Test/Review of Charger Opus BT-C3100 V2.1

[hammerjoe]

We are now in 2015 and I was wondering if this is still the charger to get in the 30-40 dollar range?

 

[hammerjoe]

Am I reading correctly that this charger doesn't have a DISCHARGE/CHARGE (one time) function? It requires two steps, first put the batteries to discharge then put them to charge?

It seems that the Charge/test is the closest but it charges the unit first wasting a cycle.

I dont know alot about charger but isnt this kind of an important feature of any smart charger to have?

 

[ChrisGarrett]

Am I reading correctly that this charger doesn't have a DISCHARGE/CHARGE (one time) function? It requires two steps, first put the batteries to discharge then put them to charge?

It seems that the Charge/test is the closest but it charges the unit first wasting a cycle.

I dont know alot about charger but isnt this kind of an important feature of any smart charger to have?

Much like the LaCrosse chargers that discharge and then charge up in one step, we generally don't like that feature because unless we're standing right over the charger and have the ability to memorize 16 digits in sequence, we miss that number.

We want to be able to know the capacity of a given battery upon discharge.

Having a single step allows us to 'know' those numbers, regardless of whether we're off doing other things.

Chris

 

[hammerjoe]

Much like the LaCrosse chargers that discharge and then charge up in one step, we generally don't like that feature because unless we're standing right over the charger and have the ability to memorize 16 digits in sequence, we miss that number.

We want to be able to know the capacity of a given battery upon discharge.

Having a single step allows us to 'know' those numbers, regardless of whether we're off doing other things.

Chris

I apologise but you confused me with your post.
Doesnt the capacity show after the battery is charged and not after discharging?
I usually put the batteries after using them in my lacrosse and use the discharge feature which discharges the rest of the battery and charges it right after.

Is this wrong/not necessary?

 

[ChrisGarrett]

I apologise but you confused me with your post.
Doesnt the capacity show after the battery is charged and not after discharging?
I usually put the batteries after using them in my lacrosse and use the discharge feature which discharges the rest of the battery and charges it right after.

Is this wrong/not necessary?

The way you test capacity on any given battery/cell, is to charge it up fully and then discharge it at X, Y or Z current. Generally, the higher the discharge current, the lower the capacity will be for equal batteries/cells, both charged up to full.

The fact that a charger immediately goes into 'charge' mode after 'discharge,' makes it problematic to know what exactly was there in the tank, unless you get lucky.

Chris

 

[hammerjoe]

I understand what you are saying now.
The Bc9009 doesnt have that function to charge a battery and they discharge it afterwards afaik.

It has a discharge and then charge feature which I use alot and that is missing with the Opus unless I want it to do it three times with the discharge refresh function.

 

[danielrhall]

It has a discharge and then charge feature which I use alot and that is missing with the Opus unless I want it to do it three times with the discharge refresh function.

To determine the capacity of a cell, it has to be discharged completely from a full charge. That's what the Test function on the Opus BT-C3100 does; charge fully first, discharge fully, and then charge fully again. The capacity that is then read out is the discharge capacity. The final charge cycle isn't actually needed to determine the discharge capacity but the initial one is. The Maha MH-C9000 calls this function Refresh and Analyze Mode.

 

[hammerjoe]

How do we recondition a cell with this charger?
Why limit the cycle of the Discharge/Charge to only three? Does that guarantee the maximum recondition of a cell with no more need for extra cycles?

 

[curlysir]

Received the BT-C3400 today and initial impressions are favorable. It has 2.1 firmware. I was able to charge 4 18650 at 1000mA, (primary reason for the purchase). The fan does make some noise when it runs but where I use the charger the noise should not be a problem, It is in the same room as my computer and I generally have a TV on so I really didn't notice it, unless I was actually trying to hear the fan. I don't think this is a charger for a bedroom as the noise would be noticeable in a very quiet room.

This replaces a Nitecore D4 which is not a bad charger if you don't mind slow charging, It will only charge 4 18650 at 375mA or 2 at 750mA. I also considered buying a XTAR VP4, but it will only charge 2 18650 at 1000mA or 4 at 500mA , Do not understand why XTAR does not make a real 4 cell version of the VP2.

The BT-C3100 2.1 and the BT-C3400 appear to be the same charger. And from what I could find are just about the only 2 currently available for less then $50 that will charge 4 18650 (or others) at 1000mA.

The only minor annoyance I have (personal preference) and it applies to all Opus chargers is the backlight, I would prefer an option to turn the backlight on and off and not have it go off after so many seconds as it does now.

 

[Tachead]

Received the BT-C3400 today and initial impressions are favorable. It has 2.1 firmware. I was able to charge 4 18650 at 1000mA, (primary reason for the purchase). The fan does make some noise when it runs but where I use the charger the noise should not be a problem, It is in the same room as my computer and I generally have a TV on so I really didn't notice it, unless I was actually trying to hear the fan. I don't think this is a charger for a bedroom as the noise would be noticeable in a very quiet room.

This replaces a Nitecore D4 which is not a bad charger if you don't mind slow charging, It will only charge 4 18650 at 375mA or 2 at 750mA. I also considered buying a XTAR VP4, but it will only charge 2 18650 at 1000mA or 4 at 500mA , Do not understand why XTAR does not make a real 4 cell version of the VP2.

The BT-C3100 2.1 and the BT-C3400 appear to be the same charger. And from what I could find are just about the only 2 currently available for less then $50 that will charge 4 18650 (or others) at 1000mA.

The only minor annoyance I have (personal preference) and it applies to all Opus chargers is the backlight, I would prefer an option to turn the backlight on and off and not have it go off after so many seconds as it does now.

Why not just get two VP-2's? That's my plan when I get a light that uses 3-4 x 18650. I just grabbed one to start with to try it but, will order another when needed(I really like it so far). Having 2 separate chargers gives redundancy too. That way if one fails you still have the other to keep you going while you wait for repair/replacement.

 

[curlysir]

Why not just get two VP-2's? That's my plan when I get a light that uses 3-4 x 18650. I just grabbed one to start with to try it but, will order another when needed(I really like it so far). Having 2 separate chargers gives redundancy too. That way if one fails you still have the other to keep you going while you wait for repair/replacement.

Already have two VP-2's. But thanks to this site I sometimes have the need to charge more then 4 batteries at a time. I bought the Nitecore D4 first and then purchased the VP-2's during the sales. After buying several 18650 powered flashlights, some using 4 batteries, I noticed the D4 was taking longer to charge then the VP-2 and realized the limitation of the D4. Started looking for a replacement for the D4 that would also charge NiMH and this lead to the C3100 and C3400. If XTAR every comes out with a true 4 cell version of the VP-2 I will probably get it too.

 

[tobrien]

has anyone heard about a v3.0 or something yet? I saw there's the "3400" but that's not anything really different it seems

 

[GreatBizarro]

Thanks for a thoroughly in depth review. Got one on order based on your information. The test ability alone is a great help as I am putting together some 18650 packs and can match cells.

 

[realista]

i shoot a picture of the internal switch. now it's easier to me to change it....

 

[tobrien]

i shoot a picture of the internal switch. now it's easier to me to change it....

nice work!!

 

[hammerjoe]

How accurate are the discharge and charge capacities displayed by the charger?

I am wondering how people are determining the real capacity of their cells.
Do a full discharge and then charge and look at the capacity displayed by the display?
Do a full charge and then discharge and look at the discharge capacity on the display?

Or do the one of the above but calculate how long it took and multiply the time by the charge/discharge current?

 

[tatasal]

How accurate are the discharge and charge capacities displayed by the charger?

I am wondering how people are determining the real capacity of their cells.
Do a full discharge and then charge and look at the capacity displayed by the display?
Do a full charge and then discharge and look at the discharge capacity on the display?

Or do the one of the above but calculate how long it took and multiply the time by the charge/discharge current?

I have this charger. I have tested its discharge capacity readings on the same cell, a Panasonic 2900mah NCR-PF cell, fully discharged first, then fully charged by my Xtar VP2, both occasions @ 1A, and the difference in discharge readings between this charger and my hobby charger, the iCharger 106B+, was 8 mah.

 

[hammerjoe]

Where are the heating sensors located? I dont see them in any pictures of this charger.

 

[yorab]

Ok, so this one clearly has the internal switch.

Has anybody yet tested the 3.7V or 4.35V positions?

BTW, what is the difference between 4.2V and 4.35V?

 

[HKJ]

Has anybody yet tested the 3.7V or 4.35V positions?

Some people has been using it.

BTW, what is the difference between 4.2V and 4.35V?

0.15V LG has some cells that need a 4.35V when charging to get maximum capacity.