Inverter / 13amp socket

[wildebus]

Well if there are conflicts regarding electrics. Ask the man. WBus. David what’s your take on earthing inverters. Brian

Well, it is like Mark says below ....

There are arguments for and against, both seem to make sense too

It is easy to read a convincing argument for both options. And the arguments change and vary depending on if your battery ground is connected to chassis ground.

I tend to think of it similar to home products - if the casing is metal, ground it, if not, not so important.
But I would say go with any recommendations from the manufacturer if they provide them. For example, if you take a Victron Phoenix Inverter, they are plastic cased but the manual tells you to connect the inverter to chassis with a cable at least half the gauge of the supply cables (which is pretty heavy cable and seems a bit OOT?)

 

[brian c]

Hi all. Interesting reading. What is the difference between negative. (As on a battery terminal) and an earthing lead as on a inverter. Can the earthing lead(inverter). Be connected to the negative on the battery or negative stud. Brian

 

[wildebus]

Hi all. Interesting reading. What is the difference between negative. (As on a battery terminal) and an earthing lead as on a inverter. Can the earthing lead(inverter). Be connected to the negative on the battery or negative stud. Brian

On a vehicle where the leisure battery -ve is connected to the chassis (so >99% of campers/motorhomes), it would be the same as far as I can see. If the battery -ve to the inverter disconnected (meaning the inverter chassis was no longer earthed), the inverter would stop working anyway.
I usually end up connecting both to the same point. With your new setup where an official chassis earth is not handy and you know the battery -ve is the same as the chassis, I'd probably connect the inverter chassis to the -ve stud (what connection does the chassis earth point have?)

 

[Deleted member 86180]

I followed the advice of my local autospark and fit a 200amp Mega fuse on the positive lead close to the terminal and grounded the earth terminal to the chassis, I’m guessing if it has an earth terminal the manufacturer intended it to be grounded?

Low wattage kettle and toaster both work a treat, can anyone recommend a good low wattage microwave?

 

[wildebus]

I followed the advice of my local autospark and fit a 200amp Mega fuse on the positive lead close to the terminal and grounded the earth terminal to the chassis, I’m guessing if it has an earth terminal the manufacturer intended it to be grounded?

Low wattage kettle and toaster both work a treat, can anyone recommend a good low wattage microwave?

Lots around. Couple of general things ....
1) If your Inverter is not a Pure Sine Wave model, you would be best off not getting one with a digital display/control, but just a mechanical dial type.
2) Remember the Wattage that is quoted for a Microwave is the OUTPUT (cooking) Power. The Input Power is ballpark around 50% greater. So for example a 700W Microwave will not run on a 1000W Inverter.

 

[Deleted member 86180]

No worries, 2000w pure sine wave, single socket with the remote switch above a dedicated twin socket. Did a few tests with the low wattage kettle and toaster (much less draw than anticipated).
700w microwave, hmm 130amp draw. All working well, the inverter fans surprised me, very quiet.

 

[wildebus]

130A Draw from the microwave is a lot! I would have expected around the 105A draw from a 700W Microwave? I have a 700W one in my motorhome - I'll run it for a few minutes and see what I get.

UPDATE: Just tried - I draw 127A from my 700W Microwave. 1234W AC power (Label rating is 1200W) but the battery load is 1536W - a 300W overhead when using the microwave (thought it would have been a fair bit less)

 

[mistericeman]

Our 900w tesco one used to show just over 90a when in use via the 3000w mod sine wave inverter according to the NASA bm2....

Worked fine (as did the kettle/slow cooker and toaster)
Though as you would expect took about twice as long to cook something as the home 1800w one...

 

[Deleted member 86180]

In the short time I used the 700watt microwave (heated up a cup of hot water on highest setting), it didn’t constantly draw 130amps, it seemed to pulse and drop much lower for a few seconds every few seconds, seemingly in time (slightly delayed) with the drop in noise they make.
Anyway I can live with it, it’ll do for short blasts like partially cooking bakers and the like

 

[mistericeman]

In the short time I used the 700watt microwave (heated up a cup of hot water on highest setting), it didn’t constantly draw 130amps, it seemed to pulse and drop much lower for a few seconds every few seconds, seemingly in time (slightly delayed) with the drop in noise they make.
Anyway I can live with it, it’ll do for short blasts like partially cooking bakers and the like

Just the way they roll lol.....

Overall a 900w watt (cooking power) will use roughly the same amount of power as a 1800w one to cook the same food to the same temp...

It just takes longer so can run on a smaller inverter and take power from the batteries in smaller bites if that makes sense.