Charger Comparison

[PeLu]

[ QUOTE ]
RussH said: I'd be willing to kick in a couple of bucks to get Silverfox an IC3 charger.

[/ QUOTE ]

Try to get the new one as soon as it is available in the US. According to my tests it looks also very good for 'normal' cells.


Further: For the 4.1V/4.2V discrepancy: I fully agree with DougS. It has to be a faulty cell. They could have lots of strange behaviour.

 

[SilverFox]

Hello Scott,

Underdog lives close to me and is willing to send me his IC3 charger and batteries.

Thanks everyone for your offers, but that need has been taken care of.

Tom

 

[SilverFox]

Hello Doug and Peter,

I believe the reduced capacity on these cells is caused by the 1.5 amp discharge rate. I will do some testing at a different rate and see what I get. The discharge curve suggests that they are really being pushed at 1.5 amps.

I only have a limited experience with bad Li-Ion cells (I have only managed to kill 5 of them so far...), but I generally notice erratic results from them when they go bad. These cells show the same capacity every cycle.

Perhaps there is a problem with my procedure. I charged the cell on the Triton, then discharged it on the Triton. I used 1.5 amps as a discharge rate because I had some data at that rate while evaluating battery combinations for the U2. I noticed a difference in capacity, so I decided to do another run. Same results. I then charged the cell on the Triton and when it was done, moved it over to my Universal Charger. I measured 4.12 volts when the Triton was finished, and it was slowly dropping. After charging on the Universal Charger, I ran a discharge on the Triton and got much better results. I then decided that I should better statistics and ended up doing a total of 5 runs on each charger. All discharging was done on the Triton and the results were very consistent.

The cells are marked Sony Energytec US18650S GA. Doug, are you sure about the 1300 mA rating? Any idea at what discharge rate they were rated at? 0.5C ?

Tom

 

[SilverFox]

Hello Chris,

Let's coordinate on parameters and see if we get comparable results.

18650 2400mAh
Charge rate of 1.0 amps
Discharge rate of 1.5 amps

Looking for the capacity difference between a charge termination of 4.1 vs 4.2 volts.

Does that sound good?

Tom

 

[SilverFox]

Update: I have added the Triton test results and some comments. Thanks BWaites for letting me borrow your Triton. How did you get along without it?

This is an excellent charger/analyzer. It has far to many features for me to cover them all, but I think it is one of the bests for NiCd and NiMh cells and packs.

It also does Li-Ion, Li-Poly and lead acid.

Tom

 

[Doug S]

[ QUOTE ]
SilverFox said:
The cells are marked Sony Energytec US18650S GA. Doug, are you sure about the 1300 mA rating? Any idea at what discharge rate they were rated at? 0.5C ?

Tom

[/ QUOTE ]

Tom, if you go back far enough, 8 years are so, Sony did make a 18650 size cell that was either 1200 or 1250mAHr. In current production the lowest offered is 1500mAHr. Sony rates their cell capacity at 0.2C. If a Li-ion cell is in good condition you will see only a 5% or so reduction at 1C vs 0.2C. This reduction was a bit higher with the older "hard carbon" technology and tended to increase with cell aging.

 

[Tweek]

[ QUOTE ]
SilverFox said:
Hello Chris,

Let's coordinate on parameters and see if we get comparable results.

18650 2400mAh
Charge rate of 1.0 amps
Discharge rate of 1.5 amps

Looking for the capacity difference between a charge termination of 4.1 vs 4.2 volts.

Does that sound good?

Tom

[/ QUOTE ]

Sounds good. I'll start on the charge/discharge with the Triton part now. My one good variable power supply died an as-yet-not-understood death yesterday, so I can at least get something going.

Chris

 

[udaman]

Sorry, I have not had time to keep up with this thread.

If you do a Google search on the Triton you will find an RC forum notation from some member who toasted his Li-Poly pack (expensive) using the Triton, IIRC, some problem having to do with some type of irregularity in the power supply being used. Some with broadband, and lots of time on their hands can look this up.

I see various threads on these RC type chargers where there are pluses and minuses to almost all of them, I would be do a bit of good, SilverFox, if you have time to link to these threads (assuming you can find all of them) and maybe post some information about them. I suppose like most things, there are differing experiences and opinions. I know the high-end charger guys who have tried lots of RC chargers tend to favor the top of the line Orbit or Shultz chargers over the Triton. RC users are more demanding, I think, on these chargers; you will find that almost all of these small manufacturers need some fix for the chargers, including the Tritons'; to address some issue or problem that comes up with extended use/feedback from users in the field.

Here's a few links I have bookmarked. But like I said, I don't have the time to research this and catch up on all the other CPF threads and projects I need to work on; and I have no idea what why I bookmarked these links.

RC Central - Reedy Quasar Pro - Great Product, Cheesy Name

RC Central - MRC Super Brain 959

The-RC-Zone.com - mrc superbrain 969

RCMicroFlight.com - March 2003 Table Of Contents

Product Review RCM January '02

RunRyder - Astro 109 or Triton

MRC Super Brain 969 AC/DC Dual-Mode Delta Peak Charger - MRC RB969

I am in need of several chargers(not just for myself), so I'm probably going to order both the Sakar 8.5min charger when it becomes available & that Uniross 15min http://www.energyfederation.org/consumer/default.php/cPath/401_444_1029. To save on shipping charges, shoot me a mailing address in a PM, and I'll have it sent directly to you. Test for a few weeks, then if they suck, I can have you ship them to some friends as gifts /ubbthreads/images/graemlins/smile.gif

I suspect that all of these fast chargers that get the batteries hot enough, shorten the number of charges you get from them and reduce capacity. I'm wondering if there is an actual possibility of premature damage. I have 7 year old 1300ma generic Chinese made AA's that seem to still work, but must be on their last legs as the sometimes get drained below 0.8v and take forever to come up to charge while getting very hot (but less than 50 or so cycles) by a Maha C204F

That does not really concern many who will give up reduced life/cycles for the convenience of needing the NiMH quickly charged up to full... after they forget to keep them charged and they self-discharge to useless levels (oh I suppose that never happens to Ginseng or bwaites and other hotwire gurus, and as such the benefits of Li-Ion slow self-discharge is not so important to them)

Do you have enough CBP1650ma AA's to test? I could order some with tabs for you to play with for a few weeks also? Do you have both Sanyo (not Energizer branded) 2100ma & 2500ma to test?

 

[SilverFox]

Hello Doug,

I got these cells from a cell phone battery pack. It was a free promotion add on. The pack was never used because of a broken connection on the circuit board (and it was a bit on the fat side for my holster). They have been in my possession for about 3 years.

When I first went to charge them, I measured 3.8+ volts. They charge up to 4.2 volts and settle in at around 4.19 volts. I have put about 20 cycles on them.

I'll do a test at 1.0 amps and see if the capacity ends up closer to 1200 mAh.

Thanks for your help on this.

Tom

 

[SilverFox]

Hello Chris,

Sounds like a plan.

Off to the chargers/dischargers/analyzers... /ubbthreads/images/graemlins/smile.gif

Tom

 

[SilverFox]

Hello Udaman,

I would love to get my hands on a Schulze ISL 6-636+, but at $480 I think I'll go and buy a couple of U2's...

I have a Ray O Vac IC3 charger headed my way. Do you think the Uniross is going to be significantly different? I'll PM my address to you, but you may want to hold off until I test the Ray O Vac.

I decided to test chargers before batteries. I figured the best batteries are only as good as what they are charges used to charge them. I will be doing rechargeable batteries at a later time. At that time I will ask people to let me "borrow" different brands for a few test runs.

Thanks for your offer.

Tom

 

[SilverFox]

Update:

I have added the results from an Energizer 1 hour charger (thanks Brody).

It did a pretty good job and the cells did not overheat.

Tom

 

[Ginseng]

I just now got caught up with this thread and I have to say KUDOS! Great work Tom. Thank you for putting in so much time. I'm glad to see that my investment in the Triton is founded. Its performance has been flawless so far and I am very pleased. I new that it really wrings the most out of your cells without stressing them too much and it's nice to be able to see that in graphical form.

Thanks again,
Wilkey

 

[SilverFox]

Hello Wilkey,

Thanks.

Just don't use Auto mode... /ubbthreads/images/graemlins/smile.gif

Tom

 

[SilverFox]

Update:

I have added the results from the Lightning Pack 4000N charger. Thanks Brody for letting me borrow it.

It features small compact size and a discharge function. "No Car Adaptor Needed" because it only works on AC. 4 slots, 2 independent channels. It charges in pairs.

It did a good job of getting a full charge and the batteries stayed cool.

If you don't mind charging in pairs and have access to AC power, this is a great charger.

Tom

 

[SilverFox]

Hello Chris,

Here are my results from charging an LG 18650 2400 mAh cell and terminating the charge at 4.2 volts and 4.1 volts.

I did a couple of runs and they seem to be quite close.

My Sony 18650 cells have a gradual drop off (rather than the sharp drop off the LG cells show here) at the 3.0 volt test termination. I believe this is why the large difference in capacity was observed. A few minutes less charge seems to have a larger impact on the Sony cells. Doug and Peter may be correct. The Sony cells seem to be behaving differently. I'll try to get a graph of the Sony cells and show the difference in the discharge curve.

At any rate, I see a little over 12% difference between the two charge termination voltages. I guess it comes down to whether or not you need the extra 10 minutes.

Tom

 

[SilverFox]

Hello Doug and Peter,

I took a big stick and I could only coax a little over 1000 mAh from my Sony 18650's. /ubbthreads/images/graemlins/smile.gif

The discharge graph starts and ends "normal," but in the middle it looks like an alkaline discharge curve. Any idea what may cause this?

Warning:
Over discharging a Li-Ion cell can damage it.

I am surprised that this cell came back after two of these grueling cycles. It appears to be performing the same as it was before the deep cycles.

Tom

 

[Tweek]

Well, I've now run a cell through several charge-discharge cycles using just my Triton for both functions. I didn't graph the data, but I did use my Fluke to record the end of charge peak voltage, which wound up being 4.212V every single time... /ubbthreads/images/graemlins/smile.gif Within about 5 minutes after charge termination, the cell voltage would drop a bit, and stabilize at 4.175V each time as well. Discharge termination voltage was also very repeatable, I measured it as cutting off at 3.036V every time. I did note more of an oddity in the recorded mAh in and out than I was expecting, though. I think this particular cell might be suffering an accelerated death, it is the one I thrashed on to determine the max rate of discharge for these cells. Anyway, some more numbers:

Charge 1: 2088mAh
Discharge 1: 2097mAh
Charge 2: 2069mAh
Discharge 2: 2076mAh
Charge 3: 2056mAh
Discharge 3: 2070mAh
Charge 4: 2050mAh
Discharge 4: 2061mAh
Charge 5: 2042mAh
Discharge 5: 2053mAh

It seems to be losing some capacity with each cycle, which is odd. I plan on cycling it some more, this time using the CBA to discharge, with the same settings. That'll be a bit before I can start that though, I'm currently trying to trickle an old Motoroal Saber pack back to life with the Triton... /ubbthreads/images/graemlins/smile.gif

I can't for the life of me figure out what killed my power supply, but the control board is hosed, and the output pass transistors are blown too. Guess I'll have to get a new one. Glad it was a freebie! /ubbthreads/images/graemlins/grin.gif

Chris

 

[Doug S]

[ QUOTE ]
SilverFox said:
Hello Doug and Peter,

I took a big stick and I could only coax a little over 1000 mAh from my Sony 18650's. /ubbthreads/images/graemlins/smile.gif

The discharge graph starts and ends "normal," but in the middle it looks like an alkaline discharge curve. Any idea what may cause this?



[/ QUOTE ]
Yes. This curve look like that of an old tired cell. Note that the midpoint voltage is fairly low indicating increased internal resistance.

[ QUOTE ]
SilverFox said:
I am surprised that this cell came back after two of these grueling cycles. It appears to be performing the same as it was before the deep cycles.

Tom

[/ QUOTE ]
Curiously going a bit below 2V at a high rate is not as damaging as it is at a low rate. The reason for this is that the internal resistance rises at end of discharge. At a high rate, you are seeing a terminal voltage that is the cell internal "electro-chemical voltage" minus the voltage drop of the discharge current thru the internal resistance. This electro-chemical voltage is what determines the damage thresholds. At low discharge rates the terminal voltage and internal electro-chemical voltage will be closer in value.

 

[SilverFox]

Hello Chris,

It looks like our numbers are quite close.

I am interested in what you get at 4.1 volts.

The Triton that I was using terminated at 4.12 volts and the cells drifted down a little from there. It seems yours is a bit higher.

Tom