2 19VDC laptop chargers in series

[Kevin Sevcik]

Originally Posted by Ether

Chose either output wire (plus or minus) from Charger A, and chose either output wire (plus or minus) from Charger B. Then measure the voltage between the two chosen outputs. The voltage reading is zero regardless of choice.

Sounds like the outputs are floating/isolated relative to each other, so you should be fine connecting them in series to get your 38VDC that you're looking for.

For the record, I suspect two of your 3-prong output models might have been a problem, however.