Xtar VP2 vs Opus BT-C3100 v2.1 vs NiteCore Intellicharger i4 V2

And that’s a valuable opinion, since you have both.
Thanks for that. Sadly it mixes things up more. As seems there is not a valid charger that charges decently and also measures capacity. Maybe charging with vp2 and analyze with liitokala.
Or just go for Hobby chargers :frowning:

Great feedback, Jaidmaster. Thank you.

For the common of mortals/beginners, LiitoKala Engineer Lii-300 could be the one and only charger to have.
Thank you for bringing that device into the thread.

If you plan on charging low voltage (<2.8V) Li-Ion batteries such as those pulled from laptop battery packs or Li-Ion batteries drained down by your flashlight because they do not have overdischarge protection, Opus BT-C3400 would be able to restore the battery to higher capacity (and prolong your battery life) than LiitoKala Engineer Lii-300 just because the first charge after such a rundown is critically important.

I have lots of laptop battery packs which I have disassembled. I discovered by experience that BT-C3400 would recover significantly more capacity of a 1.5V battery if the first charge is 200mA than a 2.5V battery if the first charge is 500mA. For example, a Panasonic 1,800mAh cell drained down to 2.5V would restore to about 1,500 mAh when the first charge was 500mA and a 1.5V battery would restore to 1,700mAh if the first charge was 200mA. Now, my first charge of any battery discharged below 2.8V is always 200mA. If I missed charging a battery at 200mA at first and charged it at 500mA and it restored to 1,500mAh, then discharging and recharging it at 200mA would not increase the capacity to 1,700mA. So, If the first opportunity is missed, it is missed forever.

Unfortunately, Lii-300 can only charge at 500mA at minimum. It also overcharges batteries to 4.23-4.26V while my BT-C3400 has never gone even to 4.21V. It cuts off exactly at 4.20V. I read a lot of charger reviews when shopping for a new charger a month ago, and since I planned to use the charger mostly for 18650 laptop pulls, I decided that Opus would serve my purpose better.

I believe HKJ once said that if you know the shortcomings of your charger and how to work around them, many chargers would be acceptable. I just did not want to insert a resistor between the battery and LiitoKala to reduce the charging current, nor to stand over the charger all the time while it would be charging my batteries so that I could pull the plug when the display showed 4.21V. If you are are prepared to do these, LiitoKala may be the best charger for your needs.

Good point ! Thanks :slight_smile:

Thanks for the additional info. But floating around there are incomplete information… I mean 1/10 of a fast charge… Yes, but what is a fast charge? It depends on the battery I think. Samsung inr18650 24R can charge at 4A. But otherwise what do you mean by fast charge? 1C? I think also that fast charge relies con the chemistry itself… Icr should have a far less “fast charge ”. Am I wrong? I’m just trying to acquire the more and more correct information from various sources. Sorry

trume_3454 - Thank you for the very useful information.

No - have not got a charger yet. Actually had a VP2 for a very short time until it was stolen and liked it but after having read post #23 that changes everything. Almost all the batteries that will be charged are laptop pulls.

In the last several days since the budget is really tight just now I was thinking about just getting a single slot 18650 1.0A charger but having just read post #23 just a moment ago it would not be anywhere near optimum to even consider that.

I am ruined. A bit of advice....do not even look at any charger you cannot afford in the near future. If a SkyRC MC3000 (found only in the current catalog (from their website) but not on their product page) came our way that would definitely seem to be the ticket but it will probably cost at or slightly over $100 and it probably will not be released for maybe two more months. Meantime we need a charger for only 18650 laptop pulls and so it seems the Opus BT-C3400 would be the best logical choice right now. Oh and there may be a few times where charging some AAA NiMH would be convenient.

Thank you all for all the input. If any additional opinions come to mind please share.

The new Xstar VC4 charger ($29.99) might be another charger to consider.
http://www.xtarlight.com/05-chanpin/p-001-1.asp?styleid=339

Yes, saw that one, thank you. I will only get one that can discharge and analyze now that it was explained how valuable a good analyzer and discharge function are ESPECIALLY for used laptop pulls.

Well, while I was waiting for another review for the lii300, i made the (maybe wrong) idea there must be something very bad about it (HKJ already burned the Lii260 and other chargers shared the same end before he completed his reviews), since he already wrote about other 5 reviews since then , and he stated that everything was almost ready a month or so ago.

So i almost made my decison for a Turnigy Reaktor 300W 20A, should be a good learning tool.
Regarding the VC4, you should wait HKJ review about it, and also keep in mind that comes without power adapter, It is feeded by a USB plug, so if you have a good 5-5.1V @2.0-2.1A power adapter for smartphone or tablet you should be good to go….I’m not that sure if using it that intensively could stress it bytheway, so keep this possibility in account

Photons Away,

If you are going to charge mostly laptop pulls, there are several factors that will affect how much original capacity can be restored:

1. The smaller the 1st charge current, the better (SkyRC MC3000 with minimum charge current of 0.1A would be better than Opus BT-C3400 with minimum charge current of 0.2A)
2. The quality of the original battery manufacturing process (some brands would probably restore better than others)
3. How many cycles the battery has already been charged in its lifetime (and perhaps, if those were full charges or partial charges) (the fewer cycles, the better)
4. The residual voltage of a laptop pull battery (the higher is still better, but I have had good success restoring 0.4-0.5 Volts batteries to 80+% original capacity)
5. How long the battery been sitting without use at that low voltage (the less time the better)
6. The ambient room temperature of the 1st battery charge environment (charge the battery the first time in the coldest room of your house or outside and use charger with a fan, like Opus BT-C3400, to reduce overheating)

Perhaps, there are more factors that I am still learning about.

You may want to keep these in mind as you have some control over at least some factors listed above. If you can wait a few months for SkyRC MC3000 and afford its price when it comes out (I doubt it would cost $100 as it would be grossly overpriced over already expensive Opus BT-C3400), it would probably be the best choice.

You may also want to read this thread:

How can this be? Li-Ion brought back from 0.1v to full power and working strong?

You cannot use my review time as an indicator on the result of the review. With the Lii300 I have bought it, that means it goes in the low priority queue. The oldest charger in that queue has been there for more than half a year with the review ready.

When I publish from the low priority queue I try to take the stuff that is most interesting at the current time and it looks like many people is interested in the Lii300.

Anyway I plan on publishing on Saturday and the charger do not get a perfect score.

ok thanks. I cannot imagine you did all those interest priority queue reasoning. I just thought usually they are FIFO with little variations based on the moment flow of interest of the subject.

It’s still a mistery to me how can you put all these efforts in buying stuff just to test them. Well, you, for what you do, and mainly for you knowledge have my respect, and your work inspired my new obsession….( i don’t know if i have to thank you or not :evil: :bigsmile: ) just kidding…thank you.

When dealers and manufacturers send me stuff they usual want it tested/reviewed ASAP, they do not really like if I have to put their stuff on hold for months. That is the main reason for running two queues.

Most of the stuff I buy to test is fairly cheap. Many of the chargers and batteries I test I got without paying for them.

I agree the vc4 “looks” to be the winner at 29.99. I am waiting for the hjk review.

The bo wrote

Well , last year I ordered a Littokala 260 , and whilst waiting for delivery , I won one of the 20 or so VP2s from Xtar’s competition givaway :bigsmile: I must admit , it is perfect.

The problem with the above, is *which* C3100 are they comparing the C3400 too? There have been 3 versions: The 1.0, the 2.0, and the 2.1. The above is likely true if the C3400 is being compared to a rev 1.0 C3100, and maybe true if compared to a rev 2.0, but is really likely untrue if compared to a rev 2.1.

What I've heard, is that the BT-C3400 is simply the BT-C3100 rev 2.1, that has had custom labels and markings made up for the seller "rdana" who sells on eBay and Amazon. Basically, if you have a C3400, then you *know* you have rev 2.1 of the software. If you buy a used C3100, you could get 1 of 3 different revs.

gcronau - Yes this is what I have gathered as well. Your post says it exactly.

Yes that is what the 3400 is, a specifically requested relabeling of the 3100 v2.1 for a specific seller, although whether or not the name was rdana or not I dont recall.

It should not be too much longer until the SkyRC M3000 becomes available. This will be THE charger to have I do believe!