Fitting a 2000w inverter

[PeterCo]

Looking at fitting a 2000w pure sine wave inverter to run an induction cooktop. Our mk3 stove is hopeless in the wind and we would like to boil the billy inside. The inverters are getting quite affordable now. The worry is the wirring to the 2x105aH AGMs while it is possible to run thick wires to the first battery, I am not sure of the wiring across to the second battery. Has anyone attempted this?

[Wetjala]

Ouch! How to kill batteries in no time at all. I think the wiring would be the least of your potential problems.

A 2000W induction cooker operating at full tilt is going to draw just over 8A at 240Vac (or more if the power factor is considered). Assuming no losses through the 2000W inverter (not realistic) then the 2000W induction cooker will draw 148A from a 13.5Vdc supply (or 167A at 12Vdc).

For simplicity if you assume a linear discharge of the battery (in reality the discharge profile is non-linear, more so for high current loads like induction cookers at full load) then 105Ah battery will fully discharge in less than 30 minutes. Paralleling two 105Ah batteries (210Ah nett) may give at most an hour of use.

A few points should be considered before embarking on this:
1) Repeatedly discharging your AGM batteries below 50% capacity significantly shortens the battery life;
2) Rapid discharging of batteries not only degrades the battery capacity as well as its operational life but the risk of total battery failure increases (and a world of pain if the battery failure goes undetected for a time);
3) You will need to consider how to properly recharge your batteries as it will take a  l o n g  time to fully recharge heavily depleted batteries using solar panels alone.

In my opinion forget using the induction/inverter combination using only batteries to supply the power. If you want to use an induction cooker then take a 2KW generator with you as this will be far cheaper in the long term once the cost of regularly replacing AGM's is considered. Also have a talk with a battery expert, like R&J Batteries in Fyshwick, to get another opinion.

Expensive cup of tea!

[Gumb]

As per the very good advice from above, don't even consider it. You don't want to run the batteries down under 50% so you only have 105 amps to use. Running anything which requires an inverter that size will flatten them in no time.

[PeterCo]

Thankyou for the warnings Time to rethink!

[Alexr]

Have a read of this site, this is what I am running in my trailer and it is faultless.
2000w Inverter, 200AH Battery and 500w Solar. All Victron hardware.

https://online.flippingbook.com/view/1020814/

https://www.safiery.com/

[peter_mcc]

The worry is the wirring to the 2x105aH AGMs while it is possible to run thick wires to the first battery, I am not sure of the wiring across to the second battery. Has anyone attempted this?

I know some aspects have been addressed below but I thought I'd help with the cabling.

It's a long time since I've played with a Mk3 but from memory you can remove the grey aluminium strip along the back channel and run the cables through there. Alternatively you could run them from the second battery out to the pump area, up to the roof, across and down. Not ideal as its further but it might be easier (use larger cables to take distance into account).

With the cooktop how about getting one and using a mains power meter to see how much power you are likely to use boiling a kettle? I've got a 1800W Dometic inverter that I'm going to put in - from my experimentation with our coffee machine it won't use that much energy (ie Ah) although the peak load is quite high.

[Frankrhona]

Looking at fitting a 2000w pure sine wave inverter to run an induction cooktop....to make a cuppa tea.

Have you looked at alternate solutions? If you are looking for a similar performance to your electric jug at home you need around 2000W (6820 BTU/hr).
As demonstrated above, it is like using your 12v system as an arc-welder. Better to use a butane stove that is portable and can also be used with the tug when out exploring. By example, the Jetboil Sumo has a 1.8 litre capacity, 6000 BTU/h / 1.75 kW and takes 4m 15sec per 1 liter to boil water and costs around $210. Not bad!
There are may other options: Google "Hiking stoves" or similar.
Cheers,
Andrew

[peter_mcc]

As an aside, boiling a kettle using an induction cooktop won't use all that much power from the batteries. Sure, it draws a heap of power at the time but it doesn't take very long.

This article goes into it in more detail:
http://insideenergy.org/2016/02/23/boiling-water-ieq/
claiming it takes 46Wh to boil 500ml of water - or about 3.8Ah from the battery if everything was 100% efficient. If you assume the inverter is 90% efficient and the induction cooktop 80% efficient you're still only at 5.3Ah to boil 2 cups of water. This lines up pretty well with what I measured using our coffee machine - I can't remember the exact figures but I was surprised at how little energy was used.

Interestingly it would be almost as efficient to use an electric kettle - and perhaps simpler. There isn't much difference in efficiency though the trick might be finding one that works on a 2000W inverter.

The gas stove idea is good but part of the OP's aim was to be able to boil the kettle inside. I wouldn't recommend using a gas or fuel stove inside the Tvan because of both fire and carbon monoxide risks.

[Frankrhona]

Another thought is induction cookware must be made of a magnetic-based material, such as cast iron or magnetic stainless steel. So, our aluminium pots won't work!
I would be happy using a small gas stove in the Tvan. Many of the hiking stoves are used in small tents, especially by mountaineers. I enjoy sailing and we use both gas and metho stoves in a yacht under sail. Caravans can't be much different?
Cheers,
Andrew

[Phil W]

PeterCo, You really need Lithium batteries for that sort of current drain. Cheers, Phil

[Phil G]

Agree with above.  I fitted a 1500W inverter to my caravan for the sole purpose of running a coffee pod machine.  It is wired close to battery with huge 2Ga cable and no fuse - I've measured around 110Amps while the machine is running but it only runs for a couple of minutes so is do-able.  I'd rather be cooking on gas.

[Beakers]

Have you looked at alternate solutions? If you are looking for a similar performance to your electric jug at home you need around 2000W (6820 BTU/hr).
As demonstrated above, it is like using your 12v system as an arc-welder. Better to use a butane stove that is portable and can also be used with the tug when out exploring. By example, the Jetboil Sumo has a 1.8 litre capacity, 6000 BTU/h / 1.75 kW and takes 4m 15sec per 1 liter to boil water and costs around $210. Not bad!
There are may other options: Google "Hiking stoves" or similar.
Cheers,
Andrew

^ This.

I personally use a Dragonfly while hiking, but mates have JetBoils. If you primarily want to just boil water FAST and easy, not much beats a JetBoil.

[Gumb]

for boiling water when free camping, we use a Kelly Kettle. We also have a Jetboil which we use if going touring the tracks for a day.

[Tin Billy]

I bought a little coleman dual fuel sportster 533 single burner .... on special still .... $93 at tentworld ..... 10500 BTU, runs on unleaded ($1.50/L) or shellite ($9.50/L). Takes 90 odd seconds to boil billy for several mugs tea. Small compact and unleaded fuel easy to get. Burner is small at 16x18x18cm. I used it recently to heat up water in big 9L pressure cooker to do 2 x 1.5kg corned beefs recently.... faultless and what would have taken I reckon an 40 odd minutes just to pressure up on the low output Tvan (MkII) stove took just 11 minutes on the coleman then turned down to low for 90 minutes at pressure. Only used 350mL of unleaded petrol. I get a lot of miles to the gallon out of this little cooker and it's very fast 

[Gumb]

No way would I be carrying a can of petrol when camping or travelling or using a stove which needs it as fuel. That's a recipe for trouble if you ask me.