Question 1

This is just a rebadged 3100 v2.2 why are you charging more than $10 more for the same device?

Accepted Answer

A couple of differences that I noticed:
-- The BT-C3400 came with a car 12V power cable while my BT-C3100 did not.
-- The BT-C3400 seems to have a continuous PWM fan control, varies the fan speed as needed so it is generally quieter while the fan on the BT-C3100 is either on or off, switches often.

Question 2

The opus c3100 when you remove screws inside there is a switch to change voltage so you can charge lifepo4 batteries. Does this have such a switch?

Accepted Answer

The switch is located inside the bottom cover, you need to remove the screws and then remove the bottom cover, there you will find a small 3 position switch with the different voltage options. What some people do is to use a dremmel to make a hole on the bottom cover so they can access the switch without having to remove the screws. Check google, there you will find tons of pictures and illustrations that show how to access the switch and so forth. Just keep in mind to use the correct voltage for the type of lithium battery that you will be charging, this is extremely important.

Question 3

Do you have a charger that will fit a 21700? i just received this and a klarus 21700 does not fit!

Accepted Answer

I do not. I no longer advertise that chargers fit 70mm cells. Most 70mm cells that are protected are actually longer than 70mm as you have found out. The sliding contacts in the C3400 will reach for a cell that is 70mm however most 21700 and other 70mm cells do not fit, they are too long. It is an aggravating situation as it seems most cell manufacturers are exceeding length. Sorry.

Question 4

Is this a cc/cv (constant current / constant voltage) charger?

Accepted Answer

The charge current can be adjusted to 200, 300, 500, 700 or 1000 Ma. The discharge rate can be adjusted 200, 300, 500 or 700 Ma for NiMH/NiCd and 1000 Ma for Li-ion.

ASIN	B07T941JCF
Amperage	2000 Milliamps
Best Sellers Rank	#156,621 in Tools & Home Improvement ( See Top 100 in Tools & Home Improvement ) #17,562 in Electrical Equipment
Brand	Opus
Color	Black
Connector Type Used on Cable	AC power plug, DC power plug
Current Rating	2000 Milliamps
Customer Reviews	4.6 out of 5 stars 255 Reviews
Input Voltage	240 Volts
Item Dimensions D x W x H	4"D x 7"W x 2"H
Manufacturer	OIC Ltd
Mfr Part Number	C3400V31CAR
Model Number	BT-C3400
Output Voltage	12 Volts (DC)
Product Dimensions	4"D x 7"W x 2"H
Specification Met	RoHS, UL, CE, FCC
UPC	727908590937
Warranty Description	One Year Limited Warranty

Opus Battery Charger Analyzer Tester for Li-ion NiMH NiCd Rechargeable Batteries C3400 BT-C3400 AA AAA C 18650

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