Thread: The Anderson plug mystery deepens

Hi Greg and the first thing I would try is to see if you can charge the battery in the camper trailer without the BMS.

Under normal circumstances your RR easier puts out enough voltage and current to charge a number of batteries at the same time.

Next, also check to see if the DC/DC device is a "LV" version. With no load on the RR, it will run at a lower voltage if your cranking battery is fully charged.

And last but not least, the power connection you have is perfect for doing what you intend. You do not need to run cables from the cranking battery to the Anderson plug.

Do you mean plugging the camper batteries into my Ctek charger directly, bypassing the Redarc BMS?
The BMS charges the batteries fine when plugged into 240 volt.

Originally Posted by GregMilner

The BMS charges the batteries fine when plugged into 240 volt.

How are the batteries charged while you are driving?

Are they connected to the BMS and the other side of the BMS is connected to your Anderson plug?

Or are your camper trailer batteries wired directly to the Anderson Plug?

Mmmm...don't know the answer to that. It's a Pioneer camper, made in Melbourne, with a Redarc BMS. Presumably, being Redarc, they've wired it in whatever the correct way is.
When we picked up the camper (it's a new one) last week from the dealer in Perth, he couldn't get the camper to charge from either his vehicle or mine (via the Anderson plugs at the rear of either vehicle) even though that morning his vehicle had been charging the camper batteries. So, this afternoon he came to our place and swapped out the BMS for a new one. Still no result.
He then discovered that the BMS he'd swapped out had blown a fuse in his car. Fuse changed, his vehicle then successfully began charging the batteries in the camper.
My car though doesn't appear to have a blown fuse, as we were still getting power to the Anderson plug at the back of the car. But it's still not charging the camper batteries, according the display of the BMS. Charges fine when plugged into 240V.

You may be getting +12v power to the Anderson plug but does it have a good earth connection ? One's not much good without the other

How about plugging a high(er) power load into the Anderson plug, a spotlight or headlight lamp for example and see if that works OK.

Where a low current device like a test lamp may not show up a high resistance connection (should there be one) it should be more apparent with a larger load.


Deano

Yes, that's the $64,000 question. I don't have anything of higher power fitted with an Anderson plug to test it, but I'm going to run it over to the sparky who fitted the plug a couple of years ago to test it. Thanks for the suggestion:-)

I run an Anderson Plug on my Prado to charge the battery in the camper while driving too, and I have wired it directly to the battery through a circuit breaker. I always wire Anderson Plugs directly to the battery with 6mm wire. I don't know what size wire is run to the power supply at the rear of your Range Rover, but I'd say it was never intended to charge a battery with through an Anderson Plug. The length of that wire, plus the wire going to the plug, plus the length from the trailer plug to the BMS will all add to higher resistance. You will need to test the voltage at the BMS connection to make sure you are getting enough for it. Having power is one thing, having enough voltage to charge the battery is another.

Hi NAAF, the cable running from the cranking battery to the rear of an L322 is either 20mm2 or 25mm2, and is way thick enough.

Plus there are plenty of L322 Range Rovers with my kits in them, happily charging batteries in camper trailers and caravans.

I think Deano might be on to something.

You need to get the right earth point in the back of the RR or you will not have a decent earth return.

Greg, tell your auto elec that the bolts holding your rear bumper on are the perfect earth point, and they are M10 and are accessible by removing the plastic storage box, below the rear fuse panel.