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correct battery? 14.4v 8-cell/ 10.8v 6-cell

post #1 of 15
Thread Starter 
I have an HP 8510p and am considering a battery off of ebay. However, they sell two different main batteries for this computer --- an 8-cell 14.4v and a 6-cell 10.8v.

Can the laptop safely use either? How does it do this? And which is better, 6 or 8 cell?
post #2 of 15
What is the wattage of your Ac Adapter? 65W original? Then stay with the 6-cell 10.8V, better chance of working correctly with your model.

cheers ...
post #3 of 15
Thread Starter 
Quote:
Originally Posted by qhn View Post
What is the wattage of your Ac Adapter? 65W original? Then stay with the 6-cell 10.8V, better chance of working correctly with your model.
Why is that? What problems could arise?

I actually have a 14.4v main battery. Actually I have both and they both work, although I'm having problems with both of them atm. Since buying a new battery is a troubleshooting step, I want to know for sure whether it can use either, or that one is correct.
post #4 of 15
OEM battery calls for 73Whr rating, I would try looking for a replacement that comes close to it.

cheers ...
post #5 of 15
Thread Starter 
I don't understand how capacity effects compatibility. I'm wondering mainly what difference the voltages might make. Do the laptops officially support both voltages? If I'm actually having that known problem with the charging "circuitry" (vreg?), then would it be less stress on that to use a lower-voltage battery?

It might also explain why I'm having trouble charging the 14.4v extended battery in a older laptop that uses 10.8v batteries. All my hp laptops work fine on my docking stations, although they might all be taking 18.5v input from that.

Buying batteries to troubleshoot gets expensive quickly, especially if you're talking new genuine HP. (Oem can mean several different things, and since HP does not actually manufacture batteries, I try to avoid that term.)
post #6 of 15
I dug up some more:

- OEM Specs call for 18.5V/4.9A/90W adapter and (capacity) 4400mAh /14.4V battery.

So you should not have any issues going with the 14.4V battery mentioned in your OP, providing that everything is working

cheers ...
post #7 of 15
Thread Starter 
Quote:
Originally Posted by qhn View Post
I dug up some more:

- OEM Specs call for 18.5V/4.9A/90W adapter and (capacity) 4400mAh /14.4V battery.

So you should not have any issues going with the 14.4V battery mentioned in your OP, providing that everything is working

cheers ...
I appreciate your response, but ... I wish you'd answer the questions I'm asking.
post #8 of 15
Quote:
Originally Posted by doug_ny View Post
I appreciate your response, but ... I wish you'd answer the questions I'm asking.
Quote:
Originally Posted by doug_ny View Post
I have an HP 8510p and am considering a battery off of ebay. However, they sell two different main batteries for this computer --- an 8-cell 14.4v and a 6-cell 10.8v.

Can the laptop safely use either? How does it do this? And which is better, 6 or 8 cell?
Go with the 14.4V, as mentioned above. Straight enough for an answer?

cheers ...
post #9 of 15
Thread Starter 
Quote:
Originally Posted by qhn View Post
Go with the 14.4V, as mentioned above. Straight enough for an answer?

cheers ...
I'm not looking for you to look things up on google for me, I can do that. I'm looking for someone who can explain what issues there will be using either voltage. I was also looking for some idea if using the lower voltage battery would help the vreg issue with charging.
post #10 of 15
Quote:
Originally Posted by doug_ny View Post
I'm not looking for you to look things up on google for me, I can do that. I'm looking for someone who can explain what issues there will be using either voltage. I was also looking for some idea if using the lower voltage battery would help the vreg issue with charging.
You might want to post this in DTF, since this is pertaining more to Desktop Boards handling than in notebooks.

cheers ...
post #11 of 15
Well remember that the battery voltage drops progressively the closer it gets to being depleted and required a recharge. It's actually quite a narrow range from full to empty if I'm remembering right, maybe on the order of 3-5V for a 14 V battery.. Thus I'd suspect if you tried to throw in a lower voltage battery then you would end up with screwed up battery percentage readings in windows, or the motherboard power circuitry would simply think you're an idiot and refuse to deal with it. I don't think it would help any charging problems since that's dealt with by the charger (except in some cases where the computer is smart and realized with a full battery + charger to power itself directly from the charger and not charger-> battery -> computer).

PS - I bought a replacement non-OEM battery from Amazon and an extra (for my bag) charger from ebay, both matching the specs of OEM and they both work fine.
post #12 of 15
Thread Starter 
Quote:
Originally Posted by dr/owned View Post
Well remember that the battery voltage drops progressively the closer it gets to being depleted and required a recharge. It's actually quite a narrow range from full to empty if I'm remembering right, maybe on the order of 3-5V for a 14 V battery.. Thus I'd suspect if you tried to throw in a lower voltage battery then you would end up with screwed up battery percentage readings in windows, or the motherboard power circuitry would simply think you're an idiot and refuse to deal with it. I don't think it would help any charging problems since that's dealt with by the charger (except in some cases where the computer is smart and realized with a full battery + charger to power itself directly from the charger and not charger-> battery -> computer).

PS - I bought a replacement non-OEM battery from Amazon and an extra (for my bag) charger from ebay, both matching the specs of OEM and they both work fine.
That's interesting... I don't know too much about rechargeable batteries. When you say the charger, you mean the charging circuit on the motherboard, or the ac/adapter, or some element inside the battery?

I think either voltage battery can be used. If 10.8v were electrically incompatible, they would have have made the connectors (main and extended) mechanically incompatible to insure no problems, or had some other protection. Those selling 10.8v batteries do claim it's compatible, and I tend to think that the laptop (charger and all) is able to handle both voltages correctly, somehow. The "smart battery IC" is necessary for calibration, so I assume it's helping to track that battery's empty/charged voltages over the life of the battery. The laptop would have to allow for different voltages for older batteries, owners with multiple batteries, and batteries being used in multiple laptops. So I tend to think this should work, I just don't know that for a fact.

I wonder if the "charging circuit" (not to mention the main battery) was damaged in either of two problems; 1) charging the original battery with an inadequate a/c adapter causeing overheating and 2) not making sufficient electrical contact with the docking station, also causing high resistance (someone put it on the dock improperly). So, if the electronics were damaged by resulting heat, they probably have less tolerance to further heat and running current through them with a lower voltage is a good way to avoid that.

But before I spend $30-80 or so on a new non-refundable battery just to troubleshoot, I wish I had a more concrete idea on any of these issues.

Incidentally, both my batteries were on the laptop last night and it appeared to have charged my main battery to 96% for once, and my extended battery to 65%. The only difference was the ac adapter (65w, versus 135w, both hp).
post #13 of 15
Erm, while it would be good engineering practice to make electrically incompatible elements physically incompatible, they might not. Not to mention they might have been told to design the thing to support one battery and that's it.

You can also find your lappie's support manual on the HP support website (near all the drivers) and it'll list all the models of batteries that are compatible. Just google the part numbers and see if both the 10.8 and 14.4 are. Mine, both the 6 cell and 12 cell are 10.8 V.

I don't think the AC adapter could cause this problem. a) If it wasn't able to provide enough wattage but had the right voltage, the battery would just take longer to charge but still be fine. b) if the voltage wasn't higher than the battery by enough, the battery would be charging the charger, which might burn out the charger but not the battery. I'd guess that the computer has protection in it to prevent wrong chargers from being plugged in. Replacing the charger is a lot cheaper than buying a new battery though, and at worst you have an extra charger. I got mine off ebay for 7 bucks and it's worked fine for a few weeks now (although the cord is shorter than OEM).

Have you tried resetting the calibration on your batteries - Turn off all "standby low battery" stuff and let the batteries drain to 0% and hard shut down the computer? Link: http://www.rm.com/Support/TechnicalA...?cref=TEC49012

Batteries can also simply wear out. My battery I had to replace with a generic non-oem one because the oem one would charge up to 100%, deplete to 30% in a few minutes, and then die.

PS - I would order a non-oem battery from Amazon rather than ebay.
post #14 of 15
Thread Starter 
thanks, btw. I'm finally ready to try this battery calibration procedure (the correct way, apparently)... and noticed that both my batteries are showing 100%. !?! I'll try it anyway....
post #15 of 15
Thread Starter 
Just an update -- I did get a new primary battery from amazon, which works fine and last about 2:30 hours. The problem now is that it's thicker than the OEM and doesn't fit on the docking station correctly. $&#@ing generic manufacturers.
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