How many Amps Hours do you use a day?

[LoudMusic]

Originally Posted by OceanSeaSpray

I have had a far bit to do with helping out people building lithium battery banks and the question of their daily consumption always comes at the forefront when deciding how much capacity is needed.

What matters is the overnight drain, because in daytime the power comes from solar and there is (normally) enough to run the boat and recharge in the same time. The most common situation seems to be 40-60Ah use overnight when running a modest fridge, small freezer and using power normally in the evening for a couple. The daily energy use would therefore be about twice that much.
Those who can stand wind generators can get some energy at night, but it is not consistent, so we don't count on it.

I don't refrigerate, so I use a lot less and almost all my power goes into the laptop. I might get to 40Ah/day total energy consumed (not battery discharged) on a long day with the design office really busy...

Assuming someone is already living on a boat with an electrical system that they want to replace/upgrade, in your opinion what is the best way to gather usage information long term?

[john61ct]

Start with Victron BMV (if not using Multi or Quattro)*and a CCGX, Color Control GX

[Erik de Jong]

The "mastervolt" equivalent is very good as well

[sailinglegend]

Originally Posted by john61ct

Obviously a nice $200 BM is great if you want the full picture. Whenever I recommend those I get a chorus of "unnecessary, overkill, KISS" replies, even when SoC is the thread topic, which is not the case here. Can't win! 8-).....

My point was a very cheap digital ammeter may only measures discharge - read the specs carefully. A not so cheap one - maybe $30 - will read charging amps too.

Yes you don't need a $200 BM.

[Catapault]

Originally Posted by Mr B

I was on a swing mooring in a bay surrounded by other yachts on swing moorings and motor boats scorching past at all hours,
I kept my lights on, I want to be seen,

You are also breaking the COLREGS for navigation lights, and potentially putting yourself in danger.

In Event of an accident, you risk being placed more at fault.

NAV lights OFF at anchor...


COLREGS exist for a reason, recklessly ignoring them dosn't make you safer...


Mark.

[Erik de Jong]

Who says he left his NAV lights on?
I always have a wholearray of lights on when at anchor in a busy area, including deck lights, cabin lights and cockpit lights. This in addition to a normal anchor light of course.

[Kelkara]

Originally Posted by Erik de Jong

Who says he left his NAV lights on?
I always have a wholearray of lights on when at anchor in a busy area, including deck lights, cabin lights and cockpit lights. This in addition to a normal anchor light of course.

As is encouraged by the COLREGS:

Rule 30(c) A vessel at anchor may, and a vessel of 100 metres and more in length shall, also use the available working or equivalent lights to illuminate her decks.

[jlcnuke]

Originally Posted by Erik de Jong

Who says he left his NAV lights on?
I always have a wholearray of lights on when at anchor in a busy area, including deck lights, cabin lights and cockpit lights. This in addition to a normal anchor light of course.

He said he left his nav lights on...

Originally Posted by Mr B

I have no idea, I would like to know that too,
Daytime, Laptop only, VHF,

At anchor, at night,
I have Nav lights on, Tricolour, front and rear Nav lights,
VHF, Salon and cockpit lights,

At sea at night, Nav Lights all round, VHF, Cockpit and Salon lights, Laptop, Self steering,
Depth sounder, Speed and wind gauges, GPS, Water pressure pump,
110 volt hot Water heater, Its always on,

Why would different parts of the world matter, Unless your running AC and or a Heater,

[OceanSeaSpray]

Originally Posted by LoudMusic

Assuming someone is already living on a boat with an electrical system that they want to replace/upgrade, in your opinion what is the best way to gather usage information long term?

It depends what you call "best". A data logger writing to a SD card or something like that could collect what you want for a very long time.

Note that unless you have TWO shunts and you separate loads from charging sources, you are not measuring everything (which was my question to Erik earlier). All power does not go through the battery, a standard battery monitor doesn't see everything.

[OceanSeaSpray]

Originally Posted by ColdEh Marine

Actually , this is during the hottest summer months up here. I don’t see nearly that high of a usage during the cooler months .

We typically see 9 to 12 amp hrs in the fridge and 17 to 20 amp hrs in the deep freeze at 12v

Yes our refrigeration systems are that efficient, and we use all led lighting .
Regards John

With refrigeration, getting rid of the heat from the radiator is almost everything when it comes to efficiency. I have seen many systems that were energy black holes and still performed poorly just for this reason.

[Ip485]

Note that unless you have TWO shunts and you separate loads from charging sources, you are not measuring everything (which was my question to Erik earlier). All power does not go through the battery, a standard battery monitor doesn't see everything. Today 18:33

I dont entirely follow.

I am currently doing a full audit of my system, and in reasonable detail, but it is based on the information provided by the BMV.

So far I have logged the batteries through a full cycle from fully charged to 50% discharged and back. I have kept a record every 30 minutes or so of the volts, Amps in and out (with the batteries off charge as run down, and on charge, but while still under load), AH remaining and AH used.

I am also going to run through all the equipment I have and record the AH used with each of the main items on and off, without the batteries being under charge.

To what extent are you suggesting these readings will be inaccurate?

My aim is to arrive at a pretty good theoretical idea of the AH used with different sets of equipment running - for example on night passage with nav lights, plotters, AIS (radar) and a few cabin lights etc and also on the hook with typical equipment running. I am interested to have a reasonabe profile of our power requirements.

I am also very interested to see just how quickly it is possible to recharge the batteries and how much charge they are capable of absorbing.
I have a Genset and solar, but I am damned if I want to run the Genset any more than absolutely necessary (for a variety of reasons). However I reckon at the moment on average my solar panels will return between 120 and 150AH per panel in a full day (theoretically), so may be capable of returning around 240 to 300AH, or equivalent to using around an average of 10AH day and night. With general losses in the theoretical calculations it seems to me that is going to fall short.

There have been quite a few threads talking about using two chargers at the same time. Usually most people seem to hold the view that with intelligent chargers this does not work. Well I can now say (at least with mine) it works very well. My chargers are both intelligent and from different manufacturers and with different outputs. They work together very well, and I can initially put around 60Amps into the bank with both running whilst under a 25AH load. It reduces down reasonably quickly and settles at around 40AH (and pretty much regardless of whether the batteries are under load or not). Theoretically the two chargers are cable of 110Amps, but in reality it would seem at 70% charge the AGMs arent capable of absorbing more than these loads. I have yet to try it at low charge levels, that will come next. However it seems to me it will be possible to establish a point at which there is nothing to gain by running both chargers and also a reasonable profile of how long it will take to bring the bank back up to a full charge.

It is all in preparation for some long term cruising, and thinking about increasing the solar power (I have 660W of solar, but 990W with one more panel may be nice).

Thank you everyone for your comments so far which I think are really interesting and the way in which for the majority the AH per day are not that dissimiliar.

I am especially interested in how much people's power use on fridges and freezers changes with the climate. I have keel coolers, and a reasonably large chest fridge and freezer (with lifting tops) and I reckon they are very well insulated. However with the sea water currently at about 5 degees C I reckon the compressors are hardly doing anything. With sea temperatures in the high 20s I imagine the AH used will rise dramatically.

(For ref. my system is 660AH Lifeline AGM brand new, 50 and 60 Amp chargers, Outback MPT with 660W solar on aft arch with some shading from the Sat dome, 8KWH Genset and Balmar HC alternator, the usual lights, but all LEDs including nav., chest fridge, freezer and bottle cooler, twin plotters with AIS and radar, power winches off house batteries, but Windlass and Bow Thruster off dedicated batteries, the usual TVs and computer, but some use of sat phone, SSB, and sat TV).

[Ip485]

BTW I wonder if anyone knows of a data logger that would record to a card and capable of being uploaded to a PC battery data?

[leftbrainstuff]

Originally Posted by Mr B

I have no idea, I would like to know that too,
Daytime, Laptop only, VHF,

At anchor, at night,
I have Nav lights on, Tricolour, front and rear Nav lights,
VHF, Salon and cockpit lights,

At sea at night, Nav Lights all round, VHF, Cockpit and Salon lights, Laptop, Self steering,
Depth sounder, Speed and wind gauges, GPS, Water pressure pump,
110 volt hot Water heater, Its always on,

Why would different parts of the world matter, Unless your running AC and or a Heater,

Insolation (solar energy) and heating or AC usage for comfort varies by latitude and location.

[leftbrainstuff]

Originally Posted by Jim Cate

Oh, I see... COLREGS are for other people...

Jim

And the ultimate aim of the colregs is to avoid collision.

A single white mast head light is often indistinguishable from background light, stars or light piollution.

We obey colregs and have a range of additional 'idiots stay away' lighting for those morons who cant, wont or havent read the colregs.

Blindless adherence to regulations is no guarantee of survival.

[Jim Cate]

We obey colregs and have a range of additional 'idiots stay away' lighting for those morons who cant, wont or havent read the colregs.

Blindless adherence to regulations is no guarantee of survival.

Yeah, but do your "idiot stay away" lights include your two sets of nav lights as Mr B was doing?

We chose to use both an all around LED lamp at the masthead and an all around LED lamp above the boom when at anchor (plus, of course, a black ball in the foretriangle). In really scary situations the foredeck light and the BBQ area deck lights can be added (all LED).

Blindless (sic) disregard for regulations isn't so good for survival either.

Jim

Jim