Test/review of Xtar PB2S Charger & power bank

samgalax · 2019-09-17T17:23:02.000Z

Interesting to see the behaviour at that hidden low mode…. Waiting for the update.

Btw… Thanks for all your hard work

HKJ · 2019-09-17T17:27:27.000Z

samgalax:

Interesting to see the behaviour at that hidden low mode…. Waiting for the update.

I have updated, there is no new curves only a few points extra in the power bank section.
What it does is disable the low current shut off.

samgalax · 2019-09-17T17:28:24.000Z

HKJ:

samgalax:

Interesting to see the behaviour at that hidden low mode…. Waiting for the update.

I have updated, there is no new curves only a few points extra in the power bank section.
What it does is disable the low current shut off.

Thank you Sir!

Klotski · 2019-09-17T17:57:28.000Z

HKJ
So if I wanted to use a solar panel to recharge the battery’s once the solar panel quit charging due to clouds or whatever it would need to be powered cycled to resume charging?
Thank you

HKJ · 2019-09-17T18:02:49.000Z

Klotski:

HKJ
So if I wanted to use a solar panel to recharge the battery’s once the solar panel quit charging due to clouds or whatever it would need to be powered cycled to resume charging?

No, I show it in this chart:

The “brown out voltage” at the bottom is how low the output from the solar panel vent.
The cyan dots shows what happens during the low voltage and the red dots show what happens when the voltage returns to full again.

On the PB2S the red dots are at full current all the time. It do not matter if it was a small or large voltage drop, it will resume full current again when it is over.

samgalax · 2019-09-17T18:10:32.000Z

That is another good point about it… Still expensive… Hope it gets lower price

chiclet_fanboi · 2019-09-18T05:56:34.000Z

Thanks for the extensive testing, did you do some USB PD tests as well (or anybody with this device)?
Mine sadly has USB PD issues (voltage drop and eventual reset) and I wanted to know if this is sort of common. Sadly I don’t have a QC compatible device at hand, I’ll try to get one.

HKJ · 2019-09-18T06:25:11.000Z

chiclet_fanboi:

Thanks for the extensive testing, did you do some USB PD tests as well (or anybody with this device)?
Mine sadly has USB PD issues (voltage drop and eventual reset) and I wanted to know if this is sort of common.

I did run a load sweep:

And a test at 5V 2A:

I did not detect any high voltage support on the USB-C connector.

samgalax · 2019-09-18T06:27:22.000Z

Hmmm… Maybe Xtar will release an updated version??

chiclet_fanboi · 2019-09-18T21:04:44.000Z

Ah, now I noticed, on your device there is no mention of USB PD. Mine has a different marking, PD is mentioned with the “USB-C Output” - the ad on aliexpress also states the PD In- and Output capability. And it works in principle - with both of my USB PD devices (Pixel 3A and Thinkpad X280) it puts out a higher voltage. Just when the devices draw a little more current (above 1 A) the voltage drops and the PB2S turns off (and restarts in 5 V mode). 5 V mode works, but at 1.9 A the voltage also starts to drop to 4.7 V on the devices meters.

EDIT: With a Samsung QC phone it sits at 8.8 V and 1.2 A. Tremendous situation, don’t know if the phone is just happy and doesn’t want more, or it doesn’t ramp up further because it detected voltage drop. I ordered a USB PD cable I can splice into for adding a multimeter and/or additional load. But thanks for the helpful answers so far!

d_t_a · 2019-09-21T02:18:23.000Z

Specs on the back side of the Xtar PB2S indicates PD3.0 support

Unfortunately I don’t have any PD3.0 supporting device for now.
But have the ZY1276 USB meter.

I was able to do PD3.0 trigger, as shown in this video (unfortunately, I can’t seem to replicate how I did it now, since the ZY1276 USB meter doesn’t want to show display when I do the same setup now…)

d_t_a · 2019-09-21T04:53:00.000Z

Here it shows the complete protocols detected (USB PD3.0)

Sometimes it doesn’t have USB PD support)

(in another try, it misses the Apple protocol)

All above were tested using a (BlitzWolf) USB-C to USB-C cable from USB-C port of PB2S connected to the USB-C “In” port of the ZY1276 USB meter.

chiclet_fanboi · 2019-09-23T19:21:36.000Z

I made a breakout board to connect my multimeter and a few switchable resistors do add load (if the device throttles because of voltage drop). First thing, the amperemeter of my unit reads way low (300-400 mA). It doesn’t matter how you trigger the higher voltage modes (QC or PD), it always behaves the same.

I managed to get 14.5 W out of the unit in both 9 and 12 V mode. In 12 V mode you can actually draw 1.4 - 1.5 A, but the voltage has dropped to about 10 V at this point. More than that and resets. In 9 V mode it didn’t drop as bad, but at 1.7 A it cuts out. My phone seems to see “oh I’m connected to a 18 W PSU, I’ll draw 18 W which therefore leads to an instant cut-off with the powerbank. I’ll measure the current the phone draws from its original mains adapter as soon as the battery SoC is low.

I got a full refund on my unit.

EDIT: Pixel 3a draws up to 1.9 A in 9 V mode.

Couchmaster · 2019-09-23T20:40:38.000Z

FYI, Illum has them on sale for $17 and change, and free shipping over $50.

d_t_a · 2020-02-25T01:12:43.000Z

While re-reading the review, I noticed that this one is the PB2S with the “Red LED” display, also mentioned here: [review] XTAR PB2S charger/powerbank - #20 by TheIntruder

Is it possible that the “Red LED” PB2S has some internal differences from the regular “white LED” variants? (The “Red LED” PB2S is possibly an earlier variant?)

ZoomieFan · 2020-03-03T09:55:09.000Z

Somehow I can’t manage to change the PB with more than 1.7A.
I use short quality USB cables and my wall chargers* are 2.4A and 4A.
Could it be limited by my cells (2x21700)?

*= Regular USB, not PD or QC

d_t_a · 2020-03-04T11:24:23.000Z

ZoomieFan:

Somehow I can’t manage to change the PB with more than 1.7A.
I use short quality USB cables and my wall chargers* are 2.4A and 4A.
Could it be limited by my cells (2x21700)?

*= Regular USB, not PD or QC

Do you mean charging the powerbank or the powerbank charging a device (eg. smartphone)?

If have a USB meter, can check the voltage. Based on my experience with powerbanks, usually a bit lower voltage causes charging current to drop.

ZoomieFan · 2020-03-04T12:06:59.000Z

When charging the PB itself, the display of the PB reports it charges at 1.7A.
And that’s the highest I ever saw. Usually the highest is 1.6A.
Sometimes 0.7A and when I pull out the charger and plug it back in it’s up to 1.6A again.

TimMc · 2021-01-04T06:21:47.000Z

Is it normal for the PB2S to terminate at 4.175V when charging a single 18650 or 4.185V when charging two 21700 cells?

XTAR kindly held a GAW for Xmas and sent me a PB2C and RC2-200. The PB2C terminates at 4.201V.

The PB2S would be perfect if it terminated at 4.20V and held 18650’s slightly more securely.

d_t_a · 2021-01-04T08:53:38.000Z

TimMc:

Is it normal for the PB2S to terminate at 4.175V when charging a single 18650 or 4.185V when charging two 21700 cells?

XTAR kindly held a GAW for Xmas and sent me a PB2C and RC2-200. The PB2C terminates at 4.201V.

The PB2S would be perfect if it terminated at 4.20V and held 18650’s slightly more securely.

I’ve also tried charging a few different batteries on the Xtar PB2S, it seems the end voltage may depend on the battery’s resistance and maybe ‘contact resistance’?

21700 battery will have better contact than 18650 on the PB2S charger/powerbank, so I think that may factor the slightly difference in end-charge voltage.
Also, a higher-resistance (not so high-drain battery) will get terminated and then have more voltage drop than a high-drain (low resistance) battery, at least that’s true for batteries when I tried charging on different chargers (which would likely also be true for the PB2S).

The charge termination current appears to affect the end-charged voltage of the battery (lower charge termination current will charge high-resistance batteries closer to the target voltage than a high charge termination current).