Charge laptop with deep-cycle battery: is it possible?

[Overlord23]

Hi all,

I would like to know if there is a way to remote working in a "camping" style.
I need to know if, given the power consumption of my laptop and the power provided by a deep-cycle battery, I am able to work remotely for like 5 working days.
Deep-Cycle batteires are not like car batteries that provides a peak of energy on engine startup. They are designed for a lower and costant energy supply.

I have a HP laptop model: HP ZBook Power G7, i7-10750H Quadro T1000 Max-Q
I don't know if I am entitled to post any links so I will list the specs here and attach a picture:
Battery charge: see the image attached
the wire plug is type L (italian wall socket)
INPUT: 100-240V ~ 2.5A    50-60 Hz
OUTPUT: 19,5V  ⎓ 7.7A    150.00 W

Laptop battery:  Non-Removable 6-Cell: 83 Wh    Lithium-Ion Polymer (LiPo).
Specs sheet says Estimated Battery Life 15.25 Hours

I was looking at power stations such as Jackery Explorer 500 or Bluetti since they are ready to use, I mean they have many different types of outlets. But I would like to do it on a lower budget.

Now the math and correct me if I'm wrong: laptop battery draws 83 Wh (peak? average? I don't know)   so 83Wh x 10 hours = 830 W
the Jackery Explorer 500 provides only 500 W... so it would be like half day of work.

So I was thinking of using a Deep-Cycle battery, I found some 12V , 220 Ah AGM   so that means around 2600 W.   That would be enough for like 3 laptop charges. And it costs the same of a Jackery 500.

Another question is how do I link the battery to the laptop. Do I have to plug the battery charge to an inverter also connected to the battery? But the battery charger requires 100-240V input

Any comment / suggestion / clarification would be appreciated, also because I am a total newbie
Thank you!

[sauronofmordor]

Wh isn't Watts/Hours, It's Watts*Hours (or 3600 Joules, 1 Watt second = 1 Joule). Wh a measure of energy storage, not power draw. Power is measured as Watts (Watts = Volts*Amps, where for consumer devices the voltage is constant and the amps go up or down based of of how many Watts/power draw your laptop needs). To get how many watts your laptop consumes you need to look at TDP (Typical Power Draw) for your laptop, then multiply that by how long you're going to be drawing that power to get how much energy storage you need. We can get your average watt draw while on battery based off of how long your laptop lasts with it's battery's energy storage, but when you plug in the laptop you might end up using far more energy per hour due to losses and because your laptop might be less power conservative while plugged in.

 

Assuming your laptop actually last 15 hours using 83 Wh of storage that means you have a TDP of around 5.5 Watts. if you want to run your 5.5 Watt laptop for a full work week (40 hours) you just multiply watts * hours to get Wh so 5.5*40=220Wh of storage. This is a bare minimum though, you would definitely need more than that especially if you want it with any sort of reliability and planning for degradation of the battery. I would probably double that number and say that you need 450 Wh, I would suggest maybe a bit more than that to be extra safe. Also make sure your source can provide at least 2.5 amps at 100V, as that's the listed input on your power supply.

[sauronofmordor]

Oh and the Jackery Explorer 500 has 518 Wh, so it'd provide a maximum of about 95 additional hours of battery life to your laptop (though efficiency losses compared to your internal laptop battery would eat into the number quite a bit. 

[manikyath]

there exist laptop chargers that run off of a car battery.

HP used to sell them as well, but not anymore it seems.

 

only issue is that you have quite a beefy laptop, so it may not like charging off a 65-ish watt car charger (i dont think you'll find high power ones that actually deliver that power)

 

another thing you can do is get a pure sine wave inverter, they arent *that* expensive anymore these days.

just a random example from google:

https://www.redarcelectronics.com/us/pure-sine-wave-inverters/400w-pure-sine-wave-inverter

 

---

 

having all that said, there's some errors in your math.

 

31 minutes ago, Overlord23 said:

Laptop battery:  Non-Removable 6-Cell: 83 Wh    Lithium-Ion Polymer (LiPo).
Specs sheet says Estimated Battery Life 15.25 Hours

let's say that the estimated battery life is overestimated by a factor of 5x (depends on what you're doing with it, but i guarantee you HP is staring at notepad with the brightness all the way down).

so we "rule of thumb" that down to 3 hours of battery life on average.

83Wh / 3h = 28W average (watthours divided by hours = watts)

 

the jackery explorer 500 claims 518Wh. 518Wh / 28W = 18.5h (Watthours divided by watts = hours)

 

or.. the less roundabout way of calculating this: 518Wh jackery divided by 83Wh laptop = 6.25 laptop charges.

 

the 12v 220Ah battery (which, by the way, you need tools to move these, i've dealt with them before, even if you're buff as heck you dont really want to move them on your own. the first lead-gel manufacturer i found on google claims 62kg weight.)

 

12v * 220Ah = 2640Wh (volts times amps = watts, volts times amphours = watthours)

or to continue the math above, about 31.8 laptop recharges.

 

however.. 220Ah batteries arent practical in any mobile fashion, they're the sort of battery that keeps a small yacht off-the-grid (or off the generator/engines) for a few days at least.  you basicly hard-mount these in a vehicle (read: hard-mount because you dont want them to slip).

 

we had a pair of those 220Ah lead-acid monsters on the family yacht, the year we replaced them (because as it turns out, batteries wear out after 40 years) we spent a few days off the grid on them.

every light bulb on board was halogen (or probably.. just fillament), the toilet was something like a 10A load when flushing, the inverter for wall outlets was from back in the "50% efficiency is good enough" days, the fridge was an OOOOLD american fridge that pulled a stupid amount of power as well... all in all recharging phones and laptops wasnt the problem

 

having all that said.. if you want to be off-the-grid for a few days.. look into something else than just batteries: solar panels, a small generator, etc. the worry of running out of power is much smaller if you have a means of replenishing that power at least to some degree.

[Spotty]

56 minutes ago, Overlord23 said:

Another question is how do I link the battery to the laptop. Do I have to plug the battery charge to an inverter also connected to the battery? But the battery charger requires 100-240V input

You will need to use an inverter to get the 100-240V AC from the 12VDC the battery provides. 12VDC to 115/240VAC are pretty common. Since the charger is rated for max 150W you will need an inverter that is rated for at least that. A 12V battery won't be exactly 12V and will vary depending on the charge level, it'll likely be around ~14V max and ~11V when discharged. Make sure your inverter can handle ~11V to ~14V input.

 

1 hour ago, Overlord23 said:

Now the math and correct me if I'm wrong: laptop battery draws 83 Wh (peak? average? I don't know)   so 83Wh x 10 hours = 830 W

Not to repeat the posts above, but 83Wh is the capacity of the battery in the laptop, not how much power it draws. For example if the laptop draws a constant 8.3W the battery will last 10 hours (8.3W x 10h =83Wh).

 

Unless you're planning on running other things off that battery, 220Ah would be overkill for just charging a laptop for a few days. But if you're planning on going camping/off grid for a few days and also want things like a small fridge running off it then sure. Just make sure your inverter can handle whatever other devices you're plugging in as well and isn't going to exceed the discharge current rate for the battery.

[Kilrah]

Note that while "deep cycle" batteries handle lower charge state better they still don't like being discharged too much or kept at lower charge states for long or lifetime will be reduced significantly, it's more like they're OK to discharge to 50% instead of 80-90% for a normal one. So you still want to oversize quite a bit.

 

Would need to measure the PC's actual draw but assuming 50W and 5x 8h days that's 2kWh, or 166Ah at 12V - 220Ah would be a decent choice given the above.

[Overlord23]

Thank you all for your replies and your time!
You have been very precises and clear.

As pointed out by @manikyath the laptop battery life depends on the use, I have a beefy laptop because I use Adobe Suite programs daily. Mostly Photoshop and Illustrator, and less time After Effects. Today I tested it on a very light use and the battery lasted 3 and a half hours.
Also I didn't connect my phone, it would draw energy from the pc too... I would use it as a usb hot-spot (as a router).

So if I go for the Jackery Explorer 500, with estimated 5 / 6 laptop charges, I would need 2 of them to work for 5 days safely. (500 € x 2pcs = 1000 € budget)

If I chose the deep-cycles batteries I could just go for like 4 or 5 batteries like this one:
60Ah 12V AGM Deep Cycle Victron Energy   (around 120 € each)
it would be slightly more Watts than a 220ah  (600€), but they weight just 20 Kg each and for almost the same price.
I could use one battery per day without drain all the power and, the day after, use the next one and so on. So I don't drain them completely and they would last longer. And I could easily handle 20kg

I think it would be better to opt for Deep-cycle batteries instead of power stations also because I don't trust the lifespan advertised by those brands. And, with the proper care, I think those deep-cycle batteries would last longer (better investment?)

 

I could just build a righ for the car trunk to store them and make them still.
I understand that the Jackery would be more user-friendly because it is designed for this, with all the USB ports and so on.
I will look more into the inverter @Spotty

Feel free to add anything else comes to your minds!
Thank you!