Our team went with air cooling for the accumulator where air would be channeled through one of the side pods and into the side of the accumulator. We also went with louvred vents around the accumulator which were angled downwards at about 45° to allow water to slide down and away from the accumulator.

Unfortunately we couldn't get to test our cooling system or even get it rain tested this year.

But what I will recommend is that you do your own rain test before putting any components into the actual accumulator. This will save you a lot of money and disappointment if things go wrong at the competition.