Thread: Running two fridges off a Traxide and Optima Yellow Top

What size fridges??

When I cross the Simpson I pulled up around 5pm and was rolling around 7am = 14hrs

Most fridges these day pull 4amp/hr so with two cycling on/off 50% of the time you will probably use 4amps/hr ish, I ran two fridges (32L and 40L) and had 2 x 110amp/hr batteries, I have now gone to one 60L.

4amps x 14hrs = 56amps......yellow top are 55amp/hr

It will be pretty cool overnight so fridges won't work as hard so may not use many amps....if you have low voltage cut should be alright

Originally Posted by weeds

What size fridges??

When I cross the Simpson I pulled up around 5pm and was rolling around 7am = 14hrs

Most fridges these day pull 4amp/hr so with two cycling on/off 50% of the time you will probably use 4amps/hr ish, I ran two fridges (32L and 40L) and had 2 x 110amp/hr batteries, I have now gone to one 60L.

4amps x 14hrs = 56amps......yellow top are 55amp/hr

It will be pretty cool overnight so fridges won't work as hard so may not use many amps....if you have low voltage cut should be alright

Thank you. They are Engel 40L. I think the current draw is 2.5A per fridge maximum according to Engel specs Engel Website

With the traxide you will be fine as long as you don't have other loads on the battery. My car with the same setup runs my single 40l Engel for 2 nights and 2 days (48hrs) without the cut out operating.

Originally Posted by plusnq

Thank you. They are Engel 40L. I think the current draw is 2.5A per fridge maximum according to Engel specs Engel Website

Spot on....

Worst case would be 35amps consumed....still discharging below 50%.....might decrease the life of battery but I factor the cost of a battery into the holiday.

Originally Posted by weeds

Worst case would be 35amps consumed....still discharging below 50%.....might decrease the life of battery but I factor the cost of a battery into the holiday.

Not sure what this means.


Shane has my setup so he has a total of around 90Ah available.


This is because he will have around 50% or 45Ah from the cranking battery before my isolator turns off and leaves his cranking battery with the remaining 50% for starting.


He will also have around 45Ah or 80% available from his Optima before it reaches 20% SoC.


So providing he has done around 3 hours driving if he had used all of that 90Ah at his last stop-over, he will have no problem power TWO fridges for close to two days.


At no time will he cycle his cranking battery below 50% SoC so he could easily get over 1,000 cycles of his cranking battery before having any effect on it’s life span.


Furthermore, because my isolators keep the cranking battery in a higher state of charge in the first place, his use will have next to no effect on his cranking battery’s life span and again, because my isolators keep the cranking battery in a higher state of charge, his cranking battery is actually going to have a longer life span, even when used as Shane pans to do over his trip.


Next, according to Optima, Shane can expect around 400 to 500 cycles of his Yellowtop battery down to 20%.


So in reality, only if Shane is away for at least 500 days, and every day he discharges his batteries down to the levels stated above, will he shorten either of his batteries life spans.


This is a highly unlikely scenario for anybody to achive, not just Shane.


Folks, there is only one catch to all of the above, as I have already warned Shane about, you must avoid continually opening and closing doors on your D3 and D4 as this CAN discharge the cranking battery below 50% SoC.

Sorry...should clarify/add, I work on 50% SoC for my AUX and not utilizing start battery and wasn't taking into account the model of isolator.

Tim sums up his system

Originally Posted by drivesafe

Not sure what this means.


Shane has my setup so he has a total of around 90Ah available.


This is because he will have around 50% or 45Ah from the cranking battery before my isolator turns off and leaves his cranking battery with the remaining 50% for starting.


He will also have around 45Ah or 80% available from his Optima before it reaches 20% SoC.


So providing he has done around 3 hours driving if he had used all of that 90Ah at his last stop-over, he will have no problem power TWO fridges for close to two days.


At no time will he cycle his cranking battery below 50% SoC so he could easily get over 1,000 cycles of his cranking battery before having any effect on it’s life span.


Furthermore, because my isolators keep the cranking battery in a higher state of charge in the first place, his use will have next to no effect on his cranking battery’s life span and again, because my isolators keep the cranking battery in a higher state of charge, his cranking battery is actually going to have a longer life span, even when used as Shane pans to do over his trip.


Next, according to Optima, Shane can expect around 400 to 500 cycles of his Yellowtop battery down to 20%.


So in reality, only if Shane is away for at least 500 days, and every day he discharges his batteries down to the levels stated above, will he shorten either of his batteries life spans.


This is a highly unlikely scenario for anybody to achive, not just Shane.


Folks, there is only one catch to all of the above, as I have already warned Shane about, you must avoid continually opening and closing doors on your D3 and D4 as this CAN discharge the cranking battery below 50% SoC.

We will be running two fridges also on our Kimberley trip, this is exactly the info I wanted to hear, I was more concerned about the heat once we get north of Capricorn, but then I realised we have rear aircon and as long as we have the car running it should be all good, as a just in case we have factored in a new battery as the Optima is around 3yrs old.

For the odd time you plan on staying somewhere for 3 nights without driving, we just asked for a powered site and plugged the battery charger in...

I think the only time we used ours was in Exmouth as we did 1 day whale sharks and the next scuba so car sat still for 3 nights. Weighs a fraction of what solar panels do, takes up no room and costs nothing if you already have one!