are correct.

To date, I've had very good luck with the NiMH's in my visor. Once, recently, I had the batteries run out entirely - I hadn't used my Visor for several days and apparently they got drained somehow. Otherwise, very good results.

The Maha charger I use can recharge a pair of AAA's in about 90-100 minutes, so I can charge them on a longish drive or more likely to work and then have them finished by the time I get home.

Registered: Dec 2000
Location: Bonn, Germany
Posts: 55

One quick note of NiCd vs. NiMH profiles

I've got a VDX running energizer 700mAh NiMHs
for about three months.

I've found that the critical values for NiCd and NiMH are close/identical, the curves are different, i.e. at what point you have drained 70% or 50%.

These may be in part to the 700mAh, but in general I find that my visor under normal use stays on 100% for half the charge and then drop off rapidly.

Kg