Opus BT-C3100 V2.0 "Dreamcharger" GROUP BUY Now @ $ 36. New coupon code - tatasal -(to close July 15) NOW CLOSED

"Mine was ordered the 9th, shipped the 13th. 1 day quicker than the two F13 lights ordered from Gearbest (ordered the 9th, shipped the 14th)."

Holy Cow! Got the charger today!! New record for me in shipping from CN. 10 days from ordering!!

Nice dude! :slight_smile:

is that expedited or regular shipping tom?

Regular - I didn't pay any extra, unless the shipped it differently, but it all looks like the regular stickers.

Just to compare, I also got an order from FastTech today - parts. Ordered May 2nd, shipped May 6th.

Hello firehopper,

Would you like to pm me with your order#? I’m here to help you.

Hello Tom E,

We’re glad that you’ve got your charger, it’s also a good news to us, thanks for posting this info. We will keep the right way for shipping and service, and improve gradually, thanks for you all support to us.

Have a great day, dear all.

Been trying it out this eve. The voltage readings seem pretty good on mine, but may vary with the # of cells in place - not sure. Seem like the voltage reading dropped when adding cells, but just not sure... Two cells I charged showed readings on the charger that matched my Fluke DMM readings - so for those, seemed pretty dead on.

I'm using a laptop pull and doing a "test" to check capacity. Also charging a 10440 at 200 mA - these will take a while. It's look'n real good so far... Pretty intuitive to use.

Mine showed up today in what must be the fastest delivery I ever got from China. I ordered on May 8th and it shipped out on May 10th. It only took 9 days to reach me after they shipped it!!

The charger looks so much like my Accupower IQ 328 charger, albeit slight larger. The fan is a little more noisier than I expected, slightly louder than my computer fan but still not loud enough to bother me.

Anyway, I always wanted to know the capacity of the Trustfire Flames 2200mAh bought more than two years ago at DX. They are the first cells I popped in the charger and right now they are still discharging.

I’m very excited to know the mah result. Trustfires have better reputation around here though than the xxxfires.

Hi guys, maybe this has been covered but i want to know few things.

or the ones who testes the charger.

How accurate is the voltmeter? i want something to give me very convenient type of use, for example, to avoid checking with multimer how much the voltage is during charging…because its pain in the ass to remove the cells from charger, and add them again if the voltmeter is showing wrong values, then measure again and so on.

I’m asking this because i plan to take care of my next cells, and charge them only to 4.1V in order to enjoy much longer lifespan, (they are at ~95% @4.1V) already spent like 80$ for batteries, and on top of that i damaged one expensive pack.

So for me its crucial to know how accurate is the voltmeter, i can check when it is 4.1V and remove the cells at once……

Also is it possible to set custom cutt off voltage? to make it always charge to 4.1V max? thanks!

You will need a good hobby charger if you desire a programmable cut-off terminal voltage at .01 volt increments.

Hi, thanks for the answer.

Do you have some experience with voltmeter precision? how much volts are there to the cells when the charging is over? (18650)

With a digital read-out charger, the charger’s digital read-out at “done” seldom remains the same with the DMM. The cell will normally settle to its resting voltage, some faster than others, with-in a few seconds after taken off the charger. My DMM itself has a few +/- allowance for tolerance. These are not high-dollar precision devices, so perfection with numbers should not be expected.

I don’t expect perfection, i just want to know are the all the cells come at same or at least close to same volts?

For example Nitecore i4 all @4.18V when fully charged, not less not more.

And Opus?

I know my LUC V4 has around 20mV variation, 4.162 to 4.178…

I don’t know the answer to that question as mine has not arrived yet! Most probably about the same voltages. In my experience, even my brand-new batch of 4 Panasonic cells has sometimes different voltages. +/- a few millivolts.

Personally I dont’ worry much about a resting voltage of even a ‘low’ *4.14V *of a Soshine cell I tested. It even exceeded its published mah rating by a few mahs. I also don’t worry much about even up to .05 +/- cell diffences in series connection.

See this review on the Soshine: Discharge Capacity Tests on Soshine 18650 2900mAh Protected, cells courtesy of Louis Huang of T-mart. NCR-PF/Soshine graph added

2 units, I asked that they be shipped together,if possible.

So far my new LG & Samsung laptop pack cells have all come out at exactly 4.20V if removed from the charger fairly soon after reaching full and settle at 4.18-4.19V after sitting overnight. Some of the older & generic brand cells drop off pretty quickly though.


Thanks guys.

I’ll make sure of it with Dora or Karen. Thanks

Currently sold 433 units. EDIT: the correct figure should be 233 units, sorry.


Opus Instrument, the maker of BT-C3100 charger/analyzer, has received numerous
complaints from their worldwide dealers complaining they can’t sell their stocks easily because of the low price of this group buy, and informed Gearbest accordingly.
Opus will allow Gearbest to sell its remaining stock on hand (at about an hour ago): * about 58pcs. EU / 15pcs. US at the the current gb price of $39, till supply lasts.

When the above supply runs out, Gearbest will still sell new stocks of the charger but will be priced at approximately $55 each.

When the remaining stocks mentioned above are all sold out, this Group Buy will be closed.

Edit: The $55 price is the minimum Opus wants in a promotion, not Gearbest’s