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I have a question about batteries. Did you use a couple of 3-cell battery packs in series or a pair of 6-cell batteries in parallel? It is similar in the case of LiPo batteries, right? That is, two packs 1S in series or two packs 2S in parallel?
I ask because according to the specifications of the ESC that you recommended, it supports up to 9 cells in NiMh or 3S in LiPo. So I estimate that I can not use two 6-cell NiMh in series or two 2S LiPo in series.
Is that so?