Question about Fridge unit current drain.

[ICENI]

On my last boat which was based in the Mediterranean I had four solar panels to assist with the current drain from the refrigerator which was usually running 24/7

My present boat (just purchased) is a 2002 Bavaria 32.   She has been standing unused, shored up in a boatyard since 2016 so the service batteries are now useless as they were dry when I first visited the boat prior to purchase!

I have been running the fridge (Standard compressor type) from a battery charger connected to the service batteries whilst living on board working on the boat.

With useless service batteries, I have no knowledge of the demands and performance of the two 140AH batteries if in new condition..

Can anyone give me any information regarding fridge performance please with service batteries of similar capacity?

My Bavaria is in the UK so that the demands will not be so great as on my previous boat but I really would like to know if going down the solar route is necessary.   I have spent and am continuing to spend lots of cash as the boat is fairly basic and if I can avoid the expense of a stainless steel gantry, the panels and a controller it would be good.

[Symphony]

2*140AH batteries is more than enough to cope with typical weekend use of the fridge in the UK. Obviously consumption depends on how much you use it, but typically the big consumption is getting it cold when you first arrive on the boat. So bringing really cold food/drink such as a frozen bottle of water, chilled Sauvignon Blanc, cold beers, frozen food helps reduce compressor time substantially from startup. You may well find the water will stay near frozen fo a couple of days (you will drink the wine and beer!) and the fridge will barely run.

Like you my experience was of fridges in the Med, but when I moved back to the UK it took a while to recognise how different it is, particularly if you follow the suggestions above.

Worth fitting a battery monitor so you can check consumption, but my experience with the 3*95AH bank in my 33, I never worry about battery capacity.

[Boatname]

Lots of variables ... how full is the fridge, what are the actual contents (cold cans once cooled are a lot better than lettuce  , what is the ambient temperature, what side of the boat is the sun, how often do you open the lid?

However, as a rule of thumb 1x140ah battery lasts 48 hours including water pump, some instrument usage and occasional lights.

This is from a mega-marina top up with the batteries holding 12.8 volts for quite some time, dropping 0.3 volts when the fridge kicks in.

I switch the battery at a resting voltage of 12.3 which shows 12.0, sometimes 11.9 volts with the fridge running. The battery doesn’t seem to mind 11.9 which surprises me but they are 5 years old now and the pattern repeats with no issue.

Given the variables I mentioned I am happy when the fridge is on for 10 minutes and off for 20.

p.s.

I thought that I had made a note somewhere regarding a previous boat and have just found this. It probably makes no sense but there may be some bones that you can pick out of it 

I have a feeling that the the 4 amps relates to when the fridge is running but someone will be along to tell me that there is no such thing as amps or amp hours or ah.

Don’t care 

My fridge runs for approx 48 hours 

“Converting Watts to Amps

The conversion of Watts to Amps at fixed voltage is governed by the equation Amps = Watts/Volts

Power input: approx. 45 to 60 watts, depending on the evaporator type

So 4 amps when running, 4 ah per hour? From 60 ah potential is  15 hours. If running for 20 mins per hour = 45 hours is 2 days”

[tckearney]

I have a ammeter on my fridge it runs at slightly under 4amps. 

[Salty]

Another variable to add into the mix is how well insulated or not the refrigerator compartment is. On my B36(2002), the refrigerator compartment was very poorly/not insulated at all, so originally the refrigeration machinery would be running very frequently and for longish periods in order to hold some degree of cool.

My boat has an “L” shaped galley area with the cool box set into the corner of the counter next to the gas cooker, where the only means of adding insulation without committing surgery to the wood panelling was by adding some internal insulation. I tried using some half inch thick foam with a self adhesive backing, but whilst it remains in place, it was not all that effective. The top of the refrigerated compartment back directly onto the underside of the galley worktop, and while that has the self adhesive foam attached internally on the underside of the top, outside of the refrigerator the counter top gets covered in condensation. Arguably a second thickness of self adhesive foam added to the inside would help to minimise that condensation.

Last winter during the lay up period I drilled a series of holes through the vertical external plywood on both sides of the galley counter. This involved removing the cooker temporarily on one side of the counter and the transverse cushioned side from the port settee on the other. I spaced the holes some six inches (150 mm) apart horizontally and maybe four inches (100 mm) vertically and worked out roughly where the ends and underside of the cool box were located so that I could squirt in some insulating foam into those areas as well. Finally I purchased some wooden dowel of a suitable size and cut this into pieces around 15 mm in length to hammer into the holes I’d drilled after the insulating foam had been injected. The job is not yet finished where I have to sand and smooth off the ends of the pieces of dowel before re-coating the area with a suitably coloured satin finish Ronseal coating.
The refrigerator has worked much better this year, but I think the type of foam used makes a difference with those stated to provide thermal insulation being the better choice.

I have two 100 watt solar panels providing current to charge my two 220 amp hour batteries during the daytime, and I tend to set the refrigerator control almost to maximum cooling during the day, and return the control to mid way during the overnight period. It seems to work well with temperatures holding generally around 4 - 6 degrees Celsius. If the control is set to maximum the fridge will produce ice.

It may be that removing the internal self adhesive foam and replacing it with something having a metallic finish with reflective properties might work better than the internal foam.

[Kibo]

I have a battery monitor. My fridge draws about 5 amps. In the Caribbean so it runs at least 50% of the time.

[Odysseus]

I have a BM1 monitor i AM In France its get hot and fridge runs 1 hour and off 1 and a 1/2 HOURS. AT BEST
It draws 6.2 amps at start and runs on 6 amps.

ODYSSEUS.

[Krill]

we have 240AH of batteries on board and a single 40w panel on the hatch garage.

We get 4-5 days with the fridge on constantly and using nav equipment, only on engine about 20mins a day in and out of places

but there are lots of variables of course, the 40w panel doesnt give a great deal of charge and its not self sufficient but more than adequate between shore power days.

we also have a battery monitor to keep an eye on them as typically i dont let them get too low, the only way i know it lasts 5 days is because the shore power charger failed without us knowing (this was before we fitted the monitor)

[tckearney]

I am interested in Salty’s idea of injecting foam to the fridge box for insulation.  Can anybody think of a reason why this could not be done by drilling inside the fridge box and hence avoiding any damage to the woodwork.  A few plastic patches covering the holes inside the fridge box would not be of any concern provided they are easily cleanable.  any reason why not ?

[Salty]

The areas where I drilled holes in the woodwork are almost all out of sight, from the saloon settee area the holes there are behind a cushion held in place with Velcro, while from the galley area the holes drilled are largely out of the line of sight being located in an area largely hidden by the cooker.
This winter I will rub down the ends of the wooden filler plugs to get the ends flush with the surrounding wood panel, and then gently rub down the wood panels before recoating with Ronseal. I’ve had a little practice in the application of Ronseal having started on the bunk support panels, and more recently in making a removable table top panel to permit access to the space under the saloon table, so I think that I won’t have too much difficulty in hiding the ends of the wood plugs that fill the holes I drilled. Next Ronseal job is to re-coat the sides of the companionway where these have faded due to sunlight.
One thing I didn’t mention was that I used some 2” masking tape to cover all of the holes before applying the foam, so that any spillage of foam didn’t run down over the woodwork and possibly mark it or become difficult to remove.

Filling from inside the fridge compartment means being able to get the filler gun and canister into that space in the right way to be able to operate it, and on how determined one is to approach the job from the inside, but I like the idea as an alternative to working from outside.

[Yngmar]

I am interested in Salty’s idea of injecting foam to the fridge box for insulation.  Can anybody think of a reason why this could not be done by drilling inside the fridge box and hence avoiding any damage to the woodwork.  A few plastic patches covering the holes inside the fridge box would not be of any concern provided they are easily cleanable.  any reason why not ?

That's how a PO did it on our boat. It worked reasonably well, although left some air gaps that are not insulated well and since the bottom wasn't properly taped up, a lot of PU foam leaked out into the space below and nearly drowned the compressor. I eventually hacked all the foam mess under the fridge away with a putty knife and a long arm, so be careful to tape up any and all gaps before doing it.

[tckearney]

Thanks guys a job for the winter months

[nightowle]

The areas where I drilled holes in the woodwork are almost all out of sight, from the saloon settee area the holes there are behind a cushion held in place with Velcro, while from the galley area the holes drilled are largely out of the line of sight being located in an area largely hidden by the cooker.
This winter I will rub down the ends of the wooden filler plugs to get the ends flush with the surrounding wood panel, and then gently rub down the wood panels before recoating with Ronseal. I’ve had a little practice in the application of Ronseal having started on the bunk support panels, and more recently in making a removable table top panel to permit access to the space under the saloon table, so I think that I won’t have too much difficulty in hiding the ends of the wood plugs that fill the holes I drilled. Next Ronseal job is to re-coat the sides of the companionway where these have faded due to sunlight.
One thing I didn’t mention was that I used some 2” masking tape to cover all of the holes before applying the foam, so that any spillage of foam didn’t run down over the woodwork and possibly mark it or become difficult to remove.

Filling from inside the fridge compartment means being able to get the filler gun and canister into that space in the right way to be able to operate it, and on how determined one is to approach the job from the inside, but I like the idea as an alternative to working from outside.

Salty,

Which Ronseal product do you use?  I don't think it's available in the U.S. and if not, I'll look for something comparable.  I've used a bit of mahogany oil to color some holes that I filled with wood filler, but it's a little too dark.  I've used some tung oil on the tabletop that looks nice.  But I'm interested to see if Ronseal is something I should search out.

[Symphony]

Ronseal is a major UK brand of finishing products - paints, varnishes etc www.ronseal.com The ones suitable for inside work on boats are the clear, matt or satin finish water based coatings. I use Ronseal interior satin which blends very well with the Bavaria finish. Ronseal are not the only maker of this sort of finish so have a look on the website to see the range then at the data sheets to see the make up so you can look for a product locally with similar characteristics.

[Matay]

Dear all,

I have an issue with my firdge and I wanted to continue under this theead as it is most related.

I have a 2013 Cruiser 45.

I have installed a digital thermostat for accuracy and isolated almost 80% of its surfave from inside.
Now durşng these summer days in south of Turkey, 30 degrees, it takes 8 min to loewr the temp from 7,5 to 5,5 but when it stops, from 5,5 to 7,5 it takes only 2 mins.

Is this normal? Your comments are well appriciated.

[Noelio Abrunhosa]

hi

if you think of drilling from inside remember the fridge has a inner liner then insulation, then outer liner then more insulation. regards Abby

[Matay]

Dear Abby,

Following some search in much detail within the forum, I did some improvements and insulations and the result seems ok now.

I have put two 12v computer fan to ventilate the compressor compartment. This helps the compressor more efficiently and stops blocking the hot air around the fridge box. Secondly, I put some insulation on outer side of the box where I can reach and some inside (inside at the bottom and just opposite side of the evaporator where I thought the inner insulation is week.

As a result, at 30 degrees outside temp, it takes 6 min to lower from 7.5 to 5,5 degrees and 4 mins at standby. Consuming appr 3.5 amp/h my daily consumption is 50.5 amp/day = 605 Watts

This seems quite satisfactory (I hope)

[Ziffius]

Noelio - that looks like drastic action - I am sure there is no insulation in or around my fridge on my Bav 39. Did a previous owner fill it with insulation perhaps??

[kavok]

This is situation on my 40 Cruiser m.y.2008:
Full fill with foam between wood and fridge box; full fill of the top and door with foam.  I also put 600 gr of  lead in the door to better close the door lip.
External electronic thermostat, four 10 cm holes in the lower compressor door with 2 pc fans, one in fresh air,  one out cold air.
Also an additional isulating sheet on the upper part of compressor box. Gas pressure 0,8 bar at the end of the on compressor phase. 5,5 amp at start, 4,7.amp after 3 minutes.  Temperature between 4°and 7° during day, 5and 8 att night. Full of food and bottle, in summer at 29° il works about 20 minutes in one hour. Last but not least the fridge containers has space, 3 cm, under the bottom to permit to cold air to free move in the fridge box. 290 W of solar panels, and 360amp light traction batteries are enough to all boat necessity for long periods.

[Noelio Abrunhosa]

Noelio - that looks like drastic action - I am sure there is no insulation in or around my fridge on my Bav 39. Did a previous owner fill it with insulation perhaps??

that is how my fridge was. has the boat was a charter boat from new i dont think they would have try to increase the insulation. i took my fridge out as my wife is short and battled to access the fridge. so now we have a dometic front opening in its place.
regards Abby