Review: Turnigy Accucell 6 Hobby Charger

Turnigy Accucell 6 Hobby Charger

Reviewer's Overall Rating: ★★★★★

Summary:

Battery types: Just about anything
Power: 12V DC in
Price Paid: $32.98 shipped plus $7.79
From: Hobby King
Date Ordered: 24 Mar 2011

Pros:

  • Charges/Discharges just about anything
  • Alarm when finished
  • Bright display
  • Configurable
  • Optional temperature probe
  • Safety cutoffs for temperature, time elapsed, and total charge
  • Data logging possible with connector (see Post 77)

Cons:

  • Complicated
  • No battery holders
  • No temperature probe included
  • Must buy power supply separately
  • Still not that quick
  • Maximum discharge rate is only 1A

Features / Value: ★★★★★

I’ve only gotten interested in flashlights in the last couple of years and when I first decided to try some lithium ion batteries, I didn’t want to jump in. So I bought the really cheap and versatile Universal Charger ($5.85 at DX), a pair of 10440’s, and a pair of protected 14500’s. Lithium ion batteries really make a difference in some lights and it wasn’t that much later I was playing around with 18650’s and P60 hosts, so I bought the 2 bay 18650 “digital” charger at DX. Both of these chargers have their detractors who say they aren’t following the correct CC/CV charging routine and may have a trickle charge or overcharge batteries. The little charger actually doesn’t usually charge over 4.13V and the other charger is more like 4.21V which is closer to 4.20V than my DMM can probably read. One problem with the 2-bay charger is that it takes a really long time. When I first bought it, I ran some tests where I would check the current and voltage of the charger as it charged a battery and found that if followed a nice pattern of high charge early, tapering off as the battery got full. But with some batteries it seems to take 3 hours or so to charge and it seems slower with 2 batteries than with one. Lastly, with XM-L lights getting more popular I thought I might want to try LiMn (IMR) cell which may or may not charge correctly on my chargers, or LiFePO which I know wouldn’t charge correctly because it has a different voltage. Rather than get anymore cheap chargers, I was thinking I should get one charger that can charge anything I want: a hobby charger. The other benefit of these is they can measure discharge capacity of cells too, similar to my Maha C9000 does for AA and AAA cells.

I’m still cheap, so while you can pay a lot more for nicer hobby chargers, you can’t spend much less than buying a Hobby King Turnigy Accucell 6 hobby charger. Most of the hobby chargers seem to be clones of one another, right down to the buttons and interface. People seem to like the Turnigy and although there is a higher power version (Accucell 8), for flashlight batteries this 50-watt version seemed like it would be fine. If I did a lot of RC stuff with higher power packs, then I would already have something with more power.


So I finally gave in and placed my order at Hobby King, which went pretty smoothly, although their shipping rates are steep: $9.99 for a $22.98 charger. They gave me a Hongkong Post tracking number and shipped within a day or two. The only problem is the charger doesn’t include a power supply and they were out of the one most people recommended buying for it. I wound up getting one on eBay from user “toymodel888” for one cent plus $7.78 shipping which is actually less than Hobby King was charging. The eBay description for the power supply says it is for the IMAX B6 B5, but that seems to just be another clone and the plug fit just fine. The power supply arrived just a couple of days after the charger and it seems nicely made, like something that would go with a name brand LCD monitor or laptop. The eBay seller includes the appropriate plug depending on where you live and correctly gave me a 3-prong US plug.



First impressions are the charger was packed well inside a corrugated cardboard box inside the shipping box. And while the shipping box was pretty beat up, the inner box was in fine shape. Also included were some cables with alligator clip ends for the battery and another set to be used for a power supply (before getting the power supply I used these to connect to a 8xAA NiMH battery pack just to see if the charger was working, though I didn’t charge anything). There was some plastic film over the LCD display which I had a hard time removing. The unit itself seems quite solid and well made with a metal enclosure. And like most flashlight stuff, it is smaller than it looks in the pictures. The display is easy to read and backlit quite brightly. It is a matrix display of 16 characters x 2 lines. One minor quibble is the color scheme for the positive and negative output follows the color scheme of the unit so it is white and brown instead of red and black like the wires that connect there.

NiMH Charging/Discharging: ★★★★

NiMH battery pack charging. The first thing I hooked up was my Versapak battery, a 3.6V NiMH pack for tools. Versapak batteries were originally NiCad, but when I bought replacements they had gone to NiMH. But the charger was still for NiCad, so I worried that it would be trickle charging or otherwise damaging the newer Versapak batteries. At 3.6V, it must be a 3-cell battery pack. So I started going through the menus on the Turnigy to see if I could get a setting for a 3-cell NiMH pack in series. Nothing. There only seems to be one setting for NiMH. I dug up the manual which you can download from Hobby King (they don’t include one in the package) and there seemed to be an automatic and manual NiMH setting screen, but all I have is manual. Even with manual, you don’t specify how many cells are involved. Instead you give it a charge rate and I guess it figures out when it is time to stop charging based on delta V or whatever. Using the alligator clips, I let it charge my Versapak at 0.6A for about 40 minutes until it was time to go to bed. The voltage was up to 4.4V or so, but I don’t know enough about Versapak batteries to know when they should be done. The light on the Versapak charger never even goes out. So I don’t think that went real well, but some of that is just me figuring out how the charger works. Eventually, I settled on a charging rate of 0.8A (a higher rate will give a better termination signal, so you want to use about 0.5C and the Versapak seemed to be about 1600mAh) and it terminated at about 4.5V (though it quickly went down to 4.15V or so when it came off the charger). The battery was definitely warm at this point, which is a little worrying. There is a port for a temperature probe, but the unit didn’t come with that accessory (EDIT: I ordered this temperature probe later and like it; more later in the review). There are also a bunch of ports for balance charging, but I don’t have any balancing rigs, so I don’t think I will use them.

Here is the left side with power input and temperature probe port underneath the vent holes. Although a temperature plug is not included, the firmware supports it and you can buy one separately at Hobby King ($2.60). The temperature sensor might be more important for NiMH than li-ion since the li-ion charge tapers off so much as the battery gets full:



NiMH discharging: When discharging a NiMH battery pack, you must enter an ending voltage because the charger doesn’t know how many cells are involved and the default of 0.1V is entirely too low. Since the Versapak is 3 cells, I entered 3V, though I think I could have gone down a little less, possibly 2.7V. After discharging that amount my electric screwdriver that the Versapak goes in still seemed strong. The at rest voltage on the discharged battery was 3.3V. I tried lowering the cutoff to 2.7V and got an alarm within 15 minutes, so even with a lower cutoff, you aren’t really losing much of the capacity. Even with the 2.7V cutoff, the at rest voltage recovered to over 3.1V.

Here are the jacks for the battery probes and different jacks for balancing battery packs with 2-6 cells:

When discharging, the fan usually comes on. I had heard problems about the fan being very noisy, but on my unit it is very quiet, like a laptop fan.

Lithium Ion Charging/Discharging: ★★★★★

Lithium Ion Charging: Next I wanted to charge a li-ion battery, so I used my fake Trustfire flame battery that I still haven’t gotten around to recycling and charged it at 1A, using the LiPo setting which is for 3.7V batteries that are charged to 4.2V, which is correct instead of the LiIo setting which is for 3.6V batteries that are charged to 4.1V. With this setting you do tell the charger how many batteries you have in series or parallel. I know li-ion cells can be charged in parallel, but I didn’t want to tackle that just yet. This time I used some magnets to hold the alligator clips to the end of the battery. One of those magnets is really powerful and the clip sticks to it securely, but the other is a little flat one and it was hard at first to get it to connect properly (I found out the Turnigy makes an alarm noise if the battery isn’t connected!). I’m better at this after using it a few times.


Now the neat part starts. While it is charging, it shows you the charge rate and the current voltage. So at first it charges at 1A as per my setting and the voltage is going up from 3.8V. Once the voltage hits 4.2V, the charge rate starts dropping: 0.9A, 0.8A, 0.7A, etc. This is a perfect CC/CV charge routine! It also tells you time elapsed and total charge applied which turns out to be mAh, though it doesn’t say that anywhere. After an hour or so the Turnigy makes an alarm sound and the battery is done. I like that it has an audio alert that it is done so I don’t have to watch every second. I measure the voltage on the battery and it is 4.21V. Perfect.

Here is the charger working. The top line of the display reads "Li1S 0.4A 4.20V" meaning it is charging 1 Li-ion (actually it thinks it is LiPo) battery in Series. The current charge rate is 0.4A (although it was originally set to 1A) and the voltage is 4.20V because it is in the CV (constant voltage) part of the charging cycle. The bottom line reads "CHG 000:20 00002" to indicate that it is charging, the elapsed time is 20 seconds, and it has charged 2 mAh so far (it had just been plugged in).



When I was charging an empty battery later on, the charger timed out at 120 minutes. This is a user setting, so I switched it to 150 minutes which should give time for a battery to completely charge. Once this is set, it is remembered even after the charger is unplugged. There is no Off button, so unplugging the charger seems to be the only way to go.

In addition to the timeout feature, you can also set the maximum total charge applied (I learned about this when charging a Panasonic 3100mAh cell and it stopped at 2600mAh). And with the optional temperature probe, it will shut off if the battery exceeds some temperature. These are fantastic features, but it would be a pain to set maximum time, maximum charge, and maximum temperature every time in addition to the charge rate.

Lithium Ion Discharging. Next I want to measure the capacity of this battery. It is supposed to be 2400mAh, but I was estimating about half of that based on how long my flashlights ran using it (part of why I got my money back). I entered the maximum discharge rate of 1A and it looked like it would discharge the battery to 3V. I don’t like to discharge my batteries down to less than 3.6V at rest, so 3V seemed low since the load sag is usually only 0.2-0.3V. I looked to see if I could change the termination point to something like 3.3V, but I don’t think you can. This isn’t a battery I care about, so I let it discharge anyway. The voltage drops off pretty quickly under a 1A load, but was at about 3.5V when I went to bed and disconnected the battery after 750mAh of capacity so far. I continued the test the next day and got 440mAh for a total of 1190mAh by the time the battery was empty at 3V. However, I measured the at-rest voltage of the battery and it had popped back up to 3.6V, so the 3V turns out to be a pretty good setting I think.

Other Features: ★★★★

Lithium Ion Storage. Another feature available is you can pick a storage setting for a battery. It is best not to store a li-ion battery full or empty, but somewhere in the middle. You can use this setting and the battery will be charged or discharged to 3.8V. That’s a nice feature, though I don’t know that I will be diligent about using it. Usually I just keep my batteries close to full and ready to go.


Balance charging. It will do balance charging with a special hookup and battery packs that I don't have, so I am not too worried about that. This is critical for battery packs because when applying a charge to cells in series, the inner cells tend not to see as much charge as the outer ones.

Temperature probe. The charger does not come with a temperature probe, but Hobby King sells one separately. I got it eventually, and I feel a lot better about charging my NiMH Versapak batteries. The default is 80 degrees Celsius, but I changed it to 45 degrees. The probe itself has a concave face to fit a round battery and has a small magnet so that it sticks to the battery. If you press the Status button during charging you will get to the temperature reading which was the correct room temperature of 26 degrees. I put the probe on my finger and the reading went up. I put it back on the battery and eventually the battery got up to 40 degrees, but cut off for being full before it got to 45. So I think this is a must and a great safety feature for only another $2.54. Though my lithium-ion batteries haven't gotten as hot as the NiMH pack, better safe than sorry on those too.

Summary: ★★★★★

Anyway, I really like this charger. I don’t have any other battery chemistries to test on it and don’t know enough or have battery packs to put this through its paces completely. But for charging li-ion batteries, this is great. Being able to set the charge rate means I can charge big batteries or little 10440’s at an appropriate charge rate of 1C (to the nearest 0.1A). The interface is a little cumbersome and definitely more complicated than even the Maha C9000 which some people at Amazon say is too complicated, but I like having some control over the charge and being able to see that is being carried out correctly.

What I would like to see is a unit that has a power supply included which hopefully would be cheaper than buying one separately. And I’d like to see some battery holders. Something plastic and fairly cheap with a spring to hold anything from a 16340 to 18670 and posts or bars that the alligator clips can attach to. Or better yet, cords could come off the holder and end with a 2-wire molex connector like the alligator clips do.

The charger has plenty of power to do more than one battery at a time in parallel or series, but for now I will wait on that. If I need to charge a bunch of batteries, I can do up to 4 at a time with my two cheap chargers and the Turnigy all going at once.

If you're just getting started with lithium-ion batteries, I don't think a hobby charger is really necessary, but if you want to evaluate your batteries and have different chemistry batteries, buying one of these will save you from buying several different chargers.

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Another awesome review there brted!

great review. I have a turnigy charger for my electric helicopters but never thought of using it for measuring capacity! thanks

Great job! Thanks for taking the time and effort to describe it in such detail.

Now I want one... thanks a lot. =/

Curious if anyone uses an old charger just to hold the cells . seems like it would be nice to pop them into something ...like an old burnt up charger with the guts ripped out of it with a quick plug on the side ???

Gutted the charger from the T-Mart deal Edit: I am photo challengedE

Wow, very thorough review as usual brted! Frontpage'd and Sticky'd.

This is an impressive charger, and a pretty decent price for such a full-featured device.

Until recently it wasn't terribly easy to get 18650 battery holders for an even slightly sensible price (you could get them from CPF for err...I forget, but let's say a million dollars each:)

So I bought one of those $4 or so chargers from DX and gutted it as soon as it arrived....the poor thing didn't even get tested :P

could you take a pic of your mod? I have one of those chargers and like it pretty well. I just ordered another one at buyincoins for ~2.70 after 10% discount and might take it apart like you to use with my hobby charger

I want to measure the capacity of some cells, specifically my trustfire flames.

What is the "empty voltage" that is safe for cells? Should I measure the capacity that is discharged, or put back in?

It's best not to let them get below 3.5v and I usually recharge mine at 3.7 or 3.8v. Those are open circuit values. Depending on the discharge rate you use they will get lower under a load and then bounce back a bit when the load is removed. Higher discharge rates will make them sag more, so I would use a lower discharge rate until you get some idea how much your cells sag under a load.

Slightly random question...Does anyone know anything about the company Turnigy? I just wondered if they were German...Accu is what batteries (or rechargeables?) are called in German.

***

Hmm Google tells me that "Battery" in German is "Batterie" and that it's "Accu" in Dutch /shrug.

Theres a photo in this thread http://budgetlightforum.cz.cc/node/1229?page=1#comment-21095

I removed everything from the inside and ran the wires out of the space left by removing a flip-out syle two pin plug. The wires are soldered straight to the contacts.

I was able to charge my batteries down to 3V. I think I tried a little lower than that and got very little additional capacity, so they were dropping quickly at that point. So 3 volts is probably safe for "under load."

I was thinking "Turnigy" is just a house brand of Hobby King. They also sell batteries under that brand, but I don't know of any other places you can get Turnigy stuff.

Hi everyone,


I just tried the nimh discharge at 1 amp. There's a huge voltage drop with a eneloop below 1,15v on the charger display, DMM shows 1,25v.

Same with charging at 1 amp, voltage totally different on accucell and dmm. Do yours show correct readings ? Already calibrated it.

Regards !

I get something similar. I just put a 18650 on it to discharge at 1.0A. The at-rest voltage of that battery had been 3.99V. The Turnigy settled in at 3.67V, but I measured 3.80V on my DMM. I don't know if it is a big concern, but it does seem like it should be closer than that.

Welcome to BLF, neverfeltbetter!

Thank you brted !

I discharged one eneloop today at 1 amp, came out at 1878mah. Seems accurate.

Voltage went from 1,5v right off the charger to 1,1xV after a few hundred mah had been discharged and stayed there forever. Li cells show the same effect.

Does not seem to have any effect on termination of charge/discharge. Li cells start low current charge at exactly 4,2v on my dmm.

Cell is discharging right now to see if it stops at 0,9v. LiIon discharge on 18650 Trustfire had accurate termination at 3.0v.

Later on I charged the 18650 and noticed the disparity in voltages again from what the Turnigy was saying vs. what I was reading with my DMM. But once the voltage crept up to 4.20V on the Turnigy, my DMM also read 4.20V. So it seems to be charging correctly.

Aloha and welcome to BLF neverfeltbetter!