Review of Charger Xtar XP4

40 posts / 0 new
Last post

Pages

HKJ
HKJ's picture
Offline
Last seen: 1 week 6 days ago
Joined: 05/24/2011 - 12:23
Posts: 7447
Location: Copenhagen, Denmark
Review of Charger Xtar XP4
Charger Xtar XP4

DSC_3844

DSC_3846 DSC_3845

Xtar is known for flashlights and a couple of good LiIon chargers. This time they have also included NiMH capabilities in the charger and together with 3 current settings and USB output it looks like a charger that can do just about everything (Except analyze).


DSC_3839 DSC_3840

DSC_3841 DSC_3842

The charger comes in a cardboard box with lots of specifications on the outside.

DSC_3843

The box contains the charger, a mains adapter, a car adapter (Probably optional), a manual and a warranty card.

DSC_3849

The front/top of the charger contains 8 leds and one button:
  • 3 blue leds to show the charger current, a short press on the button will select next charge current.
  • 1 blue usb led, this led will be on when the usb output is active. To activate the output slot #4 must have a charged LiIon battery, power must be disconnected and the button must be pressed for some time.
  • 4 red/green status leds. They are red when charging and green at other times. When slot #1 is discharging the led will flash red (Activated by a long press on the button).


DSC_3847

The charger has a 12 volt input, this input can be supply from the main adapter or from the car adapter.
The usb output is rated at 1A and uses the battery in slot #4. It can only be activated when input power is disconnected.

DSC_3848

Xtar uses this label to avoid fakes.

DSC_3852 DSC_3853

The battery + connection is slightly raised and worked with flat top batteries. The slider works fine.
The slider can work with batteries between 30.5 mm and 71.8 mm.

supportedBatteryTypes

supportedBatterySizes DSC_3876 DSC_3877 DSC_3878

DSC_3875 DSC_3874 DSC_3873 DSC_3872
DSC_3871 DSC_3869 DSC_3870

The charger can easily handle 70 mm long batteries, including flat top cells. (See my Small LiIon comparison for length of different brands).


Measurements charger
  • When not connected to power it will discharges with up to 0.6mA, except slot #4 for usb output, it will discharge with up to 11mA.
  • When power is connected with a full battery, the charger will charge with 170uA (All slots with LiIon).
  • When power is connected with a full battery, the charger will charge with 10mA/30mA/50mA trickle charge (All slots with NiMH).
  • At 0 volt on the battery the charge current is 1.6mA (Green led is on).
  • At 0.22 volt the red led turns on and the current jumps to 90mA
  • At 1.22 volt the full charge current is turned on for NiMH.
  • At about 3 volt the full charge current is turned on for LiIon.
  • Any voltage drop, reinsertion of battery or power cycling will restart charging.
  • The led is flashing red when discharging. This only works on channel #1.
  • The channels on the charger are independent, i.e. there are small differences between them.


Test with LiIon cells

Xtar%20XP4%200.25A%20(PA18650-31)%20%231

Charging a 3100mAh cell with 0.25A is slow, but works perfectly. Notice the low terminations current, this is good. Lower would be even better, when charging small batteries.

Xtar%20XP4%200.5A%20(PA18650-31)%20%231

Increasing the current to 0.5A does also look good. The termination current has increased slightly.

Xtar%20XP4%201A%20(PA18650-31)%20%231

At 1A is also good, the termination current is about 100mA which is fine.

Xtar%20XP4%201A%20(PA18650-31)%20%232
Xtar%20XP4%201A%20(PA18650-31)%20%233
Xtar%20XP4%201A%20(PA18650-31)%20%234

The other slots works just as well.

Xtar%20XP4%201A%20(BE18650-26)%20%231

The charge time for 2600mAh is slightly shorter than 3100mAh

Xtar%20XP4%201A%20(PA18650-34)%20%231

And 3400mAh has slightly longer charge time.

Xtar%20XP4%201A%20(AW16340-IMR)%20%231

My old LiIon cell is handled perfectly at full charge current.

Xtar%20XP4%200.25A%20(AW18350-IMR)%20%231

Charging a smaller cell with 0.25mA does, of course, also work.

Xtar%20XP4%201A%20(4xPA18650-31)

Charging 4 LiIon batteries at the same time does generate some heat. My probe measures 41°C on the batteries.

Temperature1
M1: 51,5°C, HS1: 77,4°C

The USB port on the back of the charger gets very hot, it is not recommended to touch it.

Temperature2
M1: 50,3°C, HS1: 70,4°C

There is also some hot spots between the batteries and I measure 50°C on the batteries. This is at the limit.


LiIonPoweron

After the charger is powered on it uses about 2 seconds on starting, then 1 second to sense battery type, before ramping up to charge current.

LiIon0.25to0.5A

Changing from 0.25A to 0.5A takes about 4 seconds.

LiIon0.5to1to0.25A

From 0.5A to 1A it takes about 8 seconds to ramp up. Reducing power is instantaneous.
Note: These times are neither good nor bad, it is just the way the charger works.



Test with NiMH cells

Xtar%20XP4%200.25A%20(eneloop)%20%231

A very slow charge of a 2000mAh AA cell and something went wrong. It terminates at 1.40 volt and has only filled 1250mAh into the cell, but then the charge current is too low for this cell, lets test with a AAA cell.
Note: The risk with low charge current is usual overcharge, not premature termination.

Xtar%20XP4%200.25A%20(eneloop%20AAA)

Again it terminates early, only about 460mAh has been filled into the cell.

Xtar%20XP4%200.5A%20(eneloop)%20%231

Let’s try 0.5A with a AA cell. Again I get about 1250mAh.
This is not very good.

Xtar%20XP4%200.5A%20(eneloop%20AAA)%20%231

With a AAA battery at 0.5A the charge is nearly ok.

Xtar%20XP4%201A%20(eneloop)%20%231

What about 1A? Again it looks nearly ok, it terminates after about 2000mAh (This is a tad early for a 2000mAh NiMH). When the charge is finished the charger continues with trickle charge.
Notice the slow charge at the start of the curve, it is probably done to detect battery type.

Xtar%20XP4%201A%20(eneloop)%20%232
Xtar%20XP4%201A%20(eneloop)%20%233
Xtar%20XP4%201A%20(eneloop)%20%234

Here are 3. other channels. Looking at the voltage curve, it looks like #2 is terminating slightly early, #3 is good and #4 is early.

Xtar%20XP4%201A%20(eneloop%20XX)%20%231

With a eneloop XX (2500mAh), the charge curve looks perfect. The voltage has reached a maximum and started to drop, before the charge is terminated.

My guess is that there is a bug in the "end of charge" detection algorithm, this means that it will not work correctly will all types/ages of NiMH batteries. A bit more work from Xtar will probably fit it.

Xtar%20XP4%201A%20(eneloop)%20full%20%231

Starting a charge with a full battery, is stopped very fast. First the charger uses two minutes to analyze the battery, then it charges 2½ minutes, before it detects the battery is full and changes to trickle charging.

Xtar%20XP4%201A%20(4xeneloop)

With 4 batteries, there was also some premature termination, but as can be seen on the temperature curve, that battery did terminate properly. Even with one early termination I recorded a temperature of 51°C
Note: I was measuring volt and current on battery #1 and temperature on battery #3.

Xtar%20XP4%201A%20(4xeneloop)%20b

Let’s try once more, this time both the battery with voltage/current sensor and the battery with thermo sensor did terminate premature. This time, without proper termination, the temperature did only reach 43°C

Temperature3
M1: 51,1°C, HS1: 74,1°C

The USB port gets very hot with NiMH batteries.

Temperature4
M1: 50,9°C, M2: 51,8°C, M3: 51,2°C, M4: 45,7°C, HS1: 81,9°C

3 batteries at 51°C, the last is charging, but is not as hot.
Somewhere down on the PCB it gets really hot. It is probably not a problem for the electronic parts and it looks like the plastic can take it, but some heat is transferred to the batteries.

Xtar%20XP4%200.25A%20(eneloop%20AAA)%20discharge+charge%20%231

In slot #1 the charger can also do a discharge. The battery I tested with was only half full. When charging there was no premature termination. When discharging the led is flashing red.

Xtar%20XP4%201A%20(eneloop)%20discharge+charge%20%231

The current is fairly low, a 2000mAh cell will take nearly 7 hours to discharge and then 2 hours to charge, because the charger only has one slot with discharge function it will take at least 35 hours to cycle a pack of four cells.

NiMHPoweron

At power on it takes two seconds before the charger starts at the low sense current.

NiMHPreToFullCharge

Here it switches from sense to full charge current.

NiMHCurrents

Manual switching between the currents happens instantaneous, with NiMH it does not use a ramp.



Test with both LiIon and NiMH cells

Xtar%20XP4%201A%20(PA18650-31+eneloop)

Charging both LiIon and eneloop does not change much. It looks like there is a bit more noise in the charge current.

Xtar%20XP4%201A%20(eneloop+PA18650)

The NiMH does also look fine.



Measurements USB output
  • The charger can only use one battery for the usb output and it has to be a LiIon battery.
  • USB out does not turn off when loaded with 200% of rated output
  • When battery is empty, the output will be turned off, but there is still drained about 5mA from the battery.
  • Output is turned off when battery voltage is slightly above 3 volt, making it useable for all 3.6/3.7 volt LiIon batteries.
  • Usb output is coded as Apple 1A



XTAR%20XP4%20load%20sweep

The output is rated at 1A and can easily deliver 2A (To not blow the usb output I stopped at 2A).

Xtar%20XP4%20out%205%20ohm%20(PA18650-31)

At 1A output it has a good efficiency and runs for about 1 3/4 hour. The output turns off when the battery is down to about 3.1 volt, but it still has a current drain of about 5mA from the battery.

Xtar%20XP4%20out%2010%20ohm%20(PA18650-31)

Reducing the current to 0.5A improves the efficiency slightly and more than doubles the time it can run.

Xtar%20XP4%20out%2010%20ohm%20(BE18650-26)

A 2600mAh gives shorter runtime.

Xtar%20XP4%20out%2010%20ohm%20(PA18650-34)

And a 3400mAh gives longer runtime.

5ohm

The usb output has very little noise, only about 7mV at 1A (67mVpp).

10ohm

At 0.5A the noise is about the same (6mV and 65mVpp).



Testing with 2500 volt and 5000 volt between mains and low volt side, did not show any safety problems.



Conclusion

The charger has many functions of varying quality:
  • The LiIon charger is good and support a wide variety of cell sizes, this is as expected from Xtar.
  • The NiMH charger obvious has a bug in the "end of charger" detection and is not very useful.
  • The NiMH discharge function is too limited with only one slot and only a slow discharge.
  • The USB output delivers very good power, low noise and stable voltage, but do not leave a empty battery in slot #4 for days.
  • The charger gets hot while working at maximum current, the battery temperature is just at the allowable limit. I would have preferred both the box and the batteries where considerable cooler, this heat does wear the batteries down faster.


Generally it is a good quad LiIon charger, but the NiMH function is not very good before Xtar get it fixed.



Notes

The charger was supplied by Xtar for a review, I believe it is the second production batch.

Here is an explanation on how I did the above charge curves: How do I test a charger
Read more about how I test USB power supplies and chargers

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Edited by: sb56637 on 06/25/2015 - 14:28
Chloe
Chloe's picture
Offline
Last seen: 5 years 4 months ago
Joined: 01/30/2013 - 14:14
Posts: 4595
Location: 联合王国

Thank you for the review, HKJ! ^^

Serenity
Offline
Last seen: 3 years 12 months ago
Joined: 08/28/2013 - 15:15
Posts: 75

Awesome review, I love the addition of the infrared pictures. Bit strange that it sometimes terminates early on NiMH cells at low currents. Although the table at the start of the review only mentions 0.5A for AAA and 1.0A for AA as supported charging currents.

HKJ
HKJ's picture
Offline
Last seen: 1 week 6 days ago
Joined: 05/24/2011 - 12:23
Posts: 7447
Location: Copenhagen, Denmark

Serenity wrote:
Awesome review, I love the addition of the infrared pictures. Bit strange that it sometimes terminates early on NiMH cells at low currents. Although the table at the start of the review only mentions 0.5A for AAA and 1.0A for AA as supported charging currents.

The current in the table at the start is my recommendation for currents, the charger can use any current.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

RaceR86
RaceR86's picture
Offline
Last seen: 5 years 9 months ago
Joined: 02/22/2012 - 08:32
Posts: 3777
Location: Norway

Exceptionally good review as always!

Thanks..

BLF LED database – collaboration spreadsheet and latest news about where to buy LEDs
http://budgetlightforum.com/node/19342

Werner
Werner's picture
Offline
Last seen: 2 years 2 months ago
Joined: 10/19/2012 - 15:00
Posts: 3679
Location: Germany

Superb review, like always.

I would rate this a “hot” charger… Wink

ohaya
Offline
Last seen: 3 years 7 months ago
Joined: 03/16/2013 - 19:01
Posts: 5337
Location: US

I wish that this review was available BEFORE I bought the XP4 :(…

Having said that, I’m a little confused about the Nimh charging thing. I thought that, based on the CPF thread that I got referred to awhile ago, that if the current was set to 0.5amps, that termination was ok with AA Nimh batteries?

That (using 0.5amps with AA Nimh) has been my (limited) experience also, after initially trying 0.25amps with AA Nimh, and then later switching to 0.5amps with AA Nimh…. seems to terminate ok, and doesn’t heat up the batteries and the charger anymore?

HKJ
HKJ's picture
Offline
Last seen: 1 week 6 days ago
Joined: 05/24/2011 - 12:23
Posts: 7447
Location: Copenhagen, Denmark

ohaya wrote:
I wish that this review was available BEFORE I bought the XP4 :(... Having said that, I'm a little confused about the Nimh charging thing. I thought that, based on the CPF thread that I got referred to awhile ago, that if the current was set to 0.5amps, that termination was ok with AA Nimh batteries? That (using 0.5amps with AA Nimh) has been my (limited) experience also, after initially trying 0.25amps with AA Nimh, and then later switching to 0.5amps with AA Nimh.... seems to terminate ok, and doesn't heat up the batteries and the charger anymore?

It has no problem terminating, the problem is that it terminates before the batteries are full.

Check the blue line in the charts, with eneloop AA, it is supposed to reach a bit above 2000mAh. There are curves where it only reach 1300mAh.

NiMH batteries are supposed to heat up a bit, when they are near the end of charging.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

ohaya
Offline
Last seen: 3 years 7 months ago
Joined: 03/16/2013 - 19:01
Posts: 5337
Location: US
HKJ wrote:

ohaya wrote:
I wish that this review was available BEFORE I bought the XP4 :(… Having said that, I’m a little confused about the Nimh charging thing. I thought that, based on the CPF thread that I got referred to awhile ago, that if the current was set to 0.5amps, that termination was ok with AA Nimh batteries? That (using 0.5amps with AA Nimh) has been my (limited) experience also, after initially trying 0.25amps with AA Nimh, and then later switching to 0.5amps with AA Nimh…. seems to terminate ok, and doesn’t heat up the batteries and the charger anymore?

It has no problem terminating, the problem is that it terminates before the batteries are full.

Check the blue line in the charts, with eneloop AA, it is supposed to reach a bit above 2000mAh. There are curves where it only reach 1300mAh.

NiMH batteries are supposed to heat up a bit, when they are near the end of charging.

I guess that I need to get a dedicated Nimh charger then :(.

Does it hurt (lower lifetime or whatever) Eneloops to undercharge them like that?

EDIT: Been thinking about this one:

http://www.amazon.com/AccuPower-IQ-328-Battery-Charger-Analyzer/dp/B004Z...

AccuPower IQ-328

HKJ
HKJ's picture
Offline
Last seen: 1 week 6 days ago
Joined: 05/24/2011 - 12:23
Posts: 7447
Location: Copenhagen, Denmark

ohaya wrote:
Does it hurt (lower lifetime or whatever) Eneloops to undercharge them like that?

No. But if you are using batteries with different charge level in series, you might hurt them (Reverse charge).

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Bergtjie
Offline
Last seen: 7 months 3 weeks ago
Joined: 06/16/2013 - 01:05
Posts: 278
Location: Cape Town

As always a very good review, it seems again the NiMh termination of a combo charger is problematic., hopefully they can fix this in final production, I would like to replace my NiteCore i4 with an adjustable current charger.

Bergtjie
Offline
Last seen: 7 months 3 weeks ago
Joined: 06/16/2013 - 01:05
Posts: 278
Location: Cape Town
ohaya wrote:
HKJ wrote:

ohaya wrote:
I wish that this review was available BEFORE I bought the XP4 :(… Having said that, I’m a little confused about the Nimh charging thing. I thought that, based on the CPF thread that I got referred to awhile ago, that if the current was set to 0.5amps, that termination was ok with AA Nimh batteries? That (using 0.5amps with AA Nimh) has been my (limited) experience also, after initially trying 0.25amps with AA Nimh, and then later switching to 0.5amps with AA Nimh…. seems to terminate ok, and doesn’t heat up the batteries and the charger anymore?

It has no problem terminating, the problem is that it terminates before the batteries are full.

Check the blue line in the charts, with eneloop AA, it is supposed to reach a bit above 2000mAh. There are curves where it only reach 1300mAh.

NiMH batteries are supposed to heat up a bit, when they are near the end of charging.

I guess that I need to get a dedicated Nimh charger then :(.

Does it hurt (lower lifetime or whatever) Eneloops to undercharge them like that?

EDIT: Been thinking about this one:

http://www.amazon.com/AccuPower-IQ-328-Battery-Charger-Analyzer/dp/B004Z...

AccuPower IQ-328

I was never happy with my i4 charger with NiMh charging , so went and bought the AccuPower IQ-328 8 months ago and the clone from DX, both do excellent jobs with NiMh , I test my NiMh cells after charging on my ZTS analyzer , and they are always fully charged.

Sirius9
Sirius9's picture
Offline
Last seen: 4 days 8 hours ago
Joined: 03/04/2012 - 19:23
Posts: 4651
Location: South Europe

Thanks for the review, I was holding my finger on the “BUY” button but now I am disappointed, it was supposed to be my main eneloop charger Flat Stare
Not going to buy it obviously.

 

iron potato
Offline
Last seen: 11 months 1 week ago
Joined: 05/08/2012 - 04:03
Posts: 384

Superb review by HKJ as always, nice addition of thermal imaging as well, cool toy equipment you have there :bigsmile:

Well, I just removed XP4 from my FT cart after reading this review Tired

CheapThrills
CheapThrills's picture
Offline
Last seen: 1 week 4 days ago
Joined: 07/02/2011 - 10:45
Posts: 3651
Location: Suomi

Thank you, very informative!

HKJ
HKJ's picture
Offline
Last seen: 1 week 6 days ago
Joined: 05/24/2011 - 12:23
Posts: 7447
Location: Copenhagen, Denmark

kreisler wrote:
I measured 85°C as hot spot for the metal contacts. Since 85°C(metal) > 50°C(battery), does it mean that the heat is transferred from the hot metal into the batteries? The thermal pictures show that the upper part of the batteries is hotter than the lower part of the batteries. So i am assuming that the heat is not generated in the cells but most of the heat just stems from the hot metal contacts, what do you think?

Yes, heat is transferred from the charger to the batteries.

Here you can see a curve from a NiMH battery, without any external heat sources (Charge rate is 1A):

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Chloe
Chloe's picture
Offline
Last seen: 5 years 4 months ago
Joined: 01/30/2013 - 14:14
Posts: 4595
Location: 联合王国
kreisler wrote:

HKJ wrote:
Yes, heat is transferred from the charger to the batteries.

H)

 

since the 85°C only happen under full load (4×1.0A Eneloop, or 4×1.0A LiIon CC-phase), it is still a great charger imho because i can reduce the load to 3×1.0A and then the heat temperature build up is less! Big Smile

Yes, the heat problem is clearly a user error! Silly

kreisler
kreisler's picture
Offline
Last seen: 7 years 11 months ago
Joined: 11/12/2011 - 23:32
Posts: 3992
Location: Deutcheland

Chloe wrote:
Yes, the heat problem is clearly a user error! :p

 

as i said, it is no problem. just insert 3 or less cells Smile

otherwise it is clearly a charger error Silly

 

HKJ, is there an auto restart feature for LiIon's like the 3.9V threshold of the WP2s? my 10440's have dropped below 4.1000V within 24hrs in the charger and the charger has not started the recharge yet omg!  Flat Stare

*FMI* i got 4 i/o sh
HKJ
HKJ's picture
Offline
Last seen: 1 week 6 days ago
Joined: 05/24/2011 - 12:23
Posts: 7447
Location: Copenhagen, Denmark

kreisler wrote:
HKJ, is there an auto restart feature for LiIon's like the 3.9V threshold of the WP2s? my 10440's have dropped below 4.1000V within 24hrs in the charger and the charger has not started the recharge yet omg!  :|

Yes, there is a restart level, but it was to close to the termination voltage to get a good reading of it.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

kreisler
kreisler's picture
Offline
Last seen: 7 years 11 months ago
Joined: 11/12/2011 - 23:32
Posts: 3992
Location: Deutcheland

Are we talking about LiIon?

True, termination voltage of Eneloop AA and AAA at 0.25A and 0.5A is sometimes 1.38xxV or even below 1.3800V.

But my question referred to LiIon. I don't see any restart near 4.1V

*FMI* i got 4 i/o sh
ohaya
Offline
Last seen: 3 years 7 months ago
Joined: 03/16/2013 - 19:01
Posts: 5337
Location: US

Hi,

I was using my XP4 to charge some 18500s (6 of them) tonight, using the 1.0 amp setting, and they all came off the charger at between 4.16 – 4.17 volts.

Is that ok? It seems a little low..

Does the XP4 have problems terminating Li-ion too soon also?

Thanks,
Jim

HKJ
HKJ's picture
Offline
Last seen: 1 week 6 days ago
Joined: 05/24/2011 - 12:23
Posts: 7447
Location: Copenhagen, Denmark

ohaya wrote:
Hi, I was using my XP4 to charge some 18500s (6 of them) tonight, using the 1.0 amp setting, and they all came off the charger at between 4.16 - 4.17 volts. Is that ok? It seems a little low.. Does the XP4 have problems terminating Li-ion too soon also? Thanks, Jim

4.16 to 4.17 is ok, it will depend on the age of the battery and the charge current, using a lower charge current will get you a slightly higher voltage (Because the termination current is less).

Xtar chargers usual works very good with LiIon.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

ohaya
Offline
Last seen: 3 years 7 months ago
Joined: 03/16/2013 - 19:01
Posts: 5337
Location: US
HKJ wrote:

ohaya wrote:
Hi, I was using my XP4 to charge some 18500s (6 of them) tonight, using the 1.0 amp setting, and they all came off the charger at between 4.16 – 4.17 volts. Is that ok? It seems a little low.. Does the XP4 have problems terminating Li-ion too soon also? Thanks, Jim

4.16 to 4.17 is ok, it will depend on the age of the battery and the charge current, using a lower charge current will get you a slightly higher voltage (Because the termination current is less).

Xtar chargers usual works very good with LiIon.

Hi,

These were all 18500s from an older, but “new” laptop pack, supposedly about 1700 mAh capacity:

http://budgetlightforum.com/node/25095

I’ll try using a lower current next time, but would you recommend 0.25 amps or 0.5 amps charge rate for these?

Thanks,
Jim

HKJ
HKJ's picture
Offline
Last seen: 1 week 6 days ago
Joined: 05/24/2011 - 12:23
Posts: 7447
Location: Copenhagen, Denmark

ohaya wrote:
Hi, These were all 18500s from an older, but "new" laptop pack, supposedly about 1700 mAh capacity: http://budgetlightforum.com/node/25095 I'll try using a lower current next time, but would you recommend 0.25 amps or 0.5 amps charge rate for these? Thanks, Jim

I will not recommend it, but if you need the maximal capacity a 0.25A charge is best (The termination current is about the same on 0.5A and 1A, i.e. you do not really get anything extra at 0.5A).

Do not expect much, you get maybe 1% extra.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

ohaya
Offline
Last seen: 3 years 7 months ago
Joined: 03/16/2013 - 19:01
Posts: 5337
Location: US
HKJ wrote:

ohaya wrote:
Hi, These were all 18500s from an older, but “new” laptop pack, supposedly about 1700 mAh capacity: http://budgetlightforum.com/node/25095 I’ll try using a lower current next time, but would you recommend 0.25 amps or 0.5 amps charge rate for these? Thanks, Jim

I will not recommend it, but if you need the maximal capacity a 0.25A charge is best (The termination current is about the same on 0.5A and 1A, i.e. you do not really get anything extra at 0.5A).

Do not expect much, you get maybe 1% extra.

Hi,

Ok, thanks for the info.

Jim

kreisler
kreisler's picture
Offline
Last seen: 7 years 11 months ago
Joined: 11/12/2011 - 23:32
Posts: 3992
Location: Deutcheland

The 18650's in the thermal image, were these protected cells or unprotected cells? Protected cells have naturally a higher thermal resistance at the plus pole because of the altered and longer thermal path (and at the minus pole because of the added PCB).

Unprotected 18650's get considerably hotter in the XP4 than protected 18650's.

Just crazy.

*FMI* i got 4 i/o sh
HKJ
HKJ's picture
Offline
Last seen: 1 week 6 days ago
Joined: 05/24/2011 - 12:23
Posts: 7447
Location: Copenhagen, Denmark

kreisler wrote:

The 18650's in the thermal image, were these protected cells or unprotected cells? Protected cells have naturally a higher thermal resistance at the plus pole because of the altered and longer thermal path (and at the minus pole because of the added PCB).

Unprotected 18650's get considerably hotter in the XP4 than protected 18650's.

I usual uses unprotected for testing, but am mixing button top and flattop.

Number 1 and 4 in the thermal image is button top, the rest is flattop.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

kreisler
kreisler's picture
Offline
Last seen: 7 years 11 months ago
Joined: 11/12/2011 - 23:32
Posts: 3992
Location: Deutcheland

HKJ wrote:
Number 1 and 4 in the thermal image is button top, the rest is flattop.

excellent test!

yes, number 4 is less hot Smile

*FMI* i got 4 i/o sh
HKJ
HKJ's picture
Offline
Last seen: 1 week 6 days ago
Joined: 05/24/2011 - 12:23
Posts: 7447
Location: Copenhagen, Denmark

kreisler wrote:
let's note that the upper part of number 2 and number 3 are 60°C hot ;)

50°C or maybe 53°C, not more. The hot part is the charger.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Serenity
Offline
Last seen: 3 years 12 months ago
Joined: 08/28/2013 - 15:15
Posts: 75

HKJ wrote:
I will not recommend it, but if you need the maximal capacity a 0.25A charge is best (The termination current is about the same on 0.5A and 1A, i.e. you do not really get anything extra at 0.5A).

Do not expect much, you get maybe 1% extra.


Any ideas on whether charging to 4.2V (while charging) with 1A, then switching to 0.5A till 4.2V and then 0.25A to finish could cause any problems? I was thinking about this because for some reason an old cell in my VP1 got hot, and I was thinking having a lower maximum current at the end would be a bit safer.
HKJ
HKJ's picture
Offline
Last seen: 1 week 6 days ago
Joined: 05/24/2011 - 12:23
Posts: 7447
Location: Copenhagen, Denmark

Serenity wrote:
HKJ wrote:
I will not recommend it, but if you need the maximal capacity a 0.25A charge is best (The termination current is about the same on 0.5A and 1A, i.e. you do not really get anything extra at 0.5A).

 

Do not expect much, you get maybe 1% extra.

Any ideas on whether charging to 4.2V (while charging) with 1A, then switching to 0.5A till 4.2V and then 0.25A to finish could cause any problems? I was thinking about this because for some reason an old cell in my VP1 got hot, and I was thinking having a lower maximum current at the end would be a bit safer.

I cannot see any problems in that.

My website with reviews of many chargers and batteries (More than 1000): https://lygte-info.dk/

Pages