5 ms·

Why can't all of this just be done in the charge controller? The logic seems pretty simple. When plugged in, accept all power, charge the high capacity battery

by pilom 11y ago

Why can't all of this just be done in the charge controller? The logic seems pretty simple. When plugged in, accept all power, charge the high capacity battery at its highest rate, any extra power available goes to the fast charging battery. On discharge, discharge the fast charging one first. Unless there are differences in charging efficiency between the batteries, I don't see how software with knowledge of my schedule could make things better?

skywhopper 11y ago
Agreed. This story didn't provide any examples that made sense to me about why there would need to be different charging strategies in different situations. If you have your device plugged in overnight, then it will be fully charged no matter what strategy you use. If you have it plugged in for only a short time, you will have wanted it to charge as fast as possible during that time, so the battery should choose whatever charging pattern maximizes energy storage at the current charge levels. I had expected this story to tell me that different battery chemistries react differently to different drain patterns, ie that low-drain usage might be better served by battery chemistry X and spiky high-drain usage by battery chemistry Y, and the OS could switch the power source between the batteries depending on the predicted near-future discharge pattern, based on what app was foregrounded or whatever. But the idea that your battery would benefit by knowing your flight schedule seems to be reaching pretty far for a justification.
- csirac2 11y ago
  If you can bring yourself to get past the SDx marketing bandwagon, the paper covers multi-battery and multi-chemistry systems. Laptops aren't the obvious use-case for this. Given that Tesla is involved, they're thinking more along the lines of cars and home/office energy storage, where you have a large and diverse set of batteries to manage, and interesting real-time pressures you just don't see in a laptop. BMS in a laptop mostly just has to keep the battery safe and avoid unnecessary charge/discharge cycles. In a more complex system trying to salvage every joule of energy and maximize lifespan of each cell, the fact that batteries are less efficient to charge (or discharge) the closer they are to full (or empty) might be taken into account when deciding which to charge/discharge (for example). A car might dump sudden regenerative braking power into high-C batteries if the main batteries can't take that charge at a given instant. Satellites often use exotic batteries able to fully charge and discharge 10 times a day for decades at a time, but these have enormous self-discharge rates measured in days. Every chemistry has a unique set of compromises. There is plenty of room for smarter BMS in consumer systems that manage complex battery storage arrays responding to thermal, aging, cycle count, charge and load pressures more intelligently.
yo-code-sucks 11y ago
Theres a company doing this, I think its..... virtualpowersystems.com

by pilom 11y ago

skywhopper 11y ago

Agreed. This story didn't provide any examples that made sense to me about why there would need to be different charging strategies in different situations. If you have your device plugged in overnight, then it will be fully charged no matter what strategy you use. If you have it plugged in for only a short time, you will have wanted it to charge as fast as possible during that time, so the battery should choose whatever charging pattern maximizes energy storage at the current charge levels. I had expected this story to tell me that different battery chemistries react differently to different drain patterns, ie that low-drain usage might be better served by battery chemistry X and spiky high-drain usage by battery chemistry Y, and the OS could switch the power source between the batteries depending on the predicted near-future discharge pattern, based on what app was foregrounded or whatever. But the idea that your battery would benefit by knowing your flight schedule seems to be reaching pretty far for a justification.

csirac2 11y ago
If you can bring yourself to get past the SDx marketing bandwagon, the paper covers multi-battery and multi-chemistry systems. Laptops aren't the obvious use-case for this. Given that Tesla is involved, they're thinking more along the lines of cars and home/office energy storage, where you have a large and diverse set of batteries to manage, and interesting real-time pressures you just don't see in a laptop. BMS in a laptop mostly just has to keep the battery safe and avoid unnecessary charge/discharge cycles. In a more complex system trying to salvage every joule of energy and maximize lifespan of each cell, the fact that batteries are less efficient to charge (or discharge) the closer they are to full (or empty) might be taken into account when deciding which to charge/discharge (for example). A car might dump sudden regenerative braking power into high-C batteries if the main batteries can't take that charge at a given instant. Satellites often use exotic batteries able to fully charge and discharge 10 times a day for decades at a time, but these have enormous self-discharge rates measured in days. Every chemistry has a unique set of compromises. There is plenty of room for smarter BMS in consumer systems that manage complex battery storage arrays responding to thermal, aging, cycle count, charge and load pressures more intelligently.

yo-code-sucks 11y ago

Theres a company doing this, I think its..... virtualpowersystems.com