DC-DC with battery and monitoring support

[Vlad502]

The idea is to use LiPo battery as power source like laptop (an ITX one). So it must use AC adapter as charger.
I readed Battery Powered PC and come with idea to use 5S BMS (18,5V-21V) with serial connection (UART) monitoring, but it hard to find this kind of BMS (i found 7S BMS) or is expensive. And need boost circuit for charging.
There is OpenUPS with balancing, monitoring and charging, but it is only 6A input/output.
Then i found combo device for charging/balancing and some monitoring: ISDT SC-608 (or Q6 Lite). Other problem is how to shut down PC properly when battery is low. So i found M4-ATX, but is 12A on 12V rail (not sure if is powerful enough). Anyone experience with this one?
All ideas and suggestions are welcome. If you have experience with this topic, i will be glad to read your opinion.
Diagramm how i think to use DC-DC with battery:

 

[Kmpkt]

Just so I am clear, you want to use an approximately 19V LiPo battery source to power an ITX motherboard with capabilities to monitor battery health, temperature and remaining capacity?

 

[Vlad502]

That is correct

 

[Kmpkt]

So I am currently working on a similar project and unfortunately it is vastly more complicated than I'd anticipated. Firstly you need to pick a battery that actually has the monitoring functions you want (I am using Bosch 18V 6.0Ah Li-ion power tool batteries).

You then need to develop a custom PCB with custom microcode and controllers to manage all of this information and put in place the mechanisms you need to make use of your battery safe (temperature, discharge, over discharge protection, etc). Once you've got this portion done, you then probably want to have a way to get the information to your PC (I am choosing Bluetooth pairing) so you can monitor the batteries on your desktop as well as set parameters for safety etc. based on use case scenario.

I currently have two very highly specialized electrical engineers working on this, so I'm not entirely sure a full featured system is within the reach of the average DIY'er. Depending on the outcome and cost of this system, I may eventually offer it as a part of my product line. If you're comfortable using basic monitoring of discharge etc. on a standard battery that is obviously much more possible, but potentially dangerous - especially if you're considering a wearable solution.

 

[Choidebu]

The keyword here is 'ACPI battery'.
Basically an industry standard of how a battery controller should expose themselves to the computer. The standard for battery has moved to OS level so first you need you decide which OS you want to support. Then decide on a hardware interface. Follow the spec, make it acpi compliant. This involves making your own controller board and writing software for it.

 

[thewizzard1]

Logic Supply has what you are looking for.
https://www.logicsupply.com/openups2/

 

[Vlad502]

Sure is more compact with 18650 cells, but still max 5A: UPS comparison chart

 

[Choidebu]

Logic Supply has what you are looking for.
https://www.logicsupply.com/openups2/

Nice find!

 

[Vlad502]

Found the thread: Running a DC-DC based computer off of a battery

I become to understand why BMS is a must. My diagramm (first post) is not completely safe. On battery mode, ISDT charger will not work (no power in) as cell monitoring/balancing as i think before (must connect first input, then battery) and there is no protection for battery.