Radio Control Zone - Reviewing the Triton Charger

Review of the Triton Charger

Abbreviations used in this post:

NiMH = Nickel Metal Hydride
Li-Ion = Lithium Ion
Li-Poly = Lithium Polymer
C = Capacity
mA = milliamps
mV = millivolts
mAh = milli amp hours

Changes in technology affect the way we live. Whether were at work, at home, or spending time with our hobbies, new advances change the way we do things. In just the last few years the batteries we use to power our model aircraft have also changed. The NiCd’s started giving way to the lighter, higher capacity NiMH’s. Not long after the their introduction experimenters started ripping apart cell phone packs to access the Li-Ion cells which were lighter and had an even larger capacity to weight ratio. Now, suppliers are making Li-Poly packs, which are even lighter and less volatile than their Li-Ion predecessor.

Each of these battery chemistries has their advantages and disadvantages. This being the case, most of us own several packs with different chemistries. Since each has their own unique charging characteristics, we end up carrying around chargers for each type.

I am very finicky about the way I charge my battery packs, so I normally build my own chargers using specialized integrated circuits which let me program the exact charging and safety parameters that I prefer. This is especially important when charging Li-Ion and Li-Poly packs, which can become unstable and volatile if not charged or discharged properly. I have owned commercial chargers that will get the job done, but I am usually disappointed in their lack of versatility and poor accuracy.

Recently I had the opportunity to purchase a slightly used Triton charger. This is a device that will charge, discharge and cycle five different battery chemistries, (NiCd, NiMH, Li-Ion, Li-Poly and Lead Acid). Could this small, lightweight charger live up to its claims? To find out if it would end up in my flight box, or on Ebay, I put it through the tests that I place on all of my chargers. Although many measurements were taken over the course of eight hours, I will not bore you with lots of figures and will just give the highlights.

A 10 to 15 volt DC source powers the Triton. Since this charger will supply up to 5 amps charging current, incorporating an AC supply would require it to be much larger, heavier and more expensive. It will charge from 1 to 24 NiCd and NiMH cells, 1 to 4 Li-Ion and Li-Poly cells and Lead Acid cells that are in combinations of 3, 6, or 12 cells. For a look at all of the specs you can use this link which will display the owners manual

The measured accuracy of the actual charging current to that, which is displayed, is within .01 amp (10 mA) up to 2.5 amps and within .1 amp (100 mA) up to 5 amps. The current regulation in this charger is very good and the displayed current is accurate.

The measured accuracy of the actual charging voltage to that, which is displayed, varies depending on the mode of the charger. When measuring static voltage of the pack the displayed voltage was within .01 volt (10 mV) of my equipment. When charging NiCd or NiMH packs, the charger is in a regulated current mode and the voltage displayed would vary as much as .150 volt (150 mV), still very acceptable. When the charger is in a regulated voltage mode used in Lithium and Lead Acid charging the accuracy is within .03 volt (30 mV).

NiCd & NiMH Charging & Discharging:
In this mode you set the charging rate and delta peak cutoff rate you desire. The charger automatically determines the number of cells in the pack and begins charging at a .1 amp (100 mA) rate. Once the battery is tested the charger begins charging at the rate you selected. Once the zero delta peak point is reached, the charge sequence discontinues and a audible beep alerts the user. The delta peak accuracy is very good. I tried to obtain false peaks without success. For AA and smaller cells I typically run delta peak voltages of 5 mV per cell for NiMH and 7 to 10 mV per cell for NiCd. When using these settings the packs would come off the charger just slightly warm to the touch. Even when running 3C rates on NiCd’s, the pack would not come off the charger hot. When topping off recently charged NiMH cells, some chargers will read the cell count wrong and overheat the pack, thinking it is one cell larger than it is. After many attempts I could not fool the Triton in this manner.

When discharging you once again set the amount of current, up to 3 amps, and the voltage threshold at which you want the discharge to cease. This is typically .8 to 1 volt per cell. The displayed accuracy was the same as in the charging sequence. I usually discharge my packs in flight, but periodically using the discharge feature can warn you in advance of any cell deterioration in a pack.

Lithium Battery Charging:
There are 4 important parameters, which must be monitored when charging lithium type batteries. First the charger must look to see if the battery being charged is above or below the 2.75 volt per cell limit. If it is below, the charger must initiate a .1 (100 mA) charge to bring the cells above this point. If this limit is not reached in a few minutes the charge should be suspended. When the cells are above this threshold the bulk charge can then be applied. The Triton charger uses a .3 volt per cell limit. If this level is not reached within 2-1/2 to 3 minutes the charge is suspended and an error message is displayed along with an audible alert. This function worked perfectly. The next phase in lithium charging is the bulk charge. This is the quick charge phase and the charger operates in a constant current mode, which is set by the user, up to 2.5 amps. Depending on the manufacturer of the cells this will vary from .7 to 1C. The charger stays in the regulated current mode until the proper cell voltage is reached. The charger then goes into a regulated voltage mode. Most manufacturers recommend this voltage should be maintained within 50 mV. My measurements showed the Triton staying within 30 mV during this phase. As this voltage is maintained the current will drop as the battery charges. Most manufacturers recommend that when this current drops to 1/10 of the bulk charge rate used that the battery charging is complete and should cease. The Triton stops the charging sequence at .1 amp (100 mA). A charging limit timer should also be activated for lithiums and this is also incorporated in the Triton. When in the constant voltage mode, the displayed current is not as accurate and actually rounds up or down. For example if the charge current actually 270 mA the display reads 300 mA.

The Triton has a built in fan, which will turn on if the temperature in the charger reaches a certain threshold. The fan will always run when charging above 2.5 amp and anytime a pack is being discharged. My Triton runs only warm to the touch when charging at high levels, which proves a very well designed heat dissipation system. Something often overlooked in lower priced chargers.

I am also pleased with the dc to dc converter efficiency in the Triton. Input current measurement shows a static current draw of .06 amp (60 mA), and when charging, the input requirement is only about .150 amp (150 mA) higher than the charging current being used.

RC Car Packs:
Okay you car guys, I know you like to roast your sub C packs. I discharged a 1500 mAh 6 cell Piranha pack. I then charged it at 5 amps and 80 mV per cell delta peak cutoff. The Triton supplied a measured current of 4.9 amps. When the sequence was complete the charger indicated that 1498 mAh had been supplied to the pack and it was only warm to the touch.

The 32 character 2 line LCD display is easy to read from various angles and provides the user with the most important information when charging. The menu function is easy to use and understand. The rotary knob allows the user to switch between menu functions and to set values. It also has a pushbutton feature which starts charging and toggles through different settings. The one thing I did not like was the fact that this knob is recessed and must be turned using the small finger hole. I would prefer a knob to grab, but having it recessed renders it less likely to be broken off. One thing I did notice is that if the knob is not pressed straight down for the pushbutton function, it is possible to change a setting if the knob rotates when it is being pressed.

Warnings:
You know the saying in the computer world “garbage in garbage out”? Well, the imbedded computer in the Triton is no different. Although the programmers have made every attempt safely and efficiently charge your batteries, the Triton still relies on important information provided by the user. The most important piece of information you must supply is the type of battery you are charging. If you hook up a Li-Ion pack and set the charger to NiMH, it’s going to charge it as a NiMH and you could end up with a damaged pack, at the least. Make certain you set the battery type and charging currents accurately. A nice feature is being able to set up to 10 memories, which can be recalled.
Never leave the charger unattended when charging. If you tend to walk away while charging, then it would probably be prudent to order the optional temperature probe. This will enable the charger to suspend operations if a pack becomes too warm.

The Triton gives you two choices for charging your lithiums, 4.1 volts per cell or 4.2 volts per cell. Check the manufactures specs for these settings. The older Li-Ion cells were topped off at 4.1 volts per cell, but some of the later cells require 4.2 volts. If your not sure use the lower setting. A properly charged lithium battery will actually be cool to the touch after charging. Suspend any charge on a lithium if it becomes warm to the touch.

Items not evaluated:
I have not had the chance to try the Triton on a lead acid battery, but I will. I also would like to do some near field radio frequency interference testing. Since the charger will be used possibly right next to a RC transmitter, I would like to make sure that it's brains do not become scrambled. Many RC'ers are also Ham Radio operators and could be operating radios while charging a battery. I will post those results in a few days.

Conclusion:
The Triton certainly measured up to its claims in my tests. The fact that you can control the most important parameters, in such fine increments, makes the Triton, in my opinion, the most versatile charger available at this time. It is certainly the most accurate and bugs free charger that I have tested. The fact that it will end up in my flight box speaks for itself. After all, I said I was finicky.

Regards,
Dale