Inverter and generator into one plug?

[nismine01]

Righto you bright sparks (pun intended) out there.

I have a large pure sine wave inverter in my caravan, it is capable of running my air conditioner for about an hour if the batteries have full charge.

There are twin 240V inlets paired into the caravan and I'm wondering if I can also plug in my pure sine wave generator.

My concern is that they might/would be out of phase with one another and not work or cook one or the other.

The generator is not big enough to run the aircon but I was hoping it would extend the running time.

If any of you knowledgeable folk out there can answer this for me I'd be most appreciative.

If necessary I could just leave the car running to keep the batteries topped up for a little longer.

Regards

Mike

[Pedro_The_Swift]

You out there Young Gav?[bighmmm]


Didnt we have a similar topic a while back? hmmm.

[austastar]

Hi,
Are the inlets running to different circuits?
I would imagine they must.
Cheers

[Homestar]

On a twin inlet system, usually the AC is sperate to everything else - is this the case with your van? If so, that's all well and good, but I'd also like to know how your inverter is usually used and how it is wired, etc. Is the neutral of the inverter earthed? Therotically if the AC is on its own circiut then no dramas plugging the inverter into that inlet but there are a couple of other safety issues to look at not just blowing up your genset and inverter.

There is another thread all about that side of it somewhere and I don't have the strength to go through it all again to be honest and get howled down by so called 'experts' so I'll leave it at that.

[Milton477]

The short answer is no.
If you were to use the genny to power a battery charger which charges the batteries while the inverter powers the aircon, then ok.

Just to clarify, the battery charger should be plugged directly into the generator & the generator should not be connected to the van.

[Dorian]

In short, your right, if you try to use the gen-set together with the inverter you will get phase problems and probably will pop something.
As suggested in a previous post if the circuits are different there is no problem running your fridge on the gen set and the AC on the inverter. I'd use and extension lead directly to the device for the genset so you don't have to worry about neutrals etc. Otherwise you most certainly have problems with the earth leakage (safety switches).

If you want to extend your Air Con time, look at charging the batteries with the gen set as you are using the inverter. Most Gensets have a 12Vdc output and you can combine this with a battery charger to get more into your batteries.

If your battery charger is a smart multi stage jobbie then you might have problems as it will probably get upset and chuck a *** (all my terms are now not PC). In that case you could contact a company ADM (or Jaycar) and get a DC power supply.

Coupling DC sources together is not normally a problem as long as they are both around the same voltage ie within a volt or so. In this case the battery will set the voltage of both supplies bringing them to the same voltage. Just ensure that all of the connections are good.

Cheers Glen.

[trout1105]

Get a bigger genset that IS capable of running the aircon Plus anything else being used at the same time and disconnect the inverter.
This way you can run ALL your gear AND recharge the battery/batteries at the same time.

[Old Farang]

Long "discussion" here:

Giandel Pure Sine Wave Inverters (https://www.aulro.com/afvb/technical-chatter/255446-giandel-pure-sine-wave-inverters.html)

[Homestar]

The short answer is no.
If you were to use the genny to power a battery charger which charges the batteries while the inverter powers the aircon, then ok.

Just to clarify, the battery charger should be plugged directly into the generator & the generator should not be connected to the van.

OP mentioned 2 inlets so if they aren’t connected then running different supplies into each is fine IF other safety precautions are taken with the inverter and it is established that both circuits are seperate.

[Toxic_Avenger]

I had a tour thru a power station once. I got to play on the simulator for a simulated turbine start-up. I had NFI what I was doing, but I do remember having to get the generator in phase with the grid.
This sort of makes sense now.

[Milton477]

OP mentioned 2 inlets so if they aren’t connected then running different supplies into each is fine IF other safety precautions are taken with the inverter and it is established that both circuits are seperate.

Homestar, I agree if as you said the supplies are totally separate.
But are they? I'd hate the OP to let the smoke out of his equipment.

A small 1kva genny will run a 25A charger but not an aircon so the easiest way to get the maximum back into the batteries with a small genny is with a battery charger, just like running the tug to help as the OP has suggested.

My aircon draws 80 amps while running so adding another 25 amps will prolong the aircon use, assuming a 50/50 cycle. Now if the OP has maybe another 20 amps of solar then....who knows how long?

One really needs more information about the van's wiring to come up with a definitive answer.

[Homestar]

I had a tour thru a power station once. I got to play on the simulator for a simulated turbine start-up. I had NFI what I was doing, but I do remember having to get the generator in phase with the grid.
This sort of makes sense now.

Yep, an out of sync closure of a large breaker will, um - break things...[biggrin] The magnetic forces involved are staggering. Have personally seen the engine mounts torn off a 2MVA genset that closed out of sync and I've seen a video of a similar unit rolling over through a brick wall when the same thing happened.

Thankfully modern microprocessors and sync check relays make this a rare occurrence, but still possible if you're not careful.

Paralleled a 1250KVA Gen to the mains through a 22kv stepup transformer yesterday - you need to cross your t's and dot your i's before doing that. [smilebigeye]

[Markf]

Have personally seen the engine mounts torn off a 2MVA genset that closed out of sync

That wasn't at the transmitter site at Shepparton in the '70's was it? IF it was, that was me....[bigwhistle] BIG mess...

[Homestar]

That wasn't at the transmitter site at Shepparton in the '70's was it? IF it was, that was me....[bigwhistle] BIG mess...

Nope - you just dobbed yourself in. [biggrin] Was a large Detroit unit in the City - had to go and sort out why it closed out of sync - remember those big horrid Woodward load sharing controllers? One of those had gone to god.

Used to manually sync units too - I had one setup that I could only adjust the speed from the genset - you'd fiddle the governor until the syncroscope was right, then have to run over to the switchboard and throw the breaker - usually by the time you got to the breaker the load had changed and the syncroscope was whizzing around again so you had to start all over again. [biggrin]

[Markf]

Used to manually sync units too

Let's just say that the SEC supply is a VERY low impedance supply and that about 15 degrees is a LOT at those power levels.....

For the purpose of the current discussion. Connecting a small ~2kW gennie and a ~1kW inverter together at some unspecified phase angle difference will certainly let the smoke out somewhere.

[Homestar]

Yep, we won't close more that 5 degrees out when connecting to the grid, wouldn't dream of trying at 15 - thankfully modern control systems make this a snap.

[nismine01]

Thanks guys for all the input, yes I was party to the 'Giandel' discussion.

I was pretty sure it (this thread) was bound for disaster.

My next plan is:-
1 find a high output 12 volt alternator,
2 take the 240V alternator (doesn't work) out of the little Honda gen set and
3 hook up the 12 volt alternator to the motor to keep the rig going.

Cheers

Mike