Dual Battery Options and Fitting

[Gold Coaster]

Think I'll most likely get one of the AGM's - is it safe to go lower in amp hour with my use or is 135 a safe bet?

Definitely go the biggest battery that you can physically fit in, especially if you are relying solely on your vehicle's alternator to do the recharging.

I'd mainly use the fridge for weekend trips but potentially throughout the week to keep a couple things in there. drive every day to and from work and everywhere in between.

If the alternator is your only means of recharging your auxilary battery don't expect to be able to keep your Waeco Fridge/Freezer running 24hrs a day.

Running time will depend on how big the Waeco is as to how many amps it will draw on average. Also where the car is parked during the day has a big bearing as the air temperature in a closed vehicle in the sun will keep result in the thermostat keeping the fridge working continuously. Another factor is the number of hours you spend driving.

So that you won't be disappointed you need to do the maths first so that you will know what the limits are.

[Sunny43.5]

I posted this link the other day on a post about extra USB outlets , some good facts and suggestions .Power and Charging Guide / Power and Charging Guide / Portable Fridges Portable Fridges Camping Fridges

[jonathan_k]

Great info thanks heaps for the walk-through!
Pretty straight forward running the cables through and under the grommet and side step into the passenger side?

Yeah, just work it out as you go and remove covers and carpet as necessary. You'll have to make a new hole or enlarge the hole in the grommet. I'll try and get a pic of mine. For running cables I like to use white curtain wire, feed this through as a leader and then you tape the actual cable to the end and pull it through. A bit of clean oil will help get it through the grommet.

Think I'll most likely get one of the AGM's - is it safe to go lower in amp hour with my use or is 135 a safe bet?

Check your dimensions first, the battery I have is snug under the drivers, perhaps you have more or less room? As Gold Coaster said above, usually you'll calculate your usage and aim to not discharge below 50% regularly, occasionally is OK. Below 30% discharge will quickly degrade the battery. Say the average draw of your fridge is 1.5Ah and you want to run it for 24 hours without charging. It will use 36Ah and you'd require 72Ah of stored power following the 50% rule. There's a calculator like Camping Warehouse - Solar Power Calculator if you want to go down that path.

As a value proposition, the price difference between an 85Ah and 135Ah (around $50) seems negligible against the time you'll invest in installing it and then relaxing not worrying if you're destroying your battery. I'm biased toward my own usage of course. If you know that you're going to drive a couple of hours every day or every second day then you can get away with an 85Ah or even like Sunny does, just run off the main battery.

And sorry for my ignorance, all rather new to me, but is the Projecta IDC25 what the bloke at Autobarn was mentioning i'd need for the fact that T5's run the smart alternator?

Yep. I'm not sure if the T5 has a smart alternator, it's likely which makes a DC/DC charger a necessity. Regardless, a DC/DC charger has several other worthwhile benefits which you can research. The Redarc stuff is high quality but you'll pay for it.

[jonathan_k]

Forgot to mention that your biggest drama will probably be crimping the terminals onto the ends of the cables, which is much easier with a crimping tool if you know someone. Whereabouts in Sydney are you?

[Mtwem]

If the alternator is your only means of recharging your auxilary battery don't expect to be able to keep your Waeco Fridge/Freezer running 24hrs a day.

Running time will depend on how big the Waeco is as to how many amps it will draw on average. Also where the car is parked during the day has a big bearing as the air temperature in a closed vehicle in the sun will keep result in the thermostat keeping the fridge working continuously. Another factor is the number of hours you spend driving.

So that you won't be disappointed you need to do the maths first so that you will know what the limits are.

Thanks mate good to know! looks like the fridge will be running roughly 1 AH per hour or so.

• I posted this link the other day on a post about extra USB outlets , some good facts and suggestions .Power and Charging Guide / Power and Charging Guide / Portable Fridges Portable Fridges Camping Fridges

  great link cheers.

• Forgot to mention that your biggest drama will probably be crimping the terminals onto the ends of the cables, which is much easier with a crimping tool if you know someone. Whereabouts in Sydney are you?

  not wrong there luckily i have a crimping tool from one of my pliers from work - located on the northern beaches in narrabeen. thanks for all your info and help jonathan! been a huge help. dimensions seems to be sweet as under the barn seat has plenty of room. if you do get around to taking a photo of your feed that would be epic. thanks mate

[Mtwem]

May change it up and during the week unless i know ill be using it turn off the fridge completely and only turn on occasionally.,
Is it as simple as just switching the fridge off and the battery wont drain or will there be a better way to ensure no AH being drained?

[Sunny43.5]

You can buy an isolater switch like they use in racing cars etc just turn it to the off and no power gets used .

[Gold Coaster]

Is it as simple as just switching the fridge off and the battery wont drain or will there be a better way to ensure no AH being drained?

Not sure what model you have but if when you turn it off if there is nothing lit up anywhere then I would yes, it's that simple.

My Waeco doesn't have an on/off switch ... I've installed a cigarette socket running off the auxilary battery which I plug it to when I want to run the fridge. To save battery power I often take it inside and run it off 240v for a few hours and whenever possible have any items that are going into it already cold.

[Mtwem]

Hi there
On the stretch of fitting it all this week.
Battery and DC DC charger are on their way and should get under way soon and will post updates how I go.
Is it necessary to have an isolator switch even with the new dc dc chargers?

Cheers

[Transporter]

The bcdc charger is your isolator.