Provided for review by Xtar
Product page @ Xtar
VC4 User manual
Before starting testing a charger you need to grade / test your batteries . Pictured ( above ) are the good ones . Been over a year since these batteries were charged , maybe more . Those AW batteries are really old , the two light blue @ 4.14 volts are Samsung and equally old . Pictured bellow are the batteries recording zero volts . Protection circuits have tripped and the batteries have most likely got there because of the parasitic drain from the protection circuit .
The battery is not really dead ! The internal voltage of the battery is low enough so that the protection circuit wont allow the battery to be charged . TC or trickle charge mode is engaged by the charger so as to sneak the voltage higher till the protection circuit allows normal operation . In the video you can see this process take place . ( If that floats your boat )
What can I say about the VC4L . Well it works , it does the TC CC CV stages of charging :
TC = Trickle Charge
CC = Constant current
CV = Constant Voltage
AA / AAA batteries - The VC4L does charge a little harder than the FC2 charger I recently tested and bye that I mean my AA batteries were some 5 degrees warmer on average . This sort of tells me that the VC4 is pushing a little more against the internal resistance . ( Charging the batteries a little more )
18650 batteries - Same as the AA , resting voltage was consistently 0.1 to 0.2 volts higher than the FC2 charger . I did not notice the 18650 getting any warmer than with the FC2 charger , but I did notice the consistently higher voltage after being charged . This means that the VC4L is putting in more charge consistently , across a range of batteries .
What I did not like - When the batteries have completed their charge cycle and you remove them . You really ( perhaps ) should not . Because if you remove the two inner most batteries and leave the outer batteries , the charge rate will change . So if you don't want to charge your little ( small capacity ) batteries at 1A , you best leave the batteries in place until all are charged . Yeah , I did this one night ! It was late , I had things to do and I removed the batteries at completion and my last two AAA came of the charger seriously hot . ( I was cooking them at 1A ) It was late and I was not thinking - just doing ! This could be problematic if you forget about this function ( as I did ) . Ch1 & Ch4 being 1A , till you add a battery to Ch2 or Ch3 .. ( Ch2 and Ch3 being 0.5A ) .
A bit of brain fade on my part for sure , but it was just too easy to do . I love the build quality , I like the charger overall and the automatic charge rate is something that needs to be treated carefully , especially with small batteries . I think the VC4L is an excellent 18650 and larger battery charger , but when it comes to those smaller cells I would really like to see a smaller charge rate and manual charge rate selection . I am still waiting for a low current charger . I would be tickled pink if Xtar did a 100 / 200 / 500 mAh charger . That would be amazing . ( 4 bay )
If your in the market for a 18650 charger , then the VC4L needs consideration for :
A) It's build quality
B) It's charge capability
C) It's generous battery capacity ( Larger physically cell capability )
D) It's consistency