Test/Review of Charger Opus BT-C100

I received mine this weekend, it was damaged in shipment a direct hit to the LCD screen. it was shipped in a simple plastic bag all the way from China. I do not want to try it out. I filed a ticket and am waiting (fingers crossed) for a replacement.
I did purchase the “insurance” when I placed my order.

thank you for your time,
how does this compare to liitokala in respect to safely charging cells, and not shortening their lifespan? Would I be better off gifting this charger, or liiotkala to a new lion user that will be using it here and there?

For new initiates, I prefer something simple like the XTAR MC1 due to the KISS principle:
http://www.mtnelectronics.com/index.php?route=product/product&path=79&product_id=177

For the typical user, all of the additional modes could be confusing. Most people won’t need the analyzing feature.

This charger looks great; I wasn’t even aware of this model until yesterday, and was glad to see HKJs updated review. I may be ordering this one soon, as I want the capacity to charge my 10440/14500s at the lower current, and would like to test my cells capacity…

Thanks for the update HKJ. Think I might hold off purchasing until the next revision.

Now if only Xtar could make a single cell analysing charger….

I got mine. For a $11 charger the functionality is impressive and it comes with a proper adapter. The charge voltage does not matter for me since I charge using a Liitokala 400 non analyzing charger and I wanted the Opus for analyzing cells mostly. One thing not mentioned in the review the screen is extremely hard to see at an angle. I keep my chargers next to my monitor’s stand and look at the screens at an angle of around 30 degrees from the horizontal plane. The Liitokala’s display is passable, the VP1’s display gorgeous but the Opus’ display requires me to lean forward to make out anything due to contrast shifting.

I just got my newest toy, the BT-C100. Everything seems in order however the instructions are below par even by Chinglish instructions standards.
I’d appreciate if you could tell me how to set the charger to 1.2V (Ni-Cd, Ni-Mh) charge voltage. No matter what I do the dispaly shows only the 3.2V, 3.7V, and 3.8V options in the upper right. I placed a Ni-Cd “C” cell in the charger set to “charge test” at 500mA. I left the charge selection display at 3.6V. The charge V increased to 1.436 and remained there, in charge mode, for many hours. I can not tell what the unit is trying to do. Coax another ~.07V in to the cell, or attempt to overcharge it as if it were a 3.6V cell. One of us seems defective, the charger, the cell, or :person_facepalming: ME! The cell and I are quite old. I would suspect that the cell is ~600mAh capacity at this point but I am not at all certain. That is why I want to test it. The cell showed 55 impedence.
Any advice is appreciated.

The charger will automatic select NiMH/NiCd below 2 volt, turning off the the display of LiIon voltages would be a good idea (I forget to put that on my list).
Usual Opus is fairly good at terminating at any charger current, but it obvious missed termination in your case, it probably has to do with the age of the cell.

Wow! I thank you for your informative and fast response. Yes, that would be a nice change. They could re-purpose the USB area of the screen to display “1.2V” since that area can not be used under 1.2V battery source anyway. It does let me try to turn the USB output “on” but it just shows 0V. At least with USB input, the USB output will not “pass through” with a 1.2V cell installed. When forbidden, a request for USB “on” should display “N/A”, or whatever variant can display in the segments available.
While I am writing suggestions for the manufacturer, I will add:
A long life -.1V termination V settting for each sensitive chemistry. Considering the new data on failure modes of Li-Ion, this setting should be of particular interest to users in hot climates, as heat + 4.1+V = early cell death.
They could also mold the cases so that multiple individual units are “gang-able”, much like metal switch boxes are here in the states. The cleanest way to implement that might be to devise a “snap strap” which clips in to the bottom of the unit and ties each side to the bottom of the next unit. They could even get fancy and add wiring which could gang all of the individual cells to suppply the USB output UPS function etc.

I have more N-Cd “C” to test. Would you have any suggestion as to what current to select so as to not go too low to miss delta-T, but not so high as to cook the battery? They are old “C”’s circa 1999. The tricky part is that their capacity was never known. They have served flashlight duty for decades. I started using them again after I weeded out a few which developed high internal impedance. If they are still OK I want to make them in to a battery pack for a piece of equipment that is finicky about cold weather voltage drop. Ni-Cds seem to be good for that use.

Perhaps I should manually cycle the old Ni-Cds a few times. Maybe that would repair enough “Voltage sag” so they could start to charge normally?

I tried to get the unit to display the discharge current setting as that could help verify what kind of cell it thought it had in it but it says 0mA. There is often a confusion with items like this as to if what is being shown on display is the “setting” (input) or the “actual, measured at this moment” (output). That is another suggestion I’d have for the manufacturer. A note on the display as to if the # displayed is referring to an “Input / Setting, or an ”Output / Reading.”
Oh, I found a way so determine if the charger knows it is a 1.2V cell, I think. Only a 1.2V cell will be given the “refresh” option :innocent:

I put an old Ni-Mh AA in the charger set to “charge test” at 300mA. It charged for 14min and (just) now states “full”. I cycled the display to mAh and it says “0”. My BC-700 usually rates this cell at ~600mAh capacity. Uugh. Not having a decent instruction manual is challenging!
If I figure this out I will make a video for everyone :slight_smile:

I thank you again.

I forgot that the charger offered charge current suggestions based on the battery impedance. I was treating the old C cells as if they were in worse shape than they are. By cycling at a higher current, and (for the first time ever) with delta-T capability, one old C nearly tripled the mAh I thought it was capable of.
Time will tell if these results are illusory.

The instructions show that I can evaluate the mAh drawn by device battery which is being charged by the USB output, but the USB’s output current will be added to the battery’s mAh reading. While in USB output mode there are two separate Ah meters on the unit. Increasing the current drawn by the USB output does not increase the charge current read by the battery’s meter. Why? Because the USB output is taking all of the current it needs from the battery. This can lead to a paradox that the instructions make no mention of. If I set the battery to charge at 200mA, then draw a full Amp or two out of the USB, the battery will be discharged even as the display clearly shows the battery is being charged at 200mA. The battery will actually DIScharge to 3.1V where the USB output will be shut off, and then actual charging can start. In order for the battery to get the current the user is expecting it to, the user MUST add the estimated USB current demand, which is roughly 2x the current going to the USB output, to the charge current.
Curious!

When using the USB input, the display sometimes flickered. I did not know where the issue was at first but now it is clear - my USB input jack has failed. If you look in the unit you can see that the assemblers must squeeze the board in, lining up the USB port to the case, near two board stand-offs. The jack is not taking the abuse well. It looks like this jack’s issues remains a headache for some engineers at Opus. Until something is changed, I thing we should consider the USB input a “bonus feature”… if yours happens to work, its a bonus, but do not count on it working well, or for long.

Someone posed a youtube video today of a BT-C100 having an issue with the USB output. Note that the Vout is reading ~4.

Any idea what the feature “Circuit Detection: Yes” is? What ever it is, it does not translate well.

I really like the charger but perhaps I should have waited for something a little farther away from the beta engineering stage. The thing is, I really can make use of this thing- now.

Due to size and price, there’s bound to be some limitations in the internal design. The fact that the USB output does not isolate from the battery when there’s power connected looks to be one of them.

Regarding the charging, I tested the discharge capacity of two matched, identical LG 18650HG2s, one charged in the VP1 and one charged in the Opus. Discharged them using the Opus, let each one of them rest for at least 3 hours, charged one of them in the VP1 and one of them in the Opus, both at 1A. Then let them rest for 3 hours and discharged them both at 700mA. mAh discharged for the cell charged in the VP1 was 2853, for the cell charged in the Opus was 2820. The difference is pretty minor so it’s not like your lights will get any appreciable runtime difference with cells charged in the Opus.

My video, focusing on the quirks I noticed about the unit, is now live on Youtube. One oddity I didn’t mention here is that if you have a 1.2V cell installed and set the unit to “refresh”, the unit lets you replace the battery with a Li-Ion and it doesn’t seem to notice. I haven’t tried it but I think the unit will try to then discharge the Li-Ion to .9V.
I really like the charger. I’m just going on about things that the charger geeks and manufacturer might find interesting.

Can someone please explain me if it’s possible to evaluate a battery charged by the USB output function? eg. I’ve a couple of Sansa clip, one of them last on for a really short amount of time. Is there a way to know how many mah it still gets?

thx

The Opus shows how many mAh it delivers on the USB output, this makes it possible to evaluate it.

I’ve got it today, honestly from the manual I can’t understand how to do that, can u elaborate a little more?

So far I’ve the charger with a 18650 in it, the 12v adaptor is plugged in, the status is “charge” and i’ve turned usb output on by holding current button.

On the right side of the display I read 5.0v and 0.4A, if I press the current button it shows 0.0Ah

on the left side there’s voltage, mAh, impedence etc. (I think this values are referred to the 18650, not to the usb right?)

Now, in which mode should I place the charger? (charge/discharge/test/impedence)
should the 12v dc be plugged or not?
and most importantly where do I read the mAh it delivers to usb?

1.0Ah is 1000mAh

I know that but i’ve waited half an hour and it didn’t move xD

With a 0.4A load it is supped to count 0.1 each 15 minutes.

I highly recommend against using this to charge an iPad over USB. The device WILL overheat and possibly melt the plastic. It smells like it is burning after only a few minutes.

Does anyone know what voltage the BT-C100 discharges to during the charge test? I’ve got it running on a Samsung 40T right now and it’s currently down to 2.95v.

Also, it’s showing 106 for the internal resistance, which seems high for a brand new battery?

Update: looks like it stopped discharging around 2.8v, at which point the voltage jumped to 3.2v. The discharged capacity was 3511 mAh. Is it lower than the rated 4000 mAh because Samsung discharges to 2.5v in their testing?

I also just tested the Samsung 40T, but on an Xtar Dragon VP4. This was in preparation for runtime graphs on my Zebralight SD700d. Got 4009mah, right on the money per manufacturer spec. The 40T was purchased from Zebralight a few weeks ago.