Will this work? Battery pack connected to laptop motherboard

Thread Starter

SethB

Joined Mar 30, 2021
21
So I have this really awesome HP Pavilion Laptop. I am currently in the search for a battery pack for it, but can't find any that work because the charging port requires 19.5v at 10.3 amps.

Which gives me this prolly not so smart but cool idea...

I know the battery in the laptop uses 11.55 volts at 4.5 amps. The battery pack I have can output 12 volts at 3amps max, 16 volts at 4.7amps max. Since it says "max" I am assuming it can throttle down the amps if it doesn't require all of them. So here is they idea: I wire the battery pack directly to the motherboard of the laptop, exactly where the currently installed battery connects. I do not think it will fry the motherboard at 16volts since the amps say max I am guessing it can throttle those down if needed. The how I wire everything is TBD, as I have a few concerns below.

Here are my concerns:
1. Will it even work?
2. If it does work, is there something in the BIOS/kernels that would ignore the extra capacity of the battery pack?
3. What are your concerns/ideas that I may be overlooking?

Thanks everyone!
 

MrSoftware

Joined Oct 29, 2013
2,015
Generally speaking; don't ever connect a supply that will give a higher voltage than the load is rated for, that will almost certainly have a bad result. For this case, view the current as a minimum rating. If the laptop requires 4.5A, then you need a supply or battery that can supply at least 4.5A. If the supply or battery can provide more current that is fine, but if the supply or battery gives too much voltage then that is not fine.

In regards to connecting an arbitrary battery directly to your laptop; if you connect a 16V battery to a circuit that is designed for a 11.5V battery, expect problems.
 

KeithWalker

Joined Jul 10, 2017
1,787
Laptop battery packs have built-in electronics that communicate with the laptop power management system. That's why they have more than just the + and - contacts. If you don't use a correct replacement pack, it will not work and may damage the PC.
 

Thread Starter

SethB

Joined Mar 30, 2021
21
Generally speaking; don't ever connect a supply that will give a higher voltage than the load is rated for, that will almost certainly have a bad result. For this case, view the current as a minimum rating. If the laptop requires 4.5A, then you need a supply or battery that can supply at least 4.5A. If the supply or battery can provide more current that is fine, but if the supply or battery gives too much voltage then that is not fine.

In regards to connecting an arbitrary battery directly to your laptop; if you connect a 16V battery to a circuit that is designed for a 11.5V battery, expect problems.
I was unsure of this. I was thinking "Oh if I match the watts it should be fine right?" But I guess not lol.
Which model is it?
Model of laptop? The laptop is an HP Pavilion 16-a0032dx
The battery pack: Krisonia NJF-5X
Laptop battery packs have built-in electronics that communicate with the laptop power management system. That's why they have more than just the + and - contacts. If you don't use a correct replacement pack, it will not work and may damage the PC.
Exactly what I was wondering, if it required those additional wires to be connected to work, which I am guessing it does and won't just be happy with getting a current.

Man this sucks. I guess if I really want a battery pack I will have to get one of those that has AC ports on them. Now correct me if I am wrong, I will need a battery pack with AC output up to 200W right? Since the charger uses 200W, a lower wattage inverter will not allow my charger to work? Someone else told me it would just charge the laptop at whatever wattage the inverter can output, meaning it would just be a slower charge. But something tells me the charger simply won't turn on.
 

andrewmm

Joined Feb 25, 2011
1,473
Remember , its the volts difference across the load that sets the current,

If some thing is rated at 12 volts, and you connect it to 16 Volts, the current will increase ( V/R = current )
increased current equals smoke escaping
and as we all know, chips are powered by smoke , as when it escapes, the chip stops .

Also ,
if the battery you connect is "low" then the mother board will try to charge your battery,
without a proper charge circuit, the battery could suffer fail
and Lion batteries are not powered by smoke, but molten lithium metal.
and when that escapes, fire will result.

One answer is to connect an external battery to the DC input connector
that way no chance of charging the battery form the PC,
so no bang, just ensure the volts are in the range the dc input can cope with.

If you have USB -C charging on the laptop, even easier,
 

Thread Starter

SethB

Joined Mar 30, 2021
21
Remember , its the volts difference across the load that sets the current,

If some thing is rated at 12 volts, and you connect it to 16 Volts, the current will increase ( V/R = current )
increased current equals smoke escaping
and as we all know, chips are powered by smoke , as when it escapes, the chip stops .

Also ,
if the battery you connect is "low" then the mother board will try to charge your battery,
without a proper charge circuit, the battery could suffer fail
and Lion batteries are not powered by smoke, but molten lithium metal.
and when that escapes, fire will result.

One answer is to connect an external battery to the DC input connector
that way no chance of charging the battery form the PC,
so no bang, just ensure the volts are in the range the dc input can cope with.

If you have USB -C charging on the laptop, even easier,
Haha I enjoyed the humor greatly!

Sadly I do not have USB-C charging.. I really really really wish they had added that tbh. That would make this laptop perfect.

I am able to connect the battery pack to the DC input of the laptop. However, when I do that, the battery pack shuts off after about ~30 seconds of charging. In the Krisdonia manual, it specifies this is because the laptop is drawing too much than the pack can output, and shuts off. What I don't understand is why can't the battery pack just charge the laptop at a slower rate than what the actual charger pack does? Is there any circuitry wizardry I can make that would allow it to charger slower?
 

KeithWalker

Joined Jul 10, 2017
1,787
Haha I enjoyed the humor greatly!

Sadly I do not have USB-C charging.. I really really really wish they had added that tbh. That would make this laptop perfect.

I am able to connect the battery pack to the DC input of the laptop. However, when I do that, the battery pack shuts off after about ~30 seconds of charging. In the Krisdonia manual, it specifies this is because the laptop is drawing too much than the pack can output, and shuts off. What I don't understand is why can't the battery pack just charge the laptop at a slower rate than what the actual charger pack does? Is there any circuitry wizardry I can make that would allow it to charger slower?
Your postings are causing some confusion. a "battery pack" is the plastic housing that contains the Li-Ion cells. You seem to be referring to the charger as the "battery pack" Please clarify.
 

MrSoftware

Joined Oct 29, 2013
2,015
It sounds like whatever device you're using to power the laptop (battery pack?) gives as much current as it can, but shuts itself off if the current is greater than what it was designed for. You can reduce the current by adding a series power resistor to the connection. That will reduce the current, but waste some energy to heat. It will also lower the voltage.
 

MisterBill2

Joined Jan 23, 2018
8,773
I have two laptops, HP probook 6450b, and they require an HP supply rated at 18.5 volts. I only have one HP supply that works and has the right connector for it. I have tried operating them with another well regulated supply that delivers 18.3 volts and is rated at 7.5 amps. Neither of the computers will even start with that supply connected, they claim it is not an HP supply, which is true, and so they refuse to even start. Worse yet, that computer battery pack is not accepted and so neither of the computers will charge it. The battery pack is rated at 11.1 volts, and so I am considering using a regulator, or maybe just a series diode, and a 12.0 volt supply to substitute for the battery pack, which claims to have 9 lithium cells.That must be 3 groups of 3 in series. So probably it is over 12 volts when fully charged.
 

Thread Starter

SethB

Joined Mar 30, 2021
21
Your postings are causing some confusion. a "battery pack" is the plastic housing that contains the Li-Ion cells. You seem to be referring to the charger as the "battery pack" Please clarify.
This is what I mean by "battery pack": https://www.amazon.com/Krisdonia-50000mAh-Portable-Battery-Charger/dp/B074N1B15F
An external source of power... not internal.
It sounds like whatever device you're using to power the laptop (battery pack?) gives as much current as it can, but shuts itself off if the current is greater than what it was designed for. You can reduce the current by adding a series power resistor to the connection. That will reduce the current, but waste some energy to heat. It will also lower the voltage.
So the battery pack I am referring to I should be calling "power bank". It is an external source of power.
Now, if I reduce the current with series power resistors, would it still provide current to the laptop and give it more juice? I essentially want to extend the time I can be without an AC plug.
 

MrSoftware

Joined Oct 29, 2013
2,015
Assuming the battery bank is turning off due to over current, and assuming there is no communication happening over the connection; a series resistor would reduce the current and possibly prevent the battery bank from turning off. But there is no guarantee that the laptop would operate on the reduced current or the resulting reduced voltage.
 

andrewmm

Joined Feb 25, 2011
1,473
This is what I mean by "battery pack": https://www.amazon.com/Krisdonia-50000mAh-Portable-Battery-Charger/dp/B074N1B15F
An external source of power... not internal.

So the battery pack I am referring to I should be calling "power bank". It is an external source of power.
Now, if I reduce the current with series power resistors, would it still provide current to the laptop and give it more juice? I essentially want to extend the time I can be without an AC plug.

The laptop is designed to charge off the expected charger,
i.e it is expecting the ability for the charger to supply the voltage it needs at the current it needs.

If you are connecting an external battery into the charger input of the laptop, then the external battery must be able to supply the desired voltage at the required current.

As an extreme, if you were to connect a car battery or a CR2212 battery, one would not expect the laptop to last the same on both sources.

If you measure the battery voltage your connecting when you connect it to the laptop, then I'd suggest you would see the voltage disappear as you external battery can not supply enough current to keep the voltage up
 

Thread Starter

SethB

Joined Mar 30, 2021
21
Assuming the battery bank is turning off due to over current, and assuming there is no communication happening over the connection; a series resistor would reduce the current and possibly prevent the battery bank from turning off. But there is no guarantee that the laptop would operate on the reduced current or the resulting reduced voltage.
The laptop is designed to charge off the expected charger,
i.e it is expecting the ability for the charger to supply the voltage it needs at the current it needs.

If you are connecting an external battery into the charger input of the laptop, then the external battery must be able to supply the desired voltage at the required current.

As an extreme, if you were to connect a car battery or a CR2212 battery, one would not expect the laptop to last the same on both sources.

If you measure the battery voltage your connecting when you connect it to the laptop, then I'd suggest you would see the voltage disappear as you external battery can not supply enough current to keep the voltage up
Thank you both!

This is what I was looking for. Now I have two ideas to achieve what I want:
1. Buy an external battery that has AC outputs, and use the charger. Now the part I am unsure of- I found one that supports up to 200W continuous out the AC ports, my charger says "200W" on it, but this I believe is the OUTPUT of the charging block. On the information for the charger, the input reads "100-240v ~ 3.0A 50-60Hz". Now from physics class, watts is equal to amps * volts. This would mean at 110V (what the battery AC output is) it can output about 2 amps. Would this battery pack work with the AC outputs or would my charger simply not turn on?

2. Buy another battery pack (the same krisdonia one) and connect them in parallel. From physics I remember that in parallel increases amps, in series increases volts. So theoretically each krisdonia power bank outputs at 19.5V at 4.7amp. Having two in parallel would be 19.5V at 9.4amp. Would approx 1 amp prevent my laptop from charging?

Otherwise, I cannot see a way to make this work.

Thanks again to everyone chatting about this with me.
 

MisterBill2

Joined Jan 23, 2018
8,773
Parallel battery packs will double the current availability, and if the voltage is correct then you should be able to make that work. But now some questions: The computer has a battery that mounts to the case very nicely. Are you able to use the HP supply for the computer to recharge this battery?? And if you are able to bring that battery to full charge that way, how long will it run the computer? Is the problem that the computer battery no longer provides enough running time because it is worn out? Or is there a different problem, such as needing to run the computer on batteries for 8 or ten hours? Or is the problem that you do not have the HP charger any more?
 

Thread Starter

SethB

Joined Mar 30, 2021
21
Parallel battery packs will double the current availability, and if the voltage is correct then you should be able to make that work. But now some questions: The computer has a battery that mounts to the case very nicely. Are you able to use the HP supply for the computer to recharge this battery?? And if you are able to bring that battery to full charge that way, how long will it run the computer? Is the problem that the computer battery no longer provides enough running time because it is worn out? Or is there a different problem, such as needing to run the computer on batteries for 8 or ten hours? Or is the problem that you do not have the HP charger any more?
My goal is to run the laptop on batteries for longer than the internal battery lasts. Depending on what I am doing, the battery life will last anywhere from 2 - 5 hours. Near the 5 hour end is usually okay. But the second I open a python GUI, startup photoshop/premiere/3ds max, or even push the brightness (cause its sunny) it suffers greatly. I work from home and while I love my setup (3 monitors and a nice desk) sitting around is boring. I would like to go work by the water or at a skyrise cafe in downtown. That is all.
 

MrSoftware

Joined Oct 29, 2013
2,015
Would it be more economically feasible to just buy a second laptop battery? Or is your laptop battery not easily swappable?

Putting 2 of those external battery packs in parallel might work.. or it might not, it's impossible to say with certainty without knowing more about them. If you want to be 100% sure your next solution is truly a solution, look for a single device that is strong enough on its own.

Laymans law of pretty much anything electrical; if you use manufacturers published specifications to try to perfectly match the supply power to the load requirements (such as the 200w in your case), odds of success are low. Overshoot what you think is required. If the AC adapter for the laptop says that it outputs 200W, be safe and get an inverter capable of 300W or 400W, your odds of success are higher.
 

Thread Starter

SethB

Joined Mar 30, 2021
21
Would it be more economically feasible to just buy a second laptop battery? Or is your laptop battery not easily swappable?
Correct. I would need a screw driver to do that. Its not really possible. I was thinking of maybe putting on another plug that is external that I could just plug another stock battery in, but I don't know how hard/feasible that is.

Putting 2 of those external battery packs in parallel might work.. or it might not, it's impossible to say with certainty without knowing more about them. If you want to be 100% sure your next solution is truly a solution, look for a single device that is strong enough on its own.
The Krisdonia battery packs have a direct DC output of 19.5v (20 on the readout) at 4.7 amps. The only thing I could see making it not work, is if it detects the voltage/current of the second battery pack and faults out. But I do not know. I am going to go with this option though as it seems most ideal.

Laymans law of pretty much anything electrical; if you use manufacturers published specifications to try to perfectly match the supply power to the load requirements (such as the 200w in your case), odds of success are low. Overshoot what you think is required. If the AC adapter for the laptop says that it outputs 200W, be safe and get an inverter capable of 300W or 400W, your odds of success are higher.
Yeah, I completely agree. The problem is finding one that is portable enough. All the ones with 350 watts of power are like the size of half a normal car battery. Not the best option. If combining battery packs doesn't work, I guess I will just have to deal with that lol.


Thanks again for all the help and guidance!
 

MrSoftware

Joined Oct 29, 2013
2,015
Do a little homework on the AC adapter before spending more money. Some laptop AC adapters communicate with the laptop, and the laptop may not work correctly if the communication doesn't work as expected. When you say your external battery shuts off, does it actually shut off? Or does the power output just go to zero? If the power output just goes to zero, it could possibly be that the laptop just stops taking power from it. I really don't know any thing about your laptop, but this is something worth looking into before spending more money. Here's an article about a Dell laptop that works this way, it's just what came up first in google but it's an example of what I'm referring to:

https://www.laptop-junction.com/toast/content/inside-dell-ac-power-adapter-mystery-revealed
 

djsfantasi

Joined Apr 11, 2010
7,693
I know you’re trying to find a solution for your existing laptop, but the suggestion to buy a device that matches your needs in the first place is sound.

I had an HP laptop where a second battery to extend the laptops operating life, was built in to the design. A second battery just snapped onto the back of the laptop. No opening the case. No matching power requirements. No screwdrivers.
 
Top