10 pin Li-Po battery connector experiment

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JaySom
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Joined: Wed Dec 23, 2020 2:34 pm

Wed Dec 23, 2020 2:38 pm

ccs_hello wrote:
Tue Jan 08, 2019 2:46 am
Adding some partial info and waiting for people who have time to drill down and thoroughly exercise the battery options.

1. If I put a 2s Li-Po in that battery connector, indeed it can be charged, it seems to be no CC or CC value set very high
circuit on LPA board itself (need to study more.)

2. Try to check the dual/concurrent power option and tried to remove one of the power sources to see it causes PC to hang. It seems to be okay for low and (up to) medium current drawn applications. Under heavy load, don't know.
It's sort of like the laptop (with built-in battery pack) behavior.

3. Note that (I am running Win10 Pro) Windows detected the battery power in place and seems to
trying to calibrate battery capacity and energy flow-in/flow-out.
Without battery pack providing fuel gauge info thru I2C (that SCL and SCK lines unused in LPA doc), the estimation may be pretty crude.

4. Power source from Li-Po 10-pin, appears to be backfeeding the DC-in 4-pin connector (with 0.6V voltage drop.)

This entire area should be a factory design topic, I am simple an observer lightly scratching the surface.
I was wondering if it would be possible to use this backfeed with a buck convertor to power a pi 4? I need to power the pi and two 7 inch touchscreens essentially from the battery but via the alpha. I’m banging my head against the wall trying various ways but I’m struggling with current issues. Any help would be greatly appreciated! Thanks :)

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ccs_hello
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Joined: Sat Oct 13, 2018 9:16 pm

Wed Dec 23, 2020 4:12 pm

The 10-pin Li-Po battery connector is intended to charge a 2S battery (terminal voltage somewhere in between 6.4V and 8.4V.) Charging current is limited to a value (how much I forgot.)

So your pseudo "power drain" module has to reasonably minick the characteristics of the above described 2S LiPo pack. It should emulate such behavior or some expected behavior may happen (e.g., under-voltage lock-out, over-current break, charging-complete 8.4V trickle charge mode, etc.)

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JaySom
Posts: 3
Joined: Wed Dec 23, 2020 2:34 pm

Wed Dec 23, 2020 11:24 pm

ccs_hello wrote:
Wed Dec 23, 2020 4:12 pm
The 10-pin Li-Po battery connector is intended to charge a 2S battery (terminal voltage somewhere in between 6.4V and 8.4V.) Charging current is limited to a value (how much I forgot.)

So your pseudo "power drain" module has to reasonably minick the characteristics of the above described 2S LiPo pack. It should emulate such behavior or some expected behavior may happen (e.g., under-voltage lock-out, over-current break, charging-complete 8.4V trickle charge mode, etc.)
Thanks for replying. I don’t fully understand your response, I’m not sure if I worded the question correctly. I have the battery hooked up to the alpha and my aim is for the alpha to power the pi 4 but I’m struggling with amperage. So with the battery back feeding the 12v 4 pin connector I was wondering if I could somehow piggyback from that. I have a buck convertor (5v 3amp) but the main goal is for the pi to basically share the battery.

Thanks again for your help. Really appreciate it!

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ccs_hello
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Fri Dec 25, 2020 4:07 am

That 4-pin DC_IN connector is for getting the power into LP Alpha/Deta, not the other way around.

BTW, it occurs to me that if you are not using LP Alpha/Delta's USB-C port, you can always use it as the "PD Source" mode. I.e., supplying power to other devices. (If needs more than 5V 0.5A....) you may need to use a USB-C "PD Trigger" dongle (e.g., set it to 5V 2A mode) to get it to supply power to your external device such as a Raspberry Pi 4.

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JaySom
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Joined: Wed Dec 23, 2020 2:34 pm

Sat Dec 26, 2020 1:23 pm

ccs_hello wrote:
Fri Dec 25, 2020 4:07 am
That 4-pin DC_IN connector is for getting the power into LP Alpha/Deta, not the other way around.

BTW, it occurs to me that if you are not using LP Alpha/Delta's USB-C port, you can always use it as the "PD Source" mode. I.e., supplying power to other devices. (If needs more than 5V 0.5A....) you may need to use a USB-C "PD Trigger" dongle (e.g., set it to 5V 2A mode) to get it to supply power to your external device such as a Raspberry Pi 4.
Thanks for that, I’ve never heard of a pd trigger before so I’ll look into that. Do you know the max amps I could pull from that port. It does power the pi via usb c to c but I’m getting the underpower lightning bolt on the pi. I’m starting to think that powering two systems with 2 usb touchscreens just isn’t going to work via the board alone and may just have to provide the pi with its own battery. Thanks again for all your help and I hope you had a great Christmas!

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