Not very long ...
Remember that your start up current on the freezer will be larger than the maintainance draw. therefore at the point that the battery can no longer support the start up then the freezer will stop working.
I would estimate that your 110 amp battery will last about 6-7 hours on a full charge to support a freezer. ( i know that the maths says different but try it ... you will be suprised)
Just as an example our deep cycle 200 amp 24v system will support 4 10watt lights for 12 hours
Also remember that inverters are battery killers for anything except the best deep discharge "leisure" type batteries.
I am famously thick when it comes to electricity, can reduce the OH to screaming point but...
is it worth all the noise and smell and cost of a generator to keep a freezer running? Is it possible to just run it for a couple hours a day to stop the food spoiling?
We get frequent powercuts here and yet nobody has a genny for the house - just the farm work. I not sure if they're the answer for more than a few hours and maybe more bother than they're worth? If they were the answer then I'm sure some folk here would have them.
diamond lil wrote:I am famously thick when it comes to electricity, can reduce the OH to screaming point but...
is it worth all the noise and smell and cost of a generator to keep a freezer running? Is it possible to just run it for a couple hours a day to stop the food spoiling?
We get frequent powercuts here and yet nobody has a genny for the house - just the farm work. I not sure if they're the answer for more than a few hours and maybe more bother than they're worth? If they were the answer then I'm sure some folk here would have them.
If you have a chest freezer you can keep it frozen for weeks with a very few hours power a day providing you dont open it.
The upright freezers are more difficult to keep cold.
The other thing to do is to try to keep the freezer as full as possible.
During power cuts we run our generator for 4 hours a day and that is enough to keep everything in good condition
Chris, Your 110 Amp-hour battery holds 110Ah X 12V = 1320 Watt-hours of energy.
Your freezer consumes 75 Watts when running (I still think this is low, mine pulls 130W) This is power and independent of the voltage it is supplied with. So crudely it will run for 1320Wh / 75W = 17.6 hours. But in real life you never get 100%. As Skippy says above, there are losses, inverters are renowned for being inefficient, especially the cheap, small ones and you never use a battery's capacity totally, 50-80% is recommended to avoid damaging it. So Skippy's 6-7 hours is a very reasonable estimate.
But, as Diamond Lil has said you will not need to run the freezer constantly (indeed the thermostat will switch it on and off at the set temperature) and once again Lil's four hours a day is a good estimate of your probable needs.
After hard use lead acid batteries regain some of their capacity when rested, so you will probably get two days, say 50 hours) of keeping your freezer frozen out of the battery before it thaws.
This theory is all very well but there are so many variables involved I strongly recommend that you actually set up your alternative supply and try it for real so you will have confidence in the system. I would guess that my 50 hours of frozen in reality is an absolute maximum and on trialing your alternative system you will actually get between zero and 25 hours.
Please try it and let us know. Real life data is incredibly important as too many people prepare without ever using their kit and when push comes to shove fail because theory is not practice.
thanks guys for all the help yes the chest freezer is full and going to have the landrover runing during start up and then let it run off the battrey for about 4hrs
I have a 700w 2 stroke and a 200w Honda 4 stroke! The Honda I have stripped down and the exhaust valve seized! I have dripped diesel down the side and freed it up! Only now neither I the valves move when you pull the starter cord? Is it worth me taking it apart more? =/
but...