Intelligent Chargers

peter yetman

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This morning I read the sales puff for a new All singing - All dancing Xtar charger.
It will detect cell type, size, capacity and IR and charge it accordingly, with no input necessary from the user.
While I can appreciate the convenience of this, especially for recharging virgins, I feel uncomfortable not being able to decide myself how best to charge my cells and would prefer a charger with more manual input.
Does anyone else have a viewpoint?
P
 

Witterings

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I'd be interested to see what rate it charges at for each different battery, most chargers default to 0.5 amp for 18650's and whilst a lower rate is better for extended battery life most are safe to charge at 1c so 2/3 amps depending on capacity and if you do want a faster charge to get them done in an hour is there an override??

When I bought my charger I specifically looked for one where you could alter the current as AAA's with about 700 mah ideally want to be charged at around 0.2 amp and if you can't change it from 0.5 it's just going to shorten the battery's life.

Is there a link to it / the spec anywhere?
 

ven

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My C4-12’s pick the rate depending on IR . All this time on I have never had an issue with what’s chosen. You can easily overide by holding the button and selecting your own rate. Presume the xtar would allow you to do this?. Using other chargers seems old now, having to press and cycle through charge rates.
 

WalkIntoTheLight

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That looks like a USB-powered version of the Xtar X4 that I use.

I normally like more control than Xtar offers, but their charger works pretty well at determining the right charge rate for lithium-ion cells. It charges my 14500's at 0.5 amps, and 18650's at 2 amps. Middle slots max out at 1 amp, so I use those more often than the 2 amp outer slots.

For NiMH cells, it seems to always use 1 amp, regardless of the cell type. That's fine for AA, but it's a little too high for AAA.

One thing that's nice about the charger, is it will charge over-discharged cells very slowly until they come up to a high enough voltage to ramp them up to 2 amps. That's a good safety feature.

Overall, I'd recommend the Xtar charger for people that want an easy-to-use 4-slot charger. But if you want more control over charging rates, you'll have to use a different brand.
 

tripplec

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Well after countless months considering what to get next and review readings of the newest chargers and others. I bit the dust and ordered a MiBOXER C4-12 charger. It just arrived today and as expected from the review here my protected NCR18650B cells fit the slots with room to spare. Auto detection varied from 1A, .5, .35mA, I toggled them all to 1.5A rate which they should be able to handle easily. My old charger only went to 1A.
The screen is crystal clear, bright and large fonts for older eyes!!

Looking good. mOhm readings aren't explained as how low it has to be in order to assign a higher charge current. No big deal but now that I have this ability I'll have to find info on what should be the norm. These batteries are new and only charged once by me and used in a big multi cres light with all 4 cells in parallel. it was a good year ago so maybe lack of use is a factor. They all started off >50% charge so they weren't near dead either.

Anyway time to learn more about this and other batteries will get cycled through it.
 

ven

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Pany B cells are pretty old, add button top and PCB i would guess 200-350 IR ish(basically high). I would think it would probably pick a rate lower than 1a, prob nearer 0.5 or 0.7a type rate. I find most cells, regardless if 16340, 18650(most high drain) or 26650, are charged within or around an hour ish. My little protected 16340 cell for the HDS gets a 0.15-0.25a rate, i still leave it as its topped off within an hour anyway.

My high drain 18650 cells typically under 80 IR, can get anything from 2.5 to 3a. My 26650's the same, no issues at all.

So as it picks with IR in mind, any protected cells will get a lower rate than you would choose.

Hope enjoy, i think its a great charger, just be careful with the bay springs on longer cells. But an easy fix if they do snap.............no big deal. Just a shame they did not use stronger and more HD springs.
 

tripplec

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Just watching it charge and I notice the current dropping on the cell displays as it got into the 80% region and higher. Its tapering off itself as seen in the test/review. I like the fact it uses an external brick charger and high current capacity. Size is irrelevant to me and a 4 cell is a must have.
 

grayjay70

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Note that a cells internal resistance measurement will vary depending on the state of charge. If you are recording the measurements over time or comparing between cells, make sure that the state of charge at which they are being measured is consistent, such as re-checking the IR after they are fully charged.
 

ven

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Just watching it charge and I notice the current dropping on the cell displays as it got into the 80% region and higher. Its tapering off itself as seen in the test/review. I like the fact it uses an external brick charger and high current capacity. Size is irrelevant to me and a 4 cell is a must have.


Yes which is a good thing, you dont want 3a at 4.19v! There are more rates than you can select manually as well, so some you might see but cant actually choose if makes sense. Not a bad thing, as there are enough charge rates to pick anyway.
 

tripplec

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Note that a cells internal resistance measurement will vary depending on the state of charge. If you are recording the measurements over time or comparing between cells, make sure that the state of charge at which they are being measured is consistent, such as re-checking the IR after they are fully charged.

Oh I see then I assume the lower they're run the IR will also be lower and it will select a higher charge rate. Hmm I learned something already.

Thanks
 

peter yetman

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This is what worries me about so called Intelligent chargers that don't give a manual overide. I'd much rather base my charging rates on my own knowledge of the cells.
P
 

tripplec

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I definitely want the option to change the current as my old charger was only selectable and not sensing as this is.

Having said that a high capacity 18650 (3400mAH I believe w/10A max load) might handle 2A, but 3A would only be viable for 26650 large cells IMO anyway. I have not requirement to push super high back flow to charge any of my cells but I don't want to trickle them either from a very low charge. How much a hurry am I in. NONE what so ever. But using .5A for these 18650's is too low and since the charger tapers down as its nearing capacity it should be fine at 1.5A as I did earlier.

Even after only a few hours is looks like a first class charger. I don't have to force the slider to get the protected cells in either which is good. I had reservation ordering this off eBAY but it is genuine will all the markings and OEM fold out manual for it.
 

grayjay70

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Oh I see then I assume the lower they're run the IR will also be lower and it will select a higher charge rate. Hmm I learned something already.

Thanks

Ive observed instances when the initial IR reading is higher and gradually drop a bit and stabilize somewhat after several minutes of charging. On the Miboxer C4 charger that I use, the automatic charging will often begin at a lower rate and slowly ramp up during the first 5-10 minutes. Might be an effect of the temperature of the cell warming up or perhaps from conductivity pathways opening up as the cell accepts charge??

I am pretty sure that the tapering/reduction and final termination of the charge rate observed as the charge cycle nears completion is performed in response the the voltage level of the cell, not the IR.
 

tripplec

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Yes I agree. The display is reading 4.20V when I observed and cycled to see what it was doing. I certainly would recommend this model. The price doesn't break the bank either. More than adequate for my requirements.
 

fmc1

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For a charger to detect the battery chemistry and charge current based on physical size and voltage is just asking for trouble IMHO. Here is an example of 5 batteries that are all exactly the same size. With the exception of the Efest 14500 at the top they are all very close in nominal voltage yet they all should be charged very differently.


UXdaj6Gl.jpg



Yes I know the one at the bottom is not a popular example. It’s a shelf queen and it’s just a conversation piece but all the others I use and charge with different programs on the MC3000.


It will be very difficult me for having 3 Skyrc MC3000’s and being able to adjust everything , to buy an “automatic” charger.

Frank
 

tripplec

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I charged a set of 4 Duracell LSD 2500mAH cell. Most started well down. Eg. 0.1 & 0.4A I waite for a short while and togglen all the slots to the max which appears to be 1A on these. Finished charging and did not overheat. I now am charging a set of 4 High Capacity Ennelop 2500mAH cells. Same issue many started aot 0.1A or 0.4A of which most have crept up. But only one got to 1A at this time .4, .75, .70A are the other 3. the .4A one appears stubborn to increase at this time. Initial charge displayed was less than 10%. I am going to see what happens over time. I am not in a rush and don't have others to put in to charge.

EDIT:
I rolled the batteries which were low rate in the slots. The IR eventually went down as the current went up. It appears the connection on insertion is not always optimum. But what can we do. No One use copper contacts or better than these plated ones.
 
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tripplec

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Oh wow, the charger finished on these Ennelop Pro high capacity and not one charge to 700mAH. 645, 655, 695 are the numbers. They were shown to be very low on the start. I guess a discharge charge analysing cycle is needed. This unit doesn't do that.
 

Witterings

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My C4-12’s pick the rate depending on IR . All this time on I have never had an issue with what’s chosen. You can easily overide by holding the button and selecting your own rate. Presume the xtar would allow you to do this?. Using other chargers seems old now, having to press and cycle through charge rates.

Came across a video for these units today, at 12.15 he's talking about it charging 14500's at 1.2amp which I agree isn't ideal for the battery and if you have to select the charge rate manually it kind of defeats the object of paying a premium for one that supposedly does it for you .... I'm guess the Xtar one will work with a similar algorithm

https://www.youtube.com/watch?v=0kOmPH_CvcE
 
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