43DC - 6kW Generator enough?

[sgharford]

I'm thinking of replacing my existing 7.5kw OhNo MDJE on my 1976 Hatteras 43 DC with a 6kW unit. I rarely use the generator as I have inverter, but when I do below is typically what is running. Does anyone run a 6 kW generator and get away with running similar load? I can get a really good deal on a Northern Lights 6kW right now, big jump/no bargain if I went up to their next size which is 9kW. Thinking I turn off water heater as precaution when cooking and should be OK.

16000 Btu Condensing Unit & Evap Fan	1400
Pump for AC	300
Water Heater	2000
Fridge	700
Stove (2 burners)	1700
Battery Charger	600
Total =	6700

[Boatsb]

If you only have one AC unit theres hope for the 6 KW.

I have a 7.5 and it supplies just a bit more than the shore power cords ( 3 x 30 amp) and Ihave a 16K and an 8K AC unit plus the rest give or take. ive never run low on power on the Genny but id rather not have an issue.

Look at sale issues if you have a small generator. If your not looking to sell for a long time it could work.

[Mike36c]

You can always shut down the water heater when cooking and don’t forget the microwave. I had the NL 9kw in my 36 and it was virtually impossible to max load. Running 16K and 9K btu A/c’s, ice machine, charger, fridge, freezer, water heater, micro, and two burner cooktop all at the same time with power to spare. The 9kw is also heavier and physically larger. Play around with the watt meters running things or better yet borrow a clamp on amp meter placed on the shore cord.

[Walter P]

I think the engineers at Hatteras were pretty good at calculating the size of the gen set for most of their
boats.....at least as they were equipped when they were built. I had 2 43 DC's and they both had 7.5KW
gen sets on them which handled most loads. If we had the oven and a burner on and the AC, hot water
heater etc, the generator seemed to handle the load better than the 30 Amp dock cord. Strangely after
many years I decided to replace the unit on my 1st 43 (had lots of hrs on it) rather than constantly having
it repaired, I had a new Onan 8 KW unit installed. Although it was a half a KW more powerful (supposedly)
it did not produce as much power for as long a period as the old 7.5. After running under heavy load it
had a tendency to overheat as well. Too large a generator is not a good thing either but I would not consider
a 6 KW for your boat, nor would I want go much more than 7.5KW.

Walt

[sgharford]

Thanks for response everyone. After sleeping on it I'm thinking the extra money spent now for 7.5 to 9kW worth it. Funny, I'm in printing business and when all things equal I have found weight to be a great factor comparing similar equipment by - more weight is better. I noticed the original MDJE is about 500 lbs while 6kW Northern lights 380 lbs while 9kW 540 lbs. The MDJE runs great (when running) with everything on - read somewhere on this forum that the MDJE 7.5kw has enough copper in it to be 10 kW unit, seems that way to me. I do have 2 x 16,000 BTU A/C's, it would be nice to run both without worrying about tripping a breaker. Was told Northern Lights running special this month on 6kW units for $9175 + $950 for sound shield and about another $1200 for removal and installation.

[Bernhard]

Good call on the larger gen set. My best advice is keep it dry. I just replaced the power end because it got wet and threw a bearing. Ugly sound when the rotor hits the stator.

[Freestyle]

The other thing you have to consider is the inverter load. On my 43 with a 7.5 kw when swtching from gen to inverter and back the inverter ate up all of the power until charged. I could always turn the charge feature of the inverter off but then would forget and be stuck with a adrained inverter and a hard working gnereator.

[Pascal]

Reserve power is always good. A 9kw running 5.5kw worth of load will run cooler too.

Most inverters pull quite a hit in charging mode as well, so with the 6kw you d always been playing with the breakers

[krush]

Soft starts on the A/C units and run a smaller genset. Inverter charge rate can be lowered for when power sharing is required.

[Pascal]

Yeah but if you lower the charge rate you spend a lot more time running the genny. Not worth it