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aeolisio
09-03-2015, 11:01 PM
First off this is not a guide because the last thing i want is someone to start a fire or damage hardware or themselves because they couldnt follow simple directions.
I have rebuilt and upgraded quite a few laptop batteries over the years and even though none of our g751 batteries have failed i did upgrade 2 of the packs for longer use. You can find walkthroughs online but to make it simple the g751 battery uses 18650 cells at 3.7v and 2933 mah. After some fighting with the plastic case i replaced those cells with Panasonic 3600 mAh batteries. The upgraded total capacity on paper went from the stock battery of 5866mAh to 7200mAh and from 86Wh to 107Wh or a 24% increase. Real world heavy usage has added another 1.25-1.5+ hours for those users. As long as you install the batteries in the same series/parellel config you wont have any problems. Use this as a reference if you need to rebuild or upgrade your own battery and this will certainly void your warranty so attempt at your own risk.

joshindaphils
09-04-2015, 02:27 AM
If you want to go down a rabbit hole on data regarding these cells go to flashlight forums hehe.

Currently it looks like highest legitimate capacity for 3.7v cells is 3600mAh. Anything above that is definitely false advertising and likely a fair amount under that capacity.

Would be interesting to see a comparison on stock cells vs. good 3600mAh cells.

aeolisio
09-04-2015, 02:48 AM
You must be looking at old data panasonic put out 4000 mah in 2009. The 2933 cells in the oem g751 tested at 2600-2700 and the 3600s tested beteen 3400-3500. Neither matches advertised specs but thats still a substantial increase.
http://news.panasonic.com/press/news/official.data/data.dir/en091225-3/en091225-3.html

joshindaphils
09-04-2015, 03:08 AM
Currently it looks like highest legitimate capacity for 3.7v cells is 3600mAh.

Pretty sure my info is accurate and up to date, wasted an hour earlier looking into it all hehe. The 4200s you tested match my data as well ;)

aeolisio
09-04-2015, 03:59 AM
Thats because neither i or some random troll on a candle forum have run them to full discharge in a lab conditions. Its the same as your MPG when you buy a new car. Best case scenario is not real world but that doesnt mean that i couldnt get these closer to 4200 under the perfect conditions and that certainly doesnt remove panasonics claims of doing it in 2009.

joshindaphils
09-04-2015, 04:11 AM
Thats because neither i or some random troll on a candle forum have run them to full discharge in a lab conditions. Its the same as your MPG when you buy a new car. Best case scenario is not real world but that doesnt mean that i couldnt get these closer to 4200 under the perfect conditions and that certainly doesnt remove panasonics claims of doing it in 2009.

Dear Aeoliso the devil is in the details the batteries you linked are 4.2v chemistries, while technically you can charge your 3.7v cells to a higher voltage you will seriously compromise the life of those cells (and is likely a mute issue in this application). I did bold and make red the 3.7v in my quote to try to drive this home.

The testing I've seen shows 3.7v cells pulling just under 3600mHa, and nothing higher. These numbers are at a good load as well. I fully understand the higher the load the shorter the effective mHa.

If you can link me a test of a battery having a 3.7v charge and yielding greater than 3600mHa I'll gladly say my post and data I read was wrong and out of date. Till then I am confident in what I read and in the accuracy of what I posted.

aeolisio
09-04-2015, 04:46 AM
First off 3.7v is 4.2v charged on 18650 li ion cells.
Your right about 1 thing the devil is in the details you should have been more specific i await your edit :). You said "If you can link me a test of a battery having a 3.7v charge and yielding greater than 3600mHa I'll gladly say my post and data I read was wrong and out of date. Till then I am confident in what I read and in the accuracy of what I posted."
http://budgetlightforum.com/node/4370
http://www.kaidomain.com/product/details.S003069

joshindaphils
09-04-2015, 05:00 AM
Oh come on really... context is kinda critical here, you know very well we are talking about 18650 cells here.

I respect you enough not to hold your hand on the minutia, should I adjust my attitude here? hehe

EDIT: and you are being are playing all pedantic and give me test not on 3.7v chemistry... fail :P

aeolisio
09-04-2015, 05:02 AM
Haha come on admit defeat nothing is implied. Ill settle for "aeolisio thank you for your wonderful battery contribution any improvement over stock battery is a win for all of us."

Edweird
09-04-2015, 06:42 AM
I'll just add my 2 cents here.
Many model/fighting lightsaber builders like UltraSabers and Saberforge as well as others use only the Panasonic and Trustfire batteries with Panasonic apparently being the best of them all.

I don't know about Ultrafire vs Trustfire but I can confirm that Panasonic 18650 ones are very reliable - I've been using them for years for things like aforementioned lightsabers and flashlights. (The NCR18650B 3400MAh 3.7v ones.)

You can get 2 for $14 atm. I was actually quite surprised to see that kind of capacity at that voltage considering the size of the things.

aeolisio
09-04-2015, 04:26 PM
I'll just add my 2 cents here.
Many model/fighting lightsaber builders like UltraSabers and Saberforge as well as others use only the Panasonic and Trustfire batteries with Panasonic apparently being the best of them all.

I don't know about Ultrafire vs Trustfire but I can confirm that Panasonic 18650 ones are very reliable - I've been using them for years for things like aforementioned lightsabers and flashlights. (The NCR18650B 3400MAh 3.7v ones.)

You can get 2 for $14 atm. I was actually quite surprised to see that kind of capacity at that voltage considering the size of the things.
I agree the panasonics are very reliable but at twice the price you could build the cheaper pack again which is far easier the second time with the case having been opened already in a few years if you needed to but more likely they will last until you upgrade. If money wasnt a problem sure but then if money isnt a problem why not just buy an oem pack for $95. You could even use some 14500's in place of the optical bay to extend the mAh if money werent an issue.

aeolisio
09-05-2015, 09:29 PM
I have had a number of requests to build upgraded and rebuild worn out packs for people so let me post this here. I work 60-80 hours a week and really dont have the time but if someone absolutely needs it i will let my son build a pack for $50 that includes the linked batteries and ill of course supervise him and test it. Or you can send whatever cells you want plus $20 for his labor. He has already build 3 packs for laptops and 5 for ebikes so he knows what he is doing. You will need to message me to set it up and send the battery or the entire laptop if you dont feel confortable removing the battery here to Los Angeles and include a prepaid return label or drop it off if you live locally. You can also find a replacement battery for as low as $95-99 dollars online and have a shop swap it or swap it yourself. Feel free to message me if you have any questions.

aeolisio
09-07-2015, 05:55 PM
Your always working on something to make the g751 better. What other things are you thinking up? Is there a way you could make the g751 battery removeable without taking out screws? Or could you make a second battery pack to carry around like those battery banks for cellphones but bigger?
The case would have to be modified and an easier connector wired inline but yes it could be removable.
You could make a second battery pack sure and wire it in or place a jack and use a barrel connector on the laptop. It would add weight though. You could even 3d print a new top cover or a skin over the top cover to hold quite a few cells. You would only be limited by the weight you would want to carry and the cost of course. You could even make a pack with removable cells and use chargers to charge and swap those cells. The question becomes how much battery life do you need and how much are you willing to pay/carry around for it.

aeolisio
09-15-2015, 10:16 PM
I wouldnt mind the weight it would be nice to have an option like removable batteries for when i cant get to an outlet. I would want to keep close to the same size though. Would i have to send you the entire laptop for you to make the battery removeable. or would a better choice be to make the pack with removeable cells. i have a nice 18650 charger and then i could jus change the batteries myself.
I would only need the battery itself if your goal was modifying the case or installing a 3d printed bottom cover yourself. The pack has very little room so if you wanted an easily removable individual cell option i would suggest a 3d printed battery case aswell to give extra room for the springs. You might consider just an add on bank of batteries and wire it in to the current battery with a removeable plug that way you could use the same charge circuit and it would just read as an increased mah and charge for longer. Thats easier than carrying a seperate charger or a handful of seperate batteries. There are too many options to list it really comes down to what you need from it. How much extra charge do you need how much weight can you add and how comfortable are you with modding.

aeolisio
09-18-2015, 10:48 PM
i rather have no battery and save weight everywhere i go has a plug
You could do a very slim battery pack with a couple 10440 cells to give you just a few minutes of emergency power and not have any issues with laptop not detecting a battery. I dont think it would be worth it just to save a few ounces.

aeolisio
09-22-2015, 04:47 AM
I like the idea of a bank of batteries as an add on so i only have to bring it when i need it. Could you make it mouse pad size and put some material on it so it can double as a mousepad. or could you add it to my cooling pad stand?
I suppose but figure out what size mouse pad your talking about and the acceptable thickness because using 18650 cells are thicker then others and would be the best bet for maximum mah. For 18650 cells your looking at a 1 inch thick mousepad plus whatever material your puytting on it and while i could 3d design it to slope downwards so that it sits flush with a desk that thickness might bother you. It could probably also be build on to or into a cooling pad that would depend on the pad. You still need to wire in a barrel connector somewhere if you are charging it with the standard power brick.

al3xrov3r
01-08-2016, 03:37 PM
does battery pack have a circuit in it?
what about MCU ( micro controller unit) 's program that contains battery's specificity?

aeolisio
04-28-2016, 11:23 PM
does battery pack have a circuit in it?
what about MCU ( micro controller unit) 's program that contains battery's specificity?
Yes it does have its own charging circuit that regulates and balance charges the cells. It uses delta peak voltage to determine charged level so the capacity of the cells doesnt matter for the circuit.

Computer-Chkn
12-23-2016, 10:27 PM
Yes it does have its own charging circuit that regulates and balance charges the cells. It uses delta peak voltage to determine charged level so the capacity of the cells doesnt matter for the circuit.

I got to reading a lot online about the chips in newer laptop batteries having a protection circuit, and if the board receives 0 voltage it gets bricked. Is this not the case with the G751 pack? I really hope so. Because I'd like to go ahead with replacing the cells instead of throwing the pack away and ordering another battery.

loonie01@gmail.com
01-30-2017, 03:28 AM
What's the best way to remove the plastic shell that's around the batteries?

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