Penlight batteries: recovery capacity NiMH batteries (part 2)

In the first part of the article service NiMH AA-batteries, we are staying on the comparative characteristics of intelligent charger (analyzer) TechnoLine BC-700, which left far behind its competitors out of the first two types of chargers, leaving them even the slightest chance.

Finger batteries

Today we will continue to address issues associated with the charger-analyzer, an example of which I will talk about how to restore the lost capacity old NiMH(nickel metal hydride) batteries, or batteries such that lost most work capacity due to long storage charges.

But before we begin to consider issues related to the restoration of battery capacity, suggest starting a conversation with another moment - testing NiMH batteries.

Testing NiMH batteries - TechnoLine BC-700, the regime «TEST»

To find out the real capacity NiMH battery pencil, that is, in what condition it is in now, we will use the mode «TEST» charger TechnoLine BC-700, pictured below.

The principle of operation mode «TEST»:
The first stage of «CHARGE» - the batteries (up to 1,49V - 1,57V);
The second stage of «DISCHARGE» - low battery (up to 0,9V) for capacitance;
The third stage «CHARGE» - charge the batteries.

Thus, after the completion of the second stage - «DISCHARGE», we can determine the true capacity of a battery.

mode «TEST»

Why test NiMH rechargeable batteries? This is necessary in order to remove the battery from the kit "weak link", which is suffering due to not only the entire set of batteries, but also the equipment in which it is installed this set of batteries. If in a set of four batteries, one battery is defective, do not expect this set of stable operation.
For example, if you insert a freshly charged set of batteries in the flash with a microcomputer (Nikon Speedlight SB-900), of which one is defective battery - do not wait for the full operation of your flash. Moreover, unbalanced rechargeable NiMH batteriescan be a cause of failure of the flash of the class. To avoid this, you should screen out of the battery pack "dead" batteries.

In the photo above, charger TechnoLine BC-700works in a mode «TEST».
On the LCD-screen displays information of current processes, which shows what is happening at the moment with a particular battery.

And what happens in a mode «TEST» following:
- Battery charging current of 200mA (pictured above, left);
- Discharge current 110mA (pictured above, right);
- The time spent on the charge (h);
- The current stress on the bank (V);
- Battery capacity after the stage «DISCHARGE» (mAh/Ah)

Toggle the display of the information for each battery by pressing button «DISPLAY» after selecting the desired section by clicking on one of the buttons (1,2,3,4). If you press the «DISPLAY» without first selecting the section - you will see one of the mode parameters «TEST» for all sections. Thus, with the help of LCD-display, we can monitor the processes, which is very convenient and useful. After completion of the testing process, LCD-display will alternately display the inscription «FULL» and the battery capacityin (mAh) or (Ah).

If the result of testing you a bit confused - it turned out that a set of NiMH batteries "zatersya Cossack," that is found low capacitance one or more batteries. In this case, we can try to recover lost battery capacity. And help us in this case is not easy mode «REFRESH», which is provided in the charger TechnoLine BC-700.

Recovery battery capacity - TechnoLine BC-700, the regime «REFRESH»

Sooner or later, capacity NiMH rechargeable batteriesbegins to fall. The reasons for loss of capacity have already been discussed in the article NiMH NiMH Battery Storage, so I will not repeat. Recovery battery capacityis a series of charge-discharge cycles, the so-called "training".
The principle is simple: - to discharge the battery 0,9V, then, is charged up to 1,49V - 1,57V; then again charge-discharge... This will continue for as long as the capacity of the battery will cease to grow. The recovery process may take a week or more... Therefore, since I have decided to resurrect their dead NiMH batteries, so have patience.

In order not to spoil the recovery batteries sudden jump of the AC line voltage, which can damage the favorite charger, or banal the sudden disappearance of the mains voltage, I advise to connect the charger to an uninterruptible power supply (UPS).

In the photo below, captured mode memory TechnoLine BC-700- «REFRESH» (recovery).
In the left part of the picture all 4 batteries are in a mode «REFRESH»; battery is discharged in the first section - «DISCHARGE», and the other three are charged - «CHARGE». This is normal, because we all know that there is absolutely identical NiMH batteries, and even more so if they are pretty little old. Note the charge current3rd and 4th section. Charging current is set is different, especially in order to demonstrate the capabilities of the memory device.

Restore battery capacity

So, the battery in the third sector is charging current 198mA, and the battery in the fourth sector is charging current 503mA. Independent sector chargergives us the ability to set charge/discharge current for each battery individually. This can come in handy in the event that both charge batteries of different capacities, for example, 1800mAh and 3000mAh.
That is, 1800mAh battery, we can set the charge current 200mA, and the battery capacity of 3000mAh can set the charging current of 500mA or any other charging currentis enabled on this charger (200mA, 500mA, 700mA).

The charging current can be set by pressing the «CURRENT». To activate the current selection after installing batteries and memory mode selection, hold down the «CURRENT» 1 second down, then, pressing select the charge current.

In the right part of the picture demonstrated the operation of the memory TechnoLine BC-700, which can operate simultaneously in two different modes. In this case, there are two modes: for sectors 1,2,3 - Mode «REFRESH» (recovery) with the charge current 500mA, and the 4-th sector is in «CHARGE» with the charge current 200mA. This can be useful when you want to just charge one or more batteries without interrupting the recovery process capacity other batteries.

Please note. While charging the NiMH battery in a mode «CHARGE», will be some excess capacity battery compared to the rating. For example, a battery capacity of 1800mAh will continue to charge to capacity 2520mAh (for LCD-display - 2.52Ah).
This is normal, do not worry, because NiMH batteries, and is required to charge 40% more of their nameplate capacity. But if battery capacity when charging more than 40% of the allowed rate, for example - is 100% (3.60Ah), in such case, this battery is in a deep coma and died just because of what she refuses to accept a charge.

A dead battery also can be identified on the basis of excessive heat, during the charging process, murdered NiMH battery basking in the order is stronger than all the rest. This is due to the chemical destruction of the battery is too high and internal resistance. The battery is better to throw it away, do not waste time on her recovery.

Heat the NiMH battery (in charge/discharge) facilitates irreversible degradation processes of chemical elements electrolyte, which leads to destruction of the structure, with the result that the internal resistance is increased, and a significant drop in battery capacity. When charging/discharging, avoid excessive heating of the battery may keep the temperature range: - touching a finger to the battery, it should be warm but not hot. If the battery temperature is too high, you should provide them with forced cooling.
You also can not charge the battery at a low/negative air temperature and/or high humidity (75-80%). Optimal conditions for service NiMH batteries - dry heated living space, the air temperature 15-25°C.

Restoring the higher capacity battery (2700mAh - 3000mAh), should be set charge current 500mA, respectively - the discharge current of 250mA, pictured above, see right hand side - Sector 2 and 3.
This is the optimal current for these batteries. If you set the battery charging current of 200mA, the charger may refuse to service your battery in such a shock, and after the first cycle of charge-discharge, simply complete the repair process; on the LCD-display will see the message - «FULL» see photo above - sector 1.

You can not change the mode of operation or the first sector of the charging current without removing all of the battery charger. If in the first sector is set charge current 200mA, then in other sectors, mode change is allowed to charge higher charge currents (500mA, 700mA). If in the first sector set the maximum charge current (700mA), - in the other sections to change the charge current to 200mA or 500mA impossible.
If, during any mode of operation, for example, the regime «REFRESH», with the button «MODE» to change to a different mode battery charger for some sectors, for example - on the mode «TEST», the selected mode is activated for all sectors.

The completion of the restoration NiMH batterieswill occur for each battery at different times, no matter what set of batteries we restore - the old batteryor only just bought at the store. Variation in time of completion of the recovery of each battery can be substantial: - from several seconds to several days. Yes, they all start at the same time, but come to the finish line at different times.
It is normal practice, do not worry, because All batteries are individuals, each with their own special "character". No matter who comes with NiMH batteries finished first, the main thing - what is the result (capacity) are returned to us.
It is important that finger NiMH rechargeable batteriesone set were identical or at least about the same capacity as their cohesion balance depends on many things.
At this until we put a point in the topic of service NiMH AA-battery. Your questions and comments waiting in the guest book. Thank you for your attention.

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