Sad state of 18650 chargers

[radellaf]

I'm new to 18650s and figure I can charge the IMR 1600mAh that is coming on my Maha C777, as long as I'm happy with a C/4 charge for cells that should be charged at 0.7-1C.

Sad state is that there are a few chargers that don't require awkward leads, magnets, and power supplies. Utter junk from DX including the DSD, and a great looking but probably crappy single cell charger also compatible with NiMH. That thing would be perfect if it was well made.

Every dedicated charger, including the vaunted Pila, though, have charge currents that are way too low. No excuse for less than 1.5A, IMHO. I don't know if lower currents are the safety hazard that they once were, but I'd rather not take chances. Last I heard, C/5 or below is very much not recommended for LiIon.

Then, there are the hobby chargers. $70 for the cheapest Bantam, and most require awkward wiring on both the input and output side and have serious QC problems. Controller boards on the Thunder resetting when the user has static electricity on his hand, cheap and loud fans that quit.

So the only really safe charge currents come with hobby setups that are, physically, pretty unsafe (loose wires, unshielded battery contacts), for near $100 if you don't want a device that you can't trust.

Wow. This market really needs a C-9000 equivalent for LiIon.

For that matter, finding a charger for D-cell NiMH that's capable of a 3-4 amp charge current seems nigh well impossible, too. Le <sigh>.


Or am I too harsh? Or wrong?

 

[Mr Happy]

For that matter, finding a charger for D-cell NiMH that's capable of a 3-4 amp charge current seems nigh well impossible, too. Le <sigh>.

I'm not sure that's a good idea. I believe manufacturer data sheets typically specify a maximum 2 A charge current for most D size NiMH cells.

 

[flatline]

The Pila's charging current might be low for charging high capacity 18650s, but if they increased it, it would be too much to charge 14500s and RCR123s, so I like it where it is.

Also, Tynergy (spelling?) makes a "hobby" charger for around $25 that seems to be well regarded. I've seen it mentioned favorably in several threads recently. You have to supply your own battery cradle if you want something more extravagant than alligator clips. I think you also need to provide your own wall wart to power it (people use laptop wall warts, I've heard).

--flatline

 

[pae77]

I'm new to 18650s . . .

Or am I too harsh? Or wrong?

Imo, you are both too harsh and wrong.

Nowadays, one can get a great budget hobby charger such as the Accucell 6 for about $39 shipped (see e.g., HobbyKing Online R/C Hobby Store : Turnigy Accucel-6 50W 6A Balancer/Charger w/ accessories ) and the only additional things you need to be able to EASILY charge any size cylindrical li-ion cells is an inexpensive ~$10 to $20 power supply (available from DX or ebay, (see e.g., 12V 5A 60W LCD Monitor AC Power Adapter Supply +cord NW - eBay (item 170312443254 end time Sep-08-10 14:45:37 PDT) if you don't already have a suitable old laptop power brick lying around) and a few rare earth magnets for a couple of bucks available from Lighthound or DX (see e.g., http://www.lighthound.com/Magnetic-Spacer--16mm_p_1046.html or http://www.lighthound.com/Magnetic-Spacer-for-Charging-14quot-x-14quot_p_1047.html or DX has similar magnets in quantity for less cost per unit with free shipping of course).

Everything else you need to get started comes with the charger referenced above.

It is NOT awkward, unsafe or difficult to attach the stock charger output leads to the ends of cylindrical cells with magnets and no soldering is required. It is just as easy as popping the cells into a cradle, imo, and actually, is more fun.

With this setup you can easily charge any size li-ion cylindrical cell at any charge current you care to select from .1 A (100 mA) to 6 A (6,000 mA).

With a very slight bit more effort and a few more magnets and wires, (or other more fancy custom setup which is totally optional and NOT required), one can easily use this setup to parallel charge more than one cell at a time.

With a very slight bit of easily acquired knowledge and research, it is very easy to learn how to safely use an inexpensive budget hobby charger and get great results with a flexible, easy to use and safe charging setup that uses a true CC/CV algorithm, can be calibrated if necessary, and, if used properly, provides optimal longevity for one's cells.

 

[radellaf]

I was looking at the AccuCell, and I imagine one of the 15 min charger wall warts might put out 2A in the right voltage range. But, seems the fan on that charger is completely unreliable.

And, while it's _OK_, having a loose cell lying on the desk with alligator clips magnetically attached to it... while I've done stuff like that plenty, it's not the kind of UL-listed cat-can-jump-on-the-desk safe that I'd expect to find when it comes to battery chargers.

That said, if I do decide to get a hobby charger, I think I'll hack & strip this one:
http://www.dealextreme.com/details.dx/sku.5837
to use as a single cell holder. Just rewire the PCB, cut off the AC plug, and add banana plugs.

So, sure, I'm an EE, I can do the hobby stuff, but was just really surprised that there's nothing better than the (pricey and weak) PILA "ready-made". But, to be fair, I guess that reading this board you get the impression that 18650s are a much more established (loose cell) battery technology than they really are.

Wish I could just pop one into my Strion charger. That's a "bulletproof" version of what I think I want, just in a totally useless form-factor.

 

[radellaf]

I'm not sure that's a good idea. I believe manufacturer data sheets typically specify a maximum 2 A charge current for most D size NiMH cells.

My best setup for that is still an old Radio Shack pulse charger with I think a 2A output. 4 bays, but parallel connected so only one charge controller. So, I charge D cells one at a time in it. OK for now, for as few of those cells that I actually use. I still like my InReTech 3 luxeon DD module in a Mag 3D.

Still, if you can't charge a 10Ah NiMH at at least 3 if not 5A, I'd think your only sure option to prevent overcharge would be to do the old 14 hour slow charge at 1A. Unreliable -dV at below C/2 and all that, unless the D cells are somehow different.
edit: Tenergy data sheet for 10Ah says "5000mA for 2.4hours, –ΔV=5mV". http://www.all-battery.com/datasheet/Data sheet NiMH D 10000mAh.pdf
That's not for their 8Ah LSD D cells, though, which are what I'd like to replace my rather old ones with.

 

[Mr Happy]

And, while it's _OK_, having a loose cell lying on the desk with alligator clips magnetically attached to it... while I've done stuff like that plenty, it's not the kind of UL-listed cat-can-jump-on-the-desk safe that I'd expect to find when it comes to battery chargers.

IMHO the cell should not be lying on the desk, but should be in a fireproof bucket or brick-lined container in some fire-proof location...

(Not sure whether I jest or not, to be honest...)

 

[donn_]

I use this for high capacity single Li-Ion charging. It's 1.8A.

I use this for high capacity multiple Li-Ion charging (in parallel holder). It's 6A.

I use this for multiple LiFePO4 charging (in parallel holder). It's 6A.

Those are all for when I'm in a hurry. I use normal chargers when I'm not.

 

[Mr Happy]

Still, if you can't charge a 10Ah NiMH at at least 3 if not 5A, I'd think your only sure option to prevent overcharge would be to do the old 14 hour slow charge at 1A. Unreliable -dV at below C/2 and all that, unless the D cells are somehow different.

I think D cells are different. It appears the 0.5C - 1.0C recommendation applies to AA size cells, and the recommendation varies with cell size. With larger cells a higher charge rate can perhaps lead to overheating, which may be why a lower rate is advised as the cells get bigger.

 

[radellaf]

flatline - IMHO if it charges multiple sizes of cell, it should support more than one charge current. I'm just looking for 18650 here. I have a separate LiFePo RCR123 charger....

donn - that first one combined with the gutted DX charger as a holder looks like it would be perfect. 1.8A, no exposed wires. $30 and some work. Thanks.

Mr Happy -- I've read a good number of battery books, including the big battery handbook, but I don't remember what all they said about larger, or REALLY large NiMH (100Ah+) cells. If I ever end up working on EV chargers professionally, I'd really enjoy what I'd get to learn.

Fireproof bucket? Yeah, not willing to take those precautions, and I know what that means. Hence, I may never use LiCo (vs IMR or LiFePo ) cells. Trouble with the LiFePo though is the different voltage. The C777 wouldn't work.

 

[pae77]

I was looking at the AccuCell, and I imagine one of the 15 min charger wall warts might put out 2A in the right voltage range. But, seems the fan on that charger is completely unreliable.

I don't think that is entirely true about the fan. The fan on my current unit has been working quietly and reliably without any added lubrication for several hours per day for a few months already. So far it shows no signs of imminent failure.

Besides, imo, the fan is really unnecessary for the kind of charging flashaholics are likely to be doing most of the time with this unit. I have noticed that when charging 18650's and other cylindrical li-ion cells at rates up to 1.8 mA (as high as I've attempted), the charger stays totally cool and cool air blows out of the charger, and I believe it would stay cool even without the fan operating, although tbh, I haven't yet tried that. But many hobby chargers using essentially the same PCB don't even come with fans which leads me to believe the fan is probably unnecessary, especially when charging at the kind of modest rates most cylindrical li-ion cells should optimally be charged at.

I have read through a rather lengthy thread on another site devoted specifically to the Accucell 6 charger and have noted that reports of failure of the fan, while not unknown, is not very common.

I think the fan is probably helpful when charging at very high rates near the limit of the charger's capacity or perhaps when using it to discharge. But I have never seen my particular unit even get the slightest bit warm when charging or discharging at the modest current rates I normally use.

Anyway, even if the fan should fail, it is not a very difficult item for the home user to replace as it simply requires opening the charger's case (2 screws), plus another 2 screws and a press on connector to remove and replace the fan.

In short, I wouldn't reject the Accucell because of the fan, but that's just my opinion and you are, of course, entitled to yours. I just didn't want to let what I regard as a rather misleading statement about the fan go without a response.

 

[donn_]

donn - that first one combined with the gutted DX charger as a holder looks like it would be perfect. 1.8A, no exposed wires. $30 and some work. Thanks.

You don't need the gutted DX holder. To do a single cell, just stick round rare earth magnets into the alligator clips.

 

[flatline]

flatline - IMHO if it charges multiple sizes of cell, it should support more than one charge current.

No argument here. The Pila came with adapters for charging 14500s, so clearly they intended the charger to be used on multiple sizes.

--flatline

 

[radellaf]

pae77 -- OK, sounds like the fan may be a minor issue that became overblown (ha!) on the reviews since those with problems write more comments. I'd love to get one to play with the USB data logging. Wish you could use it just as a voltmeter, too...

donn -- Looks like batteryspace sells 18650 holders as well as the chargers. The holders have a protection board on them which shouldn't ever need to do anything, but I guess it couldn't hurt as a 2nd level of overcharge or short circuit protection.

I don't mind using magnets temporarily, but I really prefer more mechanically stable arrangements in the long term, and more well-insulated contact points.

flatline - not unique to the Pila to be sure, but never a good design (lack of) feature. Certain NiMH chargers run 1-2Amps into AAA cells, and even the configurable C-9000 has a 100mA trickle that is too much (C/20?) for 2Ah AAs much less any AAA. Even if only switch selectable, the Pila needs at least two current levels to do (IMHO properly) everthing it's supposed to do.

 

[Aquanaut]

For that matter, finding a charger for D-cell NiMH that's capable of a 3-4 amp charge current seems nigh well impossible, too. Le <sigh>.

Here is a charger that charges 1 to 8 NiCd and NiMH cells of any size from 0.1 to 5 amps:

http://www.duratrax.com/caraccys/dtxp4005.html

I have been using it for over ten years and it has never failed me. It will charge any capacity cell in the "AUTO" mode, or you can input max capacities from 50 to 5000 mAh.

 

[radellaf]

Here is a charger that charges 1 to 8 NiCd and NiMH cells of any size from 0.1 to 5 amps:

The AccuCell may or may not be as well built, but can do a similar thing. But, I don't trust charging more than one cell in series. I could charge at 5A instead of 2, but I'd still be stuck doing one cell at a time.

Appreciate the recommendation, though.

---

I've decided not to buy any charger for the time being and make do with the c777 and the IMR 18650 for my new MG P-Rocket. But, thanks for the help as I know a lot more about the other options now.

 

[CKOD]

IMHO the cell should not be lying on the desk, but should be in a fireproof bucket or brick-lined container in some fire-proof location...

(Not sure whether I jest or not, to be honest...)

http://www.aww-kittah-aww.com/up/files/108/fireproof.JPG

What I'm using to charge my batteries in. Surplus ammo can with no rust, lined with (3) 1/2" layers of drywall to make for 1.5" of gypsum. 2 layers on the lid, and there is a gap between the lid drywall and the bottom. I put a vent in the front section, with some rolled up aluminum screen in it to act as a spark arrestor. The front section is big enough to hold my Revolectrix cellpro multi4. (Which I would suggest to anyone looking for a 4S hobby charger) I'm going to add a power and USB pass though, and I should be able to run it with the lid shut.

The charger is fantastic, espcially hooked up to the PC for programming. $60 with the usb adaptor, and I can charge Li-ion/Li-po, Li-Fe, Ni-Mh, Lead Acid, and anything else which will play nice with a CC/CV charge in the future (Ni charge does use peak detection though).

It does upto 4A into 4S li-ion batteries (limited to 50W maximum thoughput). Powering it with a cheap 6A 12v power supply (only needs 5A, but you can limit the input draw if you only have a 1A or 2A, etc supply!)

You still need to wire up cradles/holders etc, so its not as simple as just buying an IBC and throwing cells in it. But if you demand control its fantastic.

 

[radellaf]

Looks nice and fireproof.

Surprised none of these hobby chargers has more than one charging channel. People who obsess about high performance from NiMH packs are content to charge them in series?

 

[zer0ne]

Quattro and Turnigy 4x6S has 4 ports and all can be found in Hobbyking.

 

[Aquanaut]

People who obsess about high performance from NiMH packs are content to charge them in series?

I am one of the obsessed. :wave: If you check out radio control people, all of them have series connected power packs. Some of those packs are very high power where they pay big bucks to purchase packs that use cells that are capacity sorted by the manufacturer, so that when they are series charged at high amps, they are not hurt by imbalances.

Every now and then the packs are left on trickle charge after high amp charging to remove any small imbalances that might be present. This is standard procedure for the RC hobbyist. Fortunately, NiCd and NiMH react favorably to trickle balance charging.