Need input on my Second battery setup for fridge?

Cider
Here and there
Posts: 25
Joined: December 28th, 2014, 7:15 am
Location: Riverina, NSW

Need input on my Second battery setup for fridge?

Unread post by Cider » February 19th, 2017, 3:27 pm

Hi all, I'm finally getting round to permanently installing my Waeco CFX35 into my Rodeo. Planned use is daily work ute, with the odd weekend camping trip. I've installed a 240v shore power inlet to the Rodeo, with the intention to plug in when at home to keep the batteries charged and let the Waeco switch itself to 240v power.

I want to avoid spending big money on complex dual battery control gear if possible. What I have in mind is this:

1. Waeco connected to aux battery (questions: is AGM the way to go for this application, and should I set the fridge to cut out at 10.1v or 11.4v?)

2. Volt-controlled isolator (eg DBi-140) between vehicle and aux batteries (question: can I safely parallel the AGM and the vehicle's wet cell in this way?)

3. 'Smart' charger permanently mounted onboard and connected to the shore power inlet (question: can I connect the smart charger to the vehicle side of the isolator, and will the isolator then behave the same way as with the alternator (ie, connecting the aux battery and allowing it to receive charge from the vehicle side?))

All input appreciated!
2008 Rodeo RA LT Diesel.

mydmax
Need to get out more
Posts: 5384
Joined: August 4th, 2011, 10:43 pm

Re: Need input on my Second battery setup for fridge?

Unread post by mydmax » February 19th, 2017, 10:16 pm

I have used a simple large relay to connect my engine battery to the other three AGMs I used in Tub and Tvan. All charged at 14.0 or more. Same in two vehicles. Landcruiser and now Dmax.

The charger should charge the main battery and when voltage high enough auto connect the VSR to the AGM and charge it too. Can't see why not.

I wouldn't run any battery below 12v if i valued it.

Cider
Here and there
Posts: 25
Joined: December 28th, 2014, 7:15 am
Location: Riverina, NSW

Re: Need input on my Second battery setup for fridge?

Unread post by Cider » February 23rd, 2017, 5:47 pm

Thanks mydmax.

I'm currently using an old, floral battery as the aux, and just charging it at home. The Waeco is set to cut out at 11.4v ('medium') and I get about 6 hours out of it, which is (only just) better than nothing.

Your comment about using a 12v cutoff is interesting - it raises the question whether to spend big money on a posh battery and baby it, or just get a cheap cranker and flog it.

The 'low' cutoff on the Waeco is 10.1v. Be interesting to see what sort of life I'd get out of a $100 farm battery at that setting...
2008 Rodeo RA LT Diesel.

Tony F8
Here and there
Posts: 40
Joined: July 13th, 2014, 10:12 am

Re: Need input on my Second battery setup for fridge?

Unread post by Tony F8 » February 24th, 2017, 3:52 pm

Just go to your local battery shop, you can buy a good Bi-directional VSR (Vigil VSR for example) for under $100, wire it up and problems solved, simple as that, certainly no need to spend hundreds on ctek or redarc.

goldiexxxx
Been here a while
Posts: 244
Joined: March 15th, 2008, 1:46 am

Re: Need input on my Second battery setup for fridge?

Unread post by goldiexxxx » May 10th, 2017, 8:04 pm

The best advice you should take is to keep the setup as simple as possible. Secondly, you should install it yourself so you know exactly how it is installed and you know how to fix it yourself if it stops working.

Here are some answers to your questions:
1. AGM are good batteries but if you are looking at any deep cycle battery, they enjoy slow gentle charging and discharging, not being hit with 40 or so amps from an alternator. My advice is to just buy a standard starting battery for duties in a vehicle, especially in a hot engine bay. I use a $100 Maintenance Free cheapo and then replace them when they become unsatisfactory in their performance (couple years or so). I would set the Waeco to cut out at 10.1, because in reality, if you are vigilant, this will not be the norm. A daily driver will mean the batteries are always being charged as you drive the vehicle.

2. I use the Kickass duel-voltage sensing relay available online for $58. Its been working great in my Cruiser for a couple years and works to charge and isolate once either battery falls to its specified voltage. I use this because I have a solar panel which charges both batteries, or the alternator can charge both batteries. When the engine is off, the fridge will use the available capacity of both batteries until they fall to 12.8v and then they will isolate. Instead of a solar panel, you could supplement your smart charger to either battery.

3. Yes, you can connect the smart charger as you suggest. But if you only want to have it connected when at home, I would consider the PROJECTA 1.6amp trickle charger. I have a couple of these that I use to maintain my batteries at home and the 1.6amp is enough to maintain the batteries at 13.3v even with the fridge connected and being used as a beer fridge in the back of the Cruiser. I don't recommend running the fridge permanently as a beer fridge from your batteries when it has the ability to use 240v though.

My advice if you want the fridge to be working in your daily work ute, then get yourself a 80 - 100 watt solar panel and a good quality regulator. SET AND FORGET MATE!! I use the Victron Blue MPPT solar regulators, they are excellent quality, made in the Netherlands and the best value for money simple solar controller I have found. If you only have one panel, then the small 10 Amp version is all you need. Be sure to get the MPPT controller and not a PWM, the MPPTs are far more efficient at converting available solar energy into useable charging power. All connectors and parts available on ebay. Chinese panels are ok too, no need to spend big bucks at your local battery place.

Hope that helps or someone else looking for info.
Goldie

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