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Need New Dell D820 Laptop Battery


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#1 shamrock838

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Posted 28 May 2010 - 12:03 AM

Need New Dell D820 Laptop Battery:

I have a Dell Latitude D820 laptop (circa 2006) and need to replace my CF623 rechargeable Li-ion battery, which is rated at 11.1Vdc with a capacity of 85Wh (though I donít know what these numbers mean).

Checking online, I see a w-i-d-e range of new battery prices. Why such a difference?

What's my best strategy for making an intelligent, cost-conscious choice?

Thanks.

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#2 hamluis

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Posted 28 May 2010 - 12:27 PM

I would do a Google search for "replacement battery, Dell D820"...review the prices, warranties, and vendors...and probably go with what seems to be the most reliable vendor providing what I want at the lowest price.

When I had my old Compaq laptop (years ago), that's how I went about it.

Louis

#3 Sneakycyber

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Posted 28 May 2010 - 09:47 PM

Another reason for the wide range of battery prices is because of Cell types, brands and capacity. The higher the MA the longer the battery will last under load and some cells are far superior to others. I am no expert on Batteries but these guys are I have been studying cell types since I started modding and making extreme output flashlights.
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#4 shamrock838

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Posted 04 June 2010 - 11:25 PM

OK, I obtained a Model LBDED820HM 9-cell Battery CF711 312-0386 312-0394 312-0402 CF623 DF192 for Dell D820 D531 M65 from www.usbphoneworld.com. Specs include: Li-ion 11.1V, 9 cell and 85 Wh. Whatís your take on the quality of this battery and what kind of performance can I expect?

Through phone service, it seems the battery itself was not the only problem. The service guy asked if the new battery worked in my Latitude D820. It did. He then asked me to take out the new battery and plug in the ac adapter. No response. Nothing. Apparently the ac adapter had also died. So I ordered a new one from the same vendor and itís due any day now.

Now Iím wondering if the ac adapter was the only problem all along. Perhaps there is still life in the old battery. If so, will the new battery ďkeepĒ while I use the old one as long as there is life? Comments.

Thanks.

#5 Sneakycyber

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Posted 04 June 2010 - 11:33 PM

Yes Li-ion have great shelf life The best way to store a Li-ion is at about halph charge.
Prolonged battery life through moderation

Batteries live longer if treated in a gentle manner. High charge voltages, excessive charge rate and extreme load conditions have a negative effect on battery life. The longevity is often a direct result of the environmental stresses applied. The following guidelines suggest ways to prolong battery life.

-The time at which the battery stays at 4.20/cell should be as short as possible. Prolonged high voltage promotes corrosion, especially at elevated temperatures. Spinel is less sensitive to high voltage.

-3.92V/cell is the best upper voltage threshold for cobalt-based lithium-ion. Charging batteries to this voltage level has been shown to double cycle life. Lithium-ion systems for defense applications make use of the lower voltage threshold. The negative is a much lower capacity.

-The charge current of Li-ion should be moderate (0.5C for cobalt-based lithium-ion). The lower charge current reduces the time in which the cell resides at 4.20V. A 0.5C charge only adds marginally to the charge time over 1C because the topping charge will be shorter. A high current charge tends to push the voltage into voltage limit prematurely.

-Do not discharge lithium-ion too deeply. Instead, charge it frequently. Lithium-ion does not have memory problems like nickel-cadmium batteries. No deep discharges are needed for conditioning.

-Do not charge lithium-ion at or below freezing temperature. Although accepting charge, an irreversible plating of metallic lithium will occur that compromises the safety of the pack.


Not only does a lithium-ion battery live longer with a slower charge rate; moderate discharge rates also help. Figure 5 shows the cycle life as a function of charge and discharge rates. Observe the improved laboratory performance on a charge and discharge rate of 1C compared to 2 and 3C.

Credit: batteryuniversity.com

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#6 shamrock838

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Posted 06 June 2010 - 04:34 PM

Thanks for the info.

Alas, I'm not that technically conversant in such matters, so a lot of it goes over my head.

Are there newbie-oriented explanation/procedures out there that I can plug into?

Thanks.




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