10 pin Li-Po battery connector experiment

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ccs_hello
Posts: 438
Joined: Sat Oct 13, 2018 9:16 pm

Tue Jan 15, 2019 5:02 am

Testing LP Alpha's Li-Po charging function....

(in my case) LPA's CC charging is set at 1.89A and when battery voltage reaches about 8.37V, it switches over to C.V. mode.

NOTE, I have not checked these cases (if exists):
1. terminating mode (when charging current drops down to ??? voltage, charge stops)
2. top-off (trickle charging)
3. timed charging (if charging exceed ?? hours, it stops charging
4. when batt temperature exceed ?? degrees, charger will shut itself off
5. whether or not it can read the battery pack's fuel gauge IC value (and which one is calibrated)
All unknown at this point...

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ccs_hello
Posts: 438
Joined: Sat Oct 13, 2018 9:16 pm

Tue Jan 15, 2019 5:19 am

Worthwhile to point out the charger part of the LP Alpha may take up to 15W from the power supply.
E.g., if using the 45W power adapter, in corner case, it may leave only 30W for the Intel x86 to operate.

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Lutz
Posts: 214
Joined: Mon Apr 18, 2016 4:30 am
Location: Germany, NRW

Tue Jan 15, 2019 2:25 pm

ccs_hello wrote:
Tue Jan 15, 2019 5:02 am
Testing LP Alpha's Li-Po charging function....

(in my case) LPA's CC charging is set at 1.89A and when battery voltage reaches about 8.37V, it switches over to C.V. mode.
(...)
How did you check it ? Just with a LiPo battery or with the battery pack from this thread
https://www.lattepanda.com/topic-p26075.html#p26075 ?

Unfortunately my LPA is still stuck at the Chinese (NOT the German!) customs.
As soon as I have my LPA I will measure with my MSO the signals at the I2C pins if there is a data traffic attempt.

If LattePanda would at least tell us which charging IC they used, then we would know a lot more.

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ccs_hello
Posts: 438
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Tue Jan 15, 2019 2:52 pm

I made my own custom cables so the flexibility is there (also used my own Li-Po pack.)

Web-U2 [ edited for correctness ] would be my suggestion (has BT for remote data logging, can troubleshoot USB-C protocol,
can test what charging protocols are supported for the power adapter, also can measure bi-directional current flow.)

In the case of Li-Po measurement, I used a cheaper UM34C (one con is it cannot measure the current flow from OUT back to IN, only displayed "zero" Amp in this case.)
I switched my wiring (IN/OUT) to get around the minor inconvenience.

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Lutz
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Location: Germany, NRW

Tue Jan 15, 2019 3:06 pm

ccs_hello wrote:
Tue Jan 15, 2019 2:52 pm
I made my own custom cables so the flexibility is there (also used my own Li-Po pack.)

UM25C would be my suggestion (has BT for remote data logging, can troubleshoot USB-C protocol,
can test what charging protocols are supported for the power adapter, also can measure bi-directional current flow.)

In the case of Li-Po measurement, I used a cheaper UM34C (one con is it cannot measure the current flow from OUT back to IN, only displayed "zero" Amp in this case.)
I switched my wiring (IN/OUT) to get around the minor inconvenience.
Just so you don't misunderstand me about my bad English: :shock:
I did not doubt your measurements! ;)
I just wanted to know the variant of the battery.

At the moment it looks as if the LPA without a charging IC on the I2C bus takes its own settings to charge the battery and at best still monitors the temperature.
Did I understand that correctly ? :?:

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ccs_hello
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Tue Jan 15, 2019 4:10 pm

I think the battery pack's I2C linkage probably can do one (reporting battery power level via fuel gauge IC) and possibly another (indicating battery type/capacity/suggested charging profile, etc.)

LPA side has the NTC temperature feedback (I did not use it, just a straight 10K resistor),
CC and CV circuit. The x86 somehow knows the battery voltage (thus showing the "Batt Low" message and initiating graceful shutdown in Windows.)
What I reported was based on no info back from the battery pack (thus it's either the default value or it's hard-wired/hard-coded.)
It probably won't be a surprise if using laptop as the business model. Laptop came with its dedicated matching battery pack, so the engineer knows exactly what to expect. It's doesn't need to know other brands/after-market battery packs and adapt to them for obvious reasons.

Since I only tested the design and found out LPA side has CC and CV thus minimally can be stated as "can be used to charge the 2s Li-Po battery.) On the other hand, how good or how elaborate the charging circuit functions are there, I don't have an answer.

BTW, my home-made pack is a 2S3P 18650 Li-Ion pack (old SONY cells though) with a simple 2s Li-Ion protection/balancer circuit board that I soldered to it.

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ccs_hello
Posts: 438
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Wed Jan 16, 2019 12:38 pm

Add a bit of DIY info, parts needed (to calculate cost)
- authentic Panasonic, Samsung Li-Ion 18650 cell (about 3000 to 3500 mAh) $6.50 each approx.
"Do not direct-solder on battery terminals, use battery box"
Buy them from creditable vendors, too many fakes.
- battery holder for above, in 2S 2P (approx 42 Wh usable) or 2S 3P arrangement (about 63 Wh usable)
- add a 2S protector/balancer board such as this
https://www.ebay.com/itm/2S-8A-7-4V-w-B ... 2694510470
- find 10k ohm NTC such as
https://www.ebay.com/itm/10-pcs-Thermis ... 0985396232
https://www.ebay.com/itm/5-x-10K-OHM-NT ... 1024817658
- find 10pin connector (part number unknown at this time)
- I'll skip fuel gauge IC for now (the SCL and SCK signal leads)

Double check, triple check your work before connecting. You don't want to burn your $350 board in 5 seconds.

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Lutz
Posts: 214
Joined: Mon Apr 18, 2016 4:30 am
Location: Germany, NRW

Wed Jan 16, 2019 1:35 pm

ccs_hello wrote:
Wed Jan 16, 2019 12:38 pm
Add a bit of DIY info, parts needed (to calculate cost)
- authentic Panasonic, Samsung Li-Ion 18650 cell (about 3000 to 3500 mAh) $6.50 each approx.
"Do not direct-solder on battery terminals, use battery box"
Buy them from creditable vendors, too many fakes.
- battery holder for above, in 2S 2P (approx 42 Wh usable) or 2S 3P arrangement (about 63 Wh usable)
- add a 2S protector/balancer board such as this
https://www.ebay.com/itm/2S-8A-7-4V-w-B ... 2694510470
- find 10k ohm NTC such as
https://www.ebay.com/itm/10-pcs-Thermis ... 0985396232
https://www.ebay.com/itm/5-x-10K-OHM-NT ... 1024817658
- find 10pin connector (part number unknown at this time)
- I'll skip fuel gauge IC for now (the SCL and SCK signal leads)

Double check, triple check your work before connecting. You don't want to burn your $350 board in 5 seconds.
My fullest agreement!
Connecting a Lipo battery is only for experienced electronics developers and electrical engineers!

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revtor
Posts: 8
Joined: Wed Nov 14, 2018 2:36 pm

Thu Jan 17, 2019 2:01 am

Why oh why can’t a LP designer chime in here. Some one laid out the board, someone must know what was included and what was not..

Thanks for the rigorous work CCS!!

-Steve

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LittleDuckAlex
Posts: 5
Joined: Tue Jan 08, 2019 6:10 pm

Sat Jan 19, 2019 2:25 pm

ccs_hello wrote:
Tue Jan 08, 2019 1:53 pm
@ Lutz
re: that specific laptop battery pack's circuit
https://www.lattepanda.com/topic-p26075.html#p26075

A laptop factory can tune the entire system
- set and read the battery fuel gauge IC
- preset the battery charger's CC value (if charger is located on laptop's motherboard)
- integrate these and be supported with Windows (or Linux) < -- may be there is a low level driver design/configuration guide for that specific OS

LP Alpha is a maker board and the user can source his/her own battery pack (with various spec. from multiple models.)
This is why I mentioned end user will have to know and design his own.
The cited post only suggests a battery pack "hardware wise, from wiring point of view" (sort of*) compatible with LP Alpha's 10 pin connector.

* The battery pack has I2C interface for fuel gauge IC but LP Alpha's doc does not show it's being taken advantages of.
(The LP Alpha PCB seems to have circuit paths and two protection (or pull-up) resistors for that so it's still a secret, work in progress, or wait to be reverse-engineered area.)
I believe LPA can read the battery’s I2C connection as Windows displays a battery percentage when using it.

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