[Review] XTAR PB2 USB Power Bank and 18650 Charger

maukka · 2018-06-23T17:04:22.000Z

Thanks for the review! I don’t mind the battery pickyness, but the fact that it shuts down on a relatively high minimum load (300 mA) is a deal breaker. Can pretty much only charge other power banks or phones but not power other low power devices.

deleted-200707 · 2018-06-23T19:28:34.000Z

It drops out trying to charge my Sandisk Sansa Clip MP3 player. Pushing the side button restarts the charge butt then shuts off.
bummer!

Same thing on my MecArmy SGN5 and my UltraTac K18 mini charger…. :person_facepalming:

Nor my Nitecore TIP

In contrast., my Rofis MR70 charged all of them with no problem.

atbglenn · 2018-06-23T19:31:48.000Z

I tested mine with two new freshly charged Panasonic 18650GA 3500 mAh cells installed, and I got less than half the capacity when discharging using a YZXstudio ZY1270 USB Power Meter and a 2.1 amp load. I’ll do another test to confirm.
That said, I did the same test with a 20,000 mAh Xiaomi power bank and got over 13,000 mAh. That’s slightly better than their real output spec listed on the power bank.

WalkIntoTheLight · 2018-06-23T20:53:43.000Z

atbglenn:

I tested mine with two new freshly charged Panasonic 18650GA 3500 mAh cells installed, and I got less than half the capacity when discharging using a YZXstudio ZY1270 USB Power Meter and a 2.1 amp load. I’ll do another test to confirm.
That said, I did the same test with a 20,000 mAh Xiaomi power bank and got over 13,000 mAh. That’s slightly better than their real output spec listed on the power bank.

Did you measure it in watt hours, to take into account the voltage boost needed?

atbglenn · 2018-06-23T21:13:09.000Z

WalkIntoTheLight:

atbglenn:

I tested mine with two new freshly charged Panasonic 18650GA 3500 mAh cells installed, and I got less than half the capacity when discharging using a YZXstudio ZY1270 USB Power Meter and a 2.1 amp load. I’ll do another test to confirm.
That said, I did the same test with a 20,000 mAh Xiaomi power bank and got over 13,000 mAh. That’s slightly better than their real output spec listed on the power bank.

Did you measure it in watt-hours, to take into account the voltage boost needed?

No I didn’t. I’m re-testing now. It seems to be doing better now. I’ll post the display readout when I’m done. It will show the watt hours. So far with 35% left on the display shows 18.97 WH and 3.75 Ah’s. I’ll show the final results.

I might have messed up. I’m not sure if I reset the USB tester to zero. I’m now recharging the Xtar and will do another test. I will post my results tomorrow. Sorry about that.

atbglenn · 2018-06-24T16:30:41.000Z

Here’s the results of a fully charged PB2 with 2 Panasonic NCR18650GA’s drained till the PB2 shut down. The current was set at 2 amps. The PB2 shuts down when the display reads 00.

deleted-200707 · 2018-06-24T18:05:36.000Z

Well, I really wanted to like this.
Butt if it won’t charge all my stuff then it’s not as useful as my TOMO and will not go on long trips with me.

WalkIntoTheLight · 2018-06-24T18:09:57.000Z

atbglenn:

Here’s the results of a fully charged PB2 with 2 Panasonic NCR18650GA’s drained till the PB2 shut down. The current was set at 2 amps. The PB2 shuts down when the display reads 00.

Okay, so somewhere around 80% average efficiency, if the cells were drained to around 2.7v (though, there’s not much energy below 3v). Did you note what their voltage was after the test?

atbglenn · 2018-06-24T18:52:54.000Z

WalkIntoTheLight:

atbglenn:

Here’s the results of a fully charged PB2 with 2 Panasonic NCR18650GA’s drained till the PB2 shut down. The current was set at 2 amps. The PB2 shuts down when the display reads 00.

Okay, so somewhere around 80% average efficiency, if the cells were drained to around 2.7v (though, there’s not much energy below 3v). Did you note what their voltage was after the test?

Sorry I didn’t. I’ll do another test and let you know.

Newlumen · 2018-06-24T19:31:38.000Z

maukka:

Thanks for the review! I don’t mind the battery pickyness, but the fact that it shuts down on a relatively high minimum load (300 mA) is a deal breaker. Can pretty much only charge other power banks or phones but not power other low power devices.

It happened to me too… was charging nitecore tini and it stopped…

BlueSwordM · 2018-06-24T19:41:14.000Z

@atbbglen, the only measurement that matters is watt-hours, not anything else.

When drained down to 3.2V, the NCR18650GA have about 2.9Ah of capacity drained at 1.5A, so about 10.5Wh.

So, with 2 cells, 10.5Wh*2= 21Wh

92%*21Wh= 19,3Wh. So they actually have accurate specs.

IMO, the only flaw in this power is the way too high shutoff current. The minimum should be 80mA, or maybe just 50mA.

WalkIntoTheLight · 2018-06-24T19:45:15.000Z

Newlumen:

maukka:

Thanks for the review! I don’t mind the battery pickyness, but the fact that it shuts down on a relatively high minimum load (300 mA) is a deal breaker. Can pretty much only charge other power banks or phones but not power other low power devices.

It happened to me too… was charging nitecore tini and it stopped…

Yeah, doesn’t seem to power low-charge devices (under 300mA). I don’t know of any work-around for this. Pressing the side button will force-start the charging, but it will automatically turn off after a little while.

It’s definitely aimed more at the smart-phone market. And, of course, as an 18650 charger.

Well, if you were stuck on an island with a few low-power devices and a USB hub/splitter, maybe you could charge a couple of them at the same time.

deleted-200707 · 2018-06-24T19:47:11.000Z

and I have to pry my Samsung 30Q button tops out with my knife!

BlueSwordM · 2018-06-24T19:54:06.000Z

Eh. I don’t really care for button top compatibility.

Most 18650 cells are flattop anyway. However, I do wonder why they didn’t go with a sliding mechanism instead of just tabs. Would have made cell compatibility much better and the use of button tops possible.

WalkIntoTheLight · 2018-06-24T21:26:40.000Z

BlueSwordM:

Eh. I don’t really care for button top compatibility.

Most 18650 cells are flattop anyway. However, I do wonder why they didn’t go with a sliding mechanism instead of just tabs. Would have made cell compatibility much better and the use of button tops possible.

My only guess is that they were designing it to be as small as possible. Using springs and allowing for longer protected cells might increase the length by as much as 10%. I guess they assume that most people use flat-tops now. This could be aimed at vapers, not just flashaholics, and from what I understand vapers almost always use unprotected flat-tops.

I only have one light that requires button tops, the BLF Q8. And, if I had to, I could crow-bar the 30Q button-tops into it, just barely. I don’t think I’d take a large light like the Q8 on any trips were I required a portable charger, though.

Zulumoose · 2018-06-25T03:50:17.000Z

The thing is, many of us would appreciate being able to standardise on a cell. Unprotected button tops, particularly the 30Q that is often available as a set of 4 with coupon, fit the bill perfectly, especially since the Q8. Anything that turns out not to be suitable for them is a disappointment.

WalkIntoTheLight · 2018-06-25T11:03:05.000Z

Zulumoose:

The thing is, many of us would appreciate being able to standardise on a cell. Unprotected button tops, particularly the 30Q that is often available as a set of 4 with coupon, fit the bill perfectly, especially since the Q8. Anything that turns out not to be suitable for them is a disappointment.

That makes some sense, but otoh some of my lights (mainly Zebralights) can only take flat-tops, so that is what I have standardized on. The Q8 is the only light I have that requires button tops, though most of my lights will take them.

I find the button tops on 30Q’s add unnecessary resistance, if the light doesn’t require button tops. So, I prefer to use flat tops whenever possible. Granted, the resistance is small, but any extra resistance on a high-drain cell is something to avoid if possible.

Speed4goal · 2018-06-25T11:16:12.000Z

If you can half decent solder you can make your own button tops with almost 0 added resistance. It helps to scuff the top of the cells with sand paper first.

WalkIntoTheLight · 2018-06-25T13:44:52.000Z

Speed4goal:

If you can half decent solder you can make your own button tops with almost 0 added resistance. It helps to scuff the top of the cells with sand paper first.

I did do that with some cells meant for the Q8, with some success. The solder seems stuck on the tops good, but I think it might have been too cold, as it’s a horrible lumpy mess. I evened them out with a dremel tool. Well, it works, though I prefer the nicer look of real button-tops I have for it. The solder blobs were really done just to try it.

ZoomieFan · 2018-07-16T12:49:44.000Z

I think I’m gonna try this one.
If it turns out not being a very capable PB I still got a nice charger, as the charging speed isn’t great but not so bad either. Especially when charging 1 cell.