12V Guru – New power for an old caravan

Who is 12V Guru?

Q&A inspired by readers of Caravan World Magazine. BMPRO Brand Ambassador David Bayliss answers a range of questions related to your 12V battery and caravan power needs.

Question to a 12V Guru:

Hi guru, I recently bought my first caravan, an older Jayco Starcraft and want to refurb it. My first concern is getting the suspension sorted as its seen better days, but while that’s being done, I thought I’d research batteries and solar. What is best for me? I do not run a fridge (yet), only lights and fans but I’d like to be able to boil a kettle occasionally. As I’m still learning so could you maybe give me some basics to keep the lights on more and ideas on prices? I’m on a budget but don’t know where to start! Thanks in advance, Jack Williams, Vic

12V Guru answers:

Hi Jack, Sounds like a great project you have taken on. Essentially in building a “new” system to meet your next adventures, there are three steps; firstly, identify what’s already installed (what works and what needs replacing), secondly, consider what you are going to require and lastly, assess the various options relevant to your budget.

Update caravan power supply

Firstly, it sounds like you have one of the earlier Starcraft from the late 90s or early 2000? Considering the age of the van, I would suggest that the power supply should probably be swapped out anyway to ensure reliability moving forward — the newer versions have more outputs which are fused and also a low voltage disconnect to protect your battery. The Starcraft of this vintage usually have a black box that will be located under one of the seats in the dining/kitchen area — this is the caravan power supply. Explore the cavity that it has been recessed into and this will become your new power centre. From a safety perspective, make sure that you use this compartment only for power installations and NOT for storage of non-related equipment, as it could cause damage in transit. Next step in the process is to consider what you need the power system to handle. Let’s make the assumption that like the majority of caravan users across Australia, you will normally be camping at caravan parks where 240v is available, but like the idea of setting up the van to be able to handle 1-2 days of getting away to a few free camps.

Change caravan lights

The earlier Starcraft won’t have been installed with the latest of LED’s available, so best to source out a reliable range to replace the original globes which use considerably more power. The 12v incandescent bulbs consume 1.6 amps of power. A 12v LED light consumes around 0.15 Amps depending upon the brand and size. Changing to LEDs will reduce your power requirements considerably and the globes last at least 10x longer.

Choose the fridge

Adding a fridge will require between 2-5 Amps depending upon what type of model you go for. I find a 3-way fridge best, so you can use 240v if at a caravan park, gas for when free camping and 12v whilst on the move between campsites. The better quality the fridge normally means the more efficient they are and therefore consume less power. We have used the Waeco and Engel models in the past.

Setup of the caravan power supply

If you are keen to get away and do a bit of free camping, can I suggest that you will need a solar and battery setup. Now for the setup — a simple 100Amp AGM battery is probably the best solution for what you require and I suggest connecting this to one of the BMPRO Battery Management systems, such as the BP35. This enables you to connect everything from solar and 12v from the car when driving, charging and maintaining your battery. Unlike other systems, where you need to add multiple components, these units have everything in the one simple product. These systems sell for between $500-$1000 depending upon the model you choose or whether you get one with a display or not. An option is to purchase the model which has its own solar regulator and high amp charging (suitable for Lithium batteries in the future) – then you could opt for other features later.

solar options

For solar, try the folding panels option, so that you can move them around to obtain the best angle to the sun or leave it at home and travel lighter if only visiting a caravan park with 240v. For between $300-$400 you can find a decent brand with solar regulator and wiring thrown in and it can just be wired to an Anderson connector so you can disconnect when required. Good luck with the next stage of your project and keep us posted! The article first appeared in Caravan World Magazine

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11 thoughts on “12V Guru – New power for an old caravan”

  1. david holdstock

    Dear 12v Guru
    I am in the exact position you have described above-i have recently purchased a used 2011 Jayco Discovery that has a SETEC fitted but no battery /wiring /solar set up etc. I wish to be able to get a few days free camping -can you suggest a set up /components i will require ? It seems the more i look into it the more i get confused.

    1. Olga kustova

      Thanks for you reply. With the Setec charger you have fitted it will be either an ST2 of ST3 and either way you can add a battery to this charger as it already has the connections at the rear (refer to instruction manual online or if not sure seek out a good auto electrician). A standard 100Amp Deep Cycle battery is ideal and this connects straight to the Setec unit. Once setup, the Setec unit will charge your battery and provide power to your loads. Once you are off in the bush with no AC mains power the Setec unit will draw from the battery to power your loads.

      To power your battery whilst in the bush consider a solar setup such as this one from Home of 12 Volt Mt Barker

      For a monitor the best option would be not to try and remove wall panelling to hide cables but to use a BMPRO BatteryCheck which attaches to your battery and sends the info on battery status to your phone when in Bluetooth range

      Your local Jayco Dealer should be able to help you with this simple setup or call Setec customer service on (03) 9763 0962 for further technical advice.

  2. Graeme Clough

    I would like to point out that Davids comments are not entirely accurate.
    It is worth noting that the power draw ie watts or amps is different to the power consumption over period of time, which is amp hrs or number of amps over a measured period.
    3 Way fridges are an absorption type system and have a boiler in them which requires a source of heat to run. Typically the 12v element is of between 110 watts (9.2 amps) and 155 watts (12.9 amps) and way beyond the suggested 2 – 5 amps in the article. Because they are not very efficient, power consumption is high.
    Waeco and Engel are both 12 volt compressor systems which can also run on 240 power through transformer power supplies. Their power draw and also consumption is much lower but still draw around 4 – 5 amps typically.
    More importantly the compressor types are much more efficient and cool the contents very quickly whilst the absorption types take around 4 hours to freeze ice blocks.
    Also chest type fridges are more efficient than uprights as the cool air doesn’t “fall out” every time it is opened thus consume less power.
    Waeco also make thermoelectric coolers. These are very inexpensive and perform accordingly

    1. Olga kustova

      Thanks Graeme – yes are correct we weren’t clear here. The Amps drawn specified refers to a 2 Way Waeco fridge we tested and not the 3 way absorption style – the latter of which is our overall preferred model for its ability to work with gas. Easiest way to keep power drain down on any of the fridges is to keep the door closed, but hard to get out the drinks then! Happy travels!

  3. Hi David, I have purchased a new chinese imported camper that has two AGM batteries with 3 solar panels. It has a 240 v battery charger,solar regulator,1000 watt inverter and a control panel that just gives you the voltage. I have also had a plug fitted to hook up to power at caravan park.

    I have a feeling all these things run independent to each other and i only know the state of the batteries by voltage which i don’t fully understand.
    I also dont know if i can leave van plugged into 240 charger all the time without damage to batteries.
    I am trying to find someone to give me advise on systems without throwing out what i have and starting over which will be expensive

    1. Olga kustova

      Hi Wayne,

      Unfortunately we are not able to advise on your setup as to whether it is all connected and compliant as it is a third party unit and also we are not aware on the installation layout which has been included. Our suggestion would be to head to a good RV auto elect and have them check it out. Safe travels – 12V Guru

  4. Sydney Singleton

    I have a 18 ft new age caravan full ensuit 2019 model, I am interested putting a 12 volt lithium setup in it and what is my 0ption thank you from SYDNEY SINGLETON.

    1. Olga kustova

      Hi Sydney,

      Your caravan most likely has a BatteryPlus35 battery management system. Please check if it is an HA model – as this is the only lithium compatible power management system. If your unit is SI or SR, than it’s just a direct swap.

  5. Hi looking at changing from 2 x 120 amphr batteries to lithium and also upgrading Chinese electrical panel. What would you suggest as the best way to go please

    1. Olga kustova

      Hi Tim,
      Firstly, ensure you are getting quality lithium batteries. Secondly, if your caravan has a battery management system, check if it is compatible with lithium, or, if you are using a battery charger, it has a dedicated lithium charging profile.

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