recharge a laptop with a 20V tool battery?

orbital

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Feb 8, 2007
Messages
4,229
Location
WI
@orbital thank you for your effort to help.

Let me rephrase my question.

I have a HP Pavilion 15 laptop.
The charger delivers:
45W 19.5 volt 2.31 A

Would it be safe to direct drive from a Ryobi 18/20V battery into my laptop?
+

A 65 or 90W HP charger will not damage you laptop, it'll just take what it needs

edited out some analogies ....

Overall, if you're not comfortable, let the idea go.
There are many ways to get power:)
 
Last edited:

Myself

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Oct 13, 2006
Messages
33
Bit of a necro-thread by a necro-user here (I haven't logged in since 2009?), but yeah, I've done this with my Thinkpad T460 and my Evolve III Maestro, and can confirm it works exactly as OP suspects. Nothing but battery contacts and barrel plugs. The T460 takes one of those funky rectangular plugs, so I have an adapter that turns it into a nice 5521 and that's what's actually on the Ryobi pack.

Not only is it very light weight and compact, it's also highly efficient because the power only gets converted once, as the laptop ingests it.

Just be ultra careful about polarity. Double-check then check again. The Maestro in particular has a footprint on the PCBA for a reverse-polarity protection diode, but it's not installed.
 

Ernie777

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Joined
Jan 3, 2024
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Location
Roanoke Va.
I have a HP Pavilion 15 laptop.
I also have a number of Ryobi 18V batteries. They are 20V when fully charged.
My laptop takes this as a charger input
45W 19.5 volt 2.31 A AC adapter charger.

Do you think I could use a connector like this and wire it to the power input plug sized to fit my laptop?
Would i be able to run my laptop on my tool batteries?
OR would I be able to transfer the stored energy from my tool batteries to the laptop battery?

View attachment 51093

I have a HP Pavilion 15 laptop.
I also have a number of Ryobi 18V batteries. They are 20V when fully charged.
My laptop takes this as a charger input
45W 19.5 volt 2.31 A AC adapter charger.

Do you think I could use a connector like this and wire it to the power input plug sized to fit my laptop?
Would i be able to run my laptop on my tool batteries?
OR would I be able to transfer the stored energy from my tool batteries to

I have a HP Pavilion 15 laptop.
I also have a number of Ryobi 18V batteries. They are 20V when fully charged.
My laptop takes this as a charger input
45W 19.5 volt 2.31 A AC adapter charger.

Do you think I could use a connector like this and wire it to the power input plug sized to fit my laptop?
Would i be able to run my laptop on my tool batteries?
OR would I be able to transfer the stored energy from my tool batteries to the laptop battery?

View attachment 51093
SYMIK 100W Charger & 145W Power... https://www.amazon.com/dp/B0CLLHQX6H?tag=cpf0b6-20
 

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Hooked on Fenix

Flashlight Enthusiast
Joined
Dec 13, 2007
Messages
3,065
Hope that inverter works for you. I prefer the Milwaukee Top Off. It has a 45 watt USB-C port as well as the 120 volt outlet. Most modified sine wave inverters screw up electronics and stink for charging batteries, but the Milwaukee seems to work just fine.

Your original setup would not have worked and would have been potentially dangerous. First, to charge a battery, input voltage has to be higher than output voltage. Your laptop has a charger input of 19.5 volts. That's likely 5 cells at 3.9 volts each. Charger circuitry can decrease amperage and increase voltage (same wattage) to top off battery pack if needed to reach 4.2 volts per cell. Ryobi battery pack works in two sets of 5 cells reaching basically the same voltage (3.7 x 5= 18.5 volts nominal, 4.2 x 5= 21 volts). Laptop charger split the difference. You were trying to charge one device with another with roughly the same voltage. Power will transfer from the one with the higher voltage until they equalize. Then the current stops flowing. Your setup bypassed safeties for both devices. There was nothing to stop the charging from terminating at the tool battery end (current can flow backwards) or regulate voltage at the laptop end as the tool battery decreased in power. A lot can go wrong with this including a big boom. A fuse will stop a surge and helps, but it doesn't prevent the power from going the wrong way. Need higher input voltage and a rectifier diode wouldn't hurt. Glad you went a safer approach of just buying the product for your needs.
 
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