Can I use Li-Ion batteries to power a CPU and motherboard?

[StormagedonBOD]

I plan to convert an old Celeron E1500 system into a laptop. It's not much but it's honest work. I've seen some other people on this forum are doing it but with harvesting cells from old MacBooks and such. But I was wondering if I can make something like a rechargeable battery pack with basic Li-Ion batteries, the ones used in vapes and such? If so is there a wiring diagram that I can follow at home?

[Levent]

How do you plan on doing that? An ATX system has 12, 5 and 3.3 voltage feed. That CPU is ancient, is 65W and 18650s arent cheap. Even if you managed to get enough 18650s to build you a battery pack that can give enough run time, how do you plan on recharging that? This is NOT a easy task. Just get a UPS.

[Moonzy]

Yes you can, but considering that a 100Ah 12v deep cycle battery I own, which weighs 45KG, can only power a decent PC for 3 hours or so, including displays, I wouldn't take this as a practical project

 

You'll need voltage regulators to bring the voltages to the right level, if you're interested in starting this project

[StormagedonBOD]

17 minutes ago, Levent said:

How do you plan on doing that? An ATX system has 12, 5 and 3.3 voltage feed. That CPU is ancient, is 65W and 18650s arent cheap. Even if you managed to get enough 18650s to build you a battery pack that can give enough run time, how do you plan on recharging that? This is NOT a easy task. Just get a UPS.

Thanks for the info! Tbh, this whole project is in it's infancy so I haven't planed it completely. I'll probably just get (or make) something like the st-nano120. So it won't be battery powered but it will be a laptop.

[StormagedonBOD]

12 minutes ago, Moonzy said:

Yes you can, but considering that a 100Ah 12v deep cycle battery I own, which weighs 45KG, can only power a decent PC for 3 hours or so, including displays, I wouldn't take this as a practical project

 

You'll need voltage regulators to bring the voltages to the right level, if you're interested in starting this project

Do you have any low power screen recommendations? I'm gonna run the whole thing off the integrated graphics so VGA is a must. 

And yeah, this isn't that practical but it seems like a fun project and as something that I'd like to do over the next 2-3 years. 

[Moonzy]

Just now, StormagedonBOD said:

Do you have any low power screen recommendations? I'm gonna run the whole thing off the integrated graphics so VGA is a must. 

And yeah, this isn't that practical but it seems like a fun project and as something that I'd like to do over the next 2-3 years. 

I'd say you'd have more luck with a raspberry pi and a small portable display, that might be more practical than a desktop chip which efficiency isn't much of a concern

[StormagedonBOD]

11 minutes ago, Moonzy said:

I'd say you'd have more luck with a raspberry pi and a small portable display, that might be more practical than a desktop chip which efficiency isn't much of a concern

Yeah but this is more of a challenge and I for some reason hate myself enough to do this.

 

[Moonzy]

Just now, StormagedonBOD said:

Yeah but this is more of a challenge and I for some reason hate myself enough to do this.

You may look into pico-psu, as they'll handle the majority of the voltage regulation for you and you just have to supply 19v (the most common voltage for them, I think)

They tend to deliver little wattage, of around 150-200W, but they should be enough for your needs

 

So you just have to handle delivering 19v to the pico PSU

[StormagedonBOD]

5 minutes ago, Moonzy said:

You may look into pico-psu, as they'll handle the majority of the voltage regulation for you and you just have to supply 19v (the most common voltage for them, I think)

They tend to deliver little wattage, of around 150-200W, but they should be enough for your needs

 

So you just have to handle delivering 19v to the pico PSU

I found the st-nano120 but I value my wallet and don't have 100 dollars to spend. I've been thinking to get an old or new server PSU and replace the loud fan with a noctua or something similair.

[Moonzy]

3 minutes ago, StormagedonBOD said:

I found the st-nano120 but I value my wallet and don't have 100 dollars to spend. I've been thinking to get an old or new server PSU and replace the loud fan with a noctua or something similair.

You're gonna have to spend more on batteries for the project, probably

Unless you plan to have it run for only 5 minutes or something

 

This isn't a cheap project by any means

You'll need to design your own voltage regulators, which idk how well versed in that field are you, if you don't want to rely on off the shelves components

[StormagedonBOD]

7 minutes ago, Moonzy said:

You're gonna have to spend more on batteries for the project, probably

Unless you plan to have it run for only 5 minutes or something

 

This isn't a cheap project by any means

You'll need to design your own voltage regulators, which idk how well versed in that field are you, if you don't want to rely on off the shelves components

I'm studying electrical engineering but I still have lots to learn.

[Moonzy]

3 minutes ago, StormagedonBOD said:

I'm studying electrical engineering but I still have lots to learn.

I'm not too well versed in batteries and which configuration would aid in charging it and what not, but once you figure out your battery pack voltage (and capacity in Wh), you can start looking at voltage regulators

Like buck/boost converters, which is what you're probably going to use in this project

[StormagedonBOD]

11 minutes ago, Moonzy said:

I'm not too well versed in batteries and which configuration would aid in charging it and what not, but once you figure out your battery pack voltage (and capacity in Wh), you can start looking at voltage regulators

Like buck/boost converters, which is what you're probably going to use in this project

Thanks for the advice man!

 

[Moonzy]

5 minutes ago, StormagedonBOD said:

Thanks for the advice man!

No problem, I'm actually interested in this project so if you do proceed with it and decide to document it, perhaps you can make a build log in the build log subforum and tag me @Moonzy

[StormagedonBOD]

3 hours ago, Moonzy said:

No problem, I'm actually interested in this project so if you do proceed with it and decide to document it, perhaps you can make a build log in the build log subforum and tag me @Moonzy

Of course, again, thanks for the advice! I will probably start a build log next month.

 

[Hackentosher]

I’ve seen it done before with one of these. Takes 12v dc and spits out tall the other voltages a motherboard needs. Idk how much tolerance there is on the input, but a 3s pack would work for a while before the voltage dropped too low. https://www.amazon.com/dp/B07WDG49S8/ref=cm_sw_r_cp_api_glt_fabc_E7YJ0632XX8SEA253E0P?_encoding=UTF8&psc=1

[mariushm]

It's not very difficult to convert an old LCD monitor to run on DC voltage. 

 

Older LCD monitors with fluorescent tubes (CFL) usually have a power supply that produces 5v and/or 3.3v for the board with the processor and video connectors, and another section which produces 12 ... 20v for the inverter which boosts this voltage to a high voltage the fluorescent tubes need to work.

Some models also have a separate 12v (or higher) output used by the audio amplifier, if that monitor model has speakers or headphones. 

 

With such monitors, you can buy separate small inverter boards from eBay which work with a wide input voltage (typically 8v...20v but around 12v-15v is recommended),  so you could fully remove the big power supply board and just power the monitor with 12v and use a small dc-dc converter to produce 5v and/or 3.3v for the display board.

 

Newer monitor with LED backlight still have a separate display board with the processor and the video inputs, which is powered with 5v or 3.3v, but the backlights are a bit harder to control. The power supply board typically converts the AC input to something like 50v .. 100v and a led driver circuit uses this to turn on the backlight, which is basically a bunch of leds in series... for example let's say 20 leds across the whole width of the panel, each with 3v forward voltage, so you need 3v x 20 leds = 60v to turn on the backlight. 

You can probably find separate led driver boards which accept 12v or some low voltage and boost it to the voltage required for the backlights to work, but I admit I didn't bother to research this .

 

Anyway, the point I'm trying to make is that it's quite easy to convert a lcd monitor to work off a reasonable voltage like 12v, using readily available components (dc-dc converter boards, inverter boards etc).

 

For computer hardware like motherboards, I would encourage you to first decide on a more efficient hardware. That old socket 775 processor will consume a lot of power for very little performance, making the whole thing last on batteries for very short time.

I would also encourage you to look for motherboards that can be powered directly from a DC in barrel jack, or from a 12v header, or something like that, instead of a 24 pin ATX connector, because with a 24 pin ATX connector, it's more complicated. You need 12v, 5v and 3.3v at the very least, but you also need to trick the motherboard into thinking a power supply is connected to it, by sending the power_ok signals and power_good signals (so that probably involves a microcontroller or something similar)

 

You can make your battery however you want, but in general, it's way more efficient to convert voltages DOWN instead of boosting them. 

So you'll get much more life out of a battery if you make it a  4s or 5s  ( 4 x 3.7...4.2v = 14.8...16.8v)  and convert this voltage down to 12v and 5v and 3.3v ... if needed. 

If you buy a motherboard with a DC In connector, you may only need a dc-dc converter to provide a stable 12v to the motherboard, or ... if the motherboard expects 16..20v in (some Intel and Asrock boards had 16.5v DC In barrel jack connectors but worked with as low as 13-14v), it may work directly from the battery pack without any voltage stabilization.  

The easiest would probably be to use 8-12 batteries ... have 2 or 3 batteries in parallel, then connect 4 of these groups in series.  

Another benefit of sticking with 4S or 5S  (4 or 5 cells or group of cells in series) is that you can buy chargers easily for these batteries, and these chargers contain cell balancing circuitry and all that good stuff ... and you can also power such chargers with laptop adapter style power supplies (ex 16.5v...20v laptop adapters)

See for example hobbyking dot com , they have a chargers section with all kinds of chargers. 

 

You could also make it so that when you insert the barrel jack connector of your 16-20v laptop adapter into a plug, you connect your laptop adapter directly to the dc-dc converter powering the motherboard, or directly to the motherboard header, and disconnect the battery and turn on the charger to charge the battery. 

 

 

 

 

 

 

[StormagedonBOD]

Okay so I've got a bit of an update for you guys. I've bee doing some research in my spare time and I've got some ideas. 

So I've found these Pico PSU's that Are powered through a power brick using a barrel plug, but I want it to be battery powered. The original idea was to use a RC car battery but that's too complicated and in order to charge it I would have to take out the whole battery then charge it which isn't very practical. So I found some rechargeable battery packs that have a 12V output which I could connect to the Pico PSU but the maximum output current is 6A. That would give me a maximum power draw of 72W which isn't a lot. But theoretically it would work as a proof of concept. I'm not sure if that would be enough to power an old Celeron E1500 without lowering the voltages since that chips rated TDP is around 65W and that doesn't leave me with enough power for the rest of the system.

Here are some links to amazon product pages: https://www.amazon.com/dp/B07WDG49S8/ref=cm_sw_r_cp_api_glt_fabc_E7YJ0632XX8SEA253E0P?_encoding=UTF8&psc=1

https://www.amazon.com/TalentCell-PB120B1-Rechargeable-38400mAh-142-08Wh/dp/B07H8F5HYJ?ref_=ast_sto_dp

https://www.amazon.com/TalentCell-Rechargeable-11000mAh-20000mAh-Portable/dp/B01337QXMA?ref_=ast_sto_dp

The Pico PSU was also suggested by one of you, thanks Hackentosher.

 

[mariushm]

Most picoPSUs that are 12v input, don't filter the 12v and simply pass it through to the components. The picoPSU just has 2-3 dc-dc converters on the circuit board to produce 3.3v and 5v from the 12v input  (and -12v but that's irrelevant these days).

 

This is a problem in your case if you use that power bank, because as you can see in the description in the first product it says 12.6v ...9v max. 6A  and the second product says 12.6v 6A 

12.6v is not a problem, all hardware is designed to tolerate at least 12v +/- 5%, but going below 11v will be a problem.

 

Also, 6A is not enough, especially when the picoPSU will consume some current to produce those 3.3v and 5v .... for example if the motherboard needs 10-12 watts on 3.3v and 5v for onboard stuff (chipset, network, audio), you're left with 5A on 12v because a bit over 1A at 12v (12w+) will be used by the picoPSU.

 

 

[StormagedonBOD]

15 hours ago, mariushm said:

Most picoPSUs that are 12v input, don't filter the 12v and simply pass it through to the components. The picoPSU just has 2-3 dc-dc converters on the circuit board to produce 3.3v and 5v from the 12v input  (and -12v but that's irrelevant these days).

 

This is a problem in your case if you use that power bank, because as you can see in the description in the first product it says 12.6v ...9v max. 6A  and the second product says 12.6v 6A 

12.6v is not a problem, all hardware is designed to tolerate at least 12v +/- 5%, but going below 11v will be a problem.

 

Also, 6A is not enough, especially when the picoPSU will consume some current to produce those 3.3v and 5v .... for example if the motherboard needs 10-12 watts on 3.3v and 5v for onboard stuff (chipset, network, audio), you're left with 5A on 12v because a bit over 1A at 12v (12w+) will be used by the picoPSU.

 

 

That's a bummer, donno what to use otherwise. There are a bunch of websites that make proprietary batteries but those are expensive. I could, in theory, do the RC car battery idea but that's gonna require a lot of tinkering and designing. That shouldn't be that big of a challenge.

[mariushm]

RC car batteries are not optimized for continuous long use, they're optimized for high current bursts, acceleration, things like that, basically ability to give high currents but not long discharge.

If I were to do it, I'd look into regular lipo or LiFe batteries and connect 4 or more in series to obtain a voltage slightly higher than 12v even when close to discharge. For example, a regular 18650 would provide meaningful energy down to around 3v ... so if you have 4 in series, you get 12v when discharged, 4x4.25v = 17v when fully charged. 

Then, you can use a very efficient dc-dc converter to get 12v from 12v..20v or get a picoPSU that's advertised as wide input range, as those will also regulate the input voltage and accept up to 25-35v.

 

There's chargers out there which can charge battery packs with 4-5 cells in series, and provide load balancing ... and some chargers can be powered with a laptop adapter or directly mains, so charging is taken care of.

 

For example, here's a 6000 mAh pouch battery ... have 4 of these in series and you have a 24,0000 Ah battery : https://www.digikey.com/en/products/detail/mikroelektronika/MIKROE-4475/13679421

Digikey is expensive, you can get such batteries for maybe half the price in other places.

 

LiFe batteries are also an option ... but they require a charger optimized for them, as their voltage is different ... 2.0v cut-off, 3.2v nominal, 3.6v max   (compared to around 2.8v-3v turn off, 3.7v nominal , 4.25v peak for lipo batteries)

Here's an example, a 3300 mAh battery : https://www.digikey.com/en/products/detail/zeus-battery-products/PCIFR26650-3300/9828825