Use of the 12v system in the move (1 Viewer)

[PP Bear]

If we can successfully use the alternator to charge the batteries and cool the fridge when on the move, then why doesn't it have a system to heat the water on the move too

With a battery to battery charger "tricking" the alternator system into producing lots of useful electricity, then surely it wouldn't be beyond the realms of a manufacturer to introduce such a system?

 

[dave newell]

The simplest way to generate hot water while driving is via a "calorifier" which is simply a heat exchanger connected to the engine's cooling system. They are available but not cheaply as far as I know and installtion can be time consuming so expensive in labour terms too, probably why most motorhome manufacturers don't bother with them although a few do/did.

D.

 

[pappajohn]

Because 12v will never heat a usable quantity of water.

I tried one of those stupid 12v cup immersion heaters......after 25mins with the engine running the cup of water was just luke warm.

With a heat exchanger the engines cooling water can be made to heat the domestic hot water to a point.

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[peterc10]

Errrr .... why not leave the truma on when you are driving?

 

[Snowbird]

My Alde does heat the water whilst driving through a heat exchanger. At first it would not have been my choice, all those joints to keep tight and with potential leeks,but after some use I would not change the system now.

 

[Tootles]

Errrr .... why not leave the truma on when you are driving?

You might need a very long mains lead.....Or leave the gas on, not really a good idea on the move.........

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[peterc10]

Always have the gas on when on the move. It is supposed to be safe with the securemotion regulator (not sure if that is the right name). Only time it is off is when I am refilling gas bottle or in the tunnel.

 

[Snowbird]

I was told by a Truma fitter that all motorhomes are designed for the gas appliances to be used whilst the vehicle was in motion. As most American RV fridges are mains and gas only, with no 12 volt, the fridge works on gas whilst on the road.

 

[Bailey58]

Because 12v will never heat a usable quantity of water.

I tried one of those stupid 12v cup immersion heaters......after 25mins with the engine running the cup of water was just luke warm.

With a heat exchanger the engines cooling water can be made to heat the domestic hot water to a point.

We bought one for our long journeys up to Scrabster for the ferry, used to plug it in after leaving Jedburgh on our lunch break and it still wasn't hot at Inverness.

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[Tootles]

Sorry, I thought it was standard procedure for MH and Tugs when on the move, in case your involved in an RTA.
I know its a strong recommendation from the fire brigades.

 

[jockaneezer]

If you draw power from your alternator whilst on the move, your engine has to provide that power in the first place ( you get nowt for nowt in the energy game, first rule of something or other ) bit like how your mpg drops when you switch the aircon on. A heat exchanger from the vehicle’s cooling or exhaust system would provide “free” energy though.

 

[hilldweller]

why doesn't it have a system to heat the water on the move too

You've had the heat exchanger explained.

Electrically. The shear scale of the amps. Water takes a lot to heat it ( if I remember physics from 50 odd years ago, it takes more energy to heat water than anything else ), so you'd end up with much bigger alternator belt, alternator, cabling. You'd see this in fuel consumption.

The real crunch is that many people go an holiday and stop driving. All that investment wasted.

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[scotjimland]

It would need at least a 600 watt element , this would use 50Amp..
does your alternator have that capacity spare.. ?

but irrespective of the wattage, .. there is no such thing as a free lunch.. it would use extra fuel to drive the alternator..

just noticed Brian beat me to it

 

[mariner]

Elgena do a lightweight water heater that heats on 240v but also has a 12v element to keep the water hot when traveling.

 

[Minxy]

Alternatively get one of these and put it out where the sun (yes we do get it occasionally!) can get at it - it's surprising just how quickly it get hot, we've used one to warm up water for washing up, hair washing, washing smalls etc ...

the only problem is ...




...




....





that you have to ......






.....






remember to use the bloody thing!

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[jonandshell]

24volt FFR Rover gennie and a BV!

Call yourself a craftsman?!

 

[Forestboy]

Always have the gas on when on the move. It is supposed to be safe with the securemotion regulator (not sure if that is the right name). Only time it is off is when I am refilling gas bottle or in the tunnel.

Same here.

 

[Daifuse]

A great many narrowboats have calorifiers (heat exchangers) fitted as standard and they are surprisingly efficient, utilising the waste heat from the engine, but unless you spend a lot of time on the road or you're prepared to run your engine when on site just to get hot water, I don't think it's a particularly efficient way to go.

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[eddie]

Sorry, I thought it was standard procedure for MH and Tugs when on the move, in case your involved in an RTA.
I know its a strong recommendation from the fire brigades.

What about vehicles powered by LPG? My RV works on 220VAC and gas, no 12 volt option. Again most RV's are or offer "on road" hot water option. Most European motorhomes that have Alde heating have it or again have the option.

 

[Tootles]

What about vehicles powered by LPG? My RV works on 220VAC and gas, no 12 volt option. Again most RV's are or offer "on road" hot water option. Most European motorhomes that have Alde heating have it or again have the option.

Yes, Eddie, but if I wanted to power my LPG car on bottles, would that be allowed/legal??

 

[eddie]

I really don't know, but the 160Kg tank under my RV has no inertia shut off of any description, neither does the domestic tank, for such things as the fridge and freezer whilst en route.

I suspect that there is no law to be honest as one of our fitters has an LPG powered car, and his "tank" is shaped the same as his spare wheel, so it drops into the spare wheel hole in his boot and is removable. I've seen motorway maintenance lorrys driving down the road, painting white lines on the road, heated by gas boilers and big 47Kg bottles.

I never used to turn off my gas when driving even when I had gas bottles, I am not sure what the risk is? the gas would be low pressure, but what would the difference be with petrol vapour for example?

If there was a big fire the bottle would go bang irrespective of being turned on or off

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[Jim]

I haven't turned my gas off in 20 years

 

[Chockswahay]

Propane is quite safe as a liquid under pressure (i.e. in the tank). However 1 litre of liquid becomes 270 litres of gas! The only real concern is not the gas under 'normal' conditions, it is the sudden and catastrophic release of the liquid. So when the cylinder valve is 'off ' then fairly safe, however when the valve is 'open' then any rupture in the gas line between the valve and the regulator will be very dangerous indeed

I used to spend a lot of my time next to a lot of propane in a small space (hot air balloons) and always felt quite safe............................... unless there was a fire! (then it was simply a case of turn the gas off!).

In normal conditions the gas lines are unlikely to rupture.............. in a vehicle crash? well that's altogether another thing

'just sayin'

 

[Chockswahay]

Forgot to say...... you would of course need a source of ignition (plenty of sparks in a car crash?)

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[Tootles]

I just have it buried deep somewhere that it 'wasn't advised', but that was with a tug.......Will have a dig about on this.

Ahhhhhhh.........Here we go.

Hitching up checklist
You can print out this checklist to use when you next venture out with your caravan.

Here we list many of the things you’ll need to do when you head off with your caravan. You might even consider laminating your checklist if there’s a chance of rain...

When you leave home the first couple of points may already be covered, but you’ll need to remember them when you leave a campsite.

• Turn off the gas at the cylinder
• Empty the fresh- and waste-water containers and clean out any toilet cassette in an appropriate place
• Check the caravan’s windows and roof lights are closed, internal doors and cupboards are closed, loads are safely secured and the external door is locked

And so-forth.......

 

[eddie]

LOL I'm not disagreeing, I am just saying that it would be daft of me to turn of a little bottle for example when I have 160Kg tank for propulsion, and my system is designed to run on LPG at all times mains isn't available

 

[Chockswahay]

LOL I'm not disagreeing, I am just saying that it would be daft of me to turn of a little bottle for example when I have 160Kg tank for propulsion, and my system is designed to run on LPG at all times mains isn't available

But does your bottle have crash protection shut off automatically? The propulsion tank will of course

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[Tootles]

This from London Fire Brigade.....

Gas canisters

• Keep cylinders outside your caravan.
• Before going to bed or leaving the caravan, turn off all appliances.
• Turn off cylinders unless appliances (such as the fridge) are designed to run continuously..
• Never use a cooker or heater whilst a camper or caravan is moving.
• Change gas bottles only when completely empty.
• If you suspect a leak, turn off all appliances and the main cylinder valve.
• Open all doors and windows, do not smoke and do not operate electrical switches. Speak to the warden or site manager and seek specialist advice.

In the event of a fire turn off the main gas cylinder (only if you can get to it safely) and get everyone out straight away. You should then call 999 and give the location of the caravan, giving a map reference if possible or a landmark like a farm or a pub.

 

[TheCaller]

Propane is quite safe as a liquid under pressure (i.e. in the tank). However 1 litre of liquid becomes 270 litres of gas! The only real concern is not the gas under 'normal' conditions, it is the sudden and catastrophic release of the liquid. So when the cylinder valve is 'off ' then fairly safe, however when the valve is 'open' then any rupture in the gas line between the valve and the regulator will be very dangerous indeed

Good point - and calls into question some of the benefit of the Truma SecureMotion regulator. It prevents the consequences of a pipe rupture after the regulator, but not of a rupture between the bottle & the regulator, which could be far more dangerous (although somewhat less likely to happen). At least if the high pressure pipe ruptures, the appliance flames will go out irrespective of the type of regulator fitted.

I wonder if there is a study of what really causes the fires in 'gas on' accidents. Probably the worst situation is when the pipes don't rupture, but continue to feed & maintain the flame in a damaged appliance, that now brings that flame into contact with something flammable. Or when the pipe feeding one appliance ruptures, releasing gas to ignite on the flame of another appliance where the pipe remained intact.

 

[Tootles]

This was put down to the gas fridge catching fire whilst the truck was moving.

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