Review: XTAR DRAGON VP4 Plus Charger

[Gauss163]

@kresil It's not clear what the video is intended to imply. But since it presumably starts charging from empty cells, then that is one of the easiest cases, even for naive SOC algorithms, since they already know the exact SOC. Thus if they are matching to some model cell(s) (and the cell is similar) then the results will be very close. That's the trivial case for fuel gauge algorithms.

The harder (nontrivial) case is when you start charging at nonzero SOC (e.g. 30% or 40%), as is typical in normal use. Also one needs to test cells of widely varying capacities, and widely varying IR. That's where the sophisticated algorithms differentiate themselves from naive heuristics.

I was involved in doing similar tests for some professional level chargers, and they are extremely time consuming, so they are typically automated. This is not an easy task for a charger that has no means of automatic control. But perhaps it might be possible to jury rig some sort of automation.

 

[Tachead]

The % charge reading appears to be very linear in that video!

Yeah, it sure does. Especially since it has no way of knowing the capacity of the cells in it. Seams like Xtar might have a decent algorithm after all lol. What was the starting voltage in that video Kreisl? Thanks for that[emoji106]

 

[kreisl]

Starting voltage was 3.0v resting voltage offline.
Old sanyo ncr18650ga.

The YouTube is nothing to imply. It's just documentation.

 

[TinderBox (UK)]

I for one like gauss163 comments, i have learned a lot from him as he has suggested solutions to problems I have had and I value his opinion.

But this is not my thread.

John

 

[Gauss163]

Starting voltage was 3.0v resting voltage offline.
Old sanyo ncr18650ga. The YouTube is nothing to imply. It's just documentation.

Thanks for the info. It would be very interesting to see similar tests for much lower capacity cells, and for cases where the charge starts at nonzero SOC, e.g. between 40-50% SOC.

One common approach is to use interpolation to try to match up to the charge curves for a couple common chemistries (at common currents). This can work reasonably well if your cell is close to these "model" cells, but it can be way off otherwise. How well it works depends on how much thought went into the design. It's possible that they licensed some smart fuel gauge tech from one of the big guys, which might explain the big jump in cost. But there's no way to know for sure without more extensive testing.

 

[Tachead]

I for one like gauss163 comments, i have learned a lot from him as he has suggested solutions to problems I have had and I value his opinion.

But this is not my thread.

John

The problem is, he comes into every Xtar thread with nothing but negativity flinging wild accusations about marketing hype and tooting about his vast knowledge of algorithms with no proof and no first hand experience, or actual testing, with the products he is talking about. He clearly has no interest in Xtar and has shown in multiple threads that he dislikes them. Yet, he still comes into many Xtar threads with no motive other then putting down Xtars products and starting arguments with actual users. His negative trolling is disruptive and more then one user and a few mods have asked him nicely to knock it off but, he continues to troll the Xtar threads. He has even been asked to stop posting and/or banned from multiple threads but, still continues.

 

[Tachead]

Starting voltage was 3.0v resting voltage offline.
Old sanyo ncr18650ga.

The YouTube is nothing to imply. It's just documentation.

Thanks Kreisl[emoji106]. Looks like those old GA's are still holding up well. They're good cells.

 

[Gauss163]

@Tachead If, perchance, you find something erroneous in what I posted, then by all means do feel welcome to correct it. I am an equal oppurtunity debunker of marketing hype and other pseudoscience. My critiques here are by no means limited to any one brand. I've probably discussed faults (and benefits) in every popular charger at some point or another.

 

[Tachead]

@Tachead If, perchance, you find something erroneous in what I posted, then by all means do feel welcome to correct it. I am an equal oppurtunity debunker of marketing hype and other pseudoscience. My critiques here are by no means limited to any one brand. I've probably discussed faults (and benefits) in every popular charger at some point or another.

It's always negativity, algorithms, and marketing hype with you isn't it.

So your just generally a troll, not just an Xtar troll. Noted.

You should heed the advice my grandma used to give me "If you dont have anything nice to say then say nothing at all" .

 

[Gauss163]

You should heed the advice my grandma used to give me "If you dont have anything nice to say then say nothing at all" .

Would you really want to read reviews that only mentioned the positive things? We need to know both positive and negative aspects of products to properly assess them. What good would this forum be if we were excluded from telling others about the marketing hype behind 10000mAh xxxFire cells because many users who purchased them were being offended? (and yes, sadly, that does occur in some other forums).

Let me make it absolutely clear that I would be thrilled if it turns out to be the case that the Dragon is the first consumer-level analyzing charger incorporating an accurate fuel gauge algorithm. This would be a great advance for hobbyists. But knowing what I do about the challenges in implementing such, and knowing about complaints about fuel gauges on prior models, I exercise a healthy dose of skepticism until there is enough data to prove otherwise. That has everything to do with logic, and absolutely nothing at all to do with bias against any particular brand. In fact, if it turns out that the Dragon has a good fuel gauge, I may actually consider recommending it to users who could benefit from that unique capability.

 

[Tachead]

Would you really want to read reviews that only mentioned the positive things? We need to know both positive and negative aspects of products to properly assess them. What good would this forum be if we were excluded from telling other about the marketing hype behind 10000mAh xxxFire cells.

The problem is you never have anything but, negativity though Gauss(especially in the Xtar threads). And, you make wild claims based on nothing but, your opinion. You don't even own a Dragon and you have never even tested Xtars algorithms. And, where does all this marketing gimmicks talk come from? Again your head. I don't see anywhere in Xtar's marketing that they use "large firm", as you call them, algorithms or that they're percentage readout is accurate to the nano second/millivolt. In fact, their marketing is very elementary and not even that good really. All they say is the LCD displays battery capacity percentage. I just don't see the gimmicks:shrug:

Maybe you don't realize how negative you are and that you generally fit the description of a troll but, many other people do including the OP of this thread and more then one mod. Might I suggest that you follow BullzeyeBill's(Moderator)advice and step away from this thread. Maybe re-evaluate some of your posts and try and work on being less negative and more constructive. Going from thread to thread being negative and starting arguments will earn you no friends around here, or anywhere for that matter, Gauss. Most people aren't looking for just flowers and sunsets but, they don't want to constantly argue and read slanderous posts that aren't even based on first hand knowledge, experience, or facts all day either.

Anyway, I think we have derailed the Op's thread enough here. I am terribly sorry Stephen.

 

[Tachead]

Would you really want to read reviews that only mentioned the positive things? We need to know both positive and negative aspects of products to properly assess them. What good would this forum be if we were excluded from telling others about the marketing hype behind 10000mAh xxxFire cells because many users who purchased them were being offended? (and yes, sadly, that does occur in some other forums).

Let me make it absolutely clear that I would be thrilled if it turns out to be the case that the Dragon is the first consumer-level analyzing charger incorporating an accurate fuel gauge algorithm. This would be a great advance for hobbyists. But knowing what I do about the challenges in implementing such, and knowing about complaints about fuel gauges on prior models, I exercise a healthy dose of skepticism until there is enough data to prove otherwise. That has everything to do with logic, and absolutely nothing at all to do with bias against any particular brand.

You edited your post.

I don't think anyone was/is expecting the Dragon to have crazy accurate percentage readout. Nor did Xtar advertise as such. It is meant as a rough gauge, an estimate, and it is a less then $80 charger. The point is it gives a better idea of charge level then voltage readout alone. It is a bonus if it turns out to be quite accurate though.

I would have preferred it had both a percentage and voltage readout so you can see the voltage before and after the charge/discharge cycle(the only time its truly accurate) but, that is not the case. It's not much of an issue though anyway because the built in DMM is quite accurate and convenient anyway. It just takes an extra step.

 

[Greta]

Okie dokie then! I've had enough - Take 10 days off Gauss163. When you come back, I strongly recommend you avoid ALL XTAR threads. Everyone (especially ME!) is sick of your constant trolling and obvious agenda to smear XTAR. Find something else to do with your time while you're taking some time off. :banned:

 

[stephenk]

Right, back to sensible discussion...
I'll try and take a few videos over the next week showing some aspects of the operation of this charger. Let me know if you have any requests.

 

[gilson65]

Thanks stephenk for your review very much appreciated

 

[stephenk]

I've uploaded a short video of the XTAR DRAGON VP4 Plus in action.

 

[vadimax]

Once upon a time I'll take the Dragon I guess. Especially taking into consideration that my old like mammoth poop Thrunite MCC-4 gives inconsistent results: the slot #4 always undercharges and the slot #2 started to pass termination voltage (overcharge).

At the same time Xtar SV2 is superb.

One thing I miss so far: if I understand properly the Dragon cannot charge all slots at max current.

 

[stephenk]

Once upon a time I'll take the Dragon I guess. Especially taking into consideration that my old like mammoth poop Thrunite MCC-4 gives inconsistent results: the slot #4 always undercharges and the slot #2 started to pass termination voltage (overcharge).

At the same time Xtar SV2 is superb.

One thing I miss so far: if I understand properly the Dragon cannot charge all slots at max current.

It can only charge at 2A when using slots 1 and/or 4 only. It can charge at 1A using all 4 bays.

 

[stephenk]

Review updated with more clarity around discharge rates, modes, and another % charge anomaly.

 

[doctordun]

Assuming I am somewhat technical savvy, but not an expert, would I benefit from getting this charger?
I am weighing my choices for an ultimate charger and so far I only have this charger and and MC3000 in my sights.
Should I be considering any other charger and is this XTAR Dragon the best choice?