Test/Review of Charger Xtar SV2 Rocket

[Gauss163]

The graphs show reduced life by factor of 10 or more? Are you sure you know how to read a graph?

Yes, and yes.

 

[Aggressor]

Yes, and yes.

Perhaps you don't know what factor of 10 means? You really ought to google terms before using them in a sentence.

 

[Gauss163]

Perhaps you don't know what factor of 10 means? You really ought to google terms before using them in a sentence.

I have no idea what lies at the source of your confusion. But if I had to make a guess, it might be related to the fact that cells are considered end-of-life when they reach 80% of nominal capacity. Keep that in mind when you are extrapolating data from the graphs.

 

[Aggressor]

I have no idea what lies at the source of your confusion. But if I had to make a guess, it might be related to the fact that cells are considered end-of-life when they reach 80% of nominal capacity. Keep that in mind when you are extrapolating data from the graphs.

I have pretty strong idea what lies at the source of your confusion, but I am going to keep it to myself out of politeness. Who exactly (besides yourself) considers cells end-of-life when they reach 80% nominal capacity?

 

[StandardBattery]

I have pretty strong idea what lies at the source of your confusion, but I am going to keep it to myself out of politeness. Who exactly (besides yourself) considers cells end-of-life when they reach 80% nominal capacity?

Good idea, we already woke the enforcers a while back over something small, never thought they would visit this forum for such small stuff.

 

[Gauss163]

Who exactly (besides yourself) considers cells end-of-life when they reach 80% nominal capacity?

That is the industry standard when doing cycle life tests. Some may go a bit lower, to 75% or 70%. But it doesn't matter much where you draw the line, because the degradation caused by high-rate CC/CV charging is a nonlinear process, so one will see the same qualitative effects at some point.

I have pretty strong idea what lies at the source of your confusion, but I am going to keep it to myself out of politeness.

What politeness? Your puerile jabs above ("Sure you know how to read a graph" ... "maybe you don't know what a factor of 10 means") are far from polite. You won't have much luck eliciting expositions form others if you continue to behave like that.

 

[scintillator]

I am using this charger exclusively now.
About 2 months ago the spring broke on one of the sliders.
Rather than go to the hassle of returning the thing for a new one I decided to fix it.
Removed rubber feet,unscrewed the bottom and revealed the problem.
The little plastic post the spring fixes to broke.(this plastic post is way underdesigned flimsy very poor)
I was able to drill a hole in the PC board just behind the broken post and attached the spring in the hole.
Better than new.
Just my 2 cents

 

[Aggressor]

That is the industry standard when doing cycle life tests. Some may go a bit lower, to 75% or 70%. But it doesn't matter much where you draw the line, because the degradation caused by high-rate CC/CV charging is a nonlinear process, so one will see the same qualitative effects at some point.

The problem is, you made specific quantifiable claim which is not supported by this graph. You said: "In extreme cases doubling the charge rate can reduce life by a factor of 10 or more". Therefore, in the graph, we are looking to compare cases marked "C charge" with "C/2 charge", and "C/5 charge" with "C/10 charge". We are not looking to compare "C charge" with "C/10 charge", because that represents ten times the charge rate, not doubling.

And comparing relevant cases, graphs show life reduction nowhere near factor of 10, whether you make the cut at 80% remaining capacity, or at a more universally accepted 70%.

What politeness? You puerile jabs above ("Sure you know how to read a graph" ... "maybe you don't know what a factor of 10 means") are far from polite. You won't have much luck eliciting expositions form others if you continue to behave like that.

Maybe you don't know what sarcasm means?

 

[StandardBattery]

I am using this charger exclusively now.
About 2 months ago the spring broke on one of the sliders.
Rather than go to the hassle of returning the thing for a new one I decided to fix it.
Removed rubber feet,unscrewed the bottom and revealed the problem.
The little plastic post the spring fixes to broke.(this plastic post is way underdesigned flimsy very poor)
I was able to drill a hole in the PC board just behind the broken post and attached the spring in the hole.
Better than new.
Just my 2 cents

Thanks for the report. I've not used this charger yet, just have it for charging some 26650 cells a little faster than some of my other chargers I trust and easier than the hobby charger. I have not had time to make room for it with several other chargers in use or test, but I'll be recharging more 26650 cells now so I plan to get it hooked up soon.

 

[scintillator]

Yes a 26650 battery is what caused the spring post to break in slot no one.
That is mainly what I use it for also.I charge my 18650`s at one amp unless I am in a hurry,then I use 2 amp function
who knows using faster charge rate might cost me in battery life in the long run,but when you need it charged now it
is the price you pay.

 

[Gauss163]

Therefore, in the graph, we are looking to compare cases marked "C charge" with "C/2 charge", and "C/5 charge" with "C/10 charge". We are not looking to compare "C charge" with "C/10 charge", because that represents ten times the charge rate, not doubling.

I don't recall anyone claiming to compare C vs C/10. In any case, the source of your misunderstanding was revealed above. There are many other studies which illustrate this fundamental asymmetry, some of which you don't even have to extrapolate to infer the results.

 

[Aggressor]

There are many other studies which illustrate this fundamental asymmetry, some of which you don't even have to extrapolate to infer the results.

Did anyone question the existence of this asymmetry? Where?
I have questioned this claim and asked you to provide any evidence:

In extreme cases doubling the charge rate can reduce life by a factor of 10 or more

As we have seen, the graphs in the referenced study do NOT provide such evidence (if one looks at the RELEVANT cases, with DOUBLE charge rate). Any other study you want to mention, or "there are many other studies" is all we are going to get as your "evidence"?

 

[StandardBattery]

I think the cell charging discussion is now way OT for this thread. Let's get it back to this charger.

 

[Bullzeyebill]

I think the cell charging discussion is now way OT for this thread. Let's get it back to this charger.

Good idea. Keep on track.

Bill

 

[StandardBattery]

Did my first charge on this today. One battery 2A charge. 5200mAh rated 26650. Initial voltage was 3.8V (I think I forgot to record it, it would not drive Med level in my G20). It did pretty well on this simple charge. I probably would have pulled the cell earlier, but wanted to measure the exact termination voltage. This is a pretty simple charger, and you can set the charge rate before you insert the cell without issue. It would be nice if the bays could have just a couple more mm of length so that it would be easy to insert a current measurement shim probe in there with the battery. I bought this for 26650 cells, and while I could also use the BT-C3100 (v2.1) I guess I needed an excuse to try this XTAR charger and 26650 cells are the best I could come up with and leave the 3100 for analysis jobs. Termination was spot on so I'm happy, I'll just need to test the other slot and two cells at one next time. The estimated charge percentage seems accurate enough for my expectations, I don't really intend to rely on it that much, but I'll test more to see if it's accurate once it gets to 98% estimate or so, as at that level I'm happy to pull the cells early if I need them.

Start	20%
55min	42%
115min	70%
164min	96%
175min	99%
204min	100% (4.20V)

 

[gteague]

anyone have a link to a chart where i can determine what current to charge at least the most popular batteries? if someone wants to just reply to a few, here's the ones i use the most. btw, i can never remember the li-on numbering system. apologies.

nimh 2400-2800mah
cr123r
18650 (i tested the 4, 2-3 year-old cells i have in my nitecore tiny monster by charging two of them at 2a using the sv2 and the other two at 500ma using the previous xtar charger which only goes to 1a. the cells were at approximately 3.2v (they are getting old--they lose charge more quickly as they age) and in the sv2 charger they charged to approx 4.2v in less than two hours. the two in the slower charger were still less than 50% after the two hours so i transferred them to the sv2 charger and they charged to full in about 45-60 minutes. a full charge of these 4 cells inside the flashlight with the nightcore charger can take 3-5 hours even when they are at about 3.4-3.6v to start with.)

at any rate, any current recommendations for max current and ideal current for those 3 batteries would be appreciated. }

tks, /guy

 

[HKJ]

anyone have a link to a chart where i can determine what current to charge at least the most popular batteries? if someone wants to just reply to a few, here's the ones i use the most. btw, i can never remember the li-on numbering system. apologies.

From the op:

 

[ahill2]

Between the xtar vc2 plus and xtar sv2 what would you choose?

I want it for charging 18650 and some eneloop pro 5th gen,nothing more.

Thank you.

 

[StorminMatt]

Between the xtar vc2 plus and xtar sv2 what would you choose?

I want it for charging 18650 and some eneloop pro 5th gen,nothing more.

Thank you.

That depends. Each of these chargers has its advantages and disadantages. The SV2 has more charging rates. Specifically, it can charge at .25A and 2A in addition to .5A and 1A. It can also charge 26650, 32650, C, and D cells should you eventually decide to expand your horizons. But the Plus Master works with USB power, can function as a powerbank, and is more compact. All in all, I consider the SV2 to be a better home charger and the Plus Master to be a better travel charger.

There are a couple of other things I should note. First of all, HKJ noted some termination problems with the Plus Master when charging NiMH batteries. I have never had a problem myself with this on my Plus Master. But it is possible that he either got a defective sample, was charging a defective battery, or was charging the battery under conditions that the charger couldn't handle. Or maybe I just got lucky. So be aware that this COULD be an issue if you get a Plus Master. Also, Illumination Supply is currently having a sale on Xtar chargers. The SV2 is currently going for about $18 and the Plus Master about $12. Why not get both for LESS than the regular price of the SV2 alone? That's what I did, and I'm glad I did.

 

[kaptain_zero]

For the record, and barring my removal from the forum by Kelly for commenting on an Xtar product (aka Greta), I'm super happy with my SV2 charger! It works a treat and seems to charge all my lithium and NiMH cells just fine.

Regards

Christian