Existing on 12 volts only

[Gafferbill]

Hi to all

To add to the posts on surviving without mains hookup :-

My caravan has a Car or Van setting on the electrical control panel. This selects where your 12 volt supply is comming from, but it is an either/or situation. Car battery or caravan battery.

I thought it would be useful to be able to connect to both at the same time if you wanted to.

My towcar is a 4x4 diesel and has a heavy duty battery and charging system.

I fitted the towbar myself so I was able to modify the 12 volt electrical connections to the van.

These are standard connections to a 12N and 12S socket( I know these are now outdated)

However I made the addition of an extra heavy wire which runs from the battery +ve, via a 25 amp fuse to a spare terminal in the 12S socket.

This gives a permanent 12 volt supply at the 12S socket on the car, utilizing the existing earth wires.

This supply goes nowhere when towing as there is no onward connection to the caravan, there being no connection to that terminal in the caravan 12S plug.

The caravan battery is charged by the car when towing in the normal way via the automatically switched charging circuit.

When on site I am able to electrically conect the caravan battery to my car battery, in parallel, using Towsures 6 mt S connector ( product E22). This is achived by rewiring the connector socket or plug, so that the charging circuit and refridgerator circuit are supplied with 12 volt +ve from the additional permanent 12 volt supply from the car.

The two main advantages of this set up are :-

I can charge the caravan battery without my car engine running.

This is because two batteries connected in parallel will always form a charge equilibrium where one is charged more than the other.

After comming back from a day out, with the car to the site, I connect up as described and charge will flow to the van battery from the freshly charged car battery over the course of an hour or so.

Any 12 volt appliances I use whilst connected will utilise both batteries.

The other advantage is that I can run my refridgerator, on 12 volts, for up to 30 minutes whilst stationary in a layby, when making a stop on route. Very useful when travelling in hot weather on the continent. Saves gas or keeping the engine running.

If you are tempted to copy my setup you HAVE to stick to the following rules :-

NEVER start the car engine with the modified connector cable in place. Your cars starter motor may damage the modified wiring.

NEVER run the refridgerator for longer than 30 minutes using the modified wiring connector. This will be less the smaller the battery you have fitted to your car. If you do there is a danger your battery will be too discharged to start the car again. Use gas to run the refridgerator on site.

NEVER keep the connector wire in place for longer than 2 hours. or there is a danger your car battery will be too discharged to start the car again.

I look forward to hearing other ideas you may have

 

[Transporter]

See my solar-panel post in the thread at http://www.practicalcaravan.com/newforums/fm_messages.asp?FO=1&FM=407191

I'm no expert, but that seems like a simpler and less fiddly way to keep a caravan battery topped up, especially for just a tenner or two.

Would it be enough?

 

[Gafferbill]

Hi Transporter

Charging with a solar panel is proven technology but you need a fairly large panel to make much differenc. These larger panels are expensive and subject to theft.

It ideally has to track the sun (if there is any) to give it's stated output.

I have a 10watt controlled pannel that retails at

 

[AlanJ]

As a returning caravaner after 18 years I also wanted to be free of EHU's and work off 12v only.

I reviewed all the different ways of doing this:-

1. Car battery - used to do this in my old "tenting days" only cannot get any "serious amps" without danger of tow car not starting - as was the case in the old days.

2. Generator - purchased a 2Kva ?Silient Generator - tried it once and now left in garage as it was too noisey for me let alone my fellow camping neibours.

3. Solar power - OK but again not going to give me "guaranteed" power.

4. Wind power - forget it too noisey and like solar - needs guaranteed wind.

5. The answer lies in Fuel Cell Technology. I eventually purchased an EFOY fuel cell which "guarantees me 100 Amp Hours a day. They work on a chemical reaction and are almost silent and very economical to run on methanol. Down side at present is the cost of this new technology - but that will come down as they become more common.

 

[Gafferbill]

As a returning caravaner after 18 years I also wanted to be free of EHU's and work off 12v only.

I reviewed all the different ways of doing this:-

1. Car battery - used to do this in my old "tenting days" only cannot get any "serious amps" without danger of tow car not starting - as was the case in the old days.

2. Generator - purchased a 2Kva ?Silient Generator - tried it once and now left in garage as it was too noisey for me let alone my fellow camping neibours.

3. Solar power - OK but again not going to give me "guaranteed" power.

4. Wind power - forget it too noisey and like solar - needs guaranteed wind.

5. The answer lies in Fuel Cell Technology. I eventually purchased an EFOY fuel cell which "guarantees me 100 Amp Hours a day. They work on a chemical reaction and are almost silent and very economical to run on methanol. Down side at present is the cost of this new technology - but that will come down as they become more common.

Hi Alan

EFOY fuel cell and Methanol...... I guess you are a

Rich Non Smoker!!!

Do they let you on ferries or on Eurotunnel with the methanol.