12v to 24v Inverter

[SCOMAN]

Hi I recently purchased a mounted troops ration heater. I'm sure I can fit a new plug to fit a car cigarette lighter but obviously my car is only 12v. Whilst I'd love an excuse to purchase an ex MOD Landy I don't think it's a sufficient reason. Any help or direction would be appreciated.

 

[bikething]

Any idea what the power consumption is ??

 

[Dingo]

i have an inverter, i use it for the laptop whilst out on site, it will also power a small flourescent tube, i dont think it would power anything requiring lots of wattage, i will check it out tomorrow.

Adam.

check these out mate.

http://www.barden-uk.com/pure-sine-wave-power-inverters.html

http://www.conrad-anderson.co.uk/power/150-300watt-puresinewaveinverters.htm

http://www.netpcdirect.co.uk/inverter.php

 

[FGYT]

you dont want an inverter they change DC power to AC power ie 12v car (or 24v) to 240v house

you ether need a transformer or an additional 12v battery to have a serial take of to give 24v but charge in Paralell etc etc

ATB

Duncan

PS i could be wronfg and you Typod and missed a 0 of the 240v

 

[Sniper]

These things are high consumption and needed the engine running to power them unless you did'nt mind trashing your batteries. Originally designed for AFVs which had a bank of 4 batteries on line with the engine running, 2 x vehicle + 2 x radio connected giving 24v. Then they were fitted to FFR landys with 24v systems.

Given that these batteries were extreme heavy duty so they could provide a helluva lot of power to start those big engines in up to sub zero temperatures, they could power these boilers no problem. Standard car batteries and car wiring looms just could not take the amperage needed to operate the boiler.
However, assuming you could get the plugs and fittings to connect the thing up, if you got hold of a couple of truck batteries and connected them in series giving you an output of 24v, connected to a truck alternator also 24v which you could turn into a wind turbine by fitting an old truck fan and modifying the blades, in theory in a strong wind you might just manage to boil enough water for a cuppa.

 

[Sniper]

Just been reminded.......some solar panels for water heating operate on 24v so there might be a possibility down that route but have to admit don't know much about solar panels.

 

[ANDYRAF]

If I remember correctly ( if not Spamel will ) the standard boiling vessel (BV) took a 60 amp constant use fuse and never worked very well when used on a landie. Engine must be running as not many batteries could take that sort of punishment. They where mainly used on vehicles with 90 amp or better generators ie. CVR(T), CVR(W), 430 series and bigger.

Andy.

ps. Spamel will know for sure, I mean what do i know I was air force, right Spam.

 

[gregorach]

you ether need a transformer or an additional 12v battery to have a serial take of to give 24v but charge in Paralell etc etc

A transformer won't work - they only operate on AC.

 

[Matt.S]

60A @ 24V is a HELL of a lot of power to take out of the average family car cigarette lighter. They are supposed to provide about 5A @ 12V.

Solar panels generally don't produce much current. Maplin isn't an ideal source, but take a look here: http://www.maplin.co.uk/module.aspx?ModuleNo=97381&doy=27m8

That's 5 foot long, 2-1/2 foot wide, weighs about 30lb, costs a grand and would take all day to charge a bank of batteries enough to power your heater for about 40 minutes... and that's assuming no battery or conversion losses.

 

[FGYT]

A transformer won't work - they only operate on AC.

oops quite right shows how long ago i did electronics :yikes:

ATB

Duncan

 

[SCOMAN]

Hi this ration heater isn't a boiler it's an Yank MRE Heater. I'm going to try to put a picture in but I've never managed it before so I'll no doubt have snags now. Any ideas?

 

[cheapeats]

I would assume it is entirely resitive (heater coils) if you were to run it on 12volts it would operate at 1/2 power and take twice as long to heat. This might be an option. Is there any electrical ratings for current, amps, or watts. If it is low enough you might be able to use a voltage converter.

 

[SCOMAN]

I'm not too sure although I was thinking along the same lines but wasn't too sure whether it would draw all the power and knacker my cars electrics. I'm awaiting the heater in the post.

 

[Tripitaka]

Can't help but think that this is a solution looking for a problem.

Surely a Swedish Army-style trangia would be a better option? Quick, easy, compact and simple.

Don't get me wrong - I know where you are coming from. If the question is "How do I get this thing to work?" then it's an interesting topic. If the real question however is "How can heat rat packs/MREs quickly?" then this isn't the solution you need.

 

[Sniper]

Can't help but think that this is a solution looking for a problem.

Surely a Swedish Army-style trangia would be a better option? Quick, easy, compact and simple.

Don't get me wrong - I know where you are coming from. If the question is "How do I get this thing to work?" then it's an interesting topic. If the real question however is "How can heat rat packs/MREs quickly?" then this isn't the solution you need.

I'm with you there Tripitaka, good for a bit of amusement, an interesting project even, getting it up and running but unless you drive a truck with a 24 volt system I'm not sure what use it would be. Am afraid outside of this, my previous post is my only solution. It would knacker any car 12 volt system and even with a 12 - 24 step up, it would still take a fair bit of amperage to give it sufficient output to work. The other way round from 24 - 12 volt is dead easy.
If it is for normal cooking use I would definately look at a more traditional means.

 

[Matt.S]

Scoman, if you have a multimeter or a friend with one, it would be helpful if you measure the resistance. Then we'd know thw beast we're dealing with better.

 

[SCOMAN]

I fancied this as an alternative hey nothing lost I'll give it a go then ask for a recommend for a good garage specialising in electrics in the Plymouth area! Thanks for the help and advice guys

 

[crazydave]

you sure this is a vehilcle one? they did try a system whereby old radio batteries could be used to utilise the leftover charge prior to sending it back for resupply.

in which case any battery would probably do it - whats the connector on the end like?

 

[mortalmerlin]

What you want to do probably won't be possible. It is possible to build a DC-DC convertor for 12-24V DC, I can even explain how to do it.

BUT (and it's a big one) if the current levels are in the range of 60A @ 24V = 1.4kW so if you want to generate that from 12V and you can expect about 70-80% efficiency for the convertor you will need to take about 1.7kW out of your cars 12V which will come to 141 Amps. Your alternator in a landy will put out only about 70A, the rest will have to come from the battery which isn't meant to be discharged for long periods at that rate.

I think car lighter sockets are 1A or 5A so you see the problem. Just to build a convertor of this size will cost a fortune in parts, not to mention the first couple of attempts will probably not survive (but would be entertaining to watch). It would have to be wired into the car on it's own circuit and you battery will not last very long.

Personally I would try and run it at 12V and see if it will still heat, it should only draw 30A ish and you can wire it into your car (might work but will take longer to heat). I would guess it's just a simple resistive element for the heater. Give it a go with a couple of jump leads

 

[mortalmerlin]

Strange, seem to have lost a post.

I didn't see you pic of the thing at first. There is no danger, I think, of that consuming anything like 60A. If you want to build a DC/DC convertor for 12 to 24V yourself I can point you in the right direction. But I would need to know how much current the thing will draw.