Top 5 Electrical modifications / accessories

Submitted: Tuesday, Apr 22, 2014 at 08:00
ThreadID: 107395 Views:2188 Replies:3 FollowUps:6
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I recently submitted this list to Sidewinder for inclusion in his Newsletter. What do you think and are there others you could not live without?

"During a recent trip, I was discussing with my travel companion what would be on the must have list for any recreational vehicle (electrical naturally). The basics would be for all, no matter if 4WD, caravanner or camper, and have been narrowed down to my top five fitted electrical systems and parts.

1. Dual battery isolator system and auxiliary battery. More and more we are equipping our vehicles with fridges and other electrical devices requiring charging without risking draining the main battery. An isolator managing alternator charge to main and auxiliary battery, plus an auxiliary battery mounted under bonnet or in a battery box in the back is a must I think.

2. Dual battery monitor. Modern vehicle charging systems manage charging voltage and it is imperative to be able to easily see what is going on. You need to know what level of charge your batteries are receiving and the situation at both start and end of day. Battery state of charge is a critical aspect to the longevity of modern batteries and to be able to see the simple basic of voltage levels in both batteries is a stress free way of keeping an eye on this.

3. Accessory / charge cable to the rear towbar with Anderson style connector. Connected to the auxiliary battery, this access point has so many uses. On the road it provides a secure charge point from the vehicle charging system to a towed trailer or van. In camp, you can run power to camp accessories such as shower, electrical devices, or tent lights etc.. via extension lead (say 6m of 6mm2 cable). You can also connect a battery charger to this point or a regulated solar panel. No bonnet lifting or leads deforming door seals. You could also tap off it to provide an interim connection point in the back of the vehicle to connect various accessories. Of course it must be of suitable cable size to eliminate voltage loss (minimum 10mm2 cable) and be suitably fused.

4. A good 240v battery charger. In vehicle charging or solar for that matter is a slow system which seldom charges batteries to their full capacity, which again is a critical key to their longevity. A 240v charger is the most efficient to achieve this. Choose a multi stage quality smart unit which can deliver sufficient charge matched to your battery capacity. As a rule of thumb, a charger with output amps of 10-20% of battery capacity is a good start (ie 200Ah battery capacity, use 20Amp charger). Various batteries have different levels of input charge limitations but this is a good guide.

5. 12vDC to 240vAC inverter. Despite many accessories now able to run on 12v, many camp necessities do not, so a 240v source is still needed. Choose a pure sine wave model and from my experience a 600w minimum size. This will run many household items that you take with you."

Cheers. I'm off to the Victorian High Country now for the first time and I am very much looking forward to it.
Greg N
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Reply By: Member - PJR (NSW) - Tuesday, Apr 22, 2014 at 09:53

Tuesday, Apr 22, 2014 at 09:53
Interesting reading Greg. And it may help some with minimal wiring skills. However I beg to differ on the 240V inverter and need for a generator.

Add this one for safety and fault finding:
I would add a stand alone properly labelled fuse box for all 4WD and camping accessories. Start with circuits for driving/fog lights and fridge/s, compressor and diff locks. Our car has circuits for driving and fog lights as standard but I have elected to use the 4WD fuse panel that I installed. All 4WD/camping stuff together etc. Yes you could put the trailer and/or van on it as well.

And as far as possible, it should use the same style fuses or circuit breakers as the main vehicle fuse box. It also helps with safety by encouraging good wiring practices and thus minimise any fire risk.

About items 4 and 5.
Personally we have totally eliminated the need for 240V by having all accessories and plug in items as 12V operation, including all electronic toys and sat phone etc. I haven't even bothered packing the inverter for many years now. Heaps less weight to carry around.

Isn't having a second battery mainly to protect the cranking battery and to make sure that you don't get stuck by running it down with accessories and "luxury" appliances. Yes I agree for some it is necessary for medical reasons but isn't that the minority. But not for the majority unless you prefer "glamping". Subtle aren't I! (says he smiling)

It is a huge audience with many variations on 4WD and camping and touring etc that this forum addresses and not all of us have the same approach. eg We don't tow or use flood lights etc so no need for any external 12V inlet oroutlet.

Just my comments mate.

AnswerID: 531003

Follow Up By: Member - Nolo (Brisbane) - Wednesday, Apr 23, 2014 at 08:40

Wednesday, Apr 23, 2014 at 08:40
Thanks Phil. I have these and so much more but I thought I would just list basics. Like you, I have replaced most items with 12v powered options except for two. My electric toothbrush charger and my personal luxury, an ice maker. From the wonderful ebay world for only $130, it produces a tray of ice every seven minutes. Fresh ice with my whiskey is just great. Heck, sometimes I cant keep up with the machine and need some help from friends.
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Follow Up By: Member - PJR (NSW) - Wednesday, Apr 23, 2014 at 08:58

Wednesday, Apr 23, 2014 at 08:58
I needed that. I just posted something on the ANZAC thread and am still recovering.

Electric toothbrush. You have to be kidding. And ice?? Well I shouldn't talk. Recently on the Simpson at Poepells Corner there was a small gathering of about ten, from different groups, and we were all chatting away. There was silence when my wife got a couple of chocolate coated ice creams out of the freezer and gave me one. (we carry two fridges)

We don't normally take any wine or spirits though. Mayby a few beers though. Yes just a few. I rarely drink nowdays. Prefer a cup of tea any day. Not a latte sipper either.

I guess we all like a little "glamping".

But safety and easy fault finding is one of my main things.
FollowupID: 814067

Reply By: Member - John and Val - Wednesday, Apr 23, 2014 at 09:53

Wednesday, Apr 23, 2014 at 09:53
Hi Greg,

I’d agree with most of your top 5, though like Phil I’d try to avoid the need for an inverter. If it’s essential, then it’s in the top 5, and I agree with your 600W sine wave type, otherwise it’s relegated to the top 50!

I’d re-order your list a bit. I reckon heavy duty vehicles should all leave the factory with a pair of heavy cables from engine bay to the rear. Maybe fed initially by the cranking battery, but available for use with an under bonnet auxiliary battery, or simply there to efficiently charge a rear mounted aux battery or deliver power to a van/trailer. I’d make that my no 1.

If there’s any aux battery (and for virtually any camping rig an aux battery is number 1a) the isolator is essential, so I’d make that no 2. And almost as essential is decent monitoring – that’s my number 3. I fitted voltage and net amp meters years ago to monitor the aux batteries. They sit beside the rear vision mirror so are automatically monitored. I have no confidence in so-called state-of-charge metering.

Your number 4 - a decent charger is certainly up in the top 5, though there is an alternative worth considering. I use rear mounted aux batteries and one of Derek’s 30A multistage dc-dc chargers so can give my batteries a full charge without 240V. ( I do carry a 50A 12-15V mains power supply capable of running the dc-dc charger, so I guess I’m cheating, but I’ve never been forced to use it.) I’ve been very pleased with dc-dc charging, but find solar very good when camped too.


J and V
"Not everything that can be counted counts, and not everything that counts can be counted."
- Albert Einstein

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AnswerID: 531057

Follow Up By: Member - PJR (NSW) - Wednesday, Apr 23, 2014 at 15:41

Wednesday, Apr 23, 2014 at 15:41
HI John

I agree about the isolator. But it should be part and parcel of the extra dual battery setup as well as a separate fuse box and relays.

We run three batteries now with the crank on it's own and the other two in direct parallel. A 200 amp Redarc isolator is between the two "banks" and all 4WD stuff has been transferred to the twin auxilliary batteries. We don't even use the car's standard wiring and relays for any extra lights (fog and driving). Everything added for 4WD is separated and run from the auxilliary battery fuse and relay panel. Quizzed Redarc about adding a charging manager and they said not needed with my setup. That surprised me also. But it works well with the two fridges.

And it all fits under the bonnet. The blokes at Hume did a good job.

Catchy up soon

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Follow Up By: Member - Nolo (Brisbane) - Thursday, Apr 24, 2014 at 08:40

Thursday, Apr 24, 2014 at 08:40
Thats a good idea John, using the 12v supply. I think I have one of those that came with the Evakool frig. Thanks.

BTW, I see Derek's new dc-dc charger now takes solar input.

FollowupID: 814125

Follow Up By: Member - John and Val - Thursday, Apr 24, 2014 at 12:51

Thursday, Apr 24, 2014 at 12:51

Tread carefully! You need a power supply capable of delivering at least 20% more power into the dc-dc charger than the charger can deliver to the battery, and preferably supply it at a higher-than-battery voltage. Your fridge one will not be big enough and might die in the attempt!


J and V
"Not everything that can be counted counts, and not everything that counts can be counted."
- Albert Einstein

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Reply By: Robin Miller - Wednesday, Apr 23, 2014 at 14:35

Wednesday, Apr 23, 2014 at 14:35
Hi Greg None of your list make it to my top 5 and partly because like Phil & Johns comments that we all have a different focus.

For us the ability to keep your self going in harder enviroments often by yourself is top priority.

Also these days I mostly drive an automatic car and so the simplest thing like a flat battery or faulty starter needs to have a work around.

The very first thing I need is the least expensive - a good, always working digital voltmeter - costing from $4 Ebay to $20 Jaycar that plugs directly into and lives in a 12v socket is really good (not junk multi-function toys), you soon learn to know it and anticipate potential issues at a glance.
Would be nice if I had one with an inbuilt alarm but I use a unique GPS a 276c which is powered direct from 12V and has an accurate voltmeter and the ability to ring an alarm at any set voltage so we get a free kick with that one.

Often people have a deep cycle second battery - and while this has its uses it adds around 25kg to the car and instead of this we have our 2 & 3 rd options which add only 6kg.

2nd for us is therefore is a small gell cell with ability to charge directly from main battery via a Schottky diode and also be plugged across car battery, at the battery via Anderson Plugs - this maximimizes discharge current and ensures it is always fresh.

A secondary means of charging batteries comes next and for our 3rd necessity we choose a small 20watt solar panel invisibly stuck on cars roof which while small can put enough charge into the battery to start in a few hours.

The above system are permanently operational which minimizes failures.

4th Are redundant comms systems like UHF and HF radios which can be powered seperately via the previous Gell cell system.

5th Is an adequate supply of critical parts and tools like fuses, fuel pump, bulbs, Leds , wires soldering iron to enable minor repairs.
Along with the documentation and understanding of the cars systems to do and fix the above !

6th are luxury items like car powered infared heat lamps so you can be warm on those cold days where fires aren't an option.
Robin Miller

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Follow Up By: Member - Nolo (Brisbane) - Thursday, Apr 24, 2014 at 08:49

Thursday, Apr 24, 2014 at 08:49
Wise words Robin. I agree good monitoring and contingency planning is what it is all about for independant travel.

FollowupID: 814126

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