If I was to use something Like that I think I would make up timer/thermostat system that controls when the heater is on and operational..

There are some great modern day thermostats that run off a couple of AA batteries, they have all the functionality that you could need..

- 24hr timer, on/off duty cycle..
- Digital temperature control..

The heater would be set to max temp, and controlled via the Thermostat..


Thank's Phil this topic has directed me to another system that could be quite feasible in a Lithium System..

Juergen

Dear all

Lets put a lid on this. Its been a very long time since I taught electronics/electrical theory, seems I may have made a few errors in my comments. The unit I believe uses semiconductor heating which is very efficient. I dont know if I miss measured the DC current on the input.

I am struggling to understand how these things work, and frankly, dont give a toss any more.

Most times at camp we use the electric blankets plugged into the inverter as it prolongs the battery life (only 150W) this can warm us all night with little stress on the battery capacity or performance. If you consider 4 hours of TV before 2200 to 0700 with the electric blankets going its working well.

My sincere apologies if I have offended anybody with some of my comments, one tends to fix "facts" in the head and the rest of the world is wrong

Take care and safe travels

 

Hi Phil

No need to retreat !

Thank you so much for your time and effort in trying to get a suitable heater for us nomads. Even if your heater uses more power than you first thought I think a few of us will still consider it for use when we have 240 power available either at home or on the road,

thanks

 

cooee wrote:

---

 

Hi Phil

No need to retreat !

Thank you so much for your time and effort in trying to get a suitable heater for us nomads. Even if your heater uses more power than you first thought I think a few of us will still consider it for use when we have 240 power available either at home or on the road,

thanks

 

---

  I second that.

I dont know, thats why I am asking,

How much drain would an Electric Blanket put on the Batterys, 240 volt double bed Blanket,

I have two 8 D batterys, Would 270 Watts of Solar Panels cope with the drain on the Batterys from the blanket,

I have a 5000 Watt Invertor, With a 10,000 watt surge, I dont have a Generator and dont use C/P's, I only free camp,

Every thing else is 12 volt, including the TV,

Hi Phil, Thank you for that info,

My Batterys are Lead Acid 12 volt deep cycle, 8D RV, Weigh 130 Lbs each, (48 KGS) 245 Amp Hours each, so a total of 490 Amp hours combined together,

One is the coach Battery and one is the start battery, The motor charges both when driving, I have a boost switch that plugs both in when starting the motor,


I also carry another smaller battery just in case, AGM 12 volt, 200 amp hours which I keep fully charged, Its not connected, I have Huge Jumper cables, 400 amp welding cable,

You need big muscles to move these mongrels around, They are very heavy, I do have weight problem with my coach, I need to put another ton in the front of it to lower it down, Spare wheel on a frame at the front might do it, Its the only place it can go,

I took the Genny and the Gas tank out, 150 US gallon Propane tank, Both probably getting close to a ton and a half, So the front of the coach is up in the air, I replaced the gas tank with 3 X 9 Lbers, using one bottle at a time, Inconvenient, But I know how much gas I have left at any time, The steel frame and the 3mm sheet enclosures, Plus moving the batterys forwards helped, but still not enough weight in the front,

I didnt know you could get 12 volt electric blankets, Do they suck as much power as a 240 volt Blanket, ???????? I really dont want or need an invertor, It would have been only for a blanket, 240 volt,

I dont have problems with Hoons, Local Dills, Etc, But thats just me, People seem to be wary of me, and leave me alone, I dont like crowds, So I camp in quiet spots,

Here's one for your nutter to ponder, I just thought of it,

I have a 10 KVA transformer in the Coach for the 240 volt mains power to use the 110 Volt accessories I have still left in the coach, A/C's Etc, I wont be using either of the A/C's, The insulation copes very well with the heat and cold we have here, + 38C to - 4C so far,

Could I run leads from the Battery thru the 240 volt Invertor Pure Sine to the 10 KVA Transformer and run the 110 volt accessories, Microwave, Mixmaster, Vacuum cleaner,
Electric blanket, Only for short periods,
I could use the spare battery for this, and it would not be connected to the Coach in any way, Other than thru the invertor and then the Transformer,

The spare battery would be disconnected to charge it,

Hi Brian

The deal with invereters is to have the thickest cable (I have 2 10mm sq cables each for pos and neg) and the shortest distance between battery and inverter. Your inverter will draw a lot of current from the battery so get some thick cables, be sure to fuse or use a DC circuit breaker in the DC circuit. I probably wouldnt use the invereter for the vacuum cleaner or anything with a larger motor, as at start up the motor can draw a lot of current which could shut the inverter down. That being said, dont be afraid to give things a go, if it fails there will be no damage done.

For 12V electric blanket I would use 6mm sq cable to a fuse (say 25Amp) to the cigarette lighter outlet ONLY for the blanket.

I agree about the aircon etc, we hardly use ours except on very hot nights. We have 2 300mm 12V fans, electric blankets and the convection heater.

Rule of thumb, at 12V you will need a much larger current=larger cables to get the same heat (say 240W) than 240VAC. Its 20Amps Vs 1 amp, go figure. This makes a good case for inverters and/or generators.

Electrics in caravans and RVs can be a minefield if you dont get it right, I would talk to a qualified sparky or use this forum before picking up a spanner or screwdriver. There are some special techniques in electrical servicing that can be dangerous if done incorrectly. Sorry to tell you that one.

Aus-Kiwi I agree about the fat on the bones, I have enough for a few.

Safe travels

 

BTW, your batteries sound like they are up to the task.

Your question on the transformer being run by the inverter, technically in practice I would imagine a very large startup current in the transformer primary as it is highly inductive, so probably not a good idea to do that. With stuff like aircons, transformers etc they are highly inductive and draw a heap of current for a few milli seconds at startup.

 

-- Edited by Phil C on Friday 27th of June 2014 04:49:37 PM

-- Edited by Phil C on Friday 27th of June 2014 04:56:41 PM

I like being thin, Its too hard to get the fat off me, so I dont put it on to start with, Hahahaha I just lot a stone,

oldtrack123 wrote:

---

Mr B2 wrote:

---

 {1] I took the Genny and the Gas tank out, 150 US gallon Propane tank, Both probably getting close to a ton and a half, So the front of the coach is up in the air, I replaced the gas tank with 3 X 9 Lbers, using one bottle at a time, Inconvenient, But I know how much gas I have left at any time, The steel frame and the 3mm sheet enclosures, Plus moving the batterys forwards helped, but still not enough weight in the front,

[2]I didnt know you could get 12 volt electric blankets, Do they suck as much power as a 240 volt Blanket, ???????? I really dont want or need an invertor, It would have been only for a blanket, 240 volt,

I dont have problems with Hoons, Local Dills, Etc, But thats just me, People seem to be wary of me, and leave me alone, I dont like crowds, So I camp in quiet spots,

Here's one for your nutter to ponder, I just thought of it,

[3]I have a 10 KVA transformer in the Coach for the 240 volt mains power to use the 110 Volt accessories I have still left in the coach, A/C's Etc, I wont be using either of the A/C's, The insulation copes very well with the heat and cold we have here, + 38C to - 4C so far,

Could I run leads from the Battery thru the 240 volt Invertor Pure Sine to the 10 KVA Transformer and run the 110 volt accessories, Microwave, Mixmaster, Vacuum cleaner,
Electric blanket, Only for short periods,
I could use the spare battery for this, and it would not be connected to the Coach in any way, Other than thru the invertor and then the Transformer,

The spare battery would be disconnected to charge it,

---

 
Hi

[1]Well, I hope all that work was done by a licensed GAS fitter who testdd ALL the appliances , regulators  pipe work etc & issued you with a compliance certificate

[2]THe power of the blankets should be shown on th label or in the specs curent draw of the blankets

That can range from as low as 95W <200W

So it is the WATTS rating that deitermines how much power they use.

100W at 12V uses the same amount of power as 100W @ 240V, this has been explained in previous posts to this thread

[3]So you have a nonapproved set up with THAT transformer  It does not comply to the Aust  Electrical Standards

 

You have enough safety risks now with out adding anymore, by running that transformer off an inverter!!!

 

PeterQ

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 Mr B2

You raise some important safety issues here as does PeterQ. OK lets cut to the chase.

If you allow a safety margin when you hook up the inverter to the transformer eg a normal DC fuse in the battery line, and be very aware of crackles and dirty acrid smells I say give it a go, just make sure NOTHING is connected to the 110V side, then connect each appliance in turn then try multiple appliances.

I would be very interested in the results, just dont blow the crap out of yourself and your equipment.

PhilC