Why no lithium-ion cell chargers similar to the C9000?

[Battery Guy]

I really love my C9000 charger for AA and AAA NiMH cells. It is really great to be able to get reasonably accurate discharge and charge capacity, as well as an estimate of internal resistance, with a consumer grade charger that is easy to operate.

Any thoughts as to why it is taking so long for someone to make a charger similar to the C9000, but for lithium-ion cells? Here are the features I would love to see:

1.) 4-bay charger capable of charging/discharging 14500 through 26650 cells;
2.) Current ranges similar to the C9000 (100-2000 mA charge, 100-1000 mA discharge);
3.) The ability to set the cut-off voltage on charge in 0.1 V increments between 3.5 V - 4.3 V;
4.) An "analyze" function that would discharge/charge/discharge the cell and report cycling efficiency and internal resistance. A cycling efficiency >100% on a lithium-ion cell means that more charge was put into the cell than was discharged, and this indicates that an internal short circuit is present;

Any chargers out there that come even close to doing this at a cost equivalent to the C9000? Actually, I would probably be willing to spend up to $100 for a charger that had these features.

I am not an electrical engineer, so I would be really interested in learning if there is a technical reason why nobody has made a charger similar to the one described above.

Looking forward to your responses.

Cheers,
BG

 

[Eismagier]

I would say that the answer is less technical in nature, and more a matter of business. The market for loose Li-Ion/LiPo cells is minuscule. Most consumer devices that use these cells have proprietary packs and a dedicated charger. It doesn't make sense to engineer an advanced charger only to sell a couple hundred units.

 

[mrlysle]

I guess we sometimes forget that us "flashaholics" are relatively few in number compared to lots of other hobbies. But I'm with you BG. I've wondered the same thing myself. A charger with the features and flexibility of the C9000 for our Li-ion cells would be sweet! Eismagier has a good point. Maybe some of our electronic wizard members here could devise one and then either sell the plans for us to build our own, or build them for us and sell them! I for one would be willing to buy one!

 

[TranceAddict]

such features are currently exist in hobby charger

 

[jedirock]

Where can we get these hobby chargers? I don't know that I've seen any.

In addition to the original requests, I'd also want the charging cutoff voltage to go down to 2.8 or 3.0 volts at the low end. That way it can support 3.2V LiFePO4 batteries as well.

 

[flashflood]

Where can we get these hobby chargers? I don't know that I've seen any.

Google "cellpro" and "icharger" to see a couple of multi-chemistry hobby charger options. The chargers are fine -- the open problem is connecting to it. Most people use magnets or clamps. You'd think that a general-purpose variable-size battery holder would be broadly useful, but in fact no such product exists -- or at least, none of us have been able to find one. And I have looked hard.

 

[Mikl1984]

You'd think that a general-purpose variable-size battery holder would be broadly useful, but in fact no such product exists -- or at least, none of us have been able to find one. And I have looked hard.

My choice are two universal chargers, such as
http://www.dealextreme.com/p/univer...harger-with-usb-power-port-us-100v-220v-32430
http://www.dealextreme.com/p/univer...-6f22-18650-battery-ac-100-240v-eu-plug-47499
I used it with iCharger 1010B+ as cradles
Prices for special cradles are usually higher 😉

 

[HKJ]

Where can we get these hobby chargers? I don't know that I've seen any.

In addition to the original requests, I'd also want the charging cutoff voltage to go down to 2.8 or 3.0 volts at the low end. That way it can support 3.2V LiFePO4 batteries as well.

You can get hobby chargers in RC shops, they are used by people that plays with radio controlled cars/planes/boats. I have written a bit about hobby chargers in What is a Hobby Charger.
Hobby chargers can easily handle LiFePO4 batteries, they have a cutoff voltage at 3.6 volt.

 

[saeckereier]

Where can we get these hobby chargers? I don't know that I've seen any.

In addition to the original requests, I'd also want the charging cutoff voltage to go down to 2.8 or 3.0 volts at the low end. That way it can support 3.2V LiFePO4 batteries as well.

I'm pretty sure that's too low..

 

[ecrbattery]

To get a "consumer grade charger that is easy to operate", manufactures need to deal with some safety issues:

How do you prevent users from charging lithium primary?

How do you prevent wrong insertion? (some battery has the same flat contact for both the positive and negative terminal)

How do you automatically determine the correct lithium chemistry and capacity for the battery and select the appropriate charging current and cut-off voltage?

What insurer is willing to protect the manufacture when something does goes "ka-boom"? Lithium battery pack a lot more punch so the risk of fire and explosion is higher.


With the "hobby" charger, you can expect the users to be some what knowledgeable about what they doing since this is their "hobby". The same can not be said for a "consumer" charger.

 

[Battery Guy]

such features are currently exist in hobby charger

Correct me if I am wrong, but most hobby chargers do not allow you to set the charge cut-off voltage in 0.1 V increments. The ones that I have seen typically have three settings for 4.2, 4.1 and 3.6 V corresponding to li-ion, lipo and LFP, respectively. I have not seen any that allow you to go up to 4.3 V, which is needed for some of the new, high capacity cells. Hobby chargers typically do not have cradles and many require a power supply if you want to run off AC.

What makes the C9000 so nice is that it is an all-in-one unit that looks good and still has quite a bit of functionality.

There is no question that one can achieve most of the same functionality using a good hobby charger and homemade/scavenged cradles. But that seems like overkill to me, especially if all you want to do is charge single cells.

Cheers,
BG

 

[HKJ]

Correct me if I am wrong, but most hobby chargers do not allow you to set the charge cut-off voltage in 0.1 V increments. The ones that I have seen typically have three settings for 4.2, 4.1 and 3.6 V corresponding to li-ion, lipo and LFP, respectively. I have not seen any that allow you to go up to 4.3 V, which is needed for some of the new, high capacity cells.

Some hobby chargers allow adjustment of the termination voltage, on my iCharger I can adjust the following:
LiFe: 3.40 to 3.90 in 0.01 volt steps
Lilo: 3.90 to 4.20 in 0.01 volt steps
LiPo: 4.00 to 4.30 in 0.01 volt steps
Pb: 2.20 to 2.50 in 0.01 volt steps

 

[Battery Guy]

To get a "consumer grade charger that is easy to operate", manufactures need to deal with some safety issues:

How do you prevent users from charging lithium primary?

How do you prevent wrong insertion? (some battery has the same flat contact for both the positive and negative terminal)

How do you automatically determine the correct lithium chemistry and capacity for the battery and select the appropriate charging current and cut-off voltage?

What insurer is willing to protect the manufacture when something does goes "ka-boom"? Lithium battery pack a lot more punch so the risk of fire and explosion is higher.


With the "hobby" charger, you can expect the users to be some what knowledgeable about what they doing since this is their "hobby". The same can not be said for a "consumer" charger.

But there are already "dumb" cradle chargers that will charge a range of cylindrical lithium-ion cell sizes. I don't see why the same issues would not apply to those.

So take a Pila IBC, add two more independent channels make the cradle large enough to handle cell diameters up to 26 mm. Then add the ability to discharge cells and measure the capacity. Finally, allow selectable charging from 100 mA to 2000 mA in 100 mAh increments, and add a 3.6 V cut-off option. Put a nice display and friendly UI on the front and you have yourself one kick butt charger. I can't see why a charger like this would be any more or less risky than the original Pila IBC.

To prevent charging small cells at a high rate, simply have an algorithm that limits the maximum charge current based on the internal resistance of the cell. With respect charging lithium primary, there are a few things you can do to minimize the risk, but quite frankly all chargers that will accept AA and CR123 size cells need to worry about charging lithium primary, so I don't see why it would be different with this charger.

Cheers,
BG

 

[Battery Guy]

Some hobby chargers allow adjustment of the termination voltage, on my iCharger I can adjust the following:
LiFe: 3.40 to 3.90 in 0.01 volt steps
Lilo: 3.90 to 4.20 in 0.01 volt steps
LiPo: 4.00 to 4.30 in 0.01 volt steps
Pb: 2.20 to 2.50 in 0.01 volt steps

That is really good to know. Thanks HKJ!

Which model iCharger do you have?

 

[Battery Guy]

such features are currently exist in hobby charger

It seems to me that hobby chargers tend to be really good at charging multi-cell packs. So they have balancing capabilities and can charge to very high voltages.
They can also charge individual cells to be sure, but most are single channel units, and the multi-channel units are quite expensive.

This is a bit different from what many flashaholics need, many of which have a number of flashlights that take one or two loose lithium-ion cells.

 

[HKJ]

That is really good to know. Thanks HKJ!

Which model iCharger do you have?

I have the 208B, but I believe most or maybe all iChargers has that adjustment and it also exist on some other hobby chargers.