Sysmax/Nitecore/Jetbeam i4 Intellicharger Review (V2): current/voltage comparisons

selfbuilt

Flashaholic
Joined
May 27, 2006
Messages
6,936
Location
Canada
Sysmax/Nitecore i4 Intellicharger Review (V2): current/voltage comparisons

Welcome to my Sysmax/Nitecore Intellicharger i4 V2 review. :party:

UPDATE JANUARY 6, 2012: I have now reviewed a similar version of this charger, under the Jetbeam-specific branding - the Jetbeam i4 PRO.

i4V2012.jpg

i4V2013.jpg


The initial iteration of the i4 charger sparked a lot of interest here, due to its stated ability to "intelligently" handle both Li-ions and standard NiMH/NiCd rechargeable batteries. :eek:oo:

There were some problems with the first version of this charger (especially when run on North American 110V AC power), resulting in a model recall. This review will look at the new and revised V2, which addresses the earlier issues and adds some new features.

This review will be done in the style of my earlier Xtar WP2-II review. I am not as well versed in electronics or circuitry as some of the other members here, so I suggest you consult with the experts if you want to know more than just the basic current/voltage runtime relationships presented here.

Please see my original charger round-up review for more background on my testing method, and comparison to a number of basic chargers.

If you are looking for more information on how to perform measurement/testing on chargers, please see HKJ's excellent Measurement on flashlight page.

i4 Intellicharger V2 Reported Specifications
  • Li-ion: 26650, 22650, 18650, 17670, 18490, 17500, 17335, 16340 (RCR), 14500, 10440
  • NiMH / NiCd: AA, AAA, C
  • Input Voltage: AC 100-240V 50/60Hz or DC 12V
  • Input power: 10W
  • Output Voltage: 4.2V +/- 1% / 1.48V +/- 1%
  • Output Current: 350mA x 4 / 750 mA x 2
  • Capable of charging 4 batteries simultaneously
  • Each of the four battery slots monitors and charges independently
  • Automatically identifies Li-ion, Ni-MH and Ni-Cd rechargeable batteries
  • Features three charging modes (CC, CV and Trickle Charge)
  • Automatically detects battery status and selects the appropriate voltage and charge mode
  • 3 Color LED displays charging progress for each battery
  • Automatically stops charging when complete
  • Features reverse polarity protection
  • Designed for optimal heat dissipation
  • Certified by both RoHS and CE
  • Dimensions: 139mm x 96mm x36mm
  • Weight: 156g (without batteries)

    What's New in Version 2
  • The charging slot is now 2cm longer than the v1 version, to accommodate larger protected cells. (Reviewer's Note: I believe they meant to say 2mm longer)
  • The charging current drops to 750mA when charging two batteries at position #1 & #3. The current is still 750mA for and will alternate charge cycle once every second for each battery. When charging two batteries installed in slot #1 & #2 they will get 750mh respectively. The result is: charging at slot #1 & #2 will be faster than charging at slot #1 & #3 (Reviewer's Note: #2 & #4 are similarly paired, like #1 & #3)
  • Improved charging capability/safety when charging 10440 li-ion batteries
  • Works properly with US 110V System
  • MSRP: ~$25
Note the above is what the manufacturer reports for the charger – scroll down to see my actual review findings. :wave:

i4V2011.jpg

i4V2001.jpg


My i4 V2 came with just a standard 110 AC power adapter. The unit supports 100 – 240V AC, 50/60Hz, so those outside of North America can use it fine (with the appropriate terminal plug). A 12V DC car adapter is available separately.

i4V2002.jpg

i4V2003.jpg

i4V2006.jpg

i4V2009.jpg

i4V2010.jpg


The cabling and overall build seem good (good length on the cables, solid base unit). The battery trays are spring-mounted, and can easily accommodate any size from RCR to 18650 without spacers. :thumbsup: However, I found the springs lacked lube on my sample, and a couple of them were very stiff to operate out of the box. You will likely need to add some lube yourself, which is an inconvenience for the general consumer. :shrug:

As explained in the manual, while the charger has four bays, it actually only has two independent channels. If you want to charge two cells independently of each other (i.e., each charged at the full 750mA current the unit is capable of), you need to place the cells in bays #1 & #2, #2 & #3, #1 & #4, or #3 & #4.

If you place the cells in the paired bays #1 & #3, or #2 & #4, the charging current will be split between the cells. Rather than just cutting in half (i.e., 375mA per bay), the current remains at 750mA for each bay – but it alternates charging by cycling off/on once every second for each battery. This effectively results in the same thing, but the cell is actually being charged at 750mA for a 1sec on, 1sec off, cycle.

This is explained in the manual, but it would be good have the charger unit bays labelled somehow. Scroll down to see my actual testing results.

i4V2005.jpg

i4V2015.jpg

i4V2016.jpg

i4V2004.jpg


Note: I didn't have the unit plugged in for these shots, which is why you don't see any of the indicator lights lit up. :sssh:

There are three yellow lights located over each charging bay, and a blue power indicator at the top right hand side of the unit (lights up when AC/DC power is supplied).

When you insert a battery into the charger, the three yellow lights over the bay indicate the charging status. One flashing LED on the bottom means the unit is charging, and the battery is less than 1/3 full. One solid on the bottom and one flashing LED in the middle means the unit is charging, and the battery is less than 2/3 full. Two solid and one flashing LED means the unit is charging, and the battery is more than 2/3 full. Three solid LEDs means the battery is fully charged and the unit has stopped charging.

As you can see in the pics above, all standard battery sizes fit fine. I was able to get my longest high-capacity 18650s to fit (although they were a bit snug). :thumbsup: I was even able to get the 26650 from my 4Sevens X10 to charge fine. I can't guarantee that all 26550 cells will fit, however (i.e., a smaller positive button on the cell may not be able reach to the positive contact plate in the bay).

Here is a quick video overview of the physical build of the charger:



Video was recorded in 720p, but YouTube typically defaults to 360p. Once the video is running, you can click on the configuration settings icon and select the higher 480p to 720p options. You can also run full-screen.

Voltage/Current Measurements

To examine the performance of the charger, I have directly monitored charging current and voltage with a data-logging DMM (on separate runs).

For these tests, I have used my standard AW protected 18650 (2200mAh) and RCR (750mAh) cells, and Sanyo Eneloop AA NiMH. The cells used here have all had a good number of cycles on them, but are still in reasonable condition. To deplete the cells, I used my regular test bed of a fully-regulated JetBeam Jet-III ST, Jet-II or Jet-I Pro (all IBS models) on Max output – and wait until the cell’s protection circuit gets tripped. The cell is then immediately loaded into the charger for testing and recording (depleted resting voltage typically ~3.0-3.2V).

Let's start with something simple: 1x18650, and 1xRCR:

i4-18650.gif


The i4 V2 shows a charging algorithm on 1x18650 that at least approximates the CC/CV charger pattern for Li-ions. The initial charging current (measured at 750mA) is exactly as reported for this charger. :thumbsup:

In the 1x18650 run above, you can see the i4 kept the charge current very constant during the CC phase, and dropped down gradually during the CV phase. The CV phase doesn't appear to exactly constant, but it's not bad.

i4-1xRCR.gif


Ok, this a little different. :thinking: For the 1xRCR run, the unit was not able to keep the CC phase for long, and quickly dropped into the CV phase.

UPDATE: As noted in the discussion below, the charger does not seem to have a true CV phase, but rather something that approximates it. I have not tested enough chargers to know for sure what this phase normally looks like on 1xRCR.

For both runs, the unit terminated at just under 40mA charging current. This is very respectable, and means that lower capacity Li-ions can be safely charged in the light (e.g. RCR, 14500, 10440, etc.). Of course, this specific CC/CV-like pattern also means that cells will take a bit longer than in some other chargers.

Fully charged, most of my well-used cells were ~4.16-4.18V at rest. With newer cells, I measured ~4.20-4.21V at rest. This is normal (cell capacity drops with repeated cycles), and suggests the charger is charging up to the full capacity of the cells. :)

The i4 does not completely terminate when the three yellow LEDs go solid. Although my DMM dropped to zero on my 10A port, when I switched over an re-ran the termination charge on my DMM’s mA/uA port, I measured a low 110 uA current. But this is low enough to be irrelevant. Note that despite what the manual says, this is not what most people understand as a "trickle charge." A true "trickle charge" usually involves a regular pulse of mA current, to maintain the fully charged state. IMO, this is not a good thing for Li-ions – most "trickle chargers" are set too high, and over the long-term, will slowly cook your batteries (i.e. it gradually over-charges the cell, as long as it sits in the charger). The constant low uA current here is negligible, and will not lead to "trickle-charger" over-charging. For all intents and purposes, the i4 is close enough to full termination.

Note: The "dips" in the graphs above have to do with how the charger operates – it actually stops charging once every two seconds to check to see if anything has been inserted into the paired charging bay. I don't have an oscilloscope to show you the exact pattern, but I can estimate from my sampling measures that it takes just under a third of a second to check. This is enough to drop the current/voltage reading in the traces above. My sampling rate is once every 30 secs, hence the why you don't see a continuous "wall of noise", but just sporadic dips (i.e. there is a ~15% chance my DMM will be taking a reading during a charging pause).

Let's see what happens if you charge two cells in paired bays (i.e. #1 & 3, or #2 & #4)

i4-2xRCR.gif


While this may look similar to the earlier 1xRCR charge cycle, please pay attention to the timescale. As you will see, it took a lot longer to charge two cells in the paired bays. The reason for this is that the charger alternates the current between the cells (i.e. charges the first bay for a little under one sec, then stops and charges the other bay for a little under one sec, etc.). Note also the charger still does its ~1/3 sec pause every ~2 secs to check the status of the paired bay.

The net effect is roughly comparable to what would happen if each bay got a continuous half-current instead of an intermittent full current (i.e., 375mA to start, instead of 750mA), assuming the same CC/CV-like pattern.

So, effectively, this means is that it may take up to twice as long to charge cells in paired channel bays (e.g., I would expect 10+ hours to charge two 18650 cells in paired bays). You could still charge two 18650 cells in ~5 hours using the independent channels (which I recommend). But if you wanted to charge 3-4 cells at once, at least some of those cells would take twice as long.

So why does the charger do this? Well, the 750mA initial charging rate is high for lower capacity cells (e.g. 10440). If you are trying to charge cells with low capacities (basically, anything AAA-sized or smaller), it is recommended by the manufacturer that you always charge two cells at a time, in the paired bays to lower the overall average current to each cell.

Again, remember that if I had charged these cells in bays #1 & #2, #2 & #3, #3 & #4, or #1 & #4, each one would have gotten the full charge cycle and looked just like my earlier 1xRCR current charging trace.

So how does NiMH look?

i4-AA.gif


The charger runs at a CC cycle of just over ~700mA in my testing. :thumbsup:

Unlike Li-ion, NiMH chargers don't work by a CC/CV method. Instead, they typically terminate when the battery reaches a particular voltage level, based on a characteristic increase in the positive slope of voltage versus time (i.e., dV/dT). As you can see in my runtime traces, there is a very pronounced uptick in voltage just before the run terminates. But I haven't tested other NiMH chargers, so I don't know if this is what to expect for dV/dT termination. Any of the NiMH experts want to chime in here? :thinking:

The full charge capacity seems to be good. My Maha C9000 charger typically charges this cell to ~1950mA, and reports the discharge capacity as ~1850mA. When I discharged the i4-charged cell, I got ~1830mA discharge capacity, which is pretty comparable to what my Maha reports after its own charge/discharge cycle.

Oh, and some good news: it looks like you can charge both NiMH and Li-ions at the same time, even in paired bays. :) I know there were some issues reported with this on the first (recalled) version of the i4. But I've tested it in a variety of bays, and NiMH and Li-ion both charged correctly (at least based on initial charging patterns – I didn't run them until termination). The manual for the i4 V2 reports this is allowed.

Preliminary Discussion

The new second edition of the i4 Intellicharger from Sysmax appears to live up to the initial promise of this model. It successfully charged all manner of cells that I threw at it, with performance generally consistent with its specifications. :)

For Li-ions, I particularly like the use of the CC/CV-like method, with a low charging rate at the time of termination (i.e. <40mA in my tests above). This is about half that of my Pila charger, which is the gold-standard for consumer Li-ion chargers. A low termination current is important for low-capacity cells (i.e., RCR and anything smaller), which suggests you are good to charge anything here.

However, because of the relatively high initial charging current on Li-ions (750mA), you shouldn't charge anything smaller than RCR individually. Sysmax recommends you charge anything with the capacity of AAA/10440 or smaller in pairs, on the same current channel (i.e. bays #1 & #3, or #2 & #4). As this is a four-bay charger with only two independent channels, the charging current will be essentially halved when you charge two cells simultaneously in those bays. If you want to charge two cells simultaneously with the full current to each, you would need to place them in bays #1 & #2, #2 & #3, #3 & #4, or #1 & #4.

The charger suspends charging for just under 1/3 of a second every 2 seconds, to check the status of the other bay. This means that the charger is only charging a single cell ~85% of the time (or ~42% of the time, if running in paired charging bays). :shrug:

The end result of all of the above means that it takes a little longer to fully charge your cells. For one 18650 2200mAh cell (or two cells in independent channels), I would plan for at least 5 hours charging time from fully depleted (my Pila takes a little over 4 hours, in comparison). As an aside, for those who complain that four 18650s would take 10+ hours on the i4, I would point out my Pila would need 8+ hours anyway (i.e., I would have to switch the two cells out after 4 hours, or buy a second Pila!). :rolleyes:

The i4 V2 charger dropped to a negligible low uA once the status lights indicated a full-charge. Despite what the manual says, this is not a "trickle-charge" – it is in fact much better, and is practically equivalent to actual full termination. :thumbsup:

The i4 also successfully handled any NiMH cells I tried on it. Charging current was constant at ~700mA over the course of the charging cycle. The i4 will certainly not replace my Maha C9000 workhorses with their detailed featured sets (yes, I own two of them :kiss:), but it gets the job done in a reasonable amount of time. I was (pleasantly) surprised to see that I could charge both Li-ions and NiMH simultaneously – in both paired and/or independent channels – and everything seemed to work fine.

Physically, the charger handled all my cells (including one 26650). However, they do need to grease the springs at the factory – most of mine were so stiff, I was worried about bending the prongs when first trying to insert the cells. The charging light interface is intuitive, and worked consistently in my testing.

End of the day, no real surprises here – the charger lived up to its billing. I hope you found the current/voltage analysis useful. But as always, I will leave it up to the battery and charger experts here to weigh in and provide more detail on the charger specifics. :wave:

UPDATE JANUARY 6, 2012: I have now reviewed a similar version of this charger, under the Jetbeam-specific branding - the Jetbeam i4 PRO.

----

i4 V2 charger supplied by Sysmax for review.
 
Last edited:

Nake

Flashlight Enthusiast
Joined
Oct 31, 2006
Messages
1,768
Location
Cleve. OH
I'm guessing RCR2 cells should be charged in 1 & 3 and 2 & 4 also, correct?
 

peterharvey73

Flashlight Enthusiast
Joined
Apr 12, 2011
Messages
1,005
Great review as usual Selfbuilt.

So this mean I best continue to recharge a single 1x AW RCR Chemistry 16340 Protected on my Pila charger?

While the new Sysmax i4 is good for 3x18650 AW 2900 Flat Tops from an RRT-3, and 4x18650 Redilast 3100 Button Tops from a TM11?
 

Draven451

Enlightened
Joined
Jan 4, 2006
Messages
370
Location
USA
Thanks for always bringing some of the best reviews of the newest products on the market! :thumbsup:

We like it but our wallets don't like so much~*
 

selfbuilt

Flashaholic
Joined
May 27, 2006
Messages
6,936
Location
Canada
:grouphug: Thanks guys, glad you are enjoying the review. The charging/battery stuff is not really my forte, but I thought I'd try to provide as detailed an overview as I can.

I'm guessing RCR2 cells should be charged in 1 & 3 and 2 & 4 also, correct?
Yes, RCR2 should only be charged in paired bays on the same channel (1 & 3, or 2 & 4), due to their lower capacity.

So this mean I best continue to recharge a single 1x AW RCR Chemistry 16340 Protected on my Pila charger?
Well, the i4 has only a slightly higher initial current (750mA) on a single cell - but given that it is only charging for ~85% of the time, the average CC current is not so different from the the Pila. The i4 also has a lower termination current than the Pila, which is even better for RCR. End result is that is takes longer to charge on the i4, and it seems at least as suitable as the Pila.

While the new Sysmax i4 is good for 3x18650 AW 2900 Flat Tops from an RRT-3, and 4x18650 Redilast 3100 Button Tops from a TM11?
Those should all work fine.
 
Last edited:

Joe Talmadge

Flashlight Enthusiast
Joined
Aug 30, 2000
Messages
2,202
Location
Silicon Valley, CA
The i4 V2 shows the classic CC/CV charger pattern for Li-ions.

selfbuilt, thanks for the in-depth review. I'm stuck on your statement above. to my eyes, that pattern is not a classic CC/CV charger pattern. It's showing a CC phase (ignoring the open circuit voltage checking I guess), but I believe the CV phase should start when the voltage hits 4.2V, and stay at exactly 4.2V until the current drops to the termination current. Instead, on the i4, the CC phase is over at around 4V, and then switches to a not-quite-CV phase where the voltage slowly rises the rest of the way to 4.2V while the current drops off.

I don't know that it's a problem, but that second phase of charging just isn't quite a CV. Maybe a SRV (Slowly Rising Voltage) phase :) No?
 

selfbuilt

Flashaholic
Joined
May 27, 2006
Messages
6,936
Location
Canada
to my eyes, that pattern is not a classic CC/CV charger pattern. It's showing a CC phase (ignoring the open circuit voltage checking I guess), but I believe the CV phase should start when the voltage hits 4.2V, and stay at exactly 4.2V until the current drops to the termination current. Instead, on the i4, the CC phase is over at around 4V, and then switches to a not-quite-CV phase where the voltage slowly rises the rest of the way to 4.2V while the current drops off.
A good point ... I had originally written "The i4 V2 shows a charging algorithm that at least approximates the CC/CV charger pattern for Li-ions", but had shortened it because I thought the review was getting too wordy. :rolleyes: I have just re-instated that sentence, because I agree with you that it is not really constant voltage. But I have not tested enough chargers to know for sure what the CV phase should look like. Maybe someone with more experience can chime in with an opinion?
 

cactus man

Newly Enlightened
Joined
Apr 18, 2012
Messages
39
I found this product review a valuable asset!

After reading this review, I ordered the i4 charger from Wiseguys....$27.89 [shipped]

I received the original model 375/750ma on the rear label [yellow color].
I now see they have a Ver-2 model and the charging current
is specified at 500/1000ma....

I primarily charge 18650 protected batteries and AA 1.2v Ni-MH batteries.

How critical is the additional current of 125ma of the VER-2 model?
Are there other improvements that would encourage me to replace the
first generation unit with the newer VER-2 model?

If charging time is the only difference than in my case it's a moot point
and I'll keep the unit I have.

Thanks....

Cactus Man
 

fonzerelli

Newly Enlightened
Joined
Apr 10, 2012
Messages
12
Great review!

After reading about this charger, however, the price point seems too good to be true. I was wondering if there were any reasons to not get this charger, vs the Pila IBC.

I already have the Maha charger for NIMH, so I would primarily be using it to charge multiple 18650's for the new Niteye Eye-30 that I just scored a killer deal on.

I already have one Pila IBC for another light I have, but I've been contemplating getting a second one to expedite charging of four batteries at the same time. I realize that the Pila has the potential to charge four batteries faster than this new charger, but that's only if I keep a very close eye on it and swap out the first two batteries right when they finish.

I can spend around another 50 for a second Pila, or 25 and get a charger that does four at the same time.

Any thoughts?

Thank you!
 

selfbuilt

Flashaholic
Joined
May 27, 2006
Messages
6,936
Location
Canada
I received the original model 375/750ma on the rear label [yellow color].
I now see they have a Ver-2 model and the charging current
is specified at 500/1000ma....
No, that is the old model that lists the 500/1000mA charging current (i.e. V1). Nitecore/Jetbeam do not appear to have updated the content of their websites in awhile. So, while they advertise the new V2 charger on their front pages, the actual link takes you to the old page showing pictures of the original V1, with copies of the original V1 manual posted. The new V2 uses 375mA/750mA.

If you have the version with the same color label as mine, then you have the latest V2. It is confusing that they list the specs for the old V1 on the website. :sigh:

Are there other improvements that would encourage me to replace the
first generation unit with the newer VER-2 model?
Again, you seem to have the V2. But for anyone in North America actually using the V1 with the originally supplied 110 AC cable on the V1, you should stop using the charger now. :caution: The V1 of this charger was recalled in North America, due to problems with the 110V rail. As a workaround, Sysmax supplied to an adapter that lets you run the unit off the 12V DC port, through AC power.

But even at that, there were a number of problems with the V1 of this charger. Please see HKJ's excellent review of the V1 here.

After reading about this charger, however, the price point seems too good to be true. I was wondering if there were any reasons to not get this charger, vs the Pila IBC.
I typically try to avoid recommending any specific producs (well, I do recommend the Pila for Li-ion and Maha for NiMH, but that's because they are the standards around here ;)).

That said, the new V2 of the i4 and the Xtar WP2-2 that I review previously both seem to function well, and could serve as good "budget" versions of the Pila. The i4's ability to run NiMH and take four cells at a time (albeit on 2 channels) makes it particularly attractive.

I'm looking forward to HKJ's more detailed review of this charger, to see if there's anything that I missed ... :whistle:
 

cactus man

Newly Enlightened
Joined
Apr 18, 2012
Messages
39
Thank you Selfbuilt....

I am now a bit confused so please bear with me....

My unit has a yellow decal on the front "Intellicharger i4" top left

on the backside I also have a yellow decal that says "NITCORE"
the output specs show 4,2v +/- 1%, 1.48v +/-1% 375ma *4 and 750ma*2

no serial number

This unit came with a two wire AC power cord not a wall wart cube.
The AC cord is nonplarized and plugs into the blue AC socket on the charger.

Using the charger I do not experience excessive heat or any noise or odors.
The batteries charge is a reasonable amount of time.

So.... you're saying the unit I have is version-2?

and the original version-1 unit specs a higher charging current of 500ma? and 1000ma?-

I look at various vendors and it's quite confusing as they show ver-2 as the higher current model.
I also see some vendors showing the 375ma current spec


I also downloaded user instructions from various sites and they discuss the 500ma rating
my unit included a single sheet [both sides printed one side chineese] with the 375ma current spec.

What is the reason for reducing the charging current?

Thanks for your input

Cactus Man
 

ecrbattery

Newly Enlightened
Joined
Mar 17, 2011
Messages
91
Thank you for the review selfbuilt.

I have two questions for you:


In the manual, it is stated that

Precautions:
1. When used at 110V, do not charge four Li-ion rechargeable batteries simultaneously.

Any reason for not being able to do this?


SAFETY question: If you insert an Alkaline AA or an Energizer L91 Lithium Primary AA into the charger, would it reject the battery or would it still try to charge?
 

selfbuilt

Flashaholic
Joined
May 27, 2006
Messages
6,936
Location
Canada
My unit has a yellow decal on the front "Intellicharger i4" top left
So.... you're saying the unit I have is version-2?
and the original version-1 unit specs a higher charging current of 500ma? and 1000ma?-
That's right - you have the new V2 (375mA/750mA), and the manual online is for the original V1 (500mA/1000mA).

I don't know why they dropped the current, but the charger now behaves as expected at the 750mA level.

In the manual, it is stated that
Precautions:
1. When used at 110V, do not charge four Li-ion rechargeable batteries simultaneously.
Any reason for not being able to do this?
Ah, that's the old manual for V1. The Jetbeam website has NOT been updated with the new manual yet.

I will have to check to see my manual tomorrow, but I don't believe that precaution is there anymore. Similarly, the new manual also explicitly supports charging different types of cells simulateously (Li-ion and NiMH) - the old V1 had a warning against this.

I do wish they would update the website with the correct V2 manual ... :poke:

SAFETY question: If you insert an Alkaline AA or an Energizer L91 Lithium Primary AA into the charger, would it reject the battery or would it still try to charge?
A good question, and one you should ask of any NiMH charger. I don't have an answer for you, and I would NOT want to try it. Don't ever put a primary cell (of any chemistry) into a charger, unless it is explicitly capable of handing it (e.g. for discharge measures only).
 

Joe Talmadge

Flashlight Enthusiast
Joined
Aug 30, 2000
Messages
2,202
Location
Silicon Valley, CA
A good point ... I had originally written "The i4 V2 shows a charging algorithm that at least approximates the CC/CV charger pattern for Li-ions", but had shortened it because I thought the review was getting too wordy. :rolleyes: I have just re-instated that sentence, because I agree with you that it is not really constant voltage. But I have not tested enough chargers to know for sure what the CV phase should look like. Maybe someone with more experience can chime in with an opinion?

Great, I think that's a fairer way to word things up. Just to make sure I'm not crazy, I went back and looked at the curves for a few other chargers I remembered doing CC/CV more properly, and indeed, those chargers have pretty straight horizontal lines during the CV phase. The 4sevens, pila, etc. have nice flat CV lines
 

Beacon of Light

Flashlight Enthusiast
Joined
Dec 9, 2005
Messages
2,054
Cool review. What happens with all 4 slots charging the same or different batteries? Is that all 4 charging at 750 mAh? That would likely fry the RCR123s I use protected or unprotected. The WF138 or WF139 charger is pretty safe and the only reason I';d buy this is to charge 4 at a time, but not at the expense of cooking the batteries.

Was there any tests done to monitor battery temperature with your review? This is usually a major concern and factor in choosing a new charger.

How effective is this charger at reviving older battteries that will not take a charge on other smart chargers. I'd like to kickstart a bunch of over terminated RCR123s that I can only sometimes fool into charging on my WF138/9 charger.
 
Top