Oh, hi, Tatasal. I thought I had I mentioned it earlier.
It is purely an issue with the display, ie, it does not cause overcharging. This is consistent with reviews that indicated that the two systems (charging and display) are distinct.
However, for a product which is not only a charger but an analyser, it is a very unfortunate flaw. It is meant to be convenient and save time for the user by not requiring the use of a multimeter.
Do I understand it right that you expect not to use your DMM anymore if you use this charger? If so, I’m afraid you still have to. The cell, after being charged, seldom retain the voltage given by the charger at termination (4.20v) when taken off the charger. It always goes back to the chemical condition of that specific cell’s holding voltage, not what the charger amount of voltage put into it at termination. So the use of a DMM is always still a requirement, IMO. The charger does not take the place of the DMM.
Is this the issue you are talking about?
Can some of us here help our friend with his concern, whether it is charger-related or something else? Thanks in advance.
I only meant that you can see the voltage of the cell when it goes on the charger, during charging, and when it comes off the charger. That is a useful feature, provided it works properly.
I did some more testing at the behest of GearBest. The interesting thing is that it is less inaccurate for higher voltages. However, even with charged li-ions, the display is still out by more than the ±0.05v at 4.2v provided for in the specifications.
If you need to know the voltage of the cell before charging you need to measure it with a DMM BEFORE putting it on the charger, using the charger to get a voltage reading doesn’t work cause it immediately starts applying voltage so even the first reading will be effected and won’t be a true reading of the pre-charge voltage.
i’m not complaining, but if they put a voltage reader in the OPUS, why can’t it be accurate ? it should be easy to do one that works. if you can’t make it work, don’t put it in. i have not tested mine to see.
Get a 10A power supply and readings will be accurate.
Has anybody linked to a recommended power supply? I have skimmed all 45 pages of this post and I didn’t see one. I know a Xbox power supply has been recommended but I mostly see 3rd party for sale. Are these good enough or should it be OEM? Also, is there an adaptor or do I have to cut and splice a new plug?
mine arrived yesterday, took 11 days from order date. Nice shiny box but I can’t use it yet since I have no lights nor batteries :-).
The group buy Eagle Eye X6 will be my first light to use the charger.
thanks tasatal!
That is not my understanding.
In this case, I measured cells with my multimeter during the time that they had just been put onto the charger (before charging began). The result was the same as measuring the cell outside the charger.
This is an easy test to replicate and I invite you to do so.
I only use OEM. No reason not to when they're easy to find for less than $20 shipped. Why mess with the questionable quality of a third party unit? A little modding and it's mostly ready to go. The only hassle is that it has to be plugged into the charger before the wall. I'll do a review soon that shows how to mod an Xbox power supply for use with the Opus charger, but you can find lots of instructions online if you don't want to wait.
I paid for expedited shipping on my order, but when I got notice of shipment, the tracking information was for NLPost (which, 3 days later, still doesn’t recognize the tracking number). I’ve been going back and forth with their support about it, and now that I’ve gotten them to understand that I want to know why my order shipped via NLPost, and what they are going to do about it helpfully explained to me that I should have paid for expedited shipping. Ugh.
I’ve PMed their account here. We’ll see what kind of response I get.
Anyone else had similar issues?
I’ll paste some measurements I took a few weeks ago:
A pair of Eneloops:
Real voltage 1.30
Displayed voltage 1.20 and 1.21
The same cells after charging (real / display):
1.50 / 1.42 (very soon after charging complete)
1.47 / 1.38 (a few minutes later)
A pair of Panasonic NCR18650B protected cells (light green):
Real voltage for both 4.00
Displayed voltage 3.96 and 3.97
A Sanyo 18650 cell (magenta):
Real voltage 4.01
Displayed voltage 3.96
Panasonic NCR18650 cells (grey):
Real voltages 3.86 and 3.71
Displayed voltages 3.81 and 3.66
A new alkaline cell:
Real voltage 1.60
Displayed voltage 1.51
So it seems I misremembered and there are times when the voltage is just within 0.05.
I didn’t have time before, but I thought I would also charge li-ions fully now for more information.
After charging finished (I don’t know how long exactly; probably less than half an hour), the display was 4.16 and 4.14 for the two cells (Panasonic 18650B) — reinserting the cells into the same slots gives the same result, but swapping the slots gives 4.14 and 4.15 — but I measured 4.19 and 4.18.
I believe that the weight of evidence is against my multimeter being wrong.
Comparing voltages shown in the display while the charger is charging or discharging with your DMM will always show differences when you take out the cell midway just to compare. The voltage readings shown in the display, let’s say while charging, will always be higher than the voltage of the cell, that is true in all chargers which I have owned and used… (iCharger, Pila IBC and Xtar VP2) Try to take DMM readings while the cell is inside the cradle while charging, comparing the voltage of the cell, alternating the probe’s to the voltage shown on the charger’s contact. The cell being charged does not take in the voltage pumped by the charger simultaneously, it takes a while for the electrical energy coming from the charger to be converted into chemical energy on the cell being charged. That’s why it’s always better to wait for a charger to finish its charging cycle completely, (until the ma goes down to almost 10% of the rate selected, as shown in the ma rate of a hobby charger or the bt-c3100) rather than to take it off the moment the display shows 4.2V.
That is not completely correct.
There are two ways the charger can measure voltage:
The VP2 measures with current on, this means the display will show higher voltage than you measure at the battery, due to ohmic losses in the connections.
The BT-C3100 measures with current off, this means the display show a lower voltage than you measure at the battery, because you measure the average battery voltage and the charger measures the minimum voltage. In my charts you can see the voltage line is rather thick (If the DMM has a MIN function, it might match the charger voltage much better).
Both of the above statements assumes that you measure while the battery is in the charger and it is applying current.
I don’t know why I have to spell this out, but the readings I have posted above are all taken while the cell is not under load, ie, when it is either not on the charger, or has been inserted into the charger just to see what the reading is prior to charging.
There are two occasions where the readings above are connected with charging, as is plainly stated. I allowed the charger to charge a pair of Ni-MH cells (Sanyo Eneloops) and, just today, a pair of Li-ion cells (Panasonic 18560Bs) until the charger itself decided that charging was complete. As you know, this is unmistakably indicated by the indication of FULL on the display. However, the readings still pertained to cells which were not under load. Allowing the charger to fully charge cells is simply a test to demonstrate that the termination voltage is more or less correct, and it is the display which is wrong for some reason.
You cannot impugn the measurements on this basis.
@HKJ and Ryuuden: Sorry guys!
Argh! The latest from their support is that “it has a battery, and so it can only ship NLPost.” I explained that it is just a battery charger, but I am sure that at this point, it is too late. Oh, and my tracking number still doesn’t show up in NLPost’s tracking site.
It’s very kind of everyone to try to be so helpful, but I am aware of this and it has been stated multiple times.
Suppose you accept that my DMM readings are correct — because, after all, 1.6v for a fresh alkaline cell is typical, and it is more likely that charged NiMH cells will be in the vicinity of 1.5v rather than <1.4v — do you really not see the incorrect readings as a fault?
My C9000 terminates with a voltage reading in its display at 1.48V, almost 1.5V, in all 4 bays, Eneloop or Duracells.