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-- How long do your nimhs last? (http://discussion.visorcentral.com/vcforum/showthread.php?threadid=1363)

Hi all...
I got nimhs from radio shack and a rayovac 9 hour recharger. My nimhs only last like 4 days before they die out on me. i am positive they are nimh and not nicd. What is your experience with them? Are nexcells doing better? Or could it be my charger (my batteries are 100% charged after I do charger them.)

I've been getting about a week's use out of my Nexcells. Runtime tells me that that equals ~5 hours of actual operating time. I got the nexcells about 2 weeks ago. I swapped in the second set about a week ago and am just about ready to swap again.

I don't consider this to be very good either, but I've got Afterburner II set on "full blast" and I realized this morning that I've had "beam receive" turned on for most of the past 2 weeks. It'll be interesting to see how long they last now that I turned beaming off.

BTW, I hotsync about once/day on average.

bluedluxnj - what is the mAH rating on your batteries? There are some inferior NiMH batteries out there.

Double check your charger as well... make sure it is specifically for NiMH and not nicad.

Finally, make sure you're using a freshly charged set of batteries... NiMH batteries will discharge just sitting on the shelf.

Of course, your usage and environment will make a big difference also. As the batteries get hotter (because of use or environment) they will discharge faster. Therefore, intermittent use should give you more run time than always on use. Running afterburner, as the other poster mentioned, can also eat your batteries.

I've been using the 1400 mAH NexCell batteries with very good results. I used my Visor for many hours a day, often for long stretches with the backlight on, and they last at least a week. I'll see if I can't track down 'runtime' so I can get some actual numbers for everyone.

LarryD

LarryD

My NiMH's have only been lasting about a week also; about 5-6 hrs. on runtime. This is indeed disappointing, but I too have had beam receive 'on'.

Palm OS 3.1.1 fixed the issue of the beam receive battery drain. I have read discussion elsewhere that installing this patch helped with streaking and gray-scale image quality. Do you suppose Handspring neglected to code these fixes into 3.1h?

Maybe we all need to install the OS patch?

Anyone in the know on this deal?

tyler

I've got a pair of Yuasa nimh batteries that I'm using right now. According to runtime, they've been in a little over 11 days and have 5:57 of actual runtime. According to batterylevel hack, they're at 73% now. I should get another couple of days out of them. I figure I should get 7 hours or so of use.

Mine are 550mAh...perhaps this is the problem. My charger is supposed to be for both NiCd And Nimh. Is a NIMH only charger better? Actually my charger is messed up...after 10+ hours of charge, it does not indicate that it is done. It has been a long time since physics....is a long charger better than a short one. I would guess there is probably no difference.

One other thing: I've been recharging at ~2.36v. I'm wondering if I should go ahead and let them run down further (and get more runtime out of each charge).

LarryD: I thought the 1400mA NiMH's were AA's, not AAA's. Are you sure about that?

Oops... was just reviewing the thread, post nap, and realized that I posted the wrong mAH rating for my batteries... I ordered some AA and AAA at the same time.

At any rate, the correct rating for the AAA's would be 650 mAH. Higher than some, but not so significantly so. <g>

I see that someone else caught me on this to... sorry about that.

LarryD

Having read a couple of battery FAQ's recently, I'll share what I think I learned...

1) Charging the batteries slower is better... it will give them a more complete charge and maximize the number of times they can be recharged. The general quoted maximum recharges for NiMH batteries is 1000, 500 if they are fast charged.

How much extra run time you get from a slow charge was not real clear... it could be negligible, it could be significant.

2) It is acceptable, but not necessary, to recharge NiMH batteries before they have been 'functionally' discharged.

Rechargable alkaline batteries 'prefer' to be recharged at about 50% and NiCad batteries should be recharged lower to get a full use and no memory.

The caveat for NiMH is to not completely (0%) discharge them (hence the use of 'functally' in my statement above), as it could cause the voltage to reverse and render the battery unchargable.

LarryD

Well, I'm getting about 6 hours of runtime with my nimhs, but I've not run them through the cycle but a couple of times. I remember when I first started using my digital camera with nimhs, they ran out real quick, but after 5 or 6 discharge/recharge cycles they held a better charge for a longer period of time. So I would not worry about it to start with, but they should start holding a longer charge after they go through a few cycles. You may want to do this yourself a couple of times just in the charger, hit the refresh button and let it do the work.

I just started using some new Nexcell AAA's in my VDx. Over the weekend I downloaded the game "Ackeron" and was playing it heavily. My battery voltage was down to around 2.35V after only about 2+ hours of actual runtime (as reported by Runtime). Is Ackeron just a battery eater or is my Visor draining batteries prematurely? What's the minimum safe voltage for NiMH's? A lot of the battery hacks seem to set the warn level to 1.9V or lower, but the battery level display was down way under 30% (whether I used the Battery Level hack, or just shortcut .7)

From looking at other posts (above) it seems that I'm doing quite well with my "runtime".

My first set of "Energizer ACCU RECHARGEABLE" 650 mAh NiMH's gave me 8 1/2 days with 11:57 actual runtime.

My second set is still going strong after 5 days with 11:48 actual runtime.

-UPDATE
The second set ran dry after 7d7h28m with 16:07 actual runtime. _Not Bad_

Beam Receive is off (except when I use it)
Sounds (except for Alarm) are off

Dave

[This message has been edited by sdavida (edited 12-26-1999).]

I've not been changing my batteries until the Visor nags me once... usually down around 20%.

LarryD

Never ever an issue.
http://discussion.visorcentral.com/...TML/001040.html

I Hot Sync every night and seems to take care ot the problem.

I've been running my setup for about 2 weeks now and still going strong.

I'm using Rayovac Renewal rechargable Alkaline batteries. I'm on my third set of batteries since installing Runtime, & here's my stats:

Change of Battery Runtime
12/6/99 3d 02:51 1d 03:12
12/9/99 12d 23:18 1d 14:21
12/22/99 4d 22:07 0d 08:56

The 12/6/99 'battery change' had about 4-6 hours or so of use on it before I installed Runtime. Voltage reported by Runtime is approx. 2.9v from a fully recharged battery, with changes of the battery at approx. 2.35v, but as low as approx. 2.2v. The battery meter is currently sitting at 63%.

Theo, how many times a day do you sync a day, and do you run afterburner?

I am running Rayovac Renewals and got 6:25 minutes on the first set. I am hot synching 4-5 times a day and run afterburner at 22MHz. I do not remember what the voltage was when I changed them, but I remember that there was over 50% remaining. I went ahead and changed them since Rayovac says recharge frequently.

Brian

I've synced on average about once a day. Sometimes more, sometimes less. (Right now I'm relying on my Backup Module, since I left my cradle out in PA when I visited my folks for X-mas. oops.)

The last set of batteries shown is the current set. I've simply been replacing the batteries as soon as is convenient after I get a low battery warning.

Also, I'm not running Afterburner, because I spend so much time playing with PocketC, and it seems to have problems with Afterburner.

One thing I've noticed with my Nexcell NiMH's is that even thought the voltage drops during a period of extended use, once I turn the VDx off for a minute or two the voltage comes back up, often by 0.05v or more. Any chemists out there who care to explain?

I'm not a chemist, but most batteries will gain voltage slightly after a period of unuse. You can see this "phenomenon" with flashlights, car batteries, just about anything that uses batteries. Once you release the load from the battery, it has a chance to recover. The next time you turn the device on, it will show a higher voltage (ex: brighter bulb in a previously dim flashlight). After a short time with the load on again, the batteries should dip again and continue their downward voltage level.

Batteries, just like people, like to sleep every once in a while.

The recovery of voltage after a break is also going to be part of the heat issue. As you use the batteries for an extended period of time, more and more heat is generated. A hot battery will not last as long as a cool one. When you let the battery rest it cools off and gives you some recovery.

LarryD