2700 SE water heater and fridge draw - Maxum Boat Owners Club

Gleebitz · 04-08-2021, 01:31 PM

Does anyone know the power consumption of the fridge and the water heater?

I’m trying to figure out how much solar power I need for the fridge and what size generator I need for the water heater.

Thanks 😊

golfwins · 04-08-2021, 03:06 PM

I have a de0051 on my 2700 and found this on another forum for you.

"my boat is equipped with a Norcold DE0051 refrigerator, which draws approx 3 amps.
but because of the 12v rv refridgerators being able to kill a battery within a few hours, I have been leary about using the fridge on our boat, even though the de0051 uses a danfoss compresser, as opposed to the rv units using a 12v element....

so after purchasing and installing a cheap inductive amp draw meter, I find the fridge uses 1.3 amps when it runs, which is about 50% of the time after its initial cool down... so over a 24hr period, it pulls about 15 amps.
I have then installed a 200watt solar, which on the best day I have seen it delivering 5.8 amps while everything else (including the fridge) was shut off....

the amp meter shows both outgoing amps and incoming amps, so with the fridge running, I was still showing an input of 4+ amps... so i was surprised at how economical the norcold unit is. it has 5 coldness settings and we run it on 4, which cools the interior down to about 35-36 degrees... on 5 it will freeze everything in the fridge."

jparsons121 · 04-08-2021, 05:19 PM

Typical 6-gal water heater draws ~12.5 amps.
Converting to watts (@120v) is about 1500 watts.
So even a small Honda eu2000 Or equivalent will handle the load (that’s what I use)

Gleebitz · 04-08-2021, 06:50 PM

Thanks guys, really appreciate the advice. You’ve both answered my questions so happy to go with that. I reckon I’ll always be in a power deficit with the solar but I’ll only ever be away from shore for 24 hours at most. Engine will help keep it topped up too. 👍

jparsons121 · 04-08-2021, 07:50 PM

Quote:

Originally Posted by Gleebitz

Thanks guys, really appreciate the advice. You’ve both answered my questions so happy to go with that. I reckon I’ll always be in a power deficit with the solar but I’ll only ever be away from shore for 24 hours at most. Engine will help keep it topped up too. 👍

If 24hrs is your average, adding a larger battery bank might just be the trick. I don’t rely on solar, only the mains and the small generator, so having reserve capacity in the bank gives me 4-day weekends without much of a problem. I do need a day or so on shore power to bring them all the way back up, but I at least have the option to stay out longer.

With your solar, you can be trickling some power back into the bank, but not needing it to replenish it fully every day.

Gleebitz · 04-13-2021, 07:06 PM

Quote:

Originally Posted by jparsons121

Typical 6-gal water heater draws ~12.5 amps.
Converting to watts (@120v) is about 1500 watts.
So even a small Honda eu2000 Or equivalent will handle the load (that’s what I use)

I’m running on 240v electrics (British) so that would make it a 3000w draw from the water heater, using the same formula. That seems very high to me. Can that be right?

mmwjr · 04-13-2021, 08:27 PM

Quote:

Originally Posted by Gleebitz

I’m running on 240v electrics (British) so that would make it a 3000w draw from the water heater, using the same formula. That seems very high to me. Can that be right?

The power (Watts) should be the same, using a higher voltage requires less current.

Gleebitz · 04-13-2021, 09:16 PM

Quote:

Originally Posted by mmwjr

The power (Watts) should be the same, using a higher voltage requires less current.

Yeah it should be the same. Must be the formula idk. My generator runs 1800w continuously so should just about do it. Thanks 👍

mmwjr · 04-14-2021, 01:02 AM

Quote:

Originally Posted by Gleebitz

Yeah it should be the same. Must be the formula idk. My generator runs 1800w continuously so should just about do it. Thanks 👍

Since 240V is twice 120V then the current should be half or 6.25 amps.

jparsons121 · 04-14-2021, 12:20 PM

Quote:

Originally Posted by mmwjr

Since 240V is twice 120V then the current should be half or 6.25 amps.

Exactly..

mmwjr · 11-08-2021, 04:58 PM

Quote:

Originally Posted by RobertHan

With a marine water heater. You can let it run by AC power or marine engine heat. This equipment only needs minimal power as any excess can disrupt ignition.

Not sure how AC power can disrupt ignition which is DC power. Not all water heaters come plumbed into the engine cooling lines, mainly on smaller models such as my 2400 SCR.