Caravan Battery Charging from Prado

[smithie Lurker Find all posts View Profile Close smithie]

I have a 2012 Prado GXL diesel Prado and tow a new Nova Caravan. The Prado has a dedicated wire through a twelve pin plug to charge the two 100 ah batteries and fridge in the van while travelling. However, the system does not charge the batteries. I contacted Nova who indicated that the problem could be due to the type of alternator on the vehicle. I have checked the power supply from the Prado which appears to indicate that there is sufficient power to the van. The problem could be that the 12V fridge is using most of the power and does not leave sufficient power to charge batteries. Has anyone had this experience?

Regards

[Dreamer Member Find all posts View Profile Close Dreamer]

G'day Smithie,

First up, I'm not an electrician (or anything close). I recently had a similar problem that I've just managed to fix. I got some advice from people here on Pradopoint, spoke to a couple of auto electricians and did some internet research.

My Prado is also a 2012 D4D but my trailer is a 2010 model. The trailer has two 100 ah batteries and they were only charging at around 2% per hour of driving (with a 60L Engel fridge running).

The Prado has a 'smart' or 'drop voltage' alternator. My trailer had a Ctek D250S DC/DC charger that wasn't coping with the smart alternator (the input kept dropping to zero during charging). The power to the trailer comes from the Prado's crank battery via an Anderson plug. Solar panels also connected to the Anderson plug on the trailer. You say your Prado has a dedicated wire through a twelve pin plug to charge the two 100 ah batteries - only one wire or two?

I changed my charger to the new Ctek D250S 'Dual' DC/DC charger - which is designed to cope with smart alternators and has separate input requirements for solar panels. The input rate, to the trailer batteries, is now constant and I'm getting around 8% per hour of driving.

What type of DC/DC charger are you using? I would be looking into whether or not it is compatible with the smart alternator.

Hope this helps,

Lee.

[awwricecracker Member Find all posts View Profile Close awwricecracker]

G'day Smithie,



What type of DC/DC charger are you using? I would be looking into whether or not it is compatible with the smart alternator.

this is important, you will never get those batteries above 80% if it's a direct connection.

How have you checked the power from the Prado to be sufficient? How long are you driving to give the batteries time to charge? A 20A DC/DC can take the better part of a day to do one 100AH, 2 of them will take some time.

You may need to look at a supplement system, either solar or a 240v high amp charger to plug in. Also, while you're charging, if the fridge is connected to those batteries, they will never reach full charge either. You really want the load of the fridge switched over to the vehicle's circuit while driving. That alone will give you an extra 3-5A charge.

[LeighW Avid PP Poster! Find all posts View Profile Close LeighW]

First off what type of fridge do you have, if it is a three way fridge then you need to
run the power supply for the fridge directly to the cars cranking battery via either
a movement activated switch or some other form of cutout to disconnect the fridge from
the cars battery when the motors not running.

To ensure the batteries charge you need to make sure adequate cabling has been
installed for battery charging purposes, some flat plugs may have been fitted with
heavy duty cabling for this purpose, if it is a round plug the you should also have
an Anderson plug which connects the heavy duty power cable for battery charging.

The low voltage issue with the Prado can be simply rectified by using a booster diode.

I would try and steer clear of a DCDC charger if possible as if you discahrge the batteries to 50% SOC it is going to take around 6 hours plus of driving with a 20A charger to recharge them, note the fridge should not be connected to the charger. If you cant't get a reasonable charger voltage at the batteries using a booster diode and have no other choice but a DCDC charger then I would be looking at at least a 40A unit for reasoonable recharge times.

Leigh

[Pedro Advanced Member Find all posts View Profile Close Pedro]

I think a major part of your problem is size of wiring.
Minimum should be 6 B&S . Have a read of this thread http://www.pradopoint.com/showthread...205#post150205
which shows pictures of my install for a dual battery and other helpful hints from various posters.

I have a van with a 120amp AGM battery in boot ,shortly to become 2 batteries in boot.
Whilst travelling this battery is charged via an Anderson plug and 6 B&S cable which attaches to car and the 2nd battery in rear.
Fridge is run off the van battery , via 8 (yes 8) B&S cable whilst travelling and switched to mains or gas when camped.
When travelling a “stop fridge” switch http://caravansplus.com.au/catalog/p...oducts_id=6496 switches fridge off when stopped for a few minutes and restarts once in motion.

One thing I learned the hard way is not to mix an old battery which is not 100% with a new battery. It brings the new battery down to the condition of the old.

[prado2004 Advanced Member Find all posts View Profile Close prado2004]

I think a major part of your problem is size of wiring.
Minimum should be 6 B&S . Have a read of this thread http://www.pradopoint.com/showthread...205#post150205
which shows pictures of my install for a dual battery and other helpful hints from various posters.

I have a van with a 120amp AGM battery in boot ,shortly to become 2 batteries in boot.
Whilst travelling this battery is charged via an Anderson plug and 6 B&S cable which attaches to car and the 2nd battery in rear.
Fridge is run off the van battery , via 8 (yes 8) B&S cable whilst travelling and switched to mains or gas when camped.
When travelling a “stop fridge” switch http://caravansplus.com.au/catalog/p...oducts_id=6496 switches fridge off when stopped for a few minutes and restarts once in motion.

One thing I learned the hard way is not to mix an old battery which is not 100% with a new battery. It brings the new battery down to the condition of the old.

I Agree, I would run 6B&S right from the aux battery in the prado to your camper, connect the camper batteries via anderson plug. You can buy kits pretty cheap on ebay, otherwise its cheaper to buy the cable and anderson plugs separately and make it which is pretty simple.

I have a solar panel on top of my camper, check my signature for build up. It puts in so much power when driving I haven't even connected anything to the car battery yet as I dont need it. I will do it at some stage as a backup but the solar puts in more power. Very basic setup, cheap ebay panel, cheap mppt regulator and it pumps the power in & is cheaper than most of the dcdc setups...

Here is a kit for sale with 6B&S & anderson connection.

[DroversDog Lurker Find all posts View Profile Close DroversDog]

I have a 2012 Prado GXL diesel Prado and tow a new Nova Caravan. The Prado has a dedicated wire through a twelve pin plug to charge the two 100 ah batteries and fridge in the van while travelling. However, the system does not charge the batteries. I contacted Nova who indicated that the problem could be due to the type of alternator on the vehicle. I have checked the power supply from the Prado which appears to indicate that there is sufficient power to the van. The problem could be that the 12V fridge is using most of the power and does not leave sufficient power to charge batteries. Has anyone had this experience?

Regards

I've read the other posts above but I have some electrical knowledge and I've opted for a more simplistic approach with my Prado - influenced by the way Jayco wired my van in the factory. It seems to be working satisfactorily with my single 100ah battery but with two batteries you may need to go solar.

I'm actually on the road towing the van with the Prado now but I've only free-camped one night and did not drain the battery much. Charging the van battery while towing it for 6 hours brought the terminal voltage up from about 12.2V no-load to 12.9V no-load (measured a couple of hours after ceasing charging) and the terminal voltage measured 13.4V while charging just before switching the Prado motor off. What this boils down to is that while I believe the van battery will eventually charge to 100% if you drove forever, for a 6-hour run I suspect it's only going to get to 80-90% at best. This is fine if you're only going to use it to run lights, water pump, charging mobiles and maybe a couple of hours of TV for one or two nights.

Anyway, the way Jayco wired the van was using two, dedicated, what appears to be 6mm (not 6 B&S) wires, for both the 12V fridge (15A) and battery charging (that's four wires altogether) from a 12-pin flat plug. The fridge is connected to terminals 9&10 while the battery is connected to terminals 8&11. I've run two dedicated, 8 B&S +ve and -ve wires directly from the cranking battery to pins 9&10 of the trailer socket for the fridge (the +ve is actually via a 30A in-line fuse and a 30A relay that cuts power to the fridge when the ignition is off). For charging the battery, I've run the same number and size of wires from the cranking battery via a 50A circuit breaker and a RedArc Isolator to terminals 8&11 of the trailer socket.

The reason why I opted for 8 B&S wire and not 6 B&S wire is because the 8 B&S will just fit in the termination tunnels of the 12-way trailer socket if you're very careful.

I measure 11.95V at the fridge terminals switched to DC with the Prado motor idling and 13.4V at the van battery terminals. You would get better results by fitting the boost diode for the Prado alternator that LeighW mentioned but so far I have not tried that. By the way, Jayco fitted a 20A in-line fuse to the +ve of the charge wire, which seems to indicate they do not expect a huge charge current from the towing vehicle due to the total resistance of the wiring between the car battery and the van battery.

I don't know what sort of 240V/12V power supply your Nova caravan uses but with the SETEC power supply that Jayco uses there is an alternative method of charging your van battery from the car. This is via a charge lead from a spare pin in the trailer plug to a diode in the SETEC unit that is connected to the 12V rail. This will not deliver much better than a trickle charge because it relies on the same earth used for the van signalling lights, electric brakes, etc. and is a relatively light gauge. The diode also drops about 0.6V, so there's no way you would get 100% charge with that method. It could be that your Prado is wired one way and the caravan is wired the other way - or your car may not be wired for battery charging at all.

When I get home, I'll do some more measurements and the math to work out exactly what charge current the van battery is actually getting (or should be getting) from the Prado.

I'm not sure I made this clear but the bottom line is that you need two pairs of at least 8 B&S wires from the terminals of the cranking battery, fused and separately relay-switched, for the fridge and battery charging, to four separate (larger) terminals of your trailer socket. This is separate to your electric brake wiring which uses the smaller pins of your trailer socket/plug. Hope this helps a bit.

[drivesafe Senior Member Find all posts View Profile Close drivesafe]

Hi Smithie and if you are after the MOST EFFICIENT caravan fridge and house battery set up, this is it.

You can substitute the DT90 for any decent quality isolator, and this set up, combined with one of LeighW Alternator Voltage booster fuses ( if you have a low operating voltage type vehicle.), and you will have the most efficient set up for charging your house batteries and running a 3 way fridge.

This system requires let energy to charge your batteries than any other set up, which means you use less fuel to charge your batteries, particularly if you intend to do a fair bit of free camping between drives.

[sweetpea Senior Member Find all posts View Profile Close sweetpea]

Hi Smithie and if you are after the MOST EFFICIENT caravan fridge and house battery set up, this is it.

You can substitute the DT90 for any decent quality isolator, and this set up, combined with one of LeighW Alternator Voltage booster fuses ( if you have a low operating voltage type vehicle.), and you will have the most efficient set up for charging your house batteries and running a 3 way fridge.

This system requires let energy to charge your batteries than any other set up, which means you use less fuel to charge your batteries, particularly if you intend to do a fair bit of free camping between drives.

As drawn, the earth for the auxiliary battery is via the caravan battery. If the caravan is not connected, the auxiliary battery is not earthed and will not charge.

Also, as the Anderson 50 Amp connectors are not interchangeanble, would it not be better to use different connectors or at least different colours to prevent them being connected incorrectly?

S.

[winniliss Avid PP Poster! Find all posts View Profile Close winniliss]

It appears the auxiliary battery earth goes to a 'common earth stud' on the vehicle but the drawing is a bit misleading. The other option would be to run both a positive and negative cable to the auxiliary battery.

In relation to the anderson plugs you can buy paint suited for plastic so you could colour code the plugs.

[mjrandom Out of control poster! Find all posts View Profile Close mjrandom]

No need to colour code Anderson plugs, you can buy them (genuine ones) in grey, blue, black, red and yellow from memory. The plugs are all slightly different so you cannot plug one into another. I run grey for the battery / alternator feed, red for solar and black for track lights.

Redarc also show various charging set ups on their website. Worth a look.

[hulbyw Senior Member Find all posts View Profile Close hulbyw]

Don't you just love caravan manufacturers who build a caravan without adequate provision for charging the batteries (either an Anderson plug with thick cable or a DC/Dc charger in the van) then blame the tow car.
However the point of my post is to tell you how not to do it. A friend has a 40amp DC/DC charger in his 80 series and another 40amp DC/DC in his camper. He has 1 auxillary battery in the 80 and 2 in the camper. He runs 3 fridges. On the way home from the Kimberleys, he cooked his alternator and his starter battery.
A simple case of overkill. Reckon he will be swapping the 40amp chargers for 20amp jobbies soon.On the other hand,my single 40amp DC/DC setup worked fine.
Cheers......Wayne

[drivesafe Senior Member Find all posts View Profile Close drivesafe]

Hi folks and as to the Anderson plugs, you simply stack them together with two 25mm long M3 bolts and you now have a single action for connecting both the battery and fridge cables and they can’t get mixed up.


Hi winniliss, and in many cases you can run both sets of cables to the auxiliary battery but the further the auxiliary battery is from the cranking battery, you again start to increase the voltage drop in the whole set up, because of what the fridge current causes.


Hi hulbyw, in your mates case, using the no DC/DC devices would have given him faster battery charging and no runaway current loads. And lots more efficient too.