300w power from auxiliary battery

[Scullybcdali]

Looking for advice for how much power I can reliably get from a dual battery system please (note it will be installed by a professional, I am just trying to work out if it’s logistically possible to get the power I need)

I have a Zero Breeze portable AC unit which I would like to run off an auxiliary battery in my hilux (SR, 2022). The plan is to run it in the canopy to keep my dogs cool while travelling and it will need to be able to run for a long period of time (12+hrs) as when I travel, I generally travel long distances at a stretch.

It is 24v but has a 12v/24v converter available which is mostly used to charge the battery, however it can be used to run the unit. The website states:
“Don't power your ZERO BREEZE Mark 2 AC by this converter if your 12V battery can not provide sufficient and consistent power (over 300W or over 25A current). Damage may result from incorrect usage.”

I’m wondering what would be required to provide 300W and over 25A current please? Does it require extra parts? Just a higher capacity battery? Or would my altimator simply not be able to handle the drain? Is it possible and economically feasible?

I have not yet got a dual battery setup, but will be having one installed soon to run an Engle 12v fridge. Ideally I would like to be able to run both the AC and fridge at the same time however not sure if this is possible.

Would appreciate any advice (please talk to me like I’m an idiot as electronics are not my strong suit). I cannot simply go into an auto electrician in person as I live remotely on a sheep station, and hope to have it all planned and ordered, ready to be installed on my next trip back to Sydney…

Really appreciate any help!
Cheers
Mel

 

[Lucien Nunes]

25A auxiliary load is possible for a vehicle alternator but it is a significant extra demand that will probably use up most or all of its spare capacity. A 2022 vehicle will probably have an energy-saving smart alternator controlled by the ECU, which can impact on the charging efficiency of the auxiliary battery. Obviously a 100Ah 12V battery, typical for auxiliary RV duty, will run the A/C for 4 hours absolute max but more like 2-3 hours practically, before relying on the A/C's internal battery. When you next start the vehicle with the unit running, the aux load will be 25A plus the aux battery charging current which could be another 20A to begin with, and if the vehicle load is high at the same time that could max out the alternator and degrade vehicle battery charge time and system voltage.

It will probably work but I would want to test it thoroughly with the exact vehicle config under working conditions. I would expect some reduction in battery life through fast, heavy cycling, unless you only ever use the A/C with the engine running.

By comparison, a 12V compressor fridge will take a much smaller demand, often only a few amps. A power system that will reliably operate the A/C will run the fridge too.

The exterior lighting load on my boat is about 35A and it runs fine continuously on a 65A alternator. But I have large (660Ah) batteries so they can lap up charge when it's available and the alternator is just fine sat at a constant 60-70A without strain. Your vehicle alternator and smaller battery won't be quite as forgiving.

Needless to say, the wiring for heavy loads like this needs to be short, thick and very well executed to minimise voltage drop.

 

[Simon47]

While travelling, it would be much much more efficient to use an engine driven A/C system. Once upon a time it would have been fairly simple splitting the refrigerant circuit and modifying the simple controls to allow a second inside unit. These days I suspect it would be nigh on impossible due to the all electronics and software.
Once stopped, the power demand is such that you'll need a massive battery for the endurance to be much use.
I'm assuming you are referring to this A/C unit and this converter ?
I'd be asking the manufacturer if it's really suitable for long duration use like that. Nothing I see there says more than short term (intermittent) use to me.

Otherwise, Lucien has given some good advice. Keep your cable runs as short as possible, and use good sized cables - you'll want bigger than needed just for current carrying capacity as voltage drop is massively important when you only have 12V (well actually around 14V when running) to start with.

 

[Scullybcdali]

Than

25A auxiliary load is possible for a vehicle alternator but it is a significant extra demand that will probably use up most or all of its spare capacity. A 2022 vehicle will probably have an energy-saving smart alternator controlled by the ECU, which can impact on the charging efficiency of the auxiliary battery. Obviously a 100Ah 12V battery, typical for auxiliary RV duty, will run the A/C for 4 hours absolute max but more like 2-3 hours practically, before relying on the A/C's internal battery. When you next start the vehicle with the unit running, the aux load will be 25A plus the aux battery charging current which could be another 20A to begin with, and if the vehicle load is high at the same time that could max out the alternator and degrade vehicle battery charge time and system voltage.

It will probably work but I would want to test it thoroughly with the exact vehicle config under working conditions. I would expect some reduction in battery life through fast, heavy cycling, unless you only ever use the A/C with the engine running.

By comparison, a 12V compressor fridge will take a much smaller demand, often only a few amps. A power system that will reliably operate the A/C will run the fridge too.

The exterior lighting load on my boat is about 35A and it runs fine continuously on a 65A alternator. But I have large (660Ah) batteries so they can lap up charge when it's available and the alternator is just fine sat at a constant 60-70A without strain. Your vehicle alternator and smaller battery won't be quite as forgiving.

Needless to say, the wiring for heavy loads like this needs to be short, thick and very well executed to minimise voltage drop.

Thankyou very much for your help Lucien. I will only be using it while driving as I it has a battery that will run it for a while when stopped. Sounds like I really need to take the ute into a professional and let them look at exactly what they’re working with.
Appreciate your input, thankyou!

 

[Scullybcdali]

Thanks

While travelling, it would be much much more efficient to use an engine driven A/C system. Once upon a time it would have been fairly simple splitting the refrigerant circuit and modifying the simple controls to allow a second inside unit. These days I suspect it would be nigh on impossible due to the all electronics and software.
Once stopped, the power demand is such that you'll need a massive battery for the endurance to be much use.
I'm assuming you are referring to this A/C unit and this converter ?
I'd be asking the manufacturer if it's really suitable for long duration use like that. Nothing I see tterm (intermittent) use to me.

Otherwise, Lucien has given some good advice. Keep your cable runs as short as possible, and use good sized cables - you'll want bigger than needed just for current carrying capacity as voltage drop is massively important when you only have 12V (well actually around 14V when running) to start with.

Thankyou Simon. Yes they are the unit and converter that I was looking at but it sounds like their may not be suitable for what I need.
I would only need to use it while travelling as it has a small battery that can run if if I’m stopped for a while, however I’m now thinking I may just be better off to upgrade its own batteries and run it completely independently.

My original plan had been to piggy-back of the utes existing Air Con system but like you’ve said, have been told that with the electrics and sensors in newer vechicles, it’s not possible.

Who would have thought air conditioning a canopy would be so difficult?

Thankuou for your response. Appreciate the help