RMSK, Inc.        
Page 1 of 3 123 LastLast
Results 1 to 30 of 62

Thread: New XTAR WP2 II Li-ion charger

  1. #1

    Arrow New XTAR WP2 II Li-ion charger

    Features:
    XTAR WP2 charger is apply to charging for two 14500/ 14650/ 17670/ 18500/ 18650/ 18700 3.7V Li-ion battery simultaneously but independently, it can charge for 10440/16340 when use 2pcs spacers. It is designed with undervoltage lockout and algorithm (TC.CC.CV) charging method which can monitor the battery's status real time and control charging safe automatically.
    WP2 designed with USB output function, use fully charged battery can supply electricity to those devices power below 5.0V/500mA.
    WP2 Charger adopts reverse-polarity protection circuit board and over/under voltage disconnecting technology, can prevent the possibility like sundries, wrong polarity and misoperation caused short circuit.
    WP2 built battery over discharging activating function, it can repair varying degrees discharged battery and then charging automatically, it is your first choice safer and reliable Li-ion battery charger.

    more info qualitychinagoods
    Last edited by Norm; 08-26-2011 at 01:45 PM. Reason: Remove direct sales link

  2. #2

    Default Re: New XTAR WP2 II Li-ion charger

    I received today from qualitychinagoods good build quality, I think this is one of the best "low-budget" li-ion charger

    switch
    0 - USB 5.0V/500mA
    1 - 500mA
    2 - 1000mA

    pics, details









































    Last edited by gopajti; 08-26-2011 at 12:27 PM.

  3. #3
    Flashaholic* old4570's Avatar
    Join Date
    Feb 2009
    Location
    Melbourne - Australia
    Posts
    2,714

    Default Re: New XTAR WP2 II Li-ion charger

    Nice pictures :

    Charges @ 1A and 500mAh - 3 position switch at the front ...
    0 position is for the USB charge function
    1 Position is for 500mAh charge rate
    2 position is for the 1A charge position

    So far seems to perform solidly , still testing .. But looks good ..

    Did I mention those are some nice pictures ? What is the termination voltage range on that one ? If one may ask ...

  4. #4
    Flashaholic* jasonck08's Avatar
    Join Date
    Sep 2007
    Location
    Redding, CA
    Posts
    1,516

    Default Re: New XTAR WP2 II Li-ion charger

    Cool I'll be interested to see if the circuit has the same problem as with the V1 that causes the voltage and current to constantly spike up and down. I observed the same behavior in other Li-ion charge IC's when they are overheating.

  5. #5

    Default Re: New XTAR WP2 II Li-ion charger

    fully charged Jetbeam 18650









    Last edited by gopajti; 09-01-2011 at 06:25 AM.

  6. #6
    HKJ's Avatar
    Join Date
    Mar 2008
    Location
    Copenhagen, Denmark
    Posts
    9,078

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by jasonck08 View Post
    Cool I'll be interested to see if the circuit has the same problem as with the V1 that causes the voltage and current to constantly spike up and down. I observed the same behavior in other Li-ion charge IC's when they are overheating.
    I have not seen that problem on WP2, but it does turn off the charge current each second to check cell voltage.
    My website with battery, charger, usb reviews, comparisons & information: https://lygte-info.dk/
    Latest addition is multimeter reviews

  7. #7
    Flashaholic* jasonck08's Avatar
    Join Date
    Sep 2007
    Location
    Redding, CA
    Posts
    1,516

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by HKJ View Post
    I have not seen that problem on WP2, but it does turn off the charge current each second to check cell voltage.
    How do you know its turning off the charge current every second to check voltage? That's definitely not proper behavior of any Li-ion charging IC I've ever heard of... I'm more inclined to think that the IC is in thermal limiting mode and overheating, thus reducing the current to pulses to avoid frying the IC. When i measured the current a while back I constantly saw spikes form 100mA to 500mA.

  8. #8

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by jasonck08 View Post
    How do you know its turning off the charge current every second to check voltage? That's definitely not proper behavior of any Li-ion charging IC I've ever heard of... I'm more inclined to think that the IC is in thermal limiting mode and overheating, thus reducing the current to pulses to avoid frying the IC. When i measured the current a while back I constantly saw spikes form 100mA to 500mA.
    My Ultrafire WF-188 does this same pulse mode charging. I'm using the 300ma charge rate.

  9. #9
    Flashaholic* 45/70's Avatar
    Join Date
    Oct 2005
    Location
    Rural Ohio
    Posts
    2,800

    Default Re: New XTAR WP2 II Li-ion charger

    EDIT: Posted in the wrong thread, but nice pics, gopati!

    Dave
    Last edited by 45/70; 09-02-2011 at 01:10 AM. Reason: posted in wrong thread

  10. #10
    HKJ's Avatar
    Join Date
    Mar 2008
    Location
    Copenhagen, Denmark
    Posts
    9,078

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by jasonck08 View Post
    How do you know its turning off the charge current every second to check voltage? That's definitely not proper behavior of any Li-ion charging IC I've ever heard of... I'm more inclined to think that the IC is in thermal limiting mode and overheating, thus reducing the current to pulses to avoid frying the IC. When i measured the current a while back I constantly saw spikes form 100mA to 500mA.
    With a oscilloscope connected to the charger it is easy to see. This "turning off to measure voltage" is very common behaviour on LiIon chargers, it has nothing to do with overheating.
    My website with battery, charger, usb reviews, comparisons & information: https://lygte-info.dk/
    Latest addition is multimeter reviews

  11. #11
    Flashaholic* jasonck08's Avatar
    Join Date
    Sep 2007
    Location
    Redding, CA
    Posts
    1,516

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by Be-Seen Triker View Post
    My Ultrafire WF-188 does this same pulse mode charging. I'm using the 300ma charge rate.
    Quote Originally Posted by HKJ View Post
    With a oscilloscope connected to the charger it is easy to see. This "turning off to measure voltage" is very common behaviour on LiIon chargers, it has nothing to do with overheating.
    Ultrafire is a very low quality charger with only a constant current charge method. This charger claims to have a CC/CV charge profile, and as far as I am aware, this is only achievable by the use of a Li-ion charging IC. No Li-ion charging IC i've seen should exhibit this type of behavior of measuring the voltage every 1 second, and decreasing the voltage and current as a result.

    HKJ, have you logged the average charge current of the charger? I've only done 5 minutes worth of testing with the WP2, and I observed pulses of 100mA to 500mA constantly. Your charging graphs look somewhat similar to my initial testing of the LTC-4054-4.2 when the IC was overheating. It would do about the same thing, pulse for about 1 second then stop then pulse again. This only happened however during the CC stage, because there is far less heat dissipated through the IC during the CV stage.







    The pulsing and noise is quite similar. Can anyone point out what type of main chips they are using on the PCB?

  12. #12
    HKJ's Avatar
    Join Date
    Mar 2008
    Location
    Copenhagen, Denmark
    Posts
    9,078

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by jasonck08 View Post
    Ultrafire is a very low quality charger with only a constant current charge method. This charger claims to have a CC/CV charge profile, and as far as I am aware, this is only achievable by the use of a Li-ion charging IC. No Li-ion charging IC i've seen should exhibit this type of behavior of measuring the voltage every 1 second, and decreasing the voltage and current as a result.
    You can easily make a LiIon charger with a small microprocessor controlling a smps. I believe that I have seen this packed into a single IC.


    Quote Originally Posted by jasonck08 View Post
    HKJ, have you logged the average charge current of the charger? I've only done 5 minutes worth of testing with the WP2, and I observed pulses of 100mA to 500mA constantly. Your charging graphs look somewhat similar to my initial testing of the LTC-4054-4.2 when the IC was overheating. It would do about the same thing, pulse for about 1 second then stop then pulse again. This only happened however during the CC stage, because there is far less heat dissipated through the IC during the CV stage.

    The pulsing and noise is quite similar. Can anyone point out what type of main chips they are using on the PCB?
    I have not been running a average (not anymore than my meters are doing), but I have used an oscilloscope to see the current pulses, they do not look like any overheating shutdown.
    The chip used is not a LTC-4054 or any of the derivates, that chip uses linear regulation and this charger does not use linear regulation (The 62 Khz frequency in the current shows this).
    My website with battery, charger, usb reviews, comparisons & information: https://lygte-info.dk/
    Latest addition is multimeter reviews

  13. #13

    Default Re: New XTAR WP2 II Li-ion charger

    Measuring the voltage during OFF pulse would measure something that's closer to OCV, which isn't what you're aiming for when you're charging Li-Ion...

  14. #14
    HKJ's Avatar
    Join Date
    Mar 2008
    Location
    Copenhagen, Denmark
    Posts
    9,078

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by shadowjk View Post
    Measuring the voltage during OFF pulse would measure something that's closer to OCV, which isn't what you're aiming for when you're charging Li-Ion...
    You are not measuring the rest voltage, but the actual voltage at the chemistry, eliminating all resistance. As you can see on my graph the voltage will drop a bit, when charging is stopped.
    But as you also can see from the graph the charger never goes above 4.2 volt, even when charging.
    My website with battery, charger, usb reviews, comparisons & information: https://lygte-info.dk/
    Latest addition is multimeter reviews

  15. #15

    Default Re: New XTAR WP2 II Li-ion charger

    The CC/CV algorithm uses the voltage during charge, not voltage at 0 current, so I don't know what use there'd be to cycle current on/off, except that if you measure both voltages you can work out the internal resistance of the cell + circuit/lead resistances...

  16. #16
    Flashaholic* jasonck08's Avatar
    Join Date
    Sep 2007
    Location
    Redding, CA
    Posts
    1,516

    Default Re: New XTAR WP2 II Li-ion charger

    I agree the measuring of the cell voltage every second is not really what the CC/CV algorithm calls for. This pulsing / noise whether intentional or not is a design flaw in the unit IMO.

  17. #17
    *Flashaholic* Mr Happy's Avatar
    Join Date
    Nov 2007
    Location
    Southern California
    Posts
    5,390

    Default Re: New XTAR WP2 II Li-ion charger

    It's really OK to use some different algorithm than CC/CV. CC/CV not a prescribed rule that you must follow lest terrible things happen to you.

    As HKJ explains above, there are prescribed limits on the charging of the cell that must be satisfied: you should not exceed the maximum voltage (4.2 V) and you should not exceed the maximum charging current (e.g. 0.8C). Within those limits there are a whole variety of charging algorithms that could be used, and for various reasons some of them could be a better engineering choice than others. They are not wrong, merely different.

    It happens that a pure CC/CV algorithm will charge a cell to completion in the shortest time compared to any other algorithm. If that is your goal, then a pure implementation of CC/CV is good. However, if you perhaps want an efficient charger, a small charger, a light charger, or an economical charger, then charging as fast as possible may not be the goal that drives your design decisions. Good engineering as about making the right decisions for the right reasons. Blindly following rules because they are engraved on a stone tablet is never a good basis for design.

    HKJ has tested this charger and analyzed it carefully. The analysis shows it is charging safely and respecting the prescribed limits of the cells. Therefore the design is perfectly satisfactory and it is not defective at all.
    Tiefer, tiefer, irgendwo in der Tiefe gibt es ein Licht

  18. #18
    Flashaholic* jasonck08's Avatar
    Join Date
    Sep 2007
    Location
    Redding, CA
    Posts
    1,516

    Default Re: New XTAR WP2 II Li-ion charger

    @ Mr happy, true that the charger may not be damaging to cells, and probably works just fine, however the two things I have a problem with are:

    1) Claims to be a CC/CV, but it's not really.

    2) Claims 500mA / 1000mA charge current, but with constant pulses from ~100mA to 500 or 1000mA, its clearly not charging at those currents.

  19. #19
    *Flashaholic* Mr Happy's Avatar
    Join Date
    Nov 2007
    Location
    Southern California
    Posts
    5,390

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by jasonck08 View Post
    @ Mr happy, true that the charger may not be damaging to cells, and probably works just fine, however the two things I have a problem with are:

    1) Claims to be a CC/CV, but it's not really.

    2) Claims 500mA / 1000mA charge current, but with constant pulses from ~100mA to 500 or 1000mA, its clearly not charging at those currents.
    From an examination of the review measurements provided by more than one reviewer here, those claims seem close enough to me. I would be very happy to own and use the charger. (I come at this with a technical background and therefore some appreciation of the design choices faced by the designers of the charger. I think the demand for pure CC/CV behavior with perfectly smooth lines on the graphs would result in a different charger from the one you see--a charger that would likely be bigger, heavier, more expensive, hotter in operation and unlikely really to offer much practical benefit for those differences. I want the charger reviewed here, not the ideal CC/CV charger of theory.)
    Tiefer, tiefer, irgendwo in der Tiefe gibt es ein Licht

  20. #20
    HKJ's Avatar
    Join Date
    Mar 2008
    Location
    Copenhagen, Denmark
    Posts
    9,078

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by jasonck08 View Post
    @ Mr happy, true that the charger may not be damaging to cells, and probably works just fine, however the two things I have a problem with are:

    1) Claims to be a CC/CV, but it's not really.
    As you can on the curves in my review it is close to a CC/CV charger.


    Quote Originally Posted by jasonck08 View Post
    2) Claims 500mA / 1000mA charge current, but with constant pulses from ~100mA to 500 or 1000mA, its clearly not charging at those currents.
    My measurements does not show that, it shows 500 mA / 1000 mA with short breaks to measure the voltage. Please provide some oscilloscope traces showing the swing between 100mA and 500 mA current. A typical DMM is not fast enough to show the off pulses and will show some random value between the charge current and some lower value (could be 100mA, but it depends on the DMM).
    My website with battery, charger, usb reviews, comparisons & information: https://lygte-info.dk/
    Latest addition is multimeter reviews

  21. #21
    Flashaholic* 45/70's Avatar
    Join Date
    Oct 2005
    Location
    Rural Ohio
    Posts
    2,800

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by Mr Happy View Post
    It's really OK to use some different algorithm than CC/CV. CC/CV not a prescribed rule that you must follow lest terrible things happen to you.

    As HKJ explains above, there are prescribed limits on the charging of the cell that must be satisfied: you should not exceed the maximum voltage (4.2 V) and you should not exceed the maximum charging current (e.g. 0.8C). Within those limits there are a whole variety of charging algorithms that could be used, and for various reasons some of them could be a better engineering choice than others. They are not wrong, merely different.
    I agree that it is possible to charge Li-Ion cells without adhering to the manufacturer's recommendations. Most available "consumer type" chargers do just that.

    As for the "prescribed limits on the charging of" Li-Ion cells, your statement(s) are correct. At the same time however, I am not aware of any Li-Ion cell manufacturer that recommends, or suggests using a CC/CV algorithm as a guideline for charging their cells, rather all that I am aware of state that a CC/CV algorithm must be used.

    Good engineering as about making the right decisions for the right reasons. Blindly following rules because they are engraved on a stone tablet is never a good basis for design.
    This is fine, but when this includes deviating from the manufacturer's prescribed charging method, even as a hobbyist, I have trouble supporting this viewpoint.

    I want the charger reviewed here, not the ideal CC/CV charger of theory.)
    I'd still rather have one that follows the manufacturer's recommendation.

    Dave

  22. #22
    Flashaholic* jasonck08's Avatar
    Join Date
    Sep 2007
    Location
    Redding, CA
    Posts
    1,516

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by 45/70 View Post
    I agree that it is possible to charge Li-Ion cells without adhering to the manufacturer's recommendations. Most available "consumer type" chargers do just that.

    As for the "prescribed limits on the charging of" Li-Ion cells, your statement(s) are correct. At the same time however, I am not aware of any Li-Ion cell manufacturer that recommends, or suggests using a CC/CV algorithm as a guideline for charging their cells, rather all that I am aware of state that a CC/CV algorithm must be used.

    This is fine, but when this includes deviating from the manufacturer's prescribed charging method, even as a hobbyist, I have trouble supporting this viewpoint.

    I'd still rather have one that follows the manufacturer's recommendation.

    Dave
    Well said, couldn't agree more! I too wouldn't call CC/CV a guideline, but more of a requirement for a quality charger and for keeping cells healthy.

    Quote Originally Posted by Mr Happy View Post
    It's really OK to use some different algorithm than CC/CV.
    All well known manufacturers say use a CC/CV charging method, then also provide a graph for what the charging method should look like when its data logged. I don't know any cell manufacturer that states using another method is acceptable.

    Quote Originally Posted by HKJ View Post
    As you can on the curves in my review it is close to a CC/CV charger.
    My measurements does not show that, it shows 500 mA / 1000 mA with short breaks to measure the voltage. Please provide some oscilloscope traces showing the swing between 100mA and 500 mA current. A typical DMM is not fast enough to show the off pulses and will show some random value between the charge current and some lower value (could be 100mA, but it depends on the DMM).
    I observed the pulses of current with my Fluke 179 and my higher end Agilent meter. If I cared enough I suppose I could data log the current during the charging process. I can pretty much guarantee that its not going to be charging at the stated 500/1000mA due to the frequent pulses of lower currents. I don't have the luxury to own a scope.

    While its much closer than the majority of the chargers on the market we see, its still not the really CC/CV. Show that graph to an engineer from Panasonic or Sanyo they will laugh and tell the designer to go back to the drawing board.

    There is a constant current mode, but no constant voltage, and then if you take into consideration the whole pulse charging thing or noise in the charging, this charger is only about 40% of the way there towards a true CC/CV charger IMO.
    Last edited by jasonck08; 09-05-2011 at 04:45 AM.

  23. #23
    HKJ's Avatar
    Join Date
    Mar 2008
    Location
    Copenhagen, Denmark
    Posts
    9,078

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by jasonck08 View Post
    Well said, couldn't agree more! I too wouldn't call CC/CV a guideline, but more of a requirement for a quality charger and for keeping cells healthy.
    I do simply not buy this (Except if you can get somebody from a large battery manufacturer to say it damages the battery). The pulsing charger does not do anything outside the CC/CV charging enelope.


    Quote Originally Posted by jasonck08 View Post
    All well known manufacturers say use a CC/CV charging method, then also provide a graph for what the charging method should look like when its data logged. I don't know any cell manufacturer that states using another method is acceptable.
    That is the easy way to specify a charging algorithm and will probably also be the fastest, why would the manufacturer specify anything else?

    Quote Originally Posted by jasonck08 View Post
    I observed the pulses of current with my Fluke 179 and my higher end Agilent meter. If I cared enough I suppose I could data log the current during the charging process. I can pretty much guarantee that its not going to be charging at the stated 500/1000mA due to the frequent pulses of lower currents. I don't have the luxury to own a scope.

    While its much closer than the majority of the chargers on the market we see, its still not the really CC/CV. Show that graph to an engineer from Panasonic or Sanyo they will laugh and tell the designer to go back to the drawing board.

    There is a constant current mode, but no constant voltage, and then if you take into consideration the whole pulse charging thing or noise in the charging, this charger is only about 40% of the way there towards a true CC/CV charger IMO.
    Most DMM is a bit slow, at least mine is and cannot really be used to measure pulsing current, as you can see in my logging I do never record a 0 value, even though there is one each second (The meter I is the top Fluke DMM). With the scope I can easily see the 0.5 and 1A charging current and the average may be 5 to 10 % low due to the pulsing or maybe not (the current is a bit above 0.5 A on the scope, maybe this compensates for the pulsing). I have not tried to measure the exact average charge current (This is possible with my meters).

    Would I prefer a real CC/CV charger? The answer is yes, but I do not believe that the difference between this charger and a real CC/CV is large in practical use.
    My website with battery, charger, usb reviews, comparisons & information: https://lygte-info.dk/
    Latest addition is multimeter reviews

  24. #24
    Flashaholic* jonnyfgroove's Avatar
    Join Date
    Dec 2008
    Location
    Bay Area, California
    Posts
    545

    Default Re: New XTAR WP2 II Li-ion charger

    Do you guys think it would be worthwhile to replace my Ultrafire WF-139 with one of these in regards to cell health/longevity? All my Li-Ions are the AW brand.


    ETA: Thanks for answering my question, I'm going to order one.
    Last edited by jonnyfgroove; 09-06-2011 at 08:17 AM.
    "Push back the night" - Bob Weir

  25. #25
    Flashaholic* 45/70's Avatar
    Join Date
    Oct 2005
    Location
    Rural Ohio
    Posts
    2,800

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by jonnyfgroove View Post
    Do you guys think it would be worthwhile to replace my Ultrafire WF-139 with one of these in regards to cell health/longevity? All my Li-Ions are the AW brand.
    Without a doubt, the Xtar charger is a better charger than the WF-139. The WF-139 is IMO, one of the worst chargers available. The QC is hit and miss, and at best they are only a "so so" charger, that doesn't follow the recommended charging algorithm, at all. They are basically just a constant current (CC) charger.

    Dave

  26. #26
    Flashaholic scottyhazzard's Avatar
    Join Date
    Oct 2009
    Location
    Northern California
    Posts
    363

    Default Re: New XTAR WP2 II Li-ion charger

    I am a bit confused. The discussion seams to straddle the fence between semantics and science. Both valid topics for discussion but I can't keep up with the science part. I have the WF 139 and I am replacing it to protect my investment in batteries. I was under the impression that within the limits of my budget, the Xtar WP2 II was safer and not likely to over-charge my 18650's. I have one in the mail now, is it safe to use on by batteries or will it shorten their lives?
    I'm a Lumenaut, on a bold quest of discovery. To find the smallest, toughest, eyeball searing-est torch that modern science can create!

  27. #27
    HKJ's Avatar
    Join Date
    Mar 2008
    Location
    Copenhagen, Denmark
    Posts
    9,078

    Default Re: New XTAR WP2 II Li-ion charger

    Quote Originally Posted by scottyhazzard View Post
    I have one in the mail now, is it safe to use on by batteries or will it shorten their lives?
    It is one of the best cradle chargers, only the 4Sevens has a better charge curve of the chargers I have tested.
    My website with battery, charger, usb reviews, comparisons & information: https://lygte-info.dk/
    Latest addition is multimeter reviews

  28. #28
    Flashaholic scottyhazzard's Avatar
    Join Date
    Oct 2009
    Location
    Northern California
    Posts
    363

    Default Re: New XTAR WP2 II Li-ion charger

    Thanks, HKJ. Much appreciated.
    I'm a Lumenaut, on a bold quest of discovery. To find the smallest, toughest, eyeball searing-est torch that modern science can create!

  29. #29
    Enlightened Mass. Wine Guy's Avatar
    Join Date
    Dec 2009
    Location
    Ipswich, MA
    Posts
    63

    Default Re: New XTAR WP2 II Li-ion charger

    I know next to nothing about the technology, but I want to buy a 2600 mah 18650 battery for an MG P-Rocket Cree XP-G R5 flashlight I want to buy.

    Does this charger do the job well? How long does it take to charge a 18650?

    Thanks.

  30. #30

    Default Re: New XTAR WP2 II Li-ion charger

    I just received this charger a several days ago and have given it a good workout. The end voltage of most cells are between 4.15-4.17V which is consistent with what others have reported. This is true with 18650 Callies Kustom 3100 cells, XTAR 2600mah cells , and unprotected Panasonic CGR18650D 2350mah cells. The "CV" part of the charge take quite a while. I think in every instance, with maybe a 20% discharge, the charge cycle is always over an hour. The charger stays quite cool. I am sure that most of this charge period is topping off the cell (the CV part of the cycle).

    Out of a half dozen chargers I have, this is by far the most consistent and reliable one to date.
    My previous go-to charger was the modified UF WF-188 which would terminate my BRC3000 cells at 4.22V. Indeed, it was CC only as it drew 300ma thoughout the charge cycle. Needless to say, I am much more comfortable with the new XTAR WP2 II than with the WF-188. The WP2 II has terminated on its own consistenly through at least 50 cycles of various cells.

    Could someone come up with a true CC/CV charger which could also be adjusted for the recommended charge rate per the cell manufacturer's specifications for $20? ...I once looked at lab supplies for manual control. Ouch!

Page 1 of 3 123 LastLast

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •