Thread: Anderson Connect For Camper

I'm not an expert, but mine is wired like this - traxide kit (incl low voltage cutout & yellow top) in disco feeding two circuits - 1. permanent power to two 2.1a USB ports and an additional 12v socket in the boot - 2. Heavy cable to Anderson plug at rear. My van has two batteries with a ctek dc-dc charger fed from either the car, direct solar or a ac-dc charger. I don't get into debates about any of this approach - it works fine for me. HTH.

Or you could just fit solar panels and forget about it,,,

Totally true Pedro.

In my case, my 35 year old three way fridge will make mincemeat of my (extremely el-cheapo) batteries in very short order when driving from place to place if the sun hasn't kept the batteries well topped up at the past stop ... so unless I have some kind of external power supply to keep the batteries ticking along ... I'll have no ice for my Vodka and my bacon will get warm ... very bad ...

Hi Ian and this is a commonly asked question, and on many occasions I have expressed my disliking for DC/DC device but let me put some facts to you and you make up your own mind as to which would be suit your needs, and note, this following info is directly related to Land Rovers, and does not always relate to how other makes may work.

If you are just planning on the once every so often weekend away, then you probably don’t need anything in the way of charging the house batteries, as they need to be fully charged before you store your camper away after the trip, and this is only done properly with a 240VAC charger when you get home.

If you you are planning a longer trip then you need to consider how much of this trip is going to be free camping and how long each stop at a campsite is likely to be, and ultimately, how much battery power are you likely to be using.

With the setup you are getting, say the two AGMs are 100Ah and you look like using the full usable amount available, which is 160Ah.

With your DC/DC device, it will take 3 hours driving to get those two 100Ah batteries to an 80% State of Charge ( SoC ).

From around the 80% SoC, all lead acid batteries control the amount of charge they will draw, no matter how large the current supply is, from 80% and higher, it is the batteries themselves that control the charging, and as such it will now take around 2 more hours to get the batteries to around 95% SoC.

So that’s around 5 hours driving, charging with a 40 amp DC/DC device, to get your batteries to 95% SoC

Now if you charged direct from your alternator, it will take close to 6 hours. Advantage so far, to the DC/DC device.

Just change the size of the AGMs from 100Ah to 120Ah and your alternator will get them to 95% SoC in the same time or even sooner.

NOTE, if you don’t discharge the batteries down to 20% SoC, the 40 amp DC/DC device will get them to 80% SoC sooner than the Alternator can. But then you need to take into account how long you are likely to be driving for.

Lets say you only discharge your two 100Ah batteries to 50% SoC and then drive. The DC/DC device will have those two batteries to around 95% in about 3.5 hours, while your alternator will take up to 4.5 hours. Are you going to be driving for just 3.5 hours or are you going to be driving for 5 hours?

If your house batteries are two 120AH AGMs, drive time is even again.

But here's something that most people don’t known. If your batteries are low but you only drive for a short time, say 1 to 2 hours. While your batteries are not going to be anywhere near 95% SoC, you will actually replace far more used capacity in the first hour or so, if you just used your alternator.

Using a DC/DC device will give you a narrow window where they will have replaced more used capacity than what an alternator will do. But if you do short drives, they can actually be a disadvantage, and if you do long drives, there is no advantage. And again, the larger your total usable battery capacity is, the greater the advantage is for just using your alternator becomes.

Now use a setup with my isolators and this swing big time in favour of using your alternator.

To start with, with one of my setups, you go from having 160Ah available while camping, to 250Ah available.

But just using the same amount of battery power you would have with the DC/DC setup, that’s 160Ah, because this is now spread over four batteries, and taking into account these are different sizes, instead of the batteries being discharged down to 20% SoC, they will have been discharged to only about 52% SoC and when you go for your drive, your alternator will have all your batteries up to 95% SoC hours before your DC/DC device can get those two 100Ah batteries to 95%.

With one of my systems, at no time will a 40 amp DC/DC device have an advantage. With my isolators, you will always have all your batteries in a higher state of charge, no matter what drive times you do.

And Ian, there are a heaps of other advantages to using my system over a DC/DC device and I can give you more details info you want to know more.

Tim, I really appreciate the time you take to write these posts, although I don't pretend to understand them completely

For me the key issue is that my Disco is not the only anderson plug equipped vehicle that does / will tow my Van - so the setup onboard the van needs to account for this. I also use particularly crappy batteries in the van (... put it this way, at the moment the mismatched batteries in my van cost me precisely zero ... ).

Anyway, good luck to the OP as I am sure a wide range of opinions and information (expert or, in my case, quite the opposite) will be presented.

Originally Posted by Epic pooh

(... put it this way, at the moment the mismatched batteries in my van cost me precisely zero ... ).

Hi Epic and this is one of the many myths surrounding dual battery setups.

This is no such thing as “Mismatched” 12v lead acid batteries.

I’m in the middle of an installation, so I will get back to you later.

I'd be fascinated to hear your views, as far as I can understand !

My current Van batteries are an ex-Hilux cranking battery of some sort (Century I think - a big one) and a smaller AGM of some sort (it's gray!) - the AGM was booted by the previous owner for lack of capacity/age, after a week or so on a 10A Ctek charger (recon mode then float) it's been fine for my use. The ex-hilux battery was apparently not holding sufficient charge to reliably crank the hilux (diesel), but after the same treatment it's been fine ... not sure how long they'll last ... but I don't care either ... they were the right price !

Cheers,
Mick

Thanks for the replies. I have some time to ponder but am sure the Traxide unit will do the job if I decide to add the onboard battery.