Right up my alley. You dont size up the switch for 26A. The 26A is just a transient current. I can go into all the technical detail and make you find the switch data sheet, but off hand a switch rated for 10A will be adequate.

 

Do you mean an on off switch as master power to the slide system? As there is one in the van already, it needs to be on before the slide in/out buttons work.

 

Connect 240 ac to inverter to pass 240 ac to the sockets?
What's the point of that?

It's called a UPS!

 

To clarify, for the inverter I was looking at something like this Renogy inverter with UPS

Looks good.
Are you planning on having a separate battery for the inverter?

 

Looks good.
Are you planning on having a separate battery for the inverter?

Here is a diagram of the components for the complete set up as I saw it. It separates 240v mains power to BMS, Inverter and power supply. The BMS will replace the existing charger which I don’t believe works correctly. I’ve seen a BMS with 14 12V fuses built in, that can replace the current 12V fuse bank. And likely the 100Ah lead acid battery will change to 100Ah Lithium Ion.

We don’t use the van a lot off grid but when we do I need it to work, the current set up has issues mainly keeping the battery charged and then not being able to use the slide.


The relay on the right is the recent change with your help.

Ron

 

Forgot to add, the 240v to the BMS and power supply are to be on a separate circuit in the 240V power board, with a socket for each in the front boot of the van. It keeps that side separate from the 240v to the sockets from the inverter.

 

likely the 100Ah lead acid battery will change to 100Ah Lithium Ion.

Choose LiFeP04 not ion.

"we don’t use the van a lot off grid but when we do I need it to work"
For how long on a 100AH battery?
Thats appx a 90 amp draw on the battery at a 1000 watt output on the inverter.

 

Coffee maker and hair dryer would draw a bit but would be used few minutes at a time, charging a laptop wouldn’t draw that much, water heater and fridge can both run on gas, so can the heater. Aircon would be the item to draw most, but we’d run it sparingly. I will have to see about how many solar panels as this depends on the BMS. I would think at least 400w.
At the moment we can run for 3 or 4 days with the current battery and no solar, with only LED lights, tv, fresh water pump and phones on charge. Not using aircon.

I know a LiFeP04 battery allows a bit more use from the same 100Ah, but I could go a bit bigger or add a second battery. I’ll have to see how it all works first and what impact the solar will have. I’d like to be able to stay off grid for a week, maybe 2.

But adding an extra battery to this set up would be easy as long as the BMS can handle it.

 

I have three similar looking 120 volt inverters, They deliver a stepped "modified sine wave" that ie OK for power tools and soldering tools . BUT with a peak voltage of 170 volts, and they are unsatisfactory for electronic equipment. They can drive a motor OK, though.

 

I have three similar looking 120 volt inverters, They deliver a stepped "modified sine wave" that ie OK for power tools and soldering tools . BUT with a peak voltage of 170 volts, and they are unsatisfactory for electronic equipment. They can drive a motor OK, though.

Understand but in my case I have 12V motors, which run ok on a battery with sufficient charge. The problem is when the battery hasn’t got enough charge to run the motors. That is, deliver enough amps more likely as the manufacturer of the slide out also states they can run on lower than 12V but the current draw goes up. I would like a second 12V source for those motors.

The inverter is separate to that, to supply 240v when running on battery power - it will only power the few sockets in the living space of the van.

 

Really,, the 12 volt power supply could be connected directly to the battery, with a fuse, if it is a supply that is also suitable for battery charging. ALL of the travel trailers that I have seen include a permanently installed 12 volt supply that works both for the 12 volts lighting and water system, and also to power other items like the furnace and the slide-out motors.
What kind of travel trailer does not include such a power converter??

 

It does have an adapter, but since van is built for the European market and the Slide out is an local adaption for the AU/NZ market I highly doubt that the spec of the onboard adapter supplies the current to run the slide motors. Which is probably why the slide only works on 12V. I don’t have the spec for this adapter but if it is the little white box marked 12/24V it looks undersized, it will be the power supply to all European models without slide as well.

 

It does have an adapter, but since van is built for the European market and the Slide out is an local adaption for the AU/NZ market I highly doubt that the spec of the onboard adapter supplies the current to run the slide motors. Which is probably why the slide only works on 12V. I don’t have the spec for this adapter but if it is the little white box marked 12/24V it looks undersized, it will be the power supply to all European models without slide as well.

OK, I am glad to know that it does have an adapter. I seriously suggest checking it's label to know the actual specifications . The older power converters (adapters) that used a transformer were a whole lot larger , partly because they also included a bunch of fusing for all of te 12 volt circuits.
The switched supply for my computer is 65 watts, it is one inch by 2 inches by about 5 inches. it delivers 18.5 volts at3.5 amps. So your "small" supply could be quite adequate. So you really should check. For additional education, look at switcher power supplies in the Digikey catalog, and see sizes versus ratings for DC supplies .
AND, consider that the 50amp fuse was probably a compromise between protection and nuisance fuse failure. It might even be a wrong rating fuse installed in error.

 

OK, I am glad to know that it does have an adapter. I seriously suggest checking it's label to know the actual specifications . The older power converters (adapters) that used a transformer were a whole lot larger , partly because they also included a bunch of fusing for all of te 12 volt circuits.
The switched supply for my computer is 65 watts, it is one inch by 2 inches by about 5 inches. it delivers 18.5 volts at3.5 amps. So your "small" supply could be quite adequate. So you really should check. For additional education, look at switcher power supplies in the Digikey catalog, and see sizes versus ratings for DC supplies .
AND, consider that the 50amp fuse was probably a compromise between protection and nuisance fuse failure. It might even be a wrong rating fuse installed in error.

I searched for replacement power supplies for the type of caravan which comes up with a 10A power supply. I’d be more comfortable putting in that handles a bit more current than 10A so I’m ok with the power supply that is winging its way here now.

Thanks
Ron

 

When you get your 50 amp power supply, inspect it carfully for shipping damage, and read the data plate that has the actual specifications. A 50amp supply should be ablr to power all of your 12 volt system at once. . BUT before you install it, leave it plugged in and powered on for a day. No load required. THEN check the voltage and see if the supply voltage has changed, or if the supply is warm or even hot. If it is adjustable, check the adjustment. 12.0 volts will not charge a 12 volt battery very much. 13 volts will, in warm weather.