how many amp hours does a normal car battery have!
can get a car battery for 70 bucks. a deep cycle for 240. maybe im better with 2 or even three car batteries to keep solar fridge going for week. as im sure im gonna stuff the deep cycle by draining it too much.
meathead_timaru,
Jan 2, 10:23pm
You sure do like doing things the hard way. It's 7 days. a couple of chilly bins with ice will suffice - start with frozen meat and there's no chance of anything going rotten. I regularly defrost meat in the fridge for 7 days before cooking.
Anyway, starting and deep cycle batteries are different animals for different purposes. Deep cycle is for low output/long duration. Starting is high output/short duration.
Like I said in one of the many other threads, a starting battery is a very poor choice for low-output/long duration applications - deep cycling a starting battery (a car battery) will certainly result in greatly reduced capacity on that battery after few cycles.
Starting batteries don't have a Ah rating because their construction can't handle that application, but most deep cycle batteries have a CCA rating. I think my 85Ah deep cycle in the boat is about 330CCA, but I have a starting battery so I never use the deep cycle one for starting.
intrade,
Jan 2, 10:25pm
just use a gas fridge.
thejazzpianoma,
Jan 2, 10:41pm
Car Battery's = NO
If you don't want to spend the money on a fridge and battery's that will actually do the job properly go and get some dry ice and use the chilly bins as recommended above.
Just remember to transport the dry ice sensibly as it will turn to CO2, so don't put a large amount of it in a non-ventilated area with passengers.
666steve,
Jan 2, 10:42pm
You can't convert CCA to amp hours. Too many variables.
tmenz,
Jan 2, 10:47pm
They don't generally quote Amp.hour ratings of automotive batteries any more so it's a little difficult to divine. In general terms, the small batteries in small cars are about 40A.h and the bigger batteries in vehicles like diesel vans are about 70A.h, with other cars somewhere in between. Industrial and/or truck batteries tend to start at about 100A.h and go up from there. N100, N120, N150 & N200 are typical - they weigh as much as a small elephant and cost as much as the national debt of a small country! If a battery has a number like N40L or N70ZZ or whatever, the number is probably the NOMINAL Amp.hour rating but it's not necessarily so. Try Googling brand/manufacturers' sites like Century/Yuasa, Lucas, Exide etc.
Have you made any enquiries about hiring batteries from the major hire companies!
meathead_timaru,
Jan 2, 10:56pm
Any Ah rating on a starting battery will be primarily by default due to the nature of the battery i.e. motorcycle starting batteries are Ah rated because the vibration in the conditions they operate dictates a more rigid and more expensive construction method.
There's no escaping the fact that the duty dictates the type of battery for reliable, cost effective service. In this case, a domestic refrigerator running through an inverter with insufficient replenishment charging dictates big deep cycle to operate for the required period and that means big $$$.
meathead_timaru,
Jan 2, 10:57pm
Or a generator.
jacqui248,
Jan 2, 10:57pm
can you do that! really!
meathead_timaru,
Jan 2, 11:10pm
As long as you don't mind it taking a week in the sun to defrost the meat.
tmenz,
Jan 2, 11:47pm
I don't know if they have them or not but it's easy to ask!
elect70,
Jan 3, 12:00am
4 of us went on dive, stayed in tent for5 days . Just made a big chilly bin out of50mmcoolroom panelputlayer of dry ice on bottom &10 Kgice on top . Kept our food & grogcool
tmenz,
Jan 3, 4:27am
For an approximate real-world Amp.hour rating of a battery that has a legible label on it - get the Reserve Capacity (RC) off the label, this will be in minutes - multiply by 25Amps (300Watt load) to get Amp.minutes and divide by 60 to get Amp.hours. e.g. an Exide Endurance 55C has an RC of 85 minutes. 85 x 25 / 60 = 35Amp.hours @ 25Amp rate.
[The Amp.hour rating for this battery is quoted to be 55Amp.hours @ 20 hour rate. (i.e. 2.75Amps or 33Watts load), so it shows how much a battery has to be derated as the load increases!]
clark20,
Jan 3, 5:40am
For 1 weeks use I would buy a car battery and use it for the week, and then put in in my car.
jacqui248,
Jan 3, 6:09am
thanks again tmenz, so the 25 figure in that is the same with any battery!
jacqui248,
Jan 3, 6:09am
thats what i was kinda thinking.
tmenz,
Jan 3, 6:57am
Yes, I believe so. The reserve capacity time is the time you should be able to continue operating a car after an alternator belt breakage. Some knowledgeable person (or committee!) decided that the battery should be able to supply 25 Amps to keep all car functions going!
jacqui248,
Jan 3, 8:10am
ok cool thanks you.
gunsmoke4,
Jan 3, 11:25pm
are you going to be far away from a vehicle! just charge it off jumper leads! save a lot of shagging around.
jacqui248,
Jan 4, 2:37am
ok so i should of listened to some of you. im just gonna buy another decent chilli bin i feel lol.
The 1000w inverter i bought will not run the fridge! So thats teh end of that.
gammelvind,
Jan 4, 2:41am
Sounds strange! Won't start it! Would have assumed a 1000w unit would run a fridge.
jacqui248,
Jan 4, 2:59am
hmmm . but nup no go. just get FAULT, its meant ot have 2000 watt surge too!
gammelvind,
Jan 4, 3:03am
My guess, assuming you have the polarity right, is that the battery hasn't got the grunt required or the inverter has a fault.
jacqui248,
Jan 4, 3:16am
i ran a alarm clock of mine off the inverter and that worked .
gammelvind,
Jan 4, 3:25am
That makes me think that yourbattery is too small, low charged or too old.
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