Very slow charge of a Li-Ion battery can be a problem?

[esm.]

Hi.

I have some PCBs that have a Lithium battery each, charged by a dedicated IC with a programmable current from 100 to 200mA, through a resistor RPROG.
The batteries are 3.7V of 3000 to 5000mAh. 4.2V floating voltage

Somebody know if is NOT recommended to make a very slow charge to these kind of batteries? Could that reduce their useful life-time?
The dedicated charger IC restarts the charge when the voltage of the Li-ion voltage goes 5% below the floating voltage (VFLOAT = 4,2V)

 

[Harald Kapp]

This arcticle http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries says nothing about charging with very low currents.
But: even with low currents overcharging can occur if the charge current is not turned off when the battery is fully charged. And with Li-ion batteries overcharging shortens the lifetime drastically and may even be dangerous. So I advise not to use a simple resistor but a dedicated charge circuit.

Harald

 

[GreenGiant]

I work with Lithium Ion Batteries, the slower the charge the better it is for the battery.

The reason that there are fast chargers for Lithium Ion Batteries is for convenience, they are built to be the least damaging balanced against the fastest charge possible.

using the smaller current will also ensure that the battery gets fully charged, as for the constant drain/charge cycle that's not really good for them, its better to charge fully, then use almost to completely drained and charge to full again