12v set up, looking to add an inverter

[Rg_]

Hi guys in my van I have a leisure battery under the driver seat hooked up to my C-tek split charge and my fuse junction box which powers my led ceiling lights, some USB ports for charging and a battery monitor. Down the line I will add a fridge and sink etc via the 12v system.

Im looking to add an inverter to be able to house a few 240v plug sockets to charge my laptop or potentially add a small coffee machine or the odd thing like that. However I don't know where to start. I know what an Inverter does but not sure where it fits into my current circuit. Is it just a pos and neg on the leisure battery?

Also if I have a mounted set of plugs in the build how do I get these to work all the way from the inverter?

Not interested in a campsite plug in as this is more for off grid camping etc.

Thanks

 

[Rg_]

I would like to have something like this somewhere in the van, being powered from the inverter as and when if possible?

 

[Phil_G]

Hi RG
Charging a laptop is quite a small load where a small inverter and modest wiring will suffice. A coffee machine however is a huge load and will need a big inverter, a gutsy battery and really substantial cabling. They're two extremes of how your 12v system might be used. I would humbly suggest using gas for making coffee and keep the inverter setup simple
Also remember that sustainable off-gridding means replacing what you take out. Say for example your coffee machine runs a kilowatt and takes 10 minutes. Your solar or B2B needs to replace 14Ah before your next coffee break. If yours is a standard 85Ah battery, this example coffee-break would use one-third of its usable capacity.
Its entirely possible of course and many here have done big installs but it depends how much work/money you're prepared to invest - its not just a case of buying an inverter
Cheers
Phil

 

[Rg_]

Hi RG
Charging a laptop is quite a small load where a small inverter and modest wiring will suffice. A coffee machine however is a huge load and will need a big inverter, a gutsy battery and really substantial cabling. They're two extremes of how your 12v system might be used. I would humbly suggest using gas for making coffee and keep the inverter setup simple
Also remember that sustainable off-gridding means replacing what you take out. Say for example your coffee machine runs a kilowatt and takes 10 minutes. Your solar or B2B needs to replace 14Ah before your next coffee break. If yours is a standard 85Ah battery, this example coffee-break would use one-third of its usable capacity.
Its entirely possible of course and many here have done big installs but it depends how much work/money you're prepared to invest - its not just a case of buying an inverter
Cheers
Phil

Thanks for the advice. Not looking to be off grid for long periods so driving in-between would be topping the battery back up.

I guess I would just like to have a modest amount of power that I could run up a coffee or use something from the 240v plugs now and again if needed.

 

[Phil_G]

In the example given you'd need to drive for at least 45 minutes for the Ctek to replace the capacity used by one brew. Whatever current your mains appliances use at 240v, they will draw twenty times that amount from the battery - a 1000w appliance will draw eighty-three amps. That needs a serious installation, obviously it can be done but its hardly a 'modest amount of power'

 

[Rg_]

In the example given you'd need to drive for at least 45 minutes for the Ctek to replace the capacity used by one brew. Whatever current your mains appliances use at 240v, they will draw twenty times that amount from the battery - a 1000w appliance will draw eighty-three amps. That needs a serious installation, obviously it can be done but its hardly a 'modest amount of power'

I see what you mean. Maybe ill stick to just 12v.

 

[CAB]

The issue with coffee is heat. Heating water takes a lot of energy.

We have a Nowpresso for Nespresso pods. The rechargeable battery will make 2-3 espressos from cold, but if you use hot water from a kettle, it will make literally hundreds.

 

[Martinf]

I guess I would just like to have a modest amount of power that I could run up a coffee or use something from the 240v plugs now and again if needed.

As I have noted elsewhere our small Nespresso machine runs off a 1500W PSW inverter. It maxes the Leisure battery current at something like 135A but only for a short time. If running a 100Ah battery I would strongly advise a Lithium at this current. However a couple of small coffees only knock about 2% off the battery, much less than suggested above.

 

[Phil_G]

It was just an example Martin to indicate that theres more to this than buying an inverter and making coffee.
Regardless of the time taken to brew, 135 amps is a serious amount of current
It also takes your 1500w inverter beyond its spec

 

[Martinf]

It also takes your 1500w inverter beyond its spec

That’s the continuous rating of course. Peak is “4000W (few seconds)”.

 

[Celticrsmith]

Reading this, I’m looking to add an inverter to utilise my 3pin sockets from my leisure battery but as the OP asked, where would this fit in my current set up of everything bar the plugs are set up and the 230/40v only works via the EHU?

 

[Phil_G]

...discussed here: Leisure Battery Charging

 

[Shaun Witts]

Be aware that most modern coffee machines, such as Nespresso, require a Pure Sine Wave inverter to work, and will not work from the cheaper Modified Sine Wave type.
A 1500W Pure Sine Wave works fine for my Nespresso, and my 180 amp leisure battery has not yet run out of juice, but I’ve probably not made more than 3 in one go.

 

[Salty Spuds]

A £10 Moka pot on the gas gets you 2 proper espressos, just sayin’

 

[Shaun Witts]

A £10 Moka pot on the gas gets you 2 proper espressos, just sayin’

Agreed. A Pure Sine Wave Inverter for the purpose of powering a coffee machine is an excessively expensive luxury. One that I would not have if my converter had not convinced me that a Modified Sine Wave Inverter would do the job (even an MDS inverter is not cheap). So I was either stuck with an MDS that wouldn’t do one of the tasks I wanted it for, or I paid the difference for a Pure Sine Wave inverter.