Oh yes... I forgot that thread. I wonder if it would be appropriate to merge the 3 threads...

I had a quick look for your D410 on google, but could not find the spec of the PSU. What does it say? In any case, its only a guide. Often the spec is a maximum which is above what the inflight power can give, but in practice the laptop draws nowhere near that.

One more thing I just realised. The flight deck can disable inflight power and I suppose they do this during take off and landing. During my last flight it didn't come on until a couple of minutes into cruising and meal service was starting. I wonder if they ever "forget" to turn it on at all.