ProtoDAC TDA1387 X8 project

[wolf7250]

Yep, thanks  .
Do you think that the cost of the IanCanada solution is worth it to get the Battery Management System with undervoltage protection and a charging circuit?

[hifinet]

The thing posted above should not be considered safe. Actually, the LT1963 does have safety features, such as over current protection. Batteries should be removed when unattended. It's the Chevy Vega method of trying out LifePO4.

The Ali BMS has undervoltage protection and part of the charging circuit (it's missing the charging regulator). I have not verified that the voltages are actually setup for LifePO4. I assume they are. And, of course, you need to put it together with all the plugs, etc.

The IC equipment seems well designed. It just needs the linear regulator to get the 5V. As with most of the IC stuff, it's the only option available and priced accordingly. Some design development here .

[wolf7250]

Thanks for the link to that forum thread.
Interesting in this post Ian mentions that any regulator used downstream from the LifePO4 supply will degrade the power supply performance....

[hifinet]

That is probably true, but their is no other option. 5.5V max supply voltage for the TDA1387. Battery chemistry locks you into the voltages. The LT1963 is a fast transient response regulator, and one of the best ones out there. It sounds pretty darned good. It's a matter of personal taste. The UC (and probably the LifePO4 without the regulator) are too hard for my taste.

[wolf7250]

Thanks and true .

And for the record I think it's incredible that you have basically built an amazing sounding, low/no noise Power Supply yourself!

[hifinet]

It's pretty simple, and you can easily build it yourself. It's the cheapest way to try LifePO4. Just a bit of a hassle required to remove and recharge batteries. Also, some attention is required. If the batteries become over discharged, they are permanently ruined. 3.0V per cell is the discharge limit. There is a lower fire hazard with LifePO4 compared to other lithium batteries. The LT1963 will limit current to 1.5A.

[OnkelPH]

It's pretty simple, and you can easily build it yourself. It's the cheapest way to try LifePO4. Just a bit of a hassle required to remove and recharge batteries. Also, some attention is required. If the batteries become over discharged, they are permanently ruined. 3.0V per cell is the discharge limit. There is a lower fire hazard with LifePO4 compared to other lithium batteries. The LT1963 will limit current to 1.5A.

For how long can you play before recharging?

[wolf7250]

It's pretty simple, and you can easily build it yourself. It's the cheapest way to try LifePO4. Just a bit of a hassle required to remove and recharge batteries. Also, some attention is required. If the batteries become over discharged, they are permanently ruined. 3.0V per cell is the discharge limit. There is a lower fire hazard with LifePO4 compared to other lithium batteries. The LT1963 will limit current to 1.5A.

If the LT1963 regulator limits current to 1.5A then does that mean this can't be used to power a stack with a Raspberry Pi 2/3 as these require 2.5A or a stack with a 4 as this requires 3A?
Just curious for my own learning and planning.

I know you have and use a Zero W, from my understanding, this only requires 1.2A.

[hifinet]

Correct, the current limit of the LT1963 is 1.5A, so it would not be able to power the other RPis. Everything seems to be running fine with the Zero W/Kali/ProtoDAC. No undervoltage warnings.

For the Zero W/Kali/ProtoDAC stack about 8 hours. I am going to run the Zero W on a separate power supply and estimate time with Kali/ProtoDAC. Kali has a jumper that splits the RPi and Kali supplies. I am pretty sure ProtoDAC alone would run for days on a charge.

[OnkelPH]

Correct, the current limit of the LT1963 is 1.5A, so it would not be able to power the other RPis. Everything seems to be running fine with the Zero W/Kali/ProtoDAC. No undervoltage warnings.

For the Zero W/Kali/ProtoDAC stack about 8 hours. I am going to run the Zero W on a separate power supply and estimate time with Kali/ProtoDAC. Kali has a jumper that splits the RPi and Kali supplies. I am pretty sure ProtoDAC alone would run for days on a charge.

Thanks for the update. I’m planning on running only the ProtoDAC since the Q7 doesn’t have the 5v output.