Do I need a 2nd Battery??

Hello Matt,

Your worst case Ah consumption will be 3.5A times 16h equals 56Ah before you try to restart the motor.

An ordinary starter battery will have a very very hard time to deliver this amount of Ah, plus start the motor.

Your starter battery could be cactus after 10 or 20 times of doing this (if it was even capable of doing it the first time).

So the answer is yes, a second battery will certainly allow you to do this - look into a deep cycle 100Ah VRLA AGM type battery.

Best regards, Peter

Why not look at a portable battery pack that you can charge during the day when you are driving?

I am sure the others in the group will get annoyed if someone has to jump start you everyday and it's not good to drain your battery like that.

I bought the Sidewinder Flyer 2 after many months of deliberations and calculating shortcuts. The best thing is its portability and the ease with which you take it to you next ute, and you can stick in any battery you want. I have mine tied down with fridge straps with the holders drilled striaght into my hard ute line ridges.

No affiliation and referees of Derek's business are glowing.

I think it's money well spent.

http://www.sidewinder.com.au/page133.html

So will you be using the "Fridge" as a Fridge or as a freezer?

It makes a big difference to your power consumption.

For instance if you run it at 0 to 4 degrees as a fridge it will be running a lot less often that if you run it at -12 or so as a freezer.

I don't really think you'll have a problem as overnight the fridge should not use more than about 1 amp on average, and the light will be on for a max of about 5 hrs. So I think you should be only using 20AH or so. Depends on the fridge. Also depends on the size of your existing battery.

Yes definately as second battery,,, expecially id you have diesel vehicle to start,,,

agree as above --- others will be sick of jump starting you
- you shorten your engine battery life
- chances are your fridge will cycle OFF and no restart due
to low battery voltage

Hi Matt I don't really disagree with the general view that a second battery is the 'real' answer. But we're all aware that a second battery with installation (including the smarts) ends up being quite expensive.
So, if you are willing to make the effort, you can probably get by as follows:
(a) ensure that your fridge has a good power supply (not ciggy lighters and thin wires). This will reduce voltage drop and help to conserve battery power;
(b) vacuum pack your meat to reduce the need for very low temperatures, and set the freezer temp at around zero or just below (obviously this will depend on the brand of fridge and its thermostat options);
(c) use a thermometer with a remote probe to give you accurate freezer and fridge readings, and:
(d) turn off the fridge or turn it to minimum cooling every night, and rely on the insulation to get you through the night (remember the song: "Help me make it through the night"). This should be fine as long as the ambient overnight is in the teens, but won't be very nice at air temp of 30 degrees plus!
You always have the emergency arrangement of running the vehicle's engine for an hour or two if you get caught with a heat wave.
Finally, claret rather than beer has a major impact on cooling requirements!
Have fun!!

Matt,
Just get a good quality 100ah AGM Deep Cycle battery, put it into a $20 battery box and that will last you for many years and cost only ~$350

No good getting another Starting battery to run a fridge as Starting batteries are not made for the deep cycling required by the fridge, they are made for Cranking, huge output in an instant, not constant low output over a prolonged time period.

Maîneÿ . . .

Thank you all for your replies, greatly appreciated. I've taken the plunge and bought myselft one of the Sidewinder Flyers. I like the idea of portability as well as a few other functions it will give me, not the least being able to use a large or small capacity battery.

Think I'll chase up a good 100Ah AGM to put in it.

Thanks again, your replies helped me settle it in my mind for me.

Hi Siringo,

I say yes it better to get a dual battery set up, and It doesnt need to cost a fortune.

My set up cost $659 including battery and install but if you get an Arc battery box and a cheaper lead acid deep cycle battery it would be cheaper.

I've also got an engel battpack 56amp which I run in my work car.

Cheers Wilko