Empty housebattery

swede

Hello

My house battery 2*80ah. was empty after 12 hours .,the only thing was on is the fridge.

Can the fridge be the problem ? its workning good when it has Power. i have tested with 2 battery setups and the same problem.

Its an Isotherm maybe from 2002? 

Anyone has same problem? if not what can it be taking all the Power so quick.

[Deleted User]

It would be normal the have the battery be depleted by the fridge after 12 hours. I typically only have the fridge running on 12v when the engine is running. My freezer is full of frozen ice packs when I'm not hooked up to A/C shore power, so it stays cold longer. Plus I typically bring along an Igloo cooler full of ice.

My climate is warmer than yours, obviously.

Andy

swede

Fridge should empty my batterys on 12h. it most take a lot of Power to empty 2*80amp batterys something most be wrong.

DanD2

Can't remember the ah rating on mine but I'm running 3 group 31batteries and I just did a test this past weekend. Running 2 refrigerators, VHF radio on, watching TV for about 3 hrs and occasional LED lights on here and there. I turned off the battery charger and my batteries were at 12.7V. 28 hrs later, my batteries were at 12.3 volts.

Michael T

Swede, I need more info. Do you have one 280 Ah battery? If so do you have a single 8D or a couple of 6Vs? If you have a single 8D they typically have about 230 Ah unless you have a special one. Still, that is one battery and if your fridge is turned way up and your other electronics are on taking some parasitic power for 12 hours I could see your a single battery , even an 8D get low. I always prefer multiple house batteries wired properly. I prefer series 31 AGM or better yet AGM thin plate. Properly wired, 2 or better yet, 3 standard series 31 AGMs each with 105 Ah will give "on paper" 315 Ah. If wired properly, they will double their Ah to about 600Ah. In fact, any chemistry of house battery will perform incredibly better if wired correctly. I posted the procedure a year or so ago and Frenchship reviewed it a post a couple of weeks ago.

swede

I got 2 80ah housebattery .
It is fridge take all the power for me ?nothing else is on.
somthing wrong vhit the fridge maybe but what?

Michael T

Depending on a few variables - 12 hours isn't bad for 2 80 Ah batteries as that they wouldn't have a lot of duration - particularly depending on HOW they are wired. Are the batteries wired according to the diagram Frenchship posted a week or so ago? If they are you will get a lot longer duration from your Ah rating (almost twice as long depending on the battery chemistry) than just the 160 Ah you will get if the boat's + and - lead go to the first battery with short leads going straight back to the second battery. What type of battery chemistry do you have? Flooded Cell? Gel? AGM? The chemistry makes a BIG difference regarding longevity! I assume both batteries are deep-cycle. As an example I have series 31 AGM deep cycle batteries with 105 Ah each, wired properly. That gives me the equivalent of over 600 Ah. I can run two fridges ( a 2.4 and a 4.2) at 3/4 level plus a couple of fans, my lights and some use of my 12v TV for 12 hours, easily.

LaRea

Check the water level in the batteries.  Also, check whether the fridge needs to be defrosted.  A thick layer of frost can make a fridge use more power than normal.  

swede

ok

The fridge is defrosted and the batteries are ok .can it really drain mine 2 80 ah batteries so Quick ? thats sounds nearly impossible.

Michael T

To answer your questions, I ask again: What chemistry are they? AGM, AGM Thin Plate and Gel can not have their cells topped-up with water. Flooded can. Are they deep cycle? What size are they? 80 Ah does not tell us much. 80 Ah is not that robust a power source. For example: many series 24 deep cycle flooded marine batteries have 80 Ah. I need information to give you an accurate response. With what you have provided I agree with Andyd that a 12v fridge could easily run down 2X80 Ah batteries - depending on the size and type - and most certainly over a 12 hour period.

MarkB

Looks like the Dometic 90lt 12V/120V fridge draws about 13 to 15 amps at 12V.

http://www.myswag.org/index.php?topic=13578.0

So 2 x 80 Ah batters = 160 Ah total = dead in 11 to 13 hours if the fridge is the only consumer of power. Turn on your radio and a few lights and you would drop below 10 hours duration.

swede

Is that true that the fridge is taking so much power its isoterm maybe from 2002 then the boat was new.
Michael T that is closed batteries and just ordinary batteries not agm or gel.
MarkB fantastic if they take so much power idont now if its an 90l. or 65l. fridge.
Iam surprised but that lot of power use i understand why the batterys ar empty after 10 h.

MarkB

Swede - try and find the specifications for your fridge. I can tell you a compressor takes A LOT of power. The problem is if you have 120V, it's only a few amps (like 1 to 1.5 amps), but when you go to 12V, it is 10 times the amperage to need to get the same power.  Remember Power = Volts x Amps.  So if you have a 120W fridge, then you need this many amps:

120 W / 12 V = 10 amps.

Now, I believe this is the power consumption when the compressor is running. So that depends on how much warm air and heat enters the fridge. If it isn't opened, than probably it will work like 20% of the time. But if it's opened every 10 minutes, count on the compressor working 80 to 100% of the time (depending on your thermostat setting).

The other thing that you might want to look at is your fridge seal. This isn't really about changing your fridge (they all consume about the same amount of power), and although you might need to upgrade your batteries, no matter what you do, if you are letting warm air in, and that compressor is running all the time, you are probably reducing battery duration by 3 to 5 times. So check if it is sealing properly.

swede

Ok  maybe i change fridge to an new one . Idont have manual  for fridge maby i pull it out and look at the backside of fridge.
Gone look at seal and testing it how much power takes with an multimeter.

DanD2

I would change your batteries to group 31 and if you can afford, go to 3 house batteries instead of 2. I originally had 2 group 27's and was surprised at how much longer I have power with 3 group 31's.

Michael T

I agree with DD2. Get Series 31s. If you spend a lot of time at anchor - and can afford it, get three AGM Series 31s and you will have tremendous Ah (600)  and serious reserve power. If you want insane power, Ah and reserves along with 300% faster charge acceptance rates - get THIN PLATE  Series 31 AGMs - not cheap but wicked strong.

DanD2

If you decide to get AGM's and leave your starting batteries as is (I suspect they are flooded cells), make sure your charger can recognize different types of batts on different banks.

Michael T

Good call DD2!

swede

Fridge and 3 agm batteries are nearly same money. 
We are achoring a lot 2 to 3 days

MarkB

The batteries will be much easier to replace. Plus I still think you can control consumption from the fridge by turning down the thermostat and limiting how often the door is opened.  I would rather have more juice, and then later on I would change the fridge.

If you could manage both now, I would - but how old is your fridge?  Make sure if you get another one, you are cutting consumption by at least 30%, or it really won't make a difference.

Michael T

As has been aid a newer fridge probably won't make much difference on power consumption but better batteries will be useful for ALL of your electrical needs.

swede

Idont no what i should do new batteries or new fridge ar same money.
New 12v.fridge just use about 1.5 amp average so my batterybank should last for few days maybe.
The fridge are maybe from 2002 when the boat was new.
For me is nearly unbelivible that it  take so much power on 12v.

Michael T

Swede, as Mark said it's not so much the 12v as the amps.

swede

MarkB means that the fridge normaly takes about 10 amps on 12v. Or do i missunderstanding? If i choise to change batteries what size?

Michael T

I recommend Series 31 AGM (Absorbed Glass Mat) If you spend a lot of time at anchor running from your house batteries I would get 3 AGM series 31 batteries. If you have the room and can afford them.

DanD2

Although I fully agree AGM's are the way to go, Swede's boat is a 2002, his starting batteries are more than likely flooded lead cells and I highly doubt his battery charger will be able to differentiate different types on different banks.

I would suggest leaving the fridge as is, and adding 3 flooded cell group 31 batteries. As MT already stated, adding new batts, will benefit ALL your electrical needs.

swede

My charger do not recognized diffren tbatteries
a new fridge about 650$ 3 new agm batteries is lot more $.

MarkB

Swede, sounds like you want to get a new fridge. LOL.

We can only provide you advice, but of course, you do what you feel is the best for your situation.

I just don't think you will solve your problem, if you are worried about the fridge's battery drain. The new fridge won't be that much better.  Compressors are very old technology and haven't really changed that much even on the new energy star systems.  Advancements on 12V gear is even worse.

Anyhow, I think you will solve your problem better with batteries. If 3 x 31D batteries is too expensive, then install 2, and leave space for a 3rd in the future.

[Deleted User]

Another option would be to turn the fridge off and just drink English ale exclusively  

Andy

DanD2

Swede,

I fully agree with MarkB.  Also....the price for flooded cell 31's is significantly less than AGM's. As I stated earlier, I replaced my 2 group 27's with 3 group 31's and was very impressed at how much juice I had left after 28hrs......and remember, I'm running 2 fridges.

Michael T

I'm with Mark and Dan. I think - unless you KNOW your fridge is shot - I'd get at least 2 new flooded 31s instead of a new fridge......but I think we're back to square one here?