Snokelling and batteries NOT charging

[pythos]

Operation Monsun 4.0, patch 1.

making way out of Bay of Biscay, toggle snorkel depth with ctrl D, raise snorkel with "T", and engines start running, but the battery charge indicator remains dark.

I know of the CO2 problem, and accept that, from what I have heard concerning snorkel use, the boat did not get refreshing breezes, and the air inside went pretty awful. However, not being able to charge the batteries while snorkelling makes the device nigh on useless.

Any ideas what is happening here?

Boat in question, Type VIIC. July 1943.

[pythos]

So just after I made the previous post, I decide to actually LOOK to see if the batteries were charging, even though the battery charging icon was unlit.

Guess what?

They were! (fanfare).

So no need to answer my silly inquiry.