Charger without Balancer

The batteries are fitted with 2 lithium-ion cells (2x 3.6V = 7.2V). Since Li-Ion cells are sensitive to overcharging, they should not just charge in series, but only on a charger with a so-called balancers (Just look for commands in Wikipedia). The original charger from Panasonic has a Balancer, recognizable by the 4 contacts to match the four contact surfaces of the battery. However, the charger included in this bundle only has 2 contacts and invites the two cells in series with easy to 8.4V. The expected longevity of the batteries, also the original, not meet. I was a little indignant at this audacity, and wanted to set before send them back. But the batteries are OK and - my God - 6 dues for the loader halt.
In case of emergency (in the car or when I have only 5V) can be determined a few charging operations the charger of this set perform without causing major damage to the batteries having to fear. But who wants a long time what his batteries should as much as possible using the Panasonic battery charger.