Registered: Aug 2000
Location: Cincinnati, OH, USA
Posts: 79

I have been using the eXtend Computer FullCharge battery pack http://www.extendcomputer.com/ on my Visor Dlx for about 3 weeks. I noticed that there are times when the battery charge meter on the Visor, confirmed by Sys Info http://www.copseystrain.com/welcome.html , reads 100%, then drops quickly, sometimes visibly, and reads 80 to 85, then returns to 100%, as I go in and out of applications. There have been times that the meter jumps from 9% to 40% and back to down again after charging for a full day. If I turn it off and on, the meter will change. No crashes yet, but I am wondering if this is a common occurrence, or do I have a faulty battery.

Registered: Dec 1999
Location: Connecticut USA
Posts: 2682

Do you have the battery type set properly? If not, open a new memo in MemoPad. Enter the .7 shortcut as follows:

. 7 (that would be [tap] [tap] 7)

Repeat until the [NiCad] option is displayed.

I've been using the FullCharge since before Christmas and haven't seen what you're describing. In fact, my battery has only fallen below 100% once... after about a 1 hour session online with a Thinmodem (ahhh... that advantages of recharging ).

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God bless America, my home sweet home...

Registered: Aug 2000
Location: Cincinnati, OH, USA
Posts: 79

Battery has been set to NiCad per instructions from eXtend.

Registered: Dec 2000
Location:
Posts: 1

I have also experienced odd battery readings using the FullCharge battery system with my Vdx. As mgflorez noted, the battery reading will change (up and down) over short periods of time. And the battery reading indicates 100% for what seems to be an unusually long time. In fact I had to use the back lighting to get the battery to show some drain. I have changed the battery type using the suggested shortcut, and have checked it several times. I am not sure what is causing this, but it would be nice to know we are getting a reliable battery reading when we get down to the bottom of the barrel. I love the system, would just to like to know its behaving itself.

Registered: Dec 1999
Location: Connecticut USA
Posts: 2682

quote:

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Originally posted by earthrun
...the battery reading indicates 100% for what seems to be an unusually long time.

...it would be nice to know we are getting a reliable battery reading when we get down to the bottom of the barrel.

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God bless America, my home sweet home...

Registered: Oct 2000
Location:
Posts: 443

quote:

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Originally posted by mgflorez
Battery has been set to NiCad per instructions from eXtend.

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Registered: Dec 1999
Location: Connecticut USA
Posts: 2682

quote:

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Originally posted by mensachicken
Why Nicad?

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God bless America, my home sweet home...

Registered: Nov 2000
Location:
Posts: 102

I have had the same erratic battery voltage readings with the extend full charge. It is very unnerving to watch the battery meter read 100% for 2 days then suddenly start jumping from 87% to 100%. After the 3rd day without a recharge the battery drains quite rapidly. I doubt I could sustain the battery more than 5 days without recharging it. I put the unit under quite a bit of use during the course of the day, with some thinmodem use, a beaming to my printer and a limited amount of backlight use in the evening.

Registered: Oct 2000
Location:
Posts: 27

NiMH batteries require a short break-in period of 3-5 recharge cycles before they reahc their optimum discharge characteristics (maximum power over time). That could be why you're seeing the voltage fluctuations.

Both NiMH and NiCd have a very flat discharge voltage near 2.4V until the end of the charge when it drops off rapidly. It is important to recharge before the cells discharge completely to avoid damage. NiCd need to be fully discharged every use, or the cells will lose capacity (the memory effect). While NiMH cells are resistant to the memory effect, it can occur with repeated short discharges. However, it's not likely to happen unless you really abuse the cells. The FullCharge uses a processor to control the amount of current that is use to charge the cells based on use (when charging) or if the cells have reached capacity. Because NiMH discharge at 3-5%/day, if left on the charger, the cells will be charged whenever the voltage drops below the limit the processor is set to. NiCd cells typically self-discharge at a rate of around 1%/day. Cheap chargers without processor control can over charge your batteries and cook them. You will end up with decreased run time.

Incidentally, Lead Acid and Li-Ion (not the non-rechargable Lithium cells like the e2 lithium) are not subject to the memory effect. Lead Acid cells are of course heavy and if they leak, corrosive and toxic. They don't like to be fully discharged, which is why you can damage your car battery if you completely drain it.

Li-Ion cells have high energy capacities (per weight) and can be partially discharged without any ill effect. The reason you don't see Li-Ion rechargable cells in standard sizes (AAA, AA, C, D, etc.) is because the cells are sensitive to current during charging. Chargers for NiCd and NiMH have higher current flows than the Li-Ion cells can handle. From what I understand, the cells can explode. Li-Ion cells are lighter for the same capacity which makes them desirable for portable applications like PDAs or digicams. It's the liability issue that prevents making Li-Ion in standard sizes.

Hope that helps.

p

Registered: Jan 2001
Location:
Posts: 42

does the FullCharge support other nimh batteries other than those they sell?

Registered: Oct 2000
Location:
Posts: 27

I just got mine this weekend, so out of the box, no the Full Charge will not support regular batteries because the charging coupler is soldered onto the battery pack. However, those who are good at fabricating their own devices can probably accomplish the same battery pack if you use the original as a template and buy 2 AAA NiMH. I'm not a soldering master, but you might de-solder the original connection and resolder it to your new batteries. But if the batterypack lasts a year or so (and it should last longer), $20 isn't too much.

Now I need to break out the Dremel to modify my cradle so I can charge in the cradle.

Registered: Aug 2000
Location: Cincinnati, OH, USA
Posts: 79

I spoke with customer service about the rogue battery. They hypothesized that one of the cells was bad, causing the variable readings. I returned the cell. They sent me another. Bravo eXtend Computing.

Registered: Oct 2000
Location:
Posts: 443

quote:

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Originally posted by mgflorez
I returned the cell. They sent me another. Bravo eXtend Computing.

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