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Turnigy 5011 LiPo Charger Review
March 07, 2009
Last updated March 09, 2009
INTRODUCTION
Turnigy has a reputation of making the "$5 charger" which some feel represents a great value for their money and safety from its simple design. To investigate these claims I purchased the $6 version (the $5 version was sold out at the time) which is advertised to charge 2S and 3S LiPo packs at up to 1.2 Amps. This review serves two purposes, a genuine review of the charger and an investigation into the claims that these chargers are safer and a better deal than the larger microprocessor controlled chargers.
 The Turnigy 5011 LiPo battery charger The Turnigy 5011 is a simple unit with very few connectors. On the left side is a coax plug to supply power to the charger, the right side has a 2S and a 3S JST-XH plug, and the top has 3 multicolored LEDs. LED "A" corresponds to the cell connected to the positive lead of the pack, "B" is the other cell in a 2S pack or the middle cell in a 3S pack, and "C" is the cell connected to the negative lead of a 3S pack. FEATURES
SafetyThe Turnigy 5011 is safe from the perspective that it has limited capabilities and forces the use of a 2S and 3S connector which means no cell miscounts and no forgetting to set the proper chemistry and charge current. However, it is not very safe from the perspective that it has poor build quality and doesn't even charge at its advertised charge rate so most people have no idea if they are even close to a 1C charge rate. In fact, the charge rate is so low that the charge times can easily take a few hours which increases the likelihood that the charger will be left unmonitored. Safety is further compromised by having extremely poor directions which leave you more confused than before you read them.Power and current capabilitiesThe 5011 is advertised as a 2S and 3S LiPo battery charger with a 1.2 Amp charge current. It turns out that Turnigy is being sneaky with their numbers, this rating appears to be a sum of the current to all 3 cells, it is flat out a lie and intentionally misleading. I measured a maximum of 490 mA of current which on a 3S pack equates to a maximum output power of about 6.2 Watts. The input current to the charger is maximum about 820 mA for an input power of up to 10.3 Watts and a typical charger efficiency of about 50-55% (which is why it gets so warm).Low voltage restoreThe 5011 can restore cells from below 3.0 volts by applying a current of 50 mA for up to 1 minute. I could provide more detail but the datasheet with this information does not seem to be available in English.BOX CONTENTS
MANUALThe "manual" is actually just a double sided 8.5"x11" sheet of paper, but this is fine since there is not a whole lot to say about how to use this charger. However, there is little that is clear or useful about these directions as they do show a picture of a 5011 charger but say they are for a "Super Power-1" charger and it is not clear which of the three tables to use to interpret the meaning of the three LEDs. I'm not sure which language the directions were originally written in, but if their goal was an English translation then they have failed miserably. I don't even know where to begin with describing what a terrible manual this is. Some information is clearly not for the 5011 so how is one to know how much of the remainder of the directions applies to the 5011? Like I just said, there are three different tables describing the meaning of the LED colors with no indication of which one (if any) is applicable to the 5011. Based on the manual the charger should have an aluminum case, a charge rate switch, and the charge current should be 500 mA for a 2S pack and 330 mA for a 3S pack, none of these is true. Here is a choice excerpt from the manual: "Above the time for in 10C the approximate time (battery in imitates to 30C temperature ranges in by spatial battery condition outset to full battery condition total time), the lithium electricity battery 1 grain or 2,3 grains do not affect the duration of charging." Enough said. PICTURES
QUALITY CONCERNSNotice in the picture above of the bottom of the PCB, there are two areas circled where sloppy assembly and poor quality soldering could easily result in a short circuit or solder joint failure. In fact, I later discovered that in handling the charger the two leads at the bottom of the picture did short so I trimmed them. There are also some voids in the solder which suggests the use of a low quality solder paste and the possibility of thermal stresses cracking solder joints (especially considering how toasty the 5011 can get). It has been suggested that the low part count on these chargers equates to fewer parts to fail and a more reliable operation as compared to complex microcontroller based battery chargers. I counted 81 parts on the Turnigy 5011 and 113 parts on my CellPro Multi4 charger, which includes the LCD and PC interface. Considering the limited capabilities of the Turnigy 5011 I'd say it has a relatively high part count for what it is and considering the poor assembly quality it is more likely to fail than my CellPro Multi4. BATTERY CHARGING EXAMPLECharging SafetyThe safety rules for charging your batteries are probably no further away than the labels on your battery packs, some of these rules are as follows:
ACCURACYOrdinarily I'd talk about just the voltage and current accuracies of the charger, but in this case I feel a little accuracy in specifications and advertisements is in order. For current and voltage measurements I used my Fluke 87-V which has a DC voltage base accuracy of 0.05% and a DC current base accuracy of 0.2%. The instruction sheet says this charger can balance cells to within 50 mV, but then I can't be sure that they mean the 5011 or some other charger. Regardless, I found this charger to balancer far better than that at a good termination voltage. I found the average termination voltage to be 4.185 volts per cell and the average imbalance across the pack to be 8 mV with a range of 1-14 mV. I am glad to see the termination voltage is below 4.20 volts as the instructions indicated an average termination voltage of 4.21 volts so as to "increase the battery proportion", which I think means to put more charge into the battery. I'd rather undercharge to 4.185 volts and have my cells last more recharge cycles than charge to 4.21 volts to get 5 seconds more flight time. The only other advertised specification of this charger is that it can output up to 1.2 Amps. I found that regardless of battery size and voltage the charge current was 490 mA while in the constant current phase. When charging a single cell it did back off to 300 mA on one plug and 400 mA on the other output plug, but otherwise with 2S or 3S it was always the same. You might think that the charger is putting 490mA simultaneously into each cell via its balance taps, but with a pack that is perfectly in balance there is no current flow through the cell taps. For example, I measured the current from each of the four taps of a 3S pack and got the following currents in order from pack positive to negative: 492mA/6mA/-20mA/-475mA. Sum those currents up and you'll see that what goes in must come out (Kirkoff's current law) and at most you could argue the pack was getting 498mA or so. At the time these current measurements were made the pack voltage was 9.8 volts (3S2P A123 pack) so the charger output power was 4.8 Watts, at the same time the input to the charger was 823 mA at 12.48 volts which is 10.3 Watts. That means a 47% efficiency with 5.5 Watts of heat being generated in the charger, which is why it gets hot. At no time did the charger ever apply more than 490 mA which equates to a maximum output power of 6.2 Watts, not the 15 Watts you'd expect based on the manufacturer's information. This is a perfect segue into truth in advertising and what appears to be intentional misinformation. I already have demonstrated that the 1.2 Amp rating is misleading at best, in such cases many people turn to the user comments at places like Hobbycity to get their information. At this time the "most helpful" comment currently says: "This charger operate with 1.2A. Can charger a 1200mAh battery on only 1 hour!!
We scroll down a bit and find: "Fantastic addition to any electric flyer's kit. At this price I wish I'd ordered two.
It goes on and on with charge times that magically equate to 1.2 Amps. In both the above examples the charge divided by the charge time is exactly 1.2 Amps. I don't know about you, but for me a 1C charge always takes longer than an hour because of the reduced charge rate in the current voltage phase. It took the Turnigy 5011 1.6 hours to charge my 2S 640mAh pack and 58 minutes to charge a 3S 350 mAh pack! It's not till we sift through some of the "less helpful" reviews that we start to find the truth: "Beware of the marketing hype on this. 1.2 MAX amps means for a 3-cell, each cell is getting 1.2A/3 = 0.4Amps...at this rate your 1200mah 3-cell pack will charge for roughly 3 hours!
So there you have it, you can't trust Turnigy and you can't trust the Hobbycity reviews, good luck figuring out which are true and which are not. CONCLUSIONThe Turnigy 5011 is no doubt an inexpensive charger that is well suited for a few applications. Expect a charge rate of about 490 mA with 2S and 3S LiPo packs so only use it with appropriately sized batteries. At only $6 it is easy to understand the argument that you're getting a lot for your money. Ignoring shipping costs, the table below shows that the 5011 does represent a slight advantage in value of power per dollar as compared to ~50W balance chargers, but is it worth it? If it dies on you (not an uncommon problem) and you have to buy another one you are now down to 0.52 Watts per dollar, you'd have been better off to have purchased one of the other chargers since at least they have better reliability and warranties.
Pluses
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DISCLAIMERI am in no way affiliated with Turnigy or any other charger manufacturing company or retailer. I purchased the Turnigy 5011 at full retail and do not stand to benefit monetarily from positive comments, nor do I risk losing monetary benefits by posting negative comments. I reserve the right to update this review as needed to correct mistakes and update information that may come to light later. COMMENTS?If you have any questions or comments regarding this review please feel free to do so on my RC Groups blog. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
