L.P. Alpha DC power experiments and observations

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tucher
Posts: 2
Joined: Wed Oct 24, 2018 3:52 pm

Thu Oct 25, 2018 7:54 am

Thanks! So, in your tests the board works under heavy load with 10.5V input voltage, correct?

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ccs_hello
Posts: 427
Joined: Sat Oct 13, 2018 9:16 pm

Thu Oct 25, 2018 11:40 am

It is critical that power system is planned correctly:
connector(s), wire thickness, (I always add) large filter capacitor serving as the reservoir for CPU bursting (or UPS switches over/switches back), and quality switching power supply module.

With that said, yes, 10.5V in my case, works fine. <-- caveat: I am not a gamer nor an extreme overclocker/benchmark pusher/tweak scenario TDP/etc. etc.

I've used many SBC, mini PC, etc. and have found the make/break factor has been adding the large DC power feed capacitor (min. 2200uFD, larger is even better.) It adds the stability to the system.

For a system mainly based on battery pack, additional factors will be at play as well (BMS used, max discharge, capability power paths, etc.)

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ccs_hello
Posts: 427
Joined: Sat Oct 13, 2018 9:16 pm

Thu Oct 25, 2018 2:27 pm

Worthwhile to mention that when the rechargable battery is in its tailing end of discharge cycle, the rated capability will have to be derated. For example, a 2C Li-Ion 18650 cell when battery's terminal voltage is fairly low (say 3.5V <-- Li-Ion is 3.7V nominal) and a heavy load is demanded (especially instantaneously such as CPU bursting or UPS switch-over), the battery voltage may drop significantly.
Please note for any of these SBCs, the end-result will be CPU freeze or shutdown (black screen.) It is not: SBC senses insufficient power supply thus throttling down. <-- I wish that is the case but not the reality

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vnlevanduoc
Posts: 10
Joined: Fri Oct 12, 2018 2:13 pm

Sun Dec 16, 2018 11:44 am

Can I ask you something

Image

I bought a Cable Cap. Https://banlinhkien.vn/goods-10715-bo-d ... -0580.html

Is it right?

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ccs_hello
Posts: 427
Joined: Sat Oct 13, 2018 9:16 pm

Sun Dec 16, 2018 8:19 pm

Yours seems to be too large. It's 2.0mm pitch.
JST-PH2.jpg
JST-PH2.jpg (1.92 KiB) Viewed 832 times

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vnlevanduoc
Posts: 10
Joined: Fri Oct 12, 2018 2:13 pm

Mon Dec 17, 2018 3:00 am

I do not know the store
1 wire 5.0 mm
1 wire 2.54 mm
Finally, those two are not sad at all.

Do not know if you can supply a 2pin (red, black) cable?


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sutam1
Posts: 1
Joined: Fri Jan 04, 2019 11:03 pm

Fri Jan 04, 2019 11:11 pm

Good day, can you help me with my proyect, i have 21 (18650) in a 3S array, with a protection charging circuit. Each battery is rated 9900 mAh. And is marked 3.7V. Im not a electrician or engenier. Do you know how long will this setup supply power? Thanks.

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ccs_hello
Posts: 427
Joined: Sat Oct 13, 2018 9:16 pm

Sat Jan 05, 2019 2:41 am

There is no 9900mAH 18650 cell. That rating is fake. At best, it's 2500mAh or even less.
My LP Alpha with light load will consume 8-10Watts with an eDP LCD panel also powered. Highest peaking, I would guestimate it's about 30 Watts or less.
So let's take a mid-point: 15 Watts.

Assuming your 18650 battery each cell is 2000 mAh, so your 7P 3S battery will have approx 3.7 x 2 (7.4 Watt-hour) per cell.
21 of them will be 155 Watt-Hour total.
Divide that 155 WH with 15 W will be 10 hour approx.

BTW, please note although typical BMS on Li-Ion will shut it down at 3.2V terminal voltage (3S will be 9.6V),
however, LP Alpha (if using that 4-pin DC power IN connector) will shut itself down at 10V. (In between 10 and 10.5V is marginal.)
Thus the battery will not reach its full-drain protection of 3.2V set by BMS but stopped by LP Alpha at 3.3V. I.e., not all energy can be utilized.

I don't have info on the proprietary 10-pin 2S battery-pack connector.

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nyteshade
Posts: 3
Joined: Sun Jan 13, 2019 6:14 pm

Sun Jan 13, 2019 6:20 pm

So to be clear, before I go and ruin my new LP Alpha, I should be safe to plugin Apple type-C power supplies (which provide far more power in general than the supplies provided by LP) and the device will only use what it needs?

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