Charger, batteries...

Hi,

I am thinking of getting Xtar vc4 for the Lithium ion batteries because it can display the capacity of the charged battery. Do you think that this information is important or just a good to have inforamtion? From what I see on the operation of vc4, it seems that it is just a pulg-and-play device; you just put in a battery, it detects and start charging. Is this charger capable of doing discharge and charging, just like Maha C9000? I am not sure if Lithium ion need to be refreshed, like Ni-mh battery.

I am asking this because I savaged 6 18650 batteries from my old laptop battery, and all of them seems working fine, working voltage (when connected to a load) is around 3.6x. I like to know if the capacity has dropped due to ages. From what I know, Ni-mh battery will drop over the times, especially if they have not been used for quite some time. Will this happen to Lithium Battery?

Some other questions:
1) I saw that the Vc4 can revive dead battery, like to know how good is the dead battery capacity? back to the rated capacity?
2) I read of conversion rate of power bank, at around 80%, is is conversion rate mainly dependent on battery alone, or the circuit also plays an important role?

Regards.

The VC4 only shows charged capacity and cannot do any discharging or analysis. To measure capacity of the batteries you have to discharge them with a flashlight or something (Be careful not to over discharge them).
LiIon batteries (Not lithium, they are primary batteries) looses capacity from the day they are manufactured, how fast depends on voltage, temperature and usage.

The dead batteries are batteries with tripped protection, not over discharge batteries: http://lygte-info.dk/info/BatteryLowVoltage UK.html

There are two conversion rated in a power bank, one from 3.7V battery voltage to 5 volt output voltage and one for looses in the converter.
The "Capacity" chapter has a table showing battery and output capacity, the 85% column is a good guess for most power banks: http://lygte-info.dk/info/usbPowerSupplyTestHow UK.html

Thanks for the pointer. I will need quite some time to digest the information.

ComputerTime said:

Thanks for the pointer. I will need quite some time to digest the information.

Click to expand...

I have a VC4, a VP2 and a bunch of other chargers. Pony up a bit more money for the Opus BT-3100/3400 charger and call it a day.

It's multi-chemistry like the VC4, but can charge up all li-ion cells with a simple hole drilled into the bottom of the case. It will do discharges, give rudimentary internal resistance tests, charge 2 li-ions up at 2A each and 4 at 1A and do 4.35v cells. It can charge down to 200mA, for the smaller li-ions, as well.

It's not a perfect charger, but it works well on both NiMH and lithium-ion chemistries.

It's 12vdc (8-16 actually,) so it can run off of a 12v solar charging system, or in the car.

Chris

Haven't tried the Liitokala Lii 500 on my Li ion cells.. But could be worth a try .. I have the opus BT 3100 v2.2 , bt100 , Liitokala Lii 500, Xtar VC2, VC2 Plus, VP2 and Nitecore D4

The ones with info like charged mah is the vc2, opus and,Liitokalas

ChrisGarrett said:

I have a VC4, a VP2 and a bunch of other chargers. Pony up a bit more money for the Opus BT-3100/3400 charger and call it a day.

Click to expand...

Same here; good advice. I keep buying other chargers looking for something smaller, simpler, but nothing beats the Opus. I think I'll just finally break down and buy a second one to keep in my car.

I do like the VC4, though.

I have more than one flashlight and more than one battery charger. What is as important as the charger you use is the understanding of the many dynamics involved in battery chemistry and charging.

It is much easier to review a charger than review the end person using the charger.