Hello Philippe,
That is correct you should definitely not be soldering directly to the cells, you need to solder to the tabs. The developer kit cells on [link=http://www.a123racing.com]www.a123racing.com [/link] have one small tab on each end. These tabs make it very easy to solder the tabs in series or in parallel. There are instructions included when you purchase the cells telling you how they should be charged and how they can be wired up with our optional balance connectors so that your pack will work with our 15 minute Sonic Charge system.
Please let me know if you have any other questions.
Brian
[link=http://www.a123racing.com]
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