Good Day HKJ, 
SUPERB review....
Thank You Very Much,
George
I also have 2.0 version.
It came just 2 weeks before the 2.1 was announced. Usual form for me :~
Since I also have a Maha C9000 and a Xtar WP6, am I missing out on much?
The main difference is capacity shown while charging and you can get around that by using a higher current power supply.
Also note that all version 2.0 chargers are not the same, some of the improvements has been implemented, before the version was increased to 2.1.
I also have the Maha c9000. HKJ has posted somewhere in one of the threads, the c9000 undercharges as compared to the 3100 (both V2.0 and 2.1). Previously, being a big fan of the c9000, I was not inclined to easily accept it to be so, but now as I have already tested both, it appears to be true. While both my chargers (c9000 and 3100) terminates my AA cells at about 1.48V when Done or Full appears, I notice after a few hours the c9000-charged cell settles to somewhere around the 1.34V, while the 3100 maintains the 1.42 to 1.44V still.
Edit: Here it is, HKJ comments:
They have different advantages:
BT-C3100:
Looks like it has a very good termination, i.e. when it say finished the cell is charged. But then it uses a 50mA trickle charge, i.e. it is best to remove the battery within a few hours.
C9000:
It terminates on voltage, i.e. batteries may not always be filled up when it say finished. To compensate for this it uses a two hour top-off charge and then switches to a very low trickle charge, i.e. it is safe to let the batteries stay in the charger.
Ask a question in Australia, and within minutes, answers from Denmark and The Far East.
Still blows my mind.
Guess I’ll stick with My V2.0 C-3100 and get used to using it properly - and wait for V3 
Cheers.
Beer o’clock on the East Coast 
Thanks HKJ for the review.
.
After reading/comparing the reviews for 2.0 and 2.1. I’m not sure if an upgrade would be worth the money.
Regarding the capacity displayed on v 2.0: The (Euro) PS works, not a high difference like some have experienced.
A few “issues” still exist with 2.1., and still no switch to change the voltage. May be the switch will appear in a newer version (3.0 )? Is the fan still noisy?
.
Just a thought (no offense)
After selling a few thousand 2.1’er we will get a v. 2.2. or 3.0 with few improved features and few days/weeks later a GB for a few bucks more
No, it is on the inside. It would be a good idea with a upgrade to the box that made the switch accessible, but it must include some way to make it very visible what position the switch is in.
It can still be heard, but the slow starting makes it less annoying.
That is what happens with all products ;)
For this charger a real improvement will require new hardware, i.e. it is not going to happen fast.
Thank you for the professional test engineering review, including the high potting of the device. This is often overlooked in consumer products and is essential for safety.
Thanks HKJ
That what I mean. Opening every now an than becomes kind of annoying. Or doing the drill and screwdriver/pen mod.
The v. 2.0 fan could be heared across the room. I think I’ve somewhere an old Papst which could fit.
That’s true, but the cycle came quick, maybe just a FW update was necessary.
Thank you for the review
Much harder to resist V2.1 ………
Thanks for another incredibly detailed review!
HKJ, thank you as always for your incredible review. I’m particularly grateful for how you distill very technical information into something that I can grasp. Please keep up the good work. (And PM me your paypal address if you’d like a contribution to your beer/etc fund.)
Hi,
Before I spend money I think I have read this before just to make sure. If i purchased a 12v 10amp power supply will it take care of most of the issues with spikes and other issues with the V2.0? Also will it make the charge and discharge number more accurate? Thank you
A 10 amp supply is probably overkill. Unfortunately there rarely is enough detailed information on power supplies to know how small a supply could
actually be used. The issue is the charging places a very short term 10 amp demand on the supply, while the average current is only 2 amps. Most supplies
do have substantial short term overcurrent capability. However asking a 3 amp supply to delivery 10 amps for more than a few milliseconds at a time is probably asking for trouble. I use a 6 amp supply, and that seems to have solved the problem of reported charge capacity (which will almost always
be somewhat higher than discharge capacity because charging is NOT 100% efficient).
Plan B is simply place a 100,00 uFd Cap across the output of the Power supply (or input of the charger). That adds enough energy storage to supply
to sustain the short term 10 amp demand.
This ONLY impacts the reported charging mAh. Discharge does not place a substantial burden on the power supply, so the discharge mAh is going to
accurate whether you use a 3 amp or a 10 amp power supply.
When you cant make it right in the third attempt, oh well…
Tnx for the review anyway
While testing my batteries for internal resistance I saw the same high values of 120-150 in both laptop pulls and protected batteries. Unprotected new gave me 30-40 values. Is that ok?
I’m curious with this configuration.
What happens if I put one or two batteries in Slot #2 & #3 when slot #1 & #4 are charging 2000mA ?
The current is reduced to 1000mA.
ic. Thank you for the answer 
And on your wish list is a MAHA 9000…
This is way cheaper and way more useful!