Crown is major power hog
It draws a whopping 36a/flush (maybe even 50a if it's the old "deep draft" version), which can drain a battery in hurry. Combine that with the 50a draw from the L/S, and it's no wonder you're having problems...the Crown is a VERY bad choice of toilet for a sailboat! It's a dinosaur that was designed in 60s for use on houseboats and big powerboats. I think you need to spend a little more time with the manual for the L/S...'cuz it doesn't have any pumps in it...incoming waste from the toilet just pushes treated waste out. The motors only power the electrode pack, mixer and macerator--which isn't a pump, but just a "blender" blade. (What people commonly call a "macerator" is actually a pump that has a macerator blade in it.) So the answer to your question is no...unless there's a clog in it, there's nothing else in it that would prevent it from discharging, only from macerating and treating. It would just discharge untreated waste. So if it only happens when you've been using both the toilet and other devices that use 12v power and haven't run your engines enough to fully recharge the battery, the problem has to be low voltage to the toilet, especially if the toilet flushes ok for the first few flushes, then starts backing up or nothing going down. And if the toilet isn't getting enough power, neither is the L/S...and that's causing damage to the motors in it and the electrode pack. So the solution to your problem is either a LOT more 12v battery resource or a new toilet that uses a fraction of the power...or both. A Raritan SeaEra, which draws only 16a, is almost a drop-in replacement. Boatfix.com http://www.boatfix.com/elec/rartoi.asphas the best price--under $400...and if you sell the Crown on eBay, you can prob'ly get most of that back. And it's a problem you have to solve ASAP unless you want to spend about $250 to replace the electrode pack in the L/S...and maybe at least one of the motors too.Meanwhile, if you have to pee in the middle of the night, use the lee rail or don't flush every time.