I think that you might like to brush up on your components and component markings, particularly the resistors. The Surface Mount R150 resistor is 0.15 ohms (150mR) not 15 ohms, and these are the Current Shunt Resistors for the Charge/Discharge measurements for each cell/channel. The four light blue bodied power resistors with the 5 coloured bands are in the buck-converter power circuits for each channel. The Silver/Gold band is not the tolerance/accuracy band in this case - it's a value multiplier, the tolerance band is the Brown band at the end signifying 1%. The value is black-brown-black-silver-brown = 010 * 0.01 = 0.1 ohms (0R1) 1% The other two 5-band power resistors are in the 3S Battery Pack Charge circuit and are connected in parallel for power rating and/or specific resistance. The value is red-violet-black-gold-brown = 270 * 0.1 = 27R 1% - two in parallel 27//27=13.5R
I have 3 different cell testers and the XTAR VP4+ is the best of them. While it could be better, the LittoKalla S500 is crap and the OPUS C3100 is only slightly better. Neither are as good as the VP4+. They can't support cells larger than 18650's and IMHO...that's a show stopper. They also require setting up again for every new cell put in them. VP4+, it stays in the same mode and same settings until you change them...cell after cell after cell. It also supports measuring cell resistance. The VP4+ charges and discharges at 1 amp on all 4 channels while the others only charge at 1 amp and discharge at .5 amps. It's lots better than the other options.
Just my opinion maybe, but I have used, tested and purchased a LOT of chargers over the years and the one I like best is the VP4+ for testing cells. It's easy to use and all you need to do is put in another set of cells and it goes right to work testing them. Other cell testers need to be set up again for every set of cells. The current VP4+ cell testers work well and capacity results are pretty reliable. I would not judge the current product by much older versions of the VP4+! *** I have 2 of them now and both see constant use 24/7. This original one has not stopped testing cells since January. The newer one has seen constant use for the past 2 months. I'm finally getting to the end of my 18650 collection and now have about 50 that are simply too weak to use anymore. There are many others in the less than 2100mah range that will see use in flashlights or other low use scenarios. There's quite a few in the 2400mah or better range that will get used for a power wall or a bench battery pack. These cell testers have seen a TON of hours of use on them and are still going strong! *** The VP4+ has room for improvement: 1. I'd really like the LCD to display cell voltages. 2. There's lots of display space. I'd like to see all 4 cells full status on screen at the same time. 3. I'd like the plug in probes used for testing Ir and cell voltage to be eliminated and to include this information in each cells status info. ISDT, iCharger and others can do this. Why can't XTAR include this for each channel too? 4. I'd like to see an 8 and 16 channel cell tester based on the VP4+. 5. I'd like to see the VP4+ support rechargeable 9v batteries in their various forms and chemistries. 6. I'd like to see BT connectivity and a windows/android/ios app so that cell status can be tracked. The current implementation is inadequate and pretty useless. I'd like the app to be able to control what the charger is doing. 7. I'd like to see LIFE cell support. 8. I'd like to see 2 amp charge AND discharge on all 4 channels at the same time. 9. I'd like to see the balance charging port handle more than 3S. You have 12v in, use a BOOST converter so it can support up to 6S. I'd like the balance charging port status on the LCD. 10. I'd like the LCD to be dot matrix so what is displayed can 100% change depending on what is happening. Purpose built, single use LCD's are dumb!
Just on point 3. I think that the XTAR VP4+ Dragon is one of the few Charger/Analysers to use the more accurate AC impedance method to provide Internal Resistance measurements. (Correction - The VP4+ DOES NOT USE THE AC IR TEST METHOD - IT USES 4-WIRE DC IR TEST METHOD) - mea culpa and apologies for my incorrect assumption. 😬) Those Chargers that measure via the charging contacts use the (2-WIRE) DC measurement method for IR and are nowhere as accurate as the XTAR's (4-WIRE) Test Leads with their better contact surfaces.
@@Micro-Motive I understand why the VP4+ is 4 wire for IR testing and why this is better and more accurate. You can connect 4 wire probes right next to each other...literally millimeters apart! You see this in the 2 probes on the VP4+. This would allow the spring loaded contacts to do 4 wire testing. All that is needed is to turn off charging or discharging and use the same Ir functionality for each channel that is used at the 2 probes off the back of the VP4+. This quite doable, just needs to be implemented!
@@de-bodgery @De-bodgery You misunderstand the two basic issues. (HOWEVER, I ALSO MADE ASSUMPTIONS THAT WERE NOT CORRECT - mea culpa and APOLOGIES. 😳) The XTAR VP4+ Dragon DOES use the 4-wire method. (CORRECTION - YOU DID IDENTIFY THE 4-WIRE TEST METHOD CORRECTLY, even though it was by assumption.) The basic issues are:- 1. If you read the Factory Data Sheets, e.g. from LG-Chem for the HG2 3000mAh INR18650 cells, they specify two different "Internal Resistance" measurements. (a.) AC @ 1kHz and (b.) DC. The AC measurements are the primary specification, and are typically around half the value of the DC secondary specification. 2. The contact surfaces involved are critical to any low value resistance measurements. The Battery contact surfaces, the Charger contact surfaces, and the contact surfaces forces, will contribute to measurement error - typically due to contamination or oxidation. The 2-wire DC Measurement Method is unreliable - even in a consumer grade product. This is why the XTAR VP4+ Dragon use Instrument Grade probes and the 4-WIRE DC Measurement Method - to minimise measurement error at a reasonable price point. To try to implement the AC Measurement Method into the DC Charge/Discharge path would be over complicated and unrealistically expensive from both a mechanical and electrical/electronic point of view.
@@Micro-Motive You know this as fact? I see 4 pins in the USB-A connector. There are what appears to be 2 wires to the probes. You might be right, but my assumption was inside the 2 cables was actually 2 conductors each. I have several sets of the probes, I'll sacrifice one of them and make sure. *** Contacts...I do a lot of milli ohm measurements with a 4 wire meter. I run into the issues you describe quite a lot. I think the spring loaded contacts could still work if they were sharper. You can buy single cell holders that have sharper points on them that are commonly used with better cell testers. I think with the same points as they use any spring loaded cell holder would do fine. I do wish the VP4+ had better contacts. There are times where I have to wiggle a cell around or add a magnet to them to get the cell to make contact. *** A single mosfet on the output side of each of those 2 functions isolates it from the other function. The added complexity is VERY low! Compensating in firmware for the mosfet Rds is easy! ADC's are very inexpensive and come in lots of high resolution options for pennies each. Everything is already talking to the CPU via ADC's. Only significant change is 4 AC Ir circuits instead of 1 and switching on and off 4 more mosfets. This is quite easy and low cost to implement! *** I don't think XTAR implemented the solution they did for the reasons you prescribe to them. I think it was 100% about selling price. They are already the most expensive tester in this category. They would sell far fewer cell testers if they sell for $85 than they will for $75. They also considered how often average people check cell Ir...aka never and don't even know what it means. That leaves people like you and me (the minority) that actually know what to expect or what Ir is. I think they decided that 1 circuit instead of 4 would save them some manufacturing cost. They know that most people are clueless and will never know that all the other cell testers out there are badly inaccurate becasue of how they do Ir testing. They know people like you and me are not the majority. AKA...1 independent AC Ir tester vs 4 integrated AC Ir testers and slightly improved spring loaded cell holders. This all made it possible to sell at $75 instead of $85 or whatever. *** First 2 I bought, I paid $75 each for them. Later I found them for $65 so I bought 6 more. That's the best price I have found without buying direct from China.
@@de-bodgery Please don't sacrifice a set of Test Leads, I've just already disassembled mine and they have two wires in both Leads terminated on the Probes to give the 4-Wire Connection Method. See my edited previous comments for corrections and humble APOLOGIES.
Hi,i have a blown FP6277 but cannot get good reading of last numbers,where can i get substitute of that? on aliex i got 50L last number but i'm affraid mine was 88L...this is sop 8 chip and mine had capacitor manualy soldered from 8pin to u13 print on board...can i use any other chip or must be that?i unsoldered broken chip and cap(cant read value because it fluctuates to no reading) and charger works when batt is inserted ,but wont work with charger...
I'd say you need parts of the identical type. The capacitor can be from any source as long as its value and voltage rating are the same. The SOP8 IC is probably something specific like an op-amp or an ADC or a charge controller. More than likely there are more of them on the board that are not damaged that you can read the part number from.
Any chance you would know how to fix one if I connected the test probe to the usb 5v output and tested a battery now it doesn't work correctly but does power on?
So I’ve had one of these for a few years now, I keep it in a nice case and am gentle with it, but sometimes I can only charge 3 bays now and today I could only charge two bags at the same time. I’m wondering if it’s because their old batteries or if it’s the charger. If I put 3-4 batteries in one or two bays will go from red -charging to green like their full.. when I take out the extra battery the others will go back to red charging. So weird!! Any thoughts?
Great teardown thank you, I watched with interest as my VP4 plus isn't charging correctly on CH3. It's charging at around 2-3mah per second and never finishes a charge fully! If I move the lipo to another channel it checks it and then flags it as full (ps Ive tried a few lipos and have the same result) Any ideas what I need to check if I took it apart please. Any advise / help would be much appreciated.
Hi Trevor. Thanks for the feedback. My VP4+ is working on all 4 channels. 1. I think if you are seeing a very low charge rate, there is a good chance the charge mosfet for the channel is not turning on or is turning on just a very small amount. 2. These chargers have separate mosfets for the charge circuit and the discharge circuits. Does that channel discharge correctly? 3. If the charge mosfet is working correctly, it is possible the power supply for that channel is not working correctly. They are adjustable. The output voltage of the 4 little power supplies track the cell voltage and then are adjusted upwards a little to create a small voltage difference between the power supply and the cell voltage. This is done to keep the current draw to that magical 1 amp limit. 4. If the PSU's just delivered 4.2v, then a cell at 2.5v would pull more like 6-10 amps while one at 4.1v around .2 amps. Obviously the higher amp draw would burn out these light weight electronics! This might have happened actually. 5. It is possible that the tracking electronics for this one channel are not working and so it is not telling the power supply to adjust upwards enough to keep charging current high enough. The monitoring electronics are watching charge current and cell voltage. When these parameters reach certain levels the charger stops charging. I suspect that is why it stops charging after a little while. **** Do you have any electronics experience? Do you have a DMM and an oscilloscope? These 2 tools would be super useful in trouble shooting channel 3. You could compare what happens on another channel with what happens on channel 3 and see the differences. This will let you step through the circuitry until you get to the section that behaves differently.
@@de-bodgery Hi, thanks for the detailed description. I think the charger is doing the opposite to what you're saying above (if thats possible). It's charging on CH3 much faster than on all the other channels and never reaches 100%.. It has previously shown an 'n' on the 1000 column & 2 x '11' ! I tried again this morning and now its 'err' and doesn't change to green when you install a battery. Could it be a capacitor that's faulty and if so can I chack it somehow. I don't own a DMM or oscilloscope I'm afraid..
@@trevorc6793 With some diagnostic tools, you could do a lot to see what is happening to channel 3. A DMM is pretty inexpensive. A component tester will let you pull parts out of the board, test them and see if they are working or not. This is a bit harder to do since you need to remove them from the board to test them. An o-scope would let you check them in circuit while it is powered up. **** I have this component tester. These things are inexpensive and every year they get more and more features added to them. I guess it was about 2016 that I bought mine. It's still working so I never bothered getting a newer one. These things are super handy for quickly checking components. I've found many bad components with mine. If you look around, you should be able to find a plastic case for it too. This will test capacitors and lots of other components too. www.ebay.com/itm/2016-EZM328-GM328R-transistor-tester-frequency-meter-square-wave-genera/201663141755?hash=item2ef40f577b:g:plMAAOSwFe5Xzxsd **** A clamp-on amp meter would be helpful too. You have a cell external to the charging bay that needs charging. You run 2 wires to the 2 contacts in the charging bay. Clamp the meter around one of them and now you are seeing actual charge or discharge current. If things are as you are saying...charging too quickly...you'll see well over 1 amp charge current. It it's like I said, then you'll see very low current flow. **** I have all those tools as I mess with electronics a lot. Maybe if you are in the USA, you can send your VP4+ to me? There's no guarantee I can repair it. I'm far from capable of doing certain types of electronics repairs because they require expensive and specialized tools. However, large portions of these chargers are comprised of discrete components and I can deal with them readily enough. Right now, I'd give it 50/50 that it can be repaired. If it is monitoring electronics or the CPU...that's not going to be repaired easily. If it is something like a bad mosfet or cap...well that's pretty easy to deal with. **** You know what they cost new. Repair cost is only compelling if it is something easy to fix. If you did send it to me, I'd ask to keep you charger in trade for finding out if it easy to repair or not. If it ends up being easy to fix, I'd ask for shipping back to you and $30 for my time. The components more than likely will be so inexpensive as to not matter.
@@de-bodgery Thanks for the information. tbh, I don't want to delve to deep into electronics if possible. I'm happy to to attempt fairly simple things, but thats about it. Currently Xtar are sorting an exchange for me. So fingers crossed , I'll be charging safely once more....
I have a LiitoKala Lii-S500 and an OPUS BT-C3100. Both are lots less money and they show it. I've compared the 3 cell testers with each other and frankly the XTAR VP4+ is the best of them. The Lii-S500 is a steaming turd. Just really BAD electronic design with loads of places where they cut corners! It does have a nice LCD. The quality of components and design thoroughness of the VP4+ is much better than the C3100. If what you care about is decently good accuracy of cell capacities for 18650's only, the OPUS is a good choice for a little less money. However, if you want to know cell resistance and you intend to test other cells like 21700's, I suggest getting the XTAR VP4+. It's the best for good reasons and it's price reflects that.
No company is going to sell you something less than it costs to make. Are you going to sell something you make for less than it cost you? Answer that! Nintendo Switch costs less to make than the MSRP. PlayStation 5 costs less to make than the MSRP. Xbox Series X costs less to make than the MSRP. An LG OLED TV costs less to make than the MSRP. A Lamborghini costs less to make than what is sold. Do you see the pattern?! I am tired of hearing 🧠🧼, 🧠⚰️🧟♂️, 🥔🧠 complaining about how a device costs less to make than what it is being sold for. Just influencing more 🐑 and turning them into 🧠🧼, 🧠⚰️🧟♂️, 🥔🧠. JESUS CHRIST!!!
Nice detailed video! Can you give details on diode D27, I was trying to revive a 12V li-ion battery pack (without disassembling it) and instead of connecting a separate battery, I connect two in a row so basically 8+V on channel 4 and D27 went into smoke (slipt in two), I would like change it and see if it would work again. :)
The 4 channels in every cell tester or charger I've seen are not isolated from each other in any way. I'm sure you know you blew up your cell tester, but that's why. The 4 channels are electrically in parallel with each other, not series. *** You have other diodes on the board that are the same kind. Look up one of them.
Hello, I managed to dump 24v into the charger with the car charger cable. Had a mental note to pop a buck converter on the output from the solar charger 12v and then clean forgot. I blame age. So it popped the cap 220uf on the second battery channel. I have a small scope to try get the parts because i have had it less than a month. They are pretty black. If I am unable to read them could you help me with the transistors next to the blue resistor on the second cell? Would be a tremendous help. Sounds like you know your stuff!
LOL...I blame age for lots of things too! Try to make a video of what's burnt. That will help. Then I can tell you what those part values are. Most likely the components after the DC-DC for the power input are OK. However, how the DC-DC blew up defines a lot about what happens after it. This may be a 50/50 shot at getting it going again... I'm not sure if that cap you killed is in the second channel or not. This seems more likely to be a filter cap on the power input. IF you did blow parts in a channel, then the odds of repair go down a lot. IF you blew a few things in the main DC-DC, then repair is pretty likely.
@@johngreyvenstein5987 That first pic is the most telling...and of course C3 exploded. You have an o-scope. Does it do XY mode? Ever hear of a tracker? It is a super handy add-on to any XY capable o-scope. I wont have an o-scope that lacks XY mode because of the ability a tracker adds to it. All you need is a few resistors and a 6v transformer to build a tracker. I built one in the 1990's and am still using it today. th-cam.com/video/Gwo3pEH7hUE/w-d-xo.html A tracker is incredibly useful for looking at components in circuit or out of circuit. I discovered this in 1988 and have been using it ever since. Anyway, watch that video. Making your own is so easy and now you can compare components in one channel with another channel and find everything that is blown. You did blow up a channel in your charger. Do the other 3 still work OK? Did you put a cell in this charger channel and then it blew up? IF that is the case, then probably what happened is that channel turned on a larger mosfet which tolerated more voltage and the smaller components did not.
Well since I own the XTAR VC4 and it has been a rock-solid battery charger, I thought it would be a good idea to upgrade to the XTAR DRAGON VP4 Plus, Right? Wrong! In under 1 year, the plastic started cracking and the thing literally fell to pieces! It is made out of a different type of plastic than the XTAR VC4. I tried to tape it together, glue it together, epoxy it back together. Right now it has epoxy with a zip tie holding it together with Brass pins I had to put in it so that it would stay stay together and could even be used. I am sure glad I did not get rid of the XTAR VC4. That thing is built Rock Solid and still is going strong 5 years later! The Dragon VP4 Plus, not so much! I still use it when I'm charging multiple batteries or, I need to cycle some batteries. But I have to baby it because, I never know I might have to add more zip ties to hold it together or something?
About 95% of electronics from China have ABS plastic shells. It's inexpensive, easy to mold and doesn't wear out injection molds quickly. It's a generally good plastic to use for this application. *** I don't think your charger shell has anything to do with the general quality of the product. I have a Dewalt 20v battery. They are made with glass reinforced nylon...which is far superior to ABS. My battery shell has that problem too. The plastic formulation didn't get mixed well or an ingredient got missed...who knows exactly...but that's a plastics issue and XTAR doesn't make their own plastic shells. They contract that out to someone else. So like me, you got a one-off bad mix of plastic in your shell. Your charger works OK right? Just the ABS shell is a mess? If so, I wouldn't blame XTAR for this.
I watched your video on the lii 600 and you recommended this vp4+ several times so I watched this video to see what was so much better. However I wasn't instilled with any confidence. It appears that they are both over priced garbage 🗑🚮
All this stuff is over priced. I've thought about remaking this video. Now that I have seen the even poorer level of quality in most everything else, Id have to say that the XTAR VP4+ is much better made than most everything else out there. Also, it does cell Ir the most accurately of all cell testers I have seen so far. You'll still do best with a VP4+ over a Lii-600 if you care about both cell Ir and capacity. If all you care about is cell capacity, the Lii-600 is a bit cheaper and it does that well enough.
It has more features and can charge and discharge faster, but it's not very good otherwise. you can watch my videos about this charger...and I'm not thrilled with it.
nice video, im proud :) i just missed what i wanted to see, actually what i need to see to know to change of my charger. on 8:24 element D27 - the bigger one soldered on the long line, above the 4rth coil. my blew plus u9 mosfet 9926B in case relevant, everything else looks fine. what is D27 - name and model to find it around me to swap it. thanks for any help, yo
@@WaschyNumber1 The manual says it stores values, but it doesn't say how or where that I remember. Anyway, in the CPU is some flash memory that is used for this info.
@@de-bodgery OK, thank you, I think they could have made it even better if there would be a slot for a SD card and or even Bluetooth and a android app, also its a shame that they don't have made a better resistance measure cable and they don't sell even replacements for it. 🤔
@@WaschyNumber1 I know of 2 cell testers that do real 4 wire Ir testing. All the others do it through the spring clips in the bays and completely worthless for Ir measurement. THe Vp4+ is one of them that does Ir testing the right way.
FYI...I have recently bought 8 Lii-600's. So far 3 of them have gone bad and none are more than 90 days old. Steaming shit! Meanwhile, I have 2 VP4+ cell testers from almost 2 years ago that are going strong. I found this sale on Amazon for the VP4+ for $62 each and so I have bought 6 more. I've had them less than 2 weeks, but so far so good. Still my favorite cell tester! www.amazon.com/gp/product/B099KBXSYC/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1
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Mine will be here by Saturday hopefully, thank you for the expertise and helping me geek out.
I think that you might like to brush up on your components and component markings, particularly the resistors.
The Surface Mount R150 resistor is 0.15 ohms (150mR) not 15 ohms, and these are the Current Shunt Resistors for the Charge/Discharge measurements for each cell/channel.
The four light blue bodied power resistors with the 5 coloured bands are in the buck-converter power circuits for each channel.
The Silver/Gold band is not the tolerance/accuracy band in this case - it's a value multiplier, the tolerance band is the Brown band at the end signifying 1%.
The value is black-brown-black-silver-brown = 010 * 0.01 = 0.1 ohms (0R1) 1%
The other two 5-band power resistors are in the 3S Battery Pack Charge circuit and are connected in parallel for power rating and/or specific resistance.
The value is red-violet-black-gold-brown = 270 * 0.1 = 27R 1% - two in parallel 27//27=13.5R
Hello. I have a defective Vp4 plus that is missing R62. What resistance should it have?
Thanks for teardown. i was curious about if they put heatsink or not. now im sad.
I have 3 different cell testers and the XTAR VP4+ is the best of them. While it could be better, the LittoKalla S500 is crap and the OPUS C3100 is only slightly better. Neither are as good as the VP4+. They can't support cells larger than 18650's and IMHO...that's a show stopper. They also require setting up again for every new cell put in them. VP4+, it stays in the same mode and same settings until you change them...cell after cell after cell. It also supports measuring cell resistance. The VP4+ charges and discharges at 1 amp on all 4 channels while the others only charge at 1 amp and discharge at .5 amps. It's lots better than the other options.
Just my opinion maybe, but I have used, tested and purchased a LOT of chargers over the years and the one I like best is the VP4+ for testing cells. It's easy to use and all you need to do is put in another set of cells and it goes right to work testing them. Other cell testers need to be set up again for every set of cells. The current VP4+ cell testers work well and capacity results are pretty reliable. I would not judge the current product by much older versions of the VP4+!
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I have 2 of them now and both see constant use 24/7. This original one has not stopped testing cells since January. The newer one has seen constant use for the past 2 months. I'm finally getting to the end of my 18650 collection and now have about 50 that are simply too weak to use anymore. There are many others in the less than 2100mah range that will see use in flashlights or other low use scenarios. There's quite a few in the 2400mah or better range that will get used for a power wall or a bench battery pack. These cell testers have seen a TON of hours of use on them and are still going strong!
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The VP4+ has room for improvement:
1. I'd really like the LCD to display cell voltages.
2. There's lots of display space. I'd like to see all 4 cells full status on screen at the same time.
3. I'd like the plug in probes used for testing Ir and cell voltage to be eliminated and to include this information in each cells status info. ISDT, iCharger and others can do this. Why can't XTAR include this for each channel too?
4. I'd like to see an 8 and 16 channel cell tester based on the VP4+.
5. I'd like to see the VP4+ support rechargeable 9v batteries in their various forms and chemistries.
6. I'd like to see BT connectivity and a windows/android/ios app so that cell status can be tracked. The current implementation is inadequate and pretty useless. I'd like the app to be able to control what the charger is doing.
7. I'd like to see LIFE cell support.
8. I'd like to see 2 amp charge AND discharge on all 4 channels at the same time.
9. I'd like to see the balance charging port handle more than 3S. You have 12v in, use a BOOST converter so it can support up to 6S. I'd like the balance charging port status on the LCD.
10. I'd like the LCD to be dot matrix so what is displayed can 100% change depending on what is happening. Purpose built, single use LCD's are dumb!
Just on point 3. I think that the XTAR VP4+ Dragon is one of the few Charger/Analysers to use the more accurate AC impedance method to provide Internal Resistance measurements. (Correction - The VP4+ DOES NOT USE THE AC IR TEST METHOD - IT USES 4-WIRE DC IR TEST METHOD) - mea culpa and apologies for my incorrect assumption. 😬)
Those Chargers that measure via the charging contacts use the (2-WIRE) DC measurement method for IR and are nowhere as accurate as the XTAR's (4-WIRE) Test Leads with their better contact surfaces.
@@Micro-Motive I understand why the VP4+ is 4 wire for IR testing and why this is better and more accurate. You can connect 4 wire probes right next to each other...literally millimeters apart! You see this in the 2 probes on the VP4+. This would allow the spring loaded contacts to do 4 wire testing. All that is needed is to turn off charging or discharging and use the same Ir functionality for each channel that is used at the 2 probes off the back of the VP4+. This quite doable, just needs to be implemented!
@@de-bodgery @De-bodgery You misunderstand the two basic issues. (HOWEVER, I ALSO MADE ASSUMPTIONS THAT WERE NOT CORRECT - mea culpa and APOLOGIES. 😳)
The XTAR VP4+ Dragon DOES use the 4-wire method. (CORRECTION - YOU DID IDENTIFY THE 4-WIRE TEST METHOD CORRECTLY, even though it was by assumption.)
The basic issues are:-
1. If you read the Factory Data Sheets, e.g. from LG-Chem for the HG2 3000mAh INR18650 cells, they specify two different "Internal Resistance" measurements.
(a.) AC @ 1kHz and (b.) DC. The AC measurements are the primary specification, and are typically around half the value of the DC secondary specification.
2. The contact surfaces involved are critical to any low value resistance measurements.
The Battery contact surfaces, the Charger contact surfaces, and the contact surfaces forces, will contribute to measurement error - typically due to contamination or oxidation.
The 2-wire DC Measurement Method is unreliable - even in a consumer grade product.
This is why the XTAR VP4+ Dragon use Instrument Grade probes and the 4-WIRE DC Measurement Method - to minimise measurement error at a reasonable price point.
To try to implement the AC Measurement Method into the DC Charge/Discharge path would be over complicated and unrealistically expensive from both a mechanical and electrical/electronic point of view.
@@Micro-Motive You know this as fact? I see 4 pins in the USB-A connector. There are what appears to be 2 wires to the probes. You might be right, but my assumption was inside the 2 cables was actually 2 conductors each. I have several sets of the probes, I'll sacrifice one of them and make sure.
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Contacts...I do a lot of milli ohm measurements with a 4 wire meter. I run into the issues you describe quite a lot. I think the spring loaded contacts could still work if they were sharper. You can buy single cell holders that have sharper points on them that are commonly used with better cell testers. I think with the same points as they use any spring loaded cell holder would do fine. I do wish the VP4+ had better contacts. There are times where I have to wiggle a cell around or add a magnet to them to get the cell to make contact.
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A single mosfet on the output side of each of those 2 functions isolates it from the other function. The added complexity is VERY low! Compensating in firmware for the mosfet Rds is easy! ADC's are very inexpensive and come in lots of high resolution options for pennies each. Everything is already talking to the CPU via ADC's. Only significant change is 4 AC Ir circuits instead of 1 and switching on and off 4 more mosfets. This is quite easy and low cost to implement!
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I don't think XTAR implemented the solution they did for the reasons you prescribe to them. I think it was 100% about selling price. They are already the most expensive tester in this category. They would sell far fewer cell testers if they sell for $85 than they will for $75. They also considered how often average people check cell Ir...aka never and don't even know what it means. That leaves people like you and me (the minority) that actually know what to expect or what Ir is. I think they decided that 1 circuit instead of 4 would save them some manufacturing cost. They know that most people are clueless and will never know that all the other cell testers out there are badly inaccurate becasue of how they do Ir testing. They know people like you and me are not the majority. AKA...1 independent AC Ir tester vs 4 integrated AC Ir testers and slightly improved spring loaded cell holders. This all made it possible to sell at $75 instead of $85 or whatever.
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First 2 I bought, I paid $75 each for them. Later I found them for $65 so I bought 6 more. That's the best price I have found without buying direct from China.
@@de-bodgery Please don't sacrifice a set of Test Leads, I've just already disassembled mine and they have two wires in both Leads terminated on the Probes to give the 4-Wire Connection Method.
See my edited previous comments for corrections and humble APOLOGIES.
Hi,i have a blown FP6277 but cannot get good reading of last numbers,where can i get substitute of that? on aliex i got 50L last number but i'm affraid mine was 88L...this is sop 8 chip and mine had capacitor manualy soldered from 8pin to u13 print on board...can i use any other chip or must be that?i unsoldered broken chip and cap(cant read value because it fluctuates to no reading) and charger works when batt is inserted ,but wont work with charger...
I'd say you need parts of the identical type. The capacitor can be from any source as long as its value and voltage rating are the same. The SOP8 IC is probably something specific like an op-amp or an ADC or a charge controller. More than likely there are more of them on the board that are not damaged that you can read the part number from.
Any chance you would know how to fix one if I connected the test probe to the usb 5v output and tested a battery now it doesn't work correctly but does power on?
The USB port has its own DC-DC for converting 12v in to 5v. Probably that is toast and everything else is fine. I show it in this video.
So I’ve had one of these for a few years now, I keep it in a nice case and am gentle with it, but sometimes I can only charge 3 bays now and today I could only charge two bags at the same time.
I’m wondering if it’s because their old batteries or if it’s the charger.
If I put 3-4 batteries in one or two bays will go from red -charging to green like their full.. when I take out the extra battery the others will go back to red charging. So weird!! Any thoughts?
try 4 known good cells and see what happens.
@@de-bodgery thx for the reply man! I’ll have to order some new ones. Mine are like 3 years old. Hopefully that’s the issue, I’ll let you know! Cheers
Great teardown thank you, I watched with interest as my VP4 plus isn't charging correctly on CH3. It's charging at around 2-3mah per second and never finishes a charge fully! If I move the lipo to another channel it checks it and then flags it as full (ps Ive tried a few lipos and have the same result) Any ideas what I need to check if I took it apart please. Any advise / help would be much appreciated.
Hi Trevor. Thanks for the feedback. My VP4+ is working on all 4 channels.
1. I think if you are seeing a very low charge rate, there is a good chance the charge mosfet for the channel is not turning on or is turning on just a very small amount.
2. These chargers have separate mosfets for the charge circuit and the discharge circuits. Does that channel discharge correctly?
3. If the charge mosfet is working correctly, it is possible the power supply for that channel is not working correctly. They are adjustable. The output voltage of the 4 little power supplies track the cell voltage and then are adjusted upwards a little to create a small voltage difference between the power supply and the cell voltage. This is done to keep the current draw to that magical 1 amp limit.
4. If the PSU's just delivered 4.2v, then a cell at 2.5v would pull more like 6-10 amps while one at 4.1v around .2 amps. Obviously the higher amp draw would burn out these light weight electronics! This might have happened actually.
5. It is possible that the tracking electronics for this one channel are not working and so it is not telling the power supply to adjust upwards enough to keep charging current high enough. The monitoring electronics are watching charge current and cell voltage. When these parameters reach certain levels the charger stops charging. I suspect that is why it stops charging after a little while.
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Do you have any electronics experience? Do you have a DMM and an oscilloscope? These 2 tools would be super useful in trouble shooting channel 3. You could compare what happens on another channel with what happens on channel 3 and see the differences. This will let you step through the circuitry until you get to the section that behaves differently.
@@de-bodgery Hi, thanks for the detailed description. I think the charger is doing the opposite to what you're saying above (if thats possible). It's charging on CH3 much faster than on all the other channels and never reaches 100%.. It has previously shown an 'n' on the 1000 column & 2 x '11' ! I tried again this morning and now its 'err' and doesn't change to green when you install a battery. Could it be a capacitor that's faulty and if so can I chack it somehow. I don't own a DMM or oscilloscope I'm afraid..
@@trevorc6793 With some diagnostic tools, you could do a lot to see what is happening to channel 3. A DMM is pretty inexpensive. A component tester will let you pull parts out of the board, test them and see if they are working or not. This is a bit harder to do since you need to remove them from the board to test them. An o-scope would let you check them in circuit while it is powered up.
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I have this component tester. These things are inexpensive and every year they get more and more features added to them. I guess it was about 2016 that I bought mine. It's still working so I never bothered getting a newer one. These things are super handy for quickly checking components. I've found many bad components with mine. If you look around, you should be able to find a plastic case for it too. This will test capacitors and lots of other components too.
www.ebay.com/itm/2016-EZM328-GM328R-transistor-tester-frequency-meter-square-wave-genera/201663141755?hash=item2ef40f577b:g:plMAAOSwFe5Xzxsd
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A clamp-on amp meter would be helpful too. You have a cell external to the charging bay that needs charging. You run 2 wires to the 2 contacts in the charging bay. Clamp the meter around one of them and now you are seeing actual charge or discharge current. If things are as you are saying...charging too quickly...you'll see well over 1 amp charge current. It it's like I said, then you'll see very low current flow.
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I have all those tools as I mess with electronics a lot. Maybe if you are in the USA, you can send your VP4+ to me? There's no guarantee I can repair it. I'm far from capable of doing certain types of electronics repairs because they require expensive and specialized tools. However, large portions of these chargers are comprised of discrete components and I can deal with them readily enough. Right now, I'd give it 50/50 that it can be repaired. If it is monitoring electronics or the CPU...that's not going to be repaired easily. If it is something like a bad mosfet or cap...well that's pretty easy to deal with.
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You know what they cost new. Repair cost is only compelling if it is something easy to fix. If you did send it to me, I'd ask to keep you charger in trade for finding out if it easy to repair or not. If it ends up being easy to fix, I'd ask for shipping back to you and $30 for my time. The components more than likely will be so inexpensive as to not matter.
@@de-bodgery Thanks for the information. tbh, I don't want to delve to deep into electronics if possible. I'm happy to to attempt fairly simple things, but thats about it. Currently Xtar are sorting an exchange for me. So fingers crossed , I'll be charging safely once more....
Very nice review 👍 and in short this charger is not worth its $70 price tag but it’s way better than some other junk chargers out there 🤣
I have a LiitoKala Lii-S500 and an OPUS BT-C3100. Both are lots less money and they show it. I've compared the 3 cell testers with each other and frankly the XTAR VP4+ is the best of them. The Lii-S500 is a steaming turd. Just really BAD electronic design with loads of places where they cut corners! It does have a nice LCD. The quality of components and design thoroughness of the VP4+ is much better than the C3100. If what you care about is decently good accuracy of cell capacities for 18650's only, the OPUS is a good choice for a little less money. However, if you want to know cell resistance and you intend to test other cells like 21700's, I suggest getting the XTAR VP4+. It's the best for good reasons and it's price reflects that.
No company is going to sell you something less than it costs to make. Are you going to sell something you make for less than it cost you? Answer that!
Nintendo Switch costs less to make than the MSRP. PlayStation 5 costs less to make than the MSRP. Xbox Series X costs less to make than the MSRP. An LG OLED TV costs less to make than the MSRP. A Lamborghini costs less to make than what is sold. Do you see the pattern?!
I am tired of hearing 🧠🧼, 🧠⚰️🧟♂️, 🥔🧠 complaining about how a device costs less to make than what it is being sold for. Just influencing more 🐑 and turning them into 🧠🧼, 🧠⚰️🧟♂️, 🥔🧠.
JESUS CHRIST!!!
Those dudes that make solid brass 3-piece DE razors and sell them for $200+ sell them way more than it cost them to make it.
So 🛑 complaining!
Nice detailed video! Can you give details on diode D27, I was trying to revive a 12V li-ion battery pack (without disassembling it) and instead of connecting a separate battery, I connect two in a row so basically 8+V on channel 4 and D27 went into smoke (slipt in two), I would like change it and see if it would work again. :)
The 4 channels in every cell tester or charger I've seen are not isolated from each other in any way. I'm sure you know you blew up your cell tester, but that's why. The 4 channels are electrically in parallel with each other, not series.
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You have other diodes on the board that are the same kind. Look up one of them.
did you replaced your blowen D27 diode? mine just blew and I cant find the diode name. 5.1B something but what are the extra two number I have no idea
@@BombasticVirus it is a zener diode, check PTZ 5.1B. Any zener diode with the same characteristics will work, even if it is not smd
Hello, I managed to dump 24v into the charger with the car charger cable. Had a mental note to pop a buck converter on the output from the solar charger 12v and then clean forgot. I blame age. So it popped the cap 220uf on the second battery channel. I have a small scope to try get the parts because i have had it less than a month. They are pretty black. If I am unable to read them could you help me with the transistors next to the blue resistor on the second cell? Would be a tremendous help. Sounds like you know your stuff!
LOL...I blame age for lots of things too!
Try to make a video of what's burnt. That will help. Then I can tell you what those part values are. Most likely the components after the DC-DC for the power input are OK. However, how the DC-DC blew up defines a lot about what happens after it. This may be a 50/50 shot at getting it going again...
I'm not sure if that cap you killed is in the second channel or not. This seems more likely to be a filter cap on the power input. IF you did blow parts in a channel, then the odds of repair go down a lot. IF you blew a few things in the main DC-DC, then repair is pretty likely.
@@de-bodgery thank you for your reply. I will give you as much information as possible as soon as I get a free minute:)
@@de-bodgery Okay i have some pictures etc. I am not entirely sure on how to get them to you?
@@de-bodgery Okay i have uploaded them here.ibb.co/brZqtwn ibb.co/yn5gsSk ibb.co/HDsW0sp ibb.co/JzGs7Qh. Hopefully you will be able to view them...
@@johngreyvenstein5987 That first pic is the most telling...and of course C3 exploded. You have an o-scope. Does it do XY mode? Ever hear of a tracker? It is a super handy add-on to any XY capable o-scope. I wont have an o-scope that lacks XY mode because of the ability a tracker adds to it. All you need is a few resistors and a 6v transformer to build a tracker. I built one in the 1990's and am still using it today.
th-cam.com/video/Gwo3pEH7hUE/w-d-xo.html
A tracker is incredibly useful for looking at components in circuit or out of circuit. I discovered this in 1988 and have been using it ever since. Anyway, watch that video. Making your own is so easy and now you can compare components in one channel with another channel and find everything that is blown. You did blow up a channel in your charger. Do the other 3 still work OK? Did you put a cell in this charger channel and then it blew up? IF that is the case, then probably what happened is that channel turned on a larger mosfet which tolerated more voltage and the smaller components did not.
Well since I own the XTAR VC4 and it has been a rock-solid battery charger, I thought it would be a good idea to upgrade to the XTAR DRAGON VP4 Plus, Right?
Wrong! In under 1 year, the plastic started cracking and the thing literally fell to pieces!
It is made out of a different type of plastic than the XTAR VC4.
I tried to tape it together, glue it together, epoxy it back together. Right now it has epoxy with a zip tie holding it together with Brass pins I had to put in it so that it would stay stay together and could even be used. I am sure glad I did not get rid of the XTAR VC4. That thing is built Rock Solid and still is going strong 5 years later! The Dragon VP4 Plus, not so much! I still use it when I'm charging multiple batteries or, I need to cycle some batteries. But I have to baby it because, I never know I might have to add more zip ties to hold it together or something?
About 95% of electronics from China have ABS plastic shells. It's inexpensive, easy to mold and doesn't wear out injection molds quickly. It's a generally good plastic to use for this application.
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I don't think your charger shell has anything to do with the general quality of the product. I have a Dewalt 20v battery. They are made with glass reinforced nylon...which is far superior to ABS. My battery shell has that problem too. The plastic formulation didn't get mixed well or an ingredient got missed...who knows exactly...but that's a plastics issue and XTAR doesn't make their own plastic shells. They contract that out to someone else. So like me, you got a one-off bad mix of plastic in your shell. Your charger works OK right? Just the ABS shell is a mess? If so, I wouldn't blame XTAR for this.
I wonder what the hell you did with it in the bedroom. You are a 🥔🧠.
Lay off the methamphetamines.
I watched your video on the lii 600 and you recommended this vp4+ several times so I watched this video to see what was so much better. However I wasn't instilled with any confidence. It appears that they are both over priced garbage 🗑🚮
All this stuff is over priced. I've thought about remaking this video. Now that I have seen the even poorer level of quality in most everything else, Id have to say that the XTAR VP4+ is much better made than most everything else out there. Also, it does cell Ir the most accurately of all cell testers I have seen so far. You'll still do best with a VP4+ over a Lii-600 if you care about both cell Ir and capacity. If all you care about is cell capacity, the Lii-600 is a bit cheaper and it does that well enough.
and the SkyRC M3000?
It has more features and can charge and discharge faster, but it's not very good otherwise. you can watch my videos about this charger...and I'm not thrilled with it.
nice video, im proud :) i just missed what i wanted to see, actually what i need to see to know to change of my charger. on 8:24 element D27 - the bigger one soldered on the long line, above the 4rth coil. my blew plus u9 mosfet 9926B in case relevant, everything else looks fine.
what is D27 - name and model to find it around me to swap it.
thanks for any help, yo
No idea...I'd have to take one apart to find out.
@@de-bodgery that would be helpful, a lot
yep same, my D27 also blew up. @steffvatt did you find out the name of this component. i managed to understand only that is says 5.1B something
Check out the answers to my comment.
Where is the sdcard slot for the storage of the test data they have written in the manual 🤔
There isn't one. Do you see one referred to in the manual?
@@de-bodgery they have written something like that in the Manuel or I have miss read it? 🤔
@@WaschyNumber1 The manual says it stores values, but it doesn't say how or where that I remember. Anyway, in the CPU is some flash memory that is used for this info.
@@de-bodgery OK, thank you, I think they could have made it even better if there would be a slot for a SD card and or even Bluetooth and a android app, also its a shame that they don't have made a better resistance measure cable and they don't sell even replacements for it. 🤔
@@WaschyNumber1 I know of 2 cell testers that do real 4 wire Ir testing. All the others do it through the spring clips in the bays and completely worthless for Ir measurement. THe Vp4+ is one of them that does Ir testing the right way.
FYI...I have recently bought 8 Lii-600's. So far 3 of them have gone bad and none are more than 90 days old. Steaming shit! Meanwhile, I have 2 VP4+ cell testers from almost 2 years ago that are going strong. I found this sale on Amazon for the VP4+ for $62 each and so I have bought 6 more. I've had them less than 2 weeks, but so far so good. Still my favorite cell tester!
www.amazon.com/gp/product/B099KBXSYC/ref=ppx_yo_dt_b_asin_title_o09_s00?ie=UTF8&psc=1