AC and Cruising RPM...2800 SCR - Maxum Boat Owners Club

Milt P. · 06-21-2010, 01:31 AM

Took my first cruise this weekend...about 50 miles round trip. Was great!

With the twin 4.3 I cruised at 3400 rpms at 26 mph. Is this typical for two people and a full tank of gas?

I also had my AC shut down and discovered the coil was iced over. Let it thaw and work fine. Is this a typical problem?

shrew · 07-02-2010, 04:19 PM

RPM's & MPH/KPH are going to vary slightly with trim, amount of tabs being used and sea conditions. I would say this sounds pretty good for overall cruise. I've never had my AC coils ice over that I'm aware of, but I don't use it that much or for long periods of time. I'm curious to hear other's thoughts on this, but I've always tried to run at around 75% or so of the Max. RPM when conditions warrent it. Often a bit higher.

seapuppy · 07-03-2010, 06:16 AM

I've ran my AC system for days on end....icing can mean a few things.....low coolant levels.....not enough air over the coils....too much humidity....etc....so...if it keeps icing up..I'd get a technician to check it out..

SP

Milt P. · 07-05-2010, 03:30 PM

No problems this weekend...ran the AC for three days with no ice buildup. I turned the thermostat off of max cool and I think the cycling helps. Purchased a Honda EU2000 and noticed the reverse polarity light flickers..Used my circuit test and it showed a problem but the owners manual says that the generator will not test the same as a house circuit. Has anyone else noted a polarity alert?

seapuppy · 07-05-2010, 04:13 PM

yeah..not a biggy since it's AC...alternating current....portable generators are notoriously dirty electrically......just keep an eye on it....

SP

Milt P. · 07-06-2010, 11:36 PM

Thanks...Not sure what to look out for but if everyone else is using this generator so can I.

Now regarding batteries - So my house batter worked great. It ran my refrigerator all night. turn on my GPS and got a weak battery message. I didn't want to run the generator all night and figured I could charge the house battery while underway. Am I correct to believe my alternator output will charge my house battery with my quest switch on both?

seapuppy · 07-07-2010, 12:31 AM

works the same as your car....it produces electricity to charge the batt. and power the systems on the car...the boat is designed to run on the house batt. when anchored for a few hrs but then if need be..switch to a start batt.....now if your batt. is weak or too small...then it's going to be depleated sooner.....then a larger batt. is required....some folks take out the group 24 batts on a 2800 scr and drop in a group 27 batt...much larger batt and will power your systems longer..however you may need to upgrade the alt. to a unit that puts out more for charging.......

SP

Milt P. · 07-09-2010, 01:21 AM

Does anyone know how many amps my 4.3L engine/alternator puts out?
Based on the many blogs concerning the eu2000 reversed polarity alert I will ignore like everyone else.

Debbie Bakalich · 07-25-2010, 01:20 PM

Milt/Seapuppy....I just purchased my first boat, a 2800 SCR. I have spent 2 nights on it and both times woke up with the A/C barely blowing air, and not cold air. I turn it off, wait a while, turn it back on and it gets cold again..but only for a short period of time. Also, it did not come with the owners manual and I can't seem to find a 2009 MAXUM 2800 SCR? Any help is appreciated!!

Milt P. · 07-26-2010, 12:28 AM

My 2800 is 1997...many changes since. I have no problem scanning and sending my manual but not sure it would be of use to you??? I stopped setting my AC to MAX and haven't had it ice up again (allowing the AC to shut off may be like a thaw cycle???)

shrew · 07-26-2010, 01:31 PM

Quote:

Originally Posted by Debbie Bakalich

Milt/Seapuppy....I just purchased my first boat, a 2800 SCR. I have spent 2 nights on it and both times woke up with the A/C barely blowing air, and not cold air. I turn it off, wait a while, turn it back on and it gets cold again..but only for a short period of time. Also, it did not come with the owners manual and I can't seem to find a 2009 MAXUM 2800 SCR? Any help is appreciated!!

The A/C and fan are tied together. You can have fan only, or you cna have A/C with fan. When the A/C reaches the temp. set on the thermostat, it shuts off, but the fan keeps running. What you describe sounds like you woke up while the A/C was cycled off and only the fan was blowing. By shutting it off, you simply allowed the cabin temp. to rise. then when you turned it back on the cabin temp. was above the thermostat temp. so the A/C turned on again. Had you taken no action at all it most likley would have turned on again anyway. This sounds like normal behavior.

I checked my A/C this weekend for ice on the coils. I was running the A/C a bit harder than normal and did have beads of frozen water on the coils. It seems that as moisture condenses on the outside of the coils it can freeze. I believe that turning the A/C down slightly allows the ice to melt during the poeriods it is cycled off. Not setting the A/C to max should resolve that issue as was described above. In Debbie Bakalich's case, had the A/C been turned to Max. it most likely would have remained running and kept the cabin cooler, but at the expense of icing over the coils.

Boats have absolutely no insulation. The A/C is going to drop the cabin temps, but the minute it cycles off it's going to get warm quickly. I notice the same thing. I wake up when the temps and humidity rise in teh cabin, then within a minute I hear the A/C cycle on again. I think all of this is somewhat expected.

Regarding the batteries (boy this thread seems to be a bit all over the place) I replaced the group 24's with group 31's. Make sure to remember to turn your fridge down to 3 when running on batt. Also remember that playing Cd's uses more battery than radio. Radio uses a goodly amount of battery as well.

My Honda generator only shows me a reverse polarity when I run the shore cord into a Y splitter. And then only when both shore circuits are turned on at the same time. If I run just the house circuit I have no issues. I don't run the A/C off of the generator, but have been curious to see if it would work.

tackleshep · 07-26-2010, 09:53 PM

Quote:

Originally Posted by Debbie Bakalich

Milt/Seapuppy....I just purchased my first boat, a 2800 SCR. I have spent 2 nights on it and both times woke up with the A/C barely blowing air, and not cold air. I turn it off, wait a while, turn it back on and it gets cold again..but only for a short period of time. Also, it did not come with the owners manual and I can't seem to find a 2009 MAXUM 2800 SCR? Any help is appreciated!!

Might be completely missing something here but on behalf of all of us who bought 10 year old boats or older.........if I had a 2009 and had ANY questions about ANYTHING I think I'd be calling the dealer. Had a new boat two times (smaller) and if I didn't like the way the blower sounded they heard about it.