Amp Hour Load Calculator - Did I Miss Anything?

[jamielongmire]

Originally Posted by GeoPowers

Thanks for everyone’s input! I agree that 460 Ah per day is really high. I put the toggles in the spreadsheet to see what my consumption was during various scenarios. Here’s what I’m thinking I use-

During summer, at anchor only: 180-200 Ah
During summer, sailing and at anchor same day: 225 Ah
During winter, at anchor: 300-315 Ah
During winter, sailing and at anchor same day: 340-350 Ah

These #’s don’t take the radar or water-maker into account, as we don’t have them now. Realistically, we only have use for a radar for the next few years, as we will always be close to good shore water. Right now we coastal cruise. We also don’t have the solar or wind, so for now we are stuck recharging using the 80A alternator. I’m looking at both right now, but that’s another topic…


I revised my sheet so the heater and heater fans are in separate lines to account for the different run times and use of “free” heat when the engine was running. Still, that heater is an energy hog, especially when you consider it is a “diesel heater”! I’m just not sure I’m figuring this right. I still get a little over 100 Ah per day during the winter from it, based on 14hrs on the heater and 6hrs on the blowers. So really this means a 200 Ah increase in the size of my house bank? If so, we obviously need to move south for the winter!


Thanks for the input on the values, which was my main concern. To answer your specific questions:

hellosailor, it is a gas sensor and valve control, but you’re probably right on the rating being a little high. I got the number off of the manual, which I assume is its max consumption.

cdennyb, Nav instruments for me is my tridata and wind display. I got the values from the power consumption off the raymarine website, which are 45 and 65 mA. I thought this was low, too, is this an accurate way to est. the power usage? And of course you can use the sheet, glad you like it.

goboatingnow, I also got the power consumption for the chartplotter/GPS from the specs on the raymarine site. Does this work? The raymarine site shows 2.75-6 amps for the autopilot as you say, so I picked 5 amps. Am I missing any components here? I leave the chartplotter on at anchorage for the anchor alarm, unless it is a place I’m comfortable with. I fixed the TV hours, that helped!

The biggest danger I see in the sheet is verifying run times for the big draw things like the fridge and heater, and the amperage ratings for continuous use things.

Thanks again for your input- Frank

Thanks for the posting of this GeoPowers.
Noting that most of the replies on this were about the values you had entered, I am most interested in the formulas within the spreadsheet to make sure the calculations of the values are correct. To this end have you made any adjustments to the spreadsheet and if so, can you repost or send in a message to me.

Thankyou and well done on this - it will certainly make sizing an energy solution much, much easier.
regards,
Jamie