I did want to ask a Question about Batteries

[mowog]

Now this question isn't about dual battery systems fitted to the Discovery.

My D4 has a single battery and it will most likely stay that way. However I have a new caravan and it uses 2 different power sources for 2 jobs.

1. From the 12 Pin Plug power is supplied for the fridge only while towing. In the van you have to select Car on a 3 way switch for 12v power to run the fridge.

2. 50 amp Anderson plug this charges the 2 house batteries while towing.

For reasons that still make my head want to explode the selling dealer didn't set the Anderson plug so that it only had power when the D4 was running. So the Anderson plug is live all the time.

I also believe the 12v from the 12 pin is live all the time as well.

So my problem is if I need to stop for any decent length of time I have to pull the 12 pin and the Anderson plug so that the D4 battery doesn't go flat. When camp for the night its easy pull the plugs and go to gas for the fridge and the solar looks after the van batteries.

But if I stop for a an hour or so I imagine it wont take long and D4 battery will drain quickly.

So I have these 2 12v feeds that I need to shut off and that would be simple if they came from the same source.

Now a really dumb question...

There are 2 80w solar panels that charge the house batteries. With the Anderson plug connected would any charge from the solar panels flow back to the D4 battery?

Ok thats it I am going to duck for cover for a little while now.

[gghaggis]

If you have solar feeding the batteries, surely you can run without connecting the Anderson plug - that would only be needed if you've been drawing power from the batteries for a few days?

The second plug on your D4 (the white one) has both an ignition-fed 12V and a battery-fed 12V line, so you should be able to just rewire your (fridge) trailer plug to use the one you want.

Cheers,

Gordon

[mowog]

Ok didn't consider just letting the solar do the job for the van batteries while rolling...

I should have added I do use a CPAP (stops snoring) machine over night so the batteries do get well used over night. And in the cold south it will have to run a Diesel heater as well. So by morning the batteries will need some volts back.

I will get the multi meter out and check the 12 pin plug on the D4.

[roamer]

What if you put a meter on the Anderson plug leaving the van, when it's in the sun and see what ya get.

Cheers Ken

[drivesafe]

Hi mowog, do you have a dual battery isolator under the bonnet?

You can still have a dual battery isolator and no auxiliary battery in the tow vehicle, the isolator just supplies power to a CT or van.

[awabbit6]

Hi mowog, do you have a dual battery isolator under the bonnet?

You can still have a dual battery isolator and no auxiliary battery in the tow vehicle, the isolator just supplies power to a CT or van.

That's exactly how I've got my D2 set up. The isolator will disconnect the feed to the trailer when the capacity of the cranking battery is getting too low to start the car.

To answer your final question. The solar panels should be charging all batteries that are connected to them. This includes the vehicle battery via the Anderson plug.

[Blknight.aus]

If I understand your problem and recall correctly...

the problem you have (without resorting to adding a DBS to the car) is actually in the trailer.

your 3 way position switch is not correctly wired.

in one position it should hook your anderson plug on the trailer to the house batteries so you can charge from the car, in this position the fridge (assuming its one of the 3 way 12/240/gas items or one of the smarter 12/240V units)is hooked to the house batteries.

in the next position the anderson plug is in the off position and the fridge is hooked up to the house batteries

in the last position the anderson plug is off and the fridge is connected to the aux power feed from the vehicle socket.

if your setup is like the one I remember there should be a couple of low wattage 12v lights that can also be powered up with the fridge. IIRC the one I'm thinking about was done this way so that the fridge and minimum lighting could be kept operating while battery maintenance or work on the primary 12v house system was being done and in an emergancy the 12v Aux from the vehicle could be used to get minimum functionality back in a hurry.

[Brick]

Mowog,

It might be worth checking with your van dealer on how the Anderson plug is actually connected. On my van i have 2 solar panels charging my 2 van batteries. However, my Anderson plug is only connected to my van fridge so that it continues to remaincool/cold while driving. If i leave the fridge on 12 volt while disconnected from the vehicle, the fridge does not operate. My fridge is a manually switched version with options for either gas, 240 volt, or 12 volt.

Cheers

[mowog]

As explained to me.

The fridge does not connect to the house batteries for operation at all (I have confirmed this). Its control board does take power from the house batteries. The only way to run the fridge of 12v is with the 3 way switch set to car and the 12 pin trailer plug connected to the D4.

The Anderson plug only charges the van batteries.

[Blknight.aus]

that makes sense, they obviously dont expect you to leave the van hooked up to the car like you would if you stop on the side of the road somewhere for a night and not in a van park.

Welcome to down to a cost not up to a standard engineering.

Id be fitting the VSR from a D1 and a 100A relay to the van with the VSR hanging off of the car side of the relay. Since thats basically making a primitive version of a Traxride if you're not up to hacking about with wiring, grab a traxride.

[mowog]

My last van was even worse than this one. I found out the hard way that the batteries were not charged at all via the tug. But the fridge did run off the house battery.

[unseenone]

After this issue is sorted, can we use this thread to post up some other general questions for discussion, and reverse engineering in regard to batteries and specifically the DIII/DIV charging systems, or shall we start a new thread.

[drivesafe]

Hi unseenone, there is some discussion on this very subject on the thread linked to below.

Just skip the garbage at the top of the page and then the rest of this thread is covering D3/D4 voltage operations.

Your suggestion of starting a new thread is probably a better way to go.

BTW, you should have a PM from me by tomorrow.

http://www.aulro.com/afvb/d3-d4-rrs/128695-battery-posts-final-warning-2.html

[drivesafe]

My last van was even worse than this one. I found out the hard way that the batteries were not charged at all via the tug. But the fridge did run off the house battery.

Hi again mowog, these 3 way fridges are proving to be an absolute bloody nightmare.

I’ve carried out a number of experiments and a single power supply cable just does not work, even when I tried 25mm2 twin cable, there was only a marginal improvement.

The two cable set up you have, if it’s the correct size cable, is the best way to go.

There are a number of options but the diagram below gives the best results for running a 3 way fridge and being able to charge your house batteries at the same time.

https://www.aulro.com/afvb/images/imported/2011/05/914.jpg