Review of Charger Xtar XP4

[HKJ]

@ohaya

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.

[ohaya]

@HKJ

@ohaya

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/B004Z5XXZU/ref=wl_it_dp_o_pC_nS_nC?ie=UTF8&colid=1EFBQBHFZ1JBX&coliid=I7ISSRTWXHZUT

AccuPower IQ-328

[HKJ]

@ohaya

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).

[Bergtjie]

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]

@ohaya

@HKJ

@ohaya

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:

Amazon.com

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]

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
Not going to buy it obviously.

[iron_potato]

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 :weary:

[CheapThrills]

Thank you, very informative!

[HKJ]

@kreisler

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):

[Chloe]

@kreisler

@HKJ

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!

Yes, the heat problem is clearly a user error!

[kreisler]

@Chloe

Yes, the heat problem is clearly a user error!

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

otherwise it is clearly a charger error :p

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! :|

[HKJ]

@kreisler

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.

[kreisler]

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

[ohaya]

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]

@ohaya

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.

[ohaya]

@HKJ

@ohaya

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:

Toshiba battery yields 18500 cells

I received this Toshiba 3400mAH laptop battery today, $8.99 free shipping. http://www.ebay.com/itm/170893824570 [image] Fairly easy to open to reveal six 18500 cells, should be 1700mAH cells. [image] No glue! Held in by a strip of double-sided tape, not super sticky. [image] 4 cells @2.56V, 2 @1.96V The codes printed on the cells: All have this line: LDGFK15 Below that each has a different code: 002198, 006214, 020330, 017552, 016789, 013922 The last two also have a larger "C" above t…

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]

@ohaya

Hi, These were all 18500s from an older, but “new” laptop pack, supposedly about 1700 mAh capacity: Toshiba battery yields 18500 cells 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.

[ohaya]

@HKJ

@ohaya

Hi, These were all 18500s from an older, but “new” laptop pack, supposedly about 1700 mAh capacity: Toshiba battery yields 18500 cells 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]

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.

[HKJ]

@kreisler

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.