Lii500 or Opus 3100 v2.2

Hello, I want to buy a charger until now I charged them with small circuits and DIY power supplies plus a Turnigy 50A with Cheali’s firmware.

I was deciding on the Opus 3100 or the Lii500 since with the first purchase in Alexpress the Lii500 only cost me €14 and the Opus 3100 v2.2 €33 or €37…

Some help?

I’ve been trying to pick one for weeks!

Thank you.

Personally I prefer the Opus, but for the money I’d get the LiitoKala charger instead. I have, and use both. There is not enough difference in usability to double the price.

And much of the preference is likely down to getting the Opus first if I remember correctly.

I lost the offer because I couldn’t make up my mind.

But today I didn’t wait any longer and bought the Opus.

Besides it was my choice, it was only because of the offer and if I had bought the Lii500 I would also end up buying the Opus one day, I always liked the Opus.

It was time to have a charger that is plug and charge without having to assemble all the wiring with the RC charger and with the diy charging modules it was very annoying to charge batteries like that.

I guess the opus will be a good charger, without the offer there is little difference in price with the lii500.


Like I said, I have both but the only one of them that is actually plugged in just now is the Opus. I use it a lot more than just about all the chargers I have. After thirty or so years of accumulating them.

I can charge something over 40 70mm cells at a time if I have to. Pretty sure I don’t actually have that many 70mm long cells…

I don’t think you’ll regret the Opus.

I didn’t think it would charge 21700!

He was thinking of building an external adapter, I read that some do not fit.

I doubt protected 21700s would fit but I don’t own any of those.

I will not use with protection only plans.

Do these fit?


As you can see these unprotected 21700s just fit. All of my 18650s fit just fine.

Ahhh perfect!!!


I got the Opus from the seller who all buy, by the way, does not answer any message.

Lousy charger or it’s just because it’s bad.

It turns out that if the battery is at 4v or little more no longer charge it shows you full 4,19v even 4.22.

If I put to charge a with 3.9v the charge and stops at 4.19v that averages all of the charger not real.

I am a technician and I have good meters use a Fluke 177 tester and it shows 4.16V I have to remove it and mount it on a diy plate charger and charge it at 4.19v or 4.2v or correctly.

It’s a shame but this charger is no good for me, if I end up having to finish the charging on another one.

I will open a case on AliExpress because I’ve been days without response from the seller on top was the most expensive.

I do not know if you have the same problem.


The voltage it’s displaying is the voltage under charge. It’s normal for an old laptop battery to go right to 4.2v under charge when OCV is ~4v. A new high drain 21700 probably won’t do that. No charger is going to stop at 4.200v consistently or read as accurately as professional equipment. Better too low than too high.

Your expectations are a bit unrealistic. The Opus is no Fluke. No cheap commercial charger is.

As @Jeffgoldblum says, it’s better to undercharge a bit for battery longevity/health. IMO you are doing your batteries a disservice to top them off like that. The actual amount of charge you are putting is is trivial, AND you are sacrificing a small amount of longevity for essentially nothing.
You can even cut a small hole in the back of the case so you can switch the charge voltage termination (3 options available) and use it as a ‘store’ mode when set for LiFe batteries.
I have 6 different analyzing chargers. All are fine, all are just a…little…bit different. Of the lot I consider the Opus to be the one I would keep if I could only have one.

I don’t know anything about flashlights, but I am new to electronics in general.

And not being able to charge a battery that is at 4v and little more is not correct.

You can charge with any charger the battery to 100% in my case the ones I use leaves them at 4.19 is the correct 100% real and if you do not want you can cut before.

But this charger any battery that has 4.0v no longer charge it marks me 4.22.

Try and tell me you will see how you get to charge any battery you have at 4v this does not.

It is not correct not to be able to load a battery with 4.0v.

In the tab you will see the range and it is harmful from 4.25v.

All my DIY chargers go to 4.19v.

And the flashlights with chargers too.

I charge the batteries at 700ma even if it takes longer and with a sensor placed on them so I do it years many years with the lipo packs, these I charged them at more to 1C depending on the type.

The charger I buy it to be more comfortable but if I charge a battery I charge it because I need it to 100% the others I have them with storage charge I think they are 3.2.

As you can see I keep them well conserved and only charge them when I need them and I want them at 100% 4.19v.

But even if I take care of them they will die equally by oxidation is the chemistry of the battery that’s why it makes me angry to see people complaining about the batteries of the mobiles even if they take care of them they will lose their capacity equally.

I think it is defective.

Charges too low.

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No! What you see is a test battery.

I wasn’t going to use a new one from the flashlight on a new charger without knowing it.

This charger will not charge any battery that has 4v thinks it is already charged because it is either defective or because it is improperly calibrated.

Sometimes 4.0v real is 4.19v on the charger and 4.16v real is 4.22 will never charge any battery with 4v.

Try any charger and you will see that a battery with 4v will charge.

This one doesn’t even start full.

The back button is not for this is for the 3 types of voltages of the 3 types of liion LifePO4 batteries etc. 4,2v-4,35v-3,7v

It is also sealed under warranty and I do not use these batteries.

It must be good loading so I think it will be a defective unit.

I can not charge any battery only those with 3.8v because with 3.9v sometimes yes sometimes not.

My question was whether it charges well for those of you who have the charger.

A battery on charge shows minus, not plus, and on charge it goes down or up depending on the charging intensity.

But this is not the problem, the problem is that I can not charge any battery over 3.9v none.

And if I put one of 3.2 to charge it leaves it at 4.16 it is not at 100%.

I have not seen any charger that charges a battery to 100% with 4.16 the flashlight leaves it at 4.19 is perfect.

You can try it yourself but you have to use a good tester otherwise the measurement is not valid.

In English the squiggle ~ before a number just means approximately.

Could be. Wouldnt be the first defective charger.

HKJ’s test of the opus showed it sometimes got confused by older lithium ion batteries. Who knows how many changes the charger has gone through since then tho. If it’s even made the same company.

If you don’t need 1A discharging for all 4 bays or support for li-ion HV (4.35 v) get the Vapcell S4+. Its much more modern (the Opus is coming up on 5+ years old) and does everything the Opus does for about the same price. Ive had mine for 2 years and love it. Fits all my 21700s, even ones with protection and USB charging up to 77 mm long.

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You may know this, but a fully charged cell… that has terminated at 4.2 volts will not stay at that voltage over time. This is why I always ask for chargers that will show the actual voltage of the cell at rest after charging instead of the termination voltage.

The highest voltage I see after 15 minutes or so are at 4.18 volts. Many cells that are overall healthy may rest at 4.15 volts. The same happens regardless of whether I use my Opus 3100 (I think V2) my MC3000, VP4+ or any of the several hobby chargers that I sometimes use.

But, my 3100 will start chargingwhen I put a cell in that measures anything under 4.18 volts. Now that is a bit of a guess. I just tried topping off a cell with my MC3000 waiting 10 minutes and putting it into the 3100. It started charging.

I don’t think the behavior that you are describing would be considered normal. Personally, I would contact the seller and see if you can get a replacement.

But I would not be concerned about measuring 4.16 on any cell after a “full” charge and waiting a few minutes before measuring the voltage. Especially if you are using the laptop pulls that you have mentioned.

I’m sorry i did not see it

I think it is defective. I cannot charge any cell below 3.9v, it appears full.

I think it is poorly calibrated and shows more volts than the real ones and it is believed that it is charged.

Let’s see what happens and I’ll look at that model.

I thought the same thing, technology changes a lot in 5 years and I think it is one of the only ones that charges by PWM.

But it was more accurate to see the internal resistance and rule out the bad ones more quickly without doing the test and I see it in all places as a good buy, although it is the same as the S2+ flashlights with less efficient leds, many are seen because they were bought ago time.

I think it is a good charger but not to buy in 2023.

I like the MC3000 but I only charge the batteries once per output, which is only about 4 times a year at most, only on vacation. The other use is for my PCBs and electronic designs, but I mount an integrated charger for them.