Technoline BC 700 battery charger


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While I don't use too many battery powered gadgets, there are quite a few AA and AAA battery powered devices in the house. I only have a couple of mice and a veteran Yaesu VR 120 handheld scanner that has no other way to power it than with two AA batteries. And it eats them up like crazy. So I had no choice but to use rechargeable batteries.

The batteries I was using are old and on their last legs, so I had to renew them and I took the opportunity to buy this smart charger. Be warned that although it is very practical and versatile and has good reviews, it is not a fast charger.

These are the estimated charging times in its three modes, according to the manufacturer.

Size Capacity Charge (mA)Estimated charging time
AA2700 mAh700
~3 hrs 35 min
~5 hrs
~13 hrs
AAA1000 mAh700
~60 min
~84 min
~3 hr 30 min

I went for this one, although it was not the cheapest option, because it included 4 AA 2100 mAh batteries of a more or less well-known brand and for about 38 euros it seemed a good alternative to the chargers that do not offer any information about the state of the batteries.

This is what the box contains; the charger, the power supply, the four batteries and the manual in six languages.

The charger is entirely made of plastic, weighs just under 500 grams and is 75 x 37 x 129mm in size. Except for the three bottom buttons, which dance a little when you press any of them, it is well built.


This microprocessor-controlled charger charges NiCd and NiMH (AAA Micro and AA Mignon) batteries simultaneously and has three charging current ranges (200, 500 and 700 mA) that can be selected independently for each battery. Batteries up to a maximum of 3000 mAh can be charged.

When switched on, this is what appears ("null") on its display to indicate that no battery is inserted. Its display is not illuminated, so at some angles the values cannot be read.

Putting a battery in any of its slots will start charging. The best thing to do is to put one in slot 1 and select the charging current with the "current" key.

If you are not in a hurry, it is advisable to go for 200 mA to extend the life of the batteries. Once you have selected the charging current level, after 10 seconds flashing, the process will start and cannot be changed. To do this, you will have to remove the batteries, change the range and restart the charging process.

Charging function

The manufacturer points out that it may be necessary to charge and discharge new batteries several times at first before obtaining optimum charge capacity and recommends using the "Refresh" mode once on new rechargeable batteries to obtain optimum charge capacity.

During charging, the following battery information can be accessed by pressing the "Display" button:

  • Charge Current (in mA)
  • Timer (in hh:mm)
  • Terminal voltage (in V)
  • Accumulated capacities (in mAh or Ah)

Overheating protection

If the charger detects overheating of the battery (above 50°C), the charging process will stop automatically and the display will show the message "000 mA". The charging process will start again when the battery drops to a safe level. If the batteries still continue to overheat, all batteries should be removed from the charger, allowed to cool down and then charged at a lower current level.

In addition to charging, there are three other functions which can be accessed by pressing the "Mode" button.

Discharge function

As the name suggests, it will first discharge the battery and then recharge it. This is useful to avoid/remove something similar to what used to be known as the memory effect of rechargeable batteries.

It should be noted here that, although NiMH and NiCd batteries no longer have a "memory effect" as such, they can still suffer from voltage depletion, also known as voltage depression. Although this is a rather less degrading effect, manufacturers advise a more or less periodic full discharge of NiMH batteries and then a full recharge to eliminate the possibility of this voltage depletion effect.

Test function (capacity test)

The test function of the batteries follows three steps. First they are charged and then discharged to determine their capacity.

The current for discharging will be half of the current originally selected for charging the batteries

Finally, the batteries will be charged again. When the charging process is finished, their energy capacity will be displayed in units (mAh) of (Ah).

It is assumed that this test mode will also detect possible defects in the batteries, if any.

Refresh function ("Refresh") or battery maintenance programme

This function is interesting because it serves to"refresh" or reactivate the batteries. However, it is not a miracle worker. If the battery is dead, it won't bring it back to life, but if you had it lying around and it still has life left in it, it will revive and optimise it.

Old rechargeable batteries and those that have not been used for a long period of time need to be reactivated. This process is supposed to restore their optimal capacity.

The upgrade starts by discharging the batteries and then recharging them again. This cycle of discharging and charging will be repeated until the batteries reach their maximum capacity.

Trickle charge

When the battery is fully charged, the message "Full" will be displayed to alert you to remove the battery.

But if you forget to remove it or prefer to leave it in the charger, the trickle charge system will start automatically. This keeps the battery charging at a very low rate, at 5% of the selected charge current, thus keeping the battery at its maximum capacity.

Although not bad overall, one of the drawbacks I have found is that, if during the charging process you change the mode, it seems to interrupt and restart the process from the beginning (it doesn't seem to keep memory of what has already been charged or doesn't show it right away on the display).

I'm still not sure if this is the natural behaviour of the charger or just a defect of this unit, I'll try to check it.

A simple display of the battery charge percentage would not have been superfluous either.

At first, its use can be a bit confusing, but if you read the manual (which we never do) you will discover that everything is much simpler.

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