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

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

My mistake, the Trustfire Flames were rated at 2400 mAh. The charger showed 2261 mAh and 2128 mAh after the discharge test at 1000 mA completed. In my opinion, the results are really good for 2+ year old non-major branded cells.

Yeah, that’s good enough.

MAP police once again….

this forum need definitely a closed area for members only for those group buys…

And only members with over 180 posts are allowed admission.

Fortunately I think many members in blf who wanted one have secured the GB price

The people who don't want to spend 55 bucks on a charger will soon have to settle for 375mA charging per slot on the Nitecore Digicharger if it really does sell for the rumoured 30bucks or so.

I have not and can’t get one at the moment. Too bad I had to get an eneloop charger while this deal was being ironed out with the issues in V1.

Oh well, I’m sure our awesome members will get more sweet deals on other chargers at a later point!

This is not really a MAP issue. Its about other shitty vendors complaining that their stock is not being sold.

Efest luc v4 does 4x 1a or 2x 2a and is 29.99 :slight_smile:

This forum is so awesome :stuck_out_tongue: So much happens everyday!