Asynchronous I2S FIFO project, an ultimate weapon to fight the jitter

[qusp]

Originally Posted by iancanada

That should be the function of a charger. Passive battery management board need to be compatible with different kind of chemicals, as well as different voltage.

Ian

yeah Ian IMO that should really be a function of the battery management board, since the charger is not connected when under load it is not there to monitor the battery charge. there are not many different voltages, the vast majority will use LiFePO4, initially I had presumed you were using a combination of latching/non-latching relays and resistors to passively set the cut off voltages, only when I went to order the parts and take a closer look at the schematic did I notice it wasnt included. without something to do this, it will be very easy to damage and in some cases risk unstable chemical reactions.

this is IMO more important than catering for inrush current in other applications

actually i'll modify that, its more important to me for my objectives, you have your prerogatives.

[qusp]

on the other hand it should be an easy enough mod to add, using one of te optional connectors to tap/sense the voltage

[hochopeper]

Originally Posted by qusp

yeah Ian IMO that should really be a function of the battery management board, since the charger is not connected when under load it is not there to monitor the battery charge. there are not many different voltages, the vast majority will use LiFePO4, initially I had presumed you were using a combination of latching/non-latching relays and resistors to passively set the cut off voltages, only when I went to order the parts and take a closer look at the schematic did I notice it wasnt included. without something to do this, it will be very easy to damage and in some cases risk unstable chemical reactions.

Lets first clarify the situation that you're concerned about. The battery management board in its current design assumes that the device will be turned off while the batteries are not fully discharged. What about when someone walks away without turning it off and the batteries are allowed to continue to drain for an unknown period of time.

Is that the situation that you're concerned about?


I don't see a reliable way to sense voltage and trigger the relay for shut down without active devices. An under voltage threshold set by comparator and a logic gate would be what I'd add off board but it would no longer be passive...

[bigpandahk]

No matter it is added off board or included in the battery management board, it is a must have function for battery operated devices.

[PET-240]

As an aside, could we run a dropper resistor and led, giving visual confirmation of suitable voltage, run an LDR after the led to keep the "active" devices to of the loop. Or will the noise of the led's be adding noise to the power supply, though at dc it will be a constant current? If we then monitor the LDR resistance to switch off ad charge, is this not a wimpish way to do it? Not the most accurate for sure, but a simplistic method?

Just a thought.

[PET-240]

The LDR being a separate device of course but in series using the same current as the visual led.
You can probably tell I'm not an electronics genius.....

[iancanada]

Originally Posted by qusp

actually i'll modify that, its more important to me for my objectives, you have your prerogatives.

I'm interested in your solution, any details?

Ian

[iancanada]

Originally Posted by PET-240

As an aside, could we run a dropper resistor and led, giving visual confirmation of suitable voltage, run an LDR after the led to keep the "active" devices to of the loop. Or will the noise of the led's be adding noise to the power supply, though at dc it will be a constant current? If we then monitor the LDR resistance to switch off ad charge, is this not a wimpish way to do it? Not the most accurate for sure, but a simplistic method?

Just a thought.

Originally Posted by PET-240

The LDR being a separate device of course but in series using the same current as the visual led.
You can probably tell I'm not an electronics genius.....

That's good idea. An optical isolator may can do the same job as the led and ldr.

This question is connected to battery protection issue. Actually any lithium battery has a small protection board inside the battery pack. The protection board provides both over charge and over discharge protection by switching the MOSFET. However, my concern is any passive components will introduce noise ....

Ian

[iancanada]

Originally Posted by qusp

on the other hand it should be an easy enough mod to add, using one of te optional connectors to tap/sense the voltage

Current design already has a connector to monitor the battery, but how to make use of the monitoring result to cut off the relay without introducing
noise or short the ground is a question.

Ian

[qusp]

it will require working with the dual clock or fifo board signals I guess if you must have it disconnected at all times during audio. but i'll need to think some more on a more automatic plan. it will likely utilize a couple transistors, so not completely passive.

most lipo batteries with protection create more of a noise issue that any protection circuitry we might design, my A123 have nothing, any OEM bought cells usually wont either. A123 wont explode or catch fire when fully depleted, they just can get damaged, but some lipo may have pretty serious issues