Caravan simultaneous 240V and 12V

Hi Julio,
I run the same setup as Derek describes above (bought it from him also) except I do not run an inverter (because I have no need) and I do not draw power from the tow vehicle. I get my power from the solar panels on the roof.

The system is dead simple and just works.

I also have a 12v fridge/freezer and water pump that runs from the 12v system, hence the van is always running on 12v. I have 240v circuits for the A/C and a number of outlets throughout the van for the microwave, hairdryer shaver etc for when plugged into mains or genny. Obviously these don't work when not connected to mains, but the small number of times you need 240v it is a good compromise. As the Fridge, stove, extractor fan, water pump, tv, radio, lights do not need 240v, there is little inconvenience. We do hook up the genny for a hot shower though as we use an instant electric HW system and not gas as it was much cheaper and suited our needs. But most showers are taken after driving and the heat of the road helps to warm the water tanks so it is not always needed anyway. Just a bit of planning.

As it is always running I use the fridge for my overflow house fridge when the van is at home and I very rarely connect the van to mains. I only do that when long overcast and if I want to get away from everyone and use the A/C.

I don't even think too much about what voltage is what as it just works. It charges the 2 100amp AGM's during the day or if it needs a top up from the mains, without touching anything. I can check the SOC (state of charge) of the batteries by looking at the LCD readout for the panel charger.
This van is for my in-laws to use during their trip around the block and so it is setup to suit them as they don't want to think about any of that technical stuff.
It works for them as it has no connection to the tow vehicle other than running lights and electric brakes that use the standard plug arrangement.

The real beauty of this arrangement is it's simplicity. There is only one light switch type required (12v), no rush to plug into mains (unless you need the microwave), and it all works all the time the same way no matter where you are and it plugs just as it would with a "regular" van (in-laws are used to 1960's-1970's caravanning).

Contact Derek if you need info as he is only too happy to help. No i have no association other than happy customer.

Cheers Cam

Notso,

I'm in the process of trying to decide on a better system for charging the battery in my camper trailer - 120AH Fullriver.

I've checked out the Arrid web site, where they rate them at 20 amp max, which would be good, if it does deliver 20 amps.

Do you know what rate of charge you actually get when your Arrid is in use?

Currently I can only get about 6 to 7 amps per hour charge rate. That's with the 120AH battery starting @ minus 50 amp hours. Trailer battery is connected to second battery in engine bay via 'heavy cable' and 50 amp Anderson plugs to trailer.

Thanks
Brian

The unit draws maximum 20 amps from the vehicle battery to charge the battery but I doubt that it would actually achieve 20amps charge rate. I think there would be losses in the system somewhere.

The techs at Arrid are quite helpfulll with advice etc so a call to them may give you some facts on charging rates.

There are two different models of charger, one for sealed and one for other lead acid types. So it's probably worth talking to them about that too.

Notso

Do not expect that the current drawn from any battery charger will be its full rated output at all times whilst charging a battery.

Batteries that are well discharged will not draw much current when they are first connected. I have seen flat car batteries that only accepted 2A from a 16.5V power supply, they took some time to start to draw much current and after a while I had to turn the PSU down as it was supplying its full current. For a while the PSU would supply 10A and as the charge came up I would increase the voltage to 14V and as the battery came up to about 60% charge the current would start to taper off.

If you wish to prove the maximum output of a charger you first have to ascertain that it is capable of producing enough current and then you have to observe its current output through the full cycle. I can assure you that if you are charging a big enough battery that is well discharged with an Arrid twin charger then you will achieve 20A output during some portion of the charge cycle. At maximum output you will be drawing more than 20A from your alternator - you will be boosting the voltage and you do not get anything for nothing + you will have some power losses in the twin charger (possibly 15-25%)

PeterD

Correction in my third paragraph, second line:

"producing enough current and then you have" should read "producing enough voltage to charge the battery and then you have"

PeterD

Oh for the ability to edit a posting or the ability to cancel it and post again.

I'm wel aware of that, as I said I have no idea what amps it is putting into the battery, just that it's requirement is 20 amps input. The unit won't operate correctly if the line can't deliver 20 amps. It can use voltages anywhere between 11.5 and 15 if I remember correctly.

Notso

I do not think you are "wel aware of that." The twin charge is capable of putting out 20 amps of output.

20 A output at 14.5 V is 290 W. Your input could be possibly 12 V, if it is this low then 290 W of power will draw 24.2 A of current. If the Twin charge is 80% efficient then it will require an additional 25% current to drive it. We thus require 30.2 A from a 12 V line to produce an output of 20 A - a little higher than you are claiming.

PeterD

Maaate , read all the posts thouroughly and then have a beer or two and then apologise for not reading what I have said.

Ken

Unfortunately they do not. Most caravan manufacturers do not seem to understand 12V systems. They employ electrical contractors to wire their vans and they seem to know less than auto electricians about how to engineer a good deep cycle battery system and if you ask them about solar they are completely lost.

PeterD

just remembered the brand SETEC in melbourne would be them.cheers Paul

The Setec power supplies as used in Jaycos would be the last thing I would use to run a deep cycle battery. They are only capable of trickle charging a battery. They do not supply sufficient voltage to fully charge a battery.

PeterD

Forgot to mention that if you want to charge van battery you would only need to connect the Ctek to van Anderson Plug and the Ctek obviously to 240v.

Pedro