Energy consumption data

[Jim Walsh]

I've been anchored at Block Island in the Great Salt Pond for several days. Primarily I've been checking out all the cool boats, swimming, and reading "Nothing Like It In The World", the Stephen Ambrose book about the building of the first transcontinental railroad in the 1860's.
I've also finally taken the time to see what every electrical do-dad is consuming from my battery bank. Just in case anyone is curious all I have is two flooded batteries. A group 27 starting battery and a group 31 house battery. The starting battery is only used to start the engine and the house battery is used for all else. I do not have an electric windlass, nor do I have refridgeration.

I have a Victron BMV-702 battery monitor so I can tell precisely the current state of charge of either battery and the precise current which is being drawn.
I ended up with a list of 22 items and I wrote down the actual current being drawn by each.
I was surprised to find that my sump pump (7.4A) and my pressure water pump (6.35A) were my heavy hitters. Obviously when not in use they draw zero. My bilge pump (3.0A) showed me just how inefficient my sump pump is. Thankfully both are only in use for a few moments at a time. The same can be said for the water pressure pump.
My LED running lights are very efficient (0.26A) and my old incandescent steaming light (0.78A) uses the SAME amount of juice as my three LED running lights. That was an eye opener.
My VHF has a built in GPS/AIS display (0.62A) and that seems pretty economical as long as you don't actually transmit with the mic which results in a jump to 4.84A. That's another item which is seldom used so not a big energy consumer.
I had surmised that my chartplotter (2.16A) would be my largest energy consumer, especially when my radar is transmitting (1.74A), their combined use is 3.90A. I only have my chartplotter in constant use when day sailing and it is good to have a feeling for the power its consuming. When offshore I never leave it on. I just power it up as needed and shut it right down.
With my autopilot in use it draws 1.2A but that is only ever used under power so not really a concern of mine.
I changed my overhead cabin lights in the saloon, the galley, and the head to LED fixtures a few years ago. They are very efficient (0.31A). My remaining old berth and settee lights, I have six of those, are using from 0.93A to 1.73A. Guess what I'll be replacing this winter?
The old adage "turn it off if you aren't using it" is just as relevant now as when we were children, but it's helpful to know your precise energy consumption data if you wish to keep battery charging requirements to a minimum.

[Steve Laume]

You failed to include the micro wave, hair dryer, big screen TV and those underwater neon lights.

Glad you are enjoying Block Island before the Labor Day weekend show.

Watch out for those Great Whites, Steve.

[Steve Laume]

On a more serious note, have you determined how much energy it takes to charge your tablet?

I am considering the possibility of coming out of the stone age and having one on board. The laptop I have is old and I need to have it plugged in to actually use the thing. While I have been able to find wifi and an AC plug, it has been limiting in where I can use the thing. It seems like a tablet would be a far better choice.

I need to talk to you about tablets and software at some point, Steve.

[Jim Walsh]

You failed to include the micro wave, hair dryer, big screen TV and those underwater neon lights.

Glad you are enjoying Block Island before the Labor Day weekend show.

Watch out for those Great Whites, Steve.

Thanks for not mentioning my disco ball

[Jim Walsh]

On a more serious note, have you determined how much energy it takes to charge your tablet?

I am considering the possibility of coming out of the stone age and having one on board. The laptop I have is old and I need to have it plugged in to actually use the thing. While I have been able to find wifi and an AC plug, it has been limiting in where I can use the thing. It seems like a tablet would be a far better choice.

I need to talk to you about tablets and software at some point, Steve.

The tablet uses 0.4A when it first starts charging but it drops off pretty quickly to 0.2A till its done. I have a Lifeproof waterproof case for it when I'm offshore because it's one my backups should my chartplotter ever fail.

[BernieA]

We carry 2 tablets and 2cell phones. With all four charging consumption is 1.5 amps. I loaded OpenCPN on all of them as backups to our chart plotter. The heavy hitters on our boat are tri-color steaming and anchor lights, only because I haven't been up the mast to change them to LEDs. House batteries are two 6 vdc 235AH wet cells. In the Salish Sea with its often calm conditions, we rarely go a day without running the engine for at least an hour.

Bernie Armstrong
CD 28 Pinafore

[Paul D.]

If you like your remaining cabin light fixtures, SensiBulb LED cabin and berth replacement lights use only .1AH each and are as bright and warm in color as my old incandescent bulbs that burned 1.5Ah each. Replacing them is easy, but you do need to get the double bayonet to G4 adaptor:

https://www.sailorssolutions.com/?page= ... Item=SENBA

I got one or two every year till all were replaced. The newer ones have a the warmer color temperature of a soft white bulb. However, my original SensiBulb of about twelve years ago still works great, just a little bluer in color.

We use two Trojan T-105's, 225Ah, for the house bank. Big power users on Femme are the old Seafrost Fridge and the autopilot which uses the original Benmar Cetek drive motor. And yes, that device charging when you get a family aboard, does add up. The new Lewmar V2 windlass I just installed went up to a battery-chilling 69Ah, but that only runs when the motor is running and for short periods unless I sail off the anchor.

A battery monitor is a wonderful thing indeed. The Xantrex Link 10I installed fit right into where the old Cape Dory Battery voltage meters were on the panel and looks proper.

[fmueller]

Jim,

You have the shunt in series with just the house battery (I'm assuming) and therefore are just monitoring your group 31 ?

In a "1 or 2" or "1+2" setup like mine (2 group 27s and a Perko big red 3 position switch) you could just put the shunt in series with the battery switch positive and house/engine starter load - then be able to monitor either battery, or both, depending on switch position ... right? Can the shunt handle typical starter motor in-rush ?

Did you consider any of the other monitors - specifically the Xanterex Link Lite ??

thanks

Fred

[Frenchy]

Just for an added comment on battery monitors, I installed a Balmar SmartGauge and am very happy with it. Read about it
on MaineSail's website. It's very, very easy to install, no heavy wiring, accurate and reliable after three years. You
can't monitor actual usage like Jim can, but if you're only interested in state-of-charge it's great. - Jean

[Jim Walsh]

Jim,

You have the shunt in series with just the house battery (I'm assuming) and therefore are just monitoring your group 31 ?

In a "1 or 2" or "1+2" setup like mine (2 group 27s and a Perko big red 3 position switch) you could just put the shunt in series with the battery switch positive and house/engine starter load - then be able to monitor either battery, or both, depending on switch position ... right? Can the shunt handle typical starter motor in-rush ?

Did you consider any of the other monitors - specifically the Xanterex Link Lite ??

thanks

Fred

It monitors both my house and starter batteries. Yes, the shunt can handle starter battery loads. A friend installed the shunt for me since I am a danger to myself and all around me if I fool with electricity. The last time I tried to wire something I was in a forest in Tunguska, Russia. I learned my lesson.
I did not consider any other makes since I don't possess the knowledge to make an informed decision. John Ring and Steve Laume convinced me that I was living in the Stone Age by relying on the original equipment battery monitor which Cape Dory had installed in 1984. This unit fit the hole in my electrical panel previously occupied by the original unit.

[Maine Sail]

On a more serious note, have you determined how much energy it takes to charge your tablet?

I am considering the possibility of coming out of the stone age and having one on board. The laptop I have is old and I need to have it plugged in to actually use the thing. While I have been able to find wifi and an AC plug, it has been limiting in where I can use the thing. It seems like a tablet would be a far better choice.

I need to talk to you about tablets and software at some point, Steve.

This will depend a lot on the tablet or computer and the USB charging port or 120V wall wart you are using. iPads and tablets can really add up to more than most folks assume. We have multiple boat owners who now consume more energy each day in charging iToys & computers than they do for 12V refrigeration.

iPad Charging How Much Energy
https://marinehowto.com/ipad-charging-how-much-energy/