Bavaria 2003 44 Mod - Battery AC

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Jun 19, 2010
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2003 Bavaria 44 Chesapeake Bay
Been a Bavaria owner dying for this type of forum for support from other owners, which is so much better than support from mfgs and other local repair folks. Now that I have found it, I want to encourage traffic as much as possible. To that end I am going to share some of my mods that others might find useful.

On the chesapeake cruising can be greatly hampered by Temperature (hot and very muggy) and Marinas (expensive, crowded, etc.). Further our Bavaria's ports were made by Rutger...., which was dropped by Bavaria because they dont make BUG SCREENS. So i set about finding a way to have AC on the boat without a generator running while sleeping (due to concerns about CO - despite alarms that are not perfect by any means).

So we have AC set up on our 44 to run on batteries. Here is how we have it set up:

First - we installed a Bamar high output alternator that pumps up to 120 or so amps. This, of course created instant problems with our Volvo Alarm panel which alarms if it does not get 13 volts from the alternator withing 20 seconds from startup. Our somewhat reliable local volvo dealer told me only Volvo HOAs (at 80 AMPS) work with that alarm (I am not a big fan of volvo products). Luckily I got local mechanic (i highly recommend annapolis Harbour Boat Yard in Eastport for locals - typical level of timeliness for this industry BUT there work has been first rate and by my measure well priced - I GO NOWHERE ELSE) to rewire the panel to fix this annoying issue.

Second - I jacked the battery bank - currently have about 800 AH in the form of these strange AGM batteries sold by some brit i saw at a boat show (next time at boat i will figure out the name an post it). I cannot remember the name of them but they have odd shapes allowing you to boost bank size in cramped spaces. they are mixed with two regular 8ds that we had with the boat. When this whole group fails, i think i can use the same batteries to get 1200 AH in same space (under couches in salon).

Third - I already had a prosine inverter installed.

Fourth - two 7k btu high energy units installed..one forward under birth (next to 15k btu uunit installed by previous owner) and one under after port birth in front of water tank - this was a real shoe-horn self install - can send pics to anyone who wants to see it. Each draws about 40 AMPS at 12 volts through inverter.

Fifth - Generator - I originally used the Honda 2000 gas generator. Replaced this season with a 5 kw diesel in starboard lazarette.

Sixth - Engine room fan - Heat from engine when cruising NEEDS to be dissipated for the benefit of aft cabins INstalled an exhaust fan to pull hot air out of engine room under stairs.

Procedure:

Sail to anchorage. Engine charges up batteries a bit as you anchor with HOA. Then pull out Honda and use it to cool cabin from 90s to 72 or so. Turn it off around 8pm keep forward and after doors closed and switch over to battery AC to "Maintain" temperature overnight. The result is that the units cycle about 20 % of the time to maintain temp and batteries run down to about 12.3/12/4 volts from 12.9 or so by morning.

Theoretically then you charge via honda and then engine when underway (chesapeake "cruising" involves a lot of iron sailing).

Issues:

Refrigeration - Boat was originally wired for Europe (24 volt). prior owner re-wired for US but used some of the original wiring which was much lower guage. Consequently refer voltage drop was almost a full volt. Our refer system therefore basicly stopped working during the night. We fixed this by re-wiring with appropriate guage.

Honda Generator/Engine could not fully re-charge batteries. Honda was just not powerful enough to charge the batts after a full night without constantly running. This system worked ok for a night or two but you effectively "got behind" for anything longer. Therefore we installed a 5kw diesel generator this year. This thing can poor 100 AMPS into the batteries, while running both AC units at same time.

My next project is to figure out how to operate a Rollgen type system on the boat. will advise once i work that one out. Has anyone used a rollgen on a bavaria in the 40+ range? I figure an assym that we can actually operate will allow us to sail much more in the 5-10 kt winds we see here regularly
 
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