Does running the generator while boating (AC use) show GPH?

[serpa4]

If you run the generator while boating to power the AC, will that fuel for the generator be reflected in your GPH meter for running the engine?
I.e. if the boat is consuming 15 GPH at 15kts and you turn on the AC, will the gauge show an increase in GPH? I.e. 15GPH now becomes 16GPH at 15kts?
Or it just magically disappears from your tank and only reflected in your fuel gauge?
I'd check, but don't own a Ranger or Cutwater...yet.

 

[BB marine]

You must estimate the generators fuel use. Most generator manufactures rate the GPH use of each size generator. You must calculate based on hours used.

 

[serpa4]

Bummer, thanks.
Would be nice if the fuel flow sensor feeding the engine was before the generator so it would account for the extra fuel flow.

 

[Chimo]

Same thing if you have a boat with a Webasto heater using from the diesel tank.

 

[Wee Venture]

Same thing if you have a boat with a Webasto heater using from the diesel tank.

We use our webasto heater quite a bit and I have wondered about some way of measuring fuel usage in order to have a more accurate read of remaining fuel onboard. I have searched fuel flow sensors but those I have found so far are either not sensitive enough to track such a low volume or they are a highly specialized industrial unit. It also occurred to me that some sort of pulse counter on the pump could translate into an accurate measure of fuel used. Has anyone found a good way of keeping track of this?

John

 

[CAPTCRUNCH]

Maybe an hour meter in the pump electrical circuit and some math?

 

[ixlr8]

Maybe an hour meter in the pump electrical circuit and some math?

This is basically what Andrew at the factory told me to do.

 

[Wee Venture]

Just listened to the fuel pump for our Webasto. I had assumed it was a pulse diaphragm pump but it sounds like a rotary. Variable speed though, depending on demand I guess. So measuring total “on” time wouldn’t catch the changes in flow rate but maybe it all averages out.

If anyone has added this mod I would be interested in your experience. Is it reasonably consistent/accurate? Did you just connect a standard engine hour meter to the pump leads? And what multiplier do you use to convert from hours to gallons (or liters for those of you north of the border)? Thanks.

John

 

[ixlr8]

From what Andrew told me, the Webasto output is a constant, it doesn't vary, it is either on or off. When on, it flows a constant amount of fuel. So using run time and fuel flow, one will get an accurate amount of fuel use. The fuel flow amount should be in the manual.

 

[Automaticman865]

When I fill my fuel tank I usually subtract 3 gallons and set my total fuel to 97 down from the 100 as full. Then every time I fill up I find that my generator use (3 gal) + fill amount is usally within the 3 gallon margin over time due to my use.
Stuart

 

[FlyMeAway]

Wait, does this conversation mean that these boats don't have a fuel tank / fuel level indicator?

 

[Wee Venture]

Wait, does this conversation mean that these boats don't have a fuel tank / fuel level indicator?

We have two methods of determining “fuel remaining.” One is to read the traditional fuel gauge in the tank, which I don’t trust except for a very general indication. (I admit I haven’t yet gone through the calibration procedure that I have seen referenced here in Tugnuts, but a lot of previous experience suggests to me that rheostat type gauges are notoriously unreliable and get worse as they age. Correct me if your experience differs.) The other way is to depend on the Garmin/engine electronics to calculate fuel used, subtract it from previously set “fuel on board” and give a reading on fuel remaining. I have found this second method to be very reliable. The only problem is that it doesn’t keep track of fuel drawn from the main tank by some other means than the engine.

John