Hyrbrid Inverter and generator to run AC?

[Searching_Ut]

I’m looking for inputs from those using hybrid inverters, especially in conjunction with generators to run high load devices like the AC. I currently have 600 watts of solar on the roof of my 5er, with a samlex pure sine inverter powering the whole rig AC wise. The inverter is wired through an auto transfer switch, and I put in an isolation relay to automatically turn off the Intellipower DC converter when the Inverter is switched on, but all other power management we do manually. (Fridge and Hot water to Gas, AC Off etc.)

I’m going to put more solar on the roof taking the system up to 1000 watts, and the plan for when I retire next year is to replace the current 3 group 24 batteries to 4 6 volt jars. I’m not sure what I want to do inverter wise at this time though. I’m thinking of going to a 2000 watt hybrid, such as the Xantrex freedom SW2012 12V 2000W. Besides allowing the wife to potentially use her hair dryer for short periods without my having to go out and fire up on of the 2 champion 2000 watt inverter generators we have, and maybe even some microwave popcorn in the evening. Currently I have to run both generators in parallel to run one of my 15k AC units. Would I be able to get away with just one generator being used, with the xantrex taking care of the compressor starting surge, and using the solar/batteries to fill in the generator output deficit? Looks good on paper, but I’d love to hear from folks actually making it work, if in fact it is working for them.

[pianotuna]

Hi,

I did not say the inverter struggled. I said the fault light (over load) came on for a brief time (less than a second). I did not monitor the DC voltage, nor track the AC voltage.

Prior to the Magnum, I had a cobra 2500 MSW. It too would start the roof air (easier than the microwave, actually). But being MSW I did not wish to run the motor in the air conditioner.

My unit is a 13500 Dometic from 2004.

time2roll wrote:
I can't imagine 3000w sine wave inverter struggles to start your air.
My Prosine 1800 run the air better than utility power. (RIP)
My replacement GoPower 2000w has no issues either.
Mine is a 12 yo Dometic 13.5. Inverter has 5' of 4/0 cable to the four aging GC2.

Could you need a start cap or something?

2oldman had the same issue and ended up with some monster 48v inverter.

[Searching_Ut]

The first hand experience is greatly appreciated guys. As an update, I decided against going the hybrid route. To begin with, I'd have to do a fair bit of re-wiring as the batteries in my 5er are in the front bay, with the dc converter being behind the basement with an undersized wiring run of at least 15 feet given the route Heartland decided to run it. Since even with the hybrid inverter I'd need to run the generator too, might as well even parallel them, or get a bigger generator if that seems like too much trouble.

The final electrical upgrades I've decided to run and install as soon as the weather improves a little more are:

4 X EGC2 Duracell wet cell golf cart batteries (Deka GC15s, 230ah) Battery box built, batteries on charge in garage, ready to install.

600 watt Samlex PST inverter (installed right after got trailer) and an additional Xantrex Prosine 2000 watt inverter both auto transfer switch wired to whole house. DC converter auto disconnect, fridge, ac and water heater disconnect to be done manually. Can't even use the recliners in this rig without AC power. 600 watt has been more than enough for the last year, but wife wants to be able to use Microwave for short spurts, and about 5 mins of hair dryer (1200 watt) in morning. How things change over the years, didn't even have a generator for camping most of my life.

Upgrade solar to 1000 watt, 10 X 100 watts all parallel, dual Bogart SC2030 charge controllers, panels running full length of rig to help with shade issues in assorted semi shaded areas.

[time2roll]

I can't imagine 3000w sine wave inverter struggles to start your air.
My Prosine 1800 run the air better than utility power. (RIP)
My replacement GoPower 2000w has no issues either.
Mine is a 12 yo Dometic 13.5. Inverter has 5' of 4/0 cable to the four aging GC2.

Could you need a start cap or something?

2oldman had the same issue and ended up with some monster 48v inverter.

[pianotuna]

Hi ctilsie242,

I just tried my roof air on the Magnum 3012 inverter with the batteries totally full two days ago. The red fault light on the remote came on for perhaps 1/2 second.

I would go for Victron and 24 volts, Outback and 24 volts, and Magnum and 24 volts, as a minimum.

At least for the Magnum 3012, load support is NOT voltage support, so don't expect it to do surge support in combination with external power (shore or generator) or to prevent low voltage damage to the roof air. Switching to load support on the Magnum is slower than the switching to voltage support on the Sola Basic autoformer.

There are some reports that the Sola Basic doesn't switch fast enough in some situations.

If my Magnum had not been under warranty, I would have moved to Victron (and 48 volts for the bank).

So, although the 12 volt Magnum can start the roof air, I really think it is pushing the Magnum too hard. I get ground fault errors from some, but not all GFCI shore power outlets. Apparently Victron does not exhibit this behavior.

A 24 volt inverter only has to work 50% as hard as a 12 volt. In an ideal world I'd move to a 48 volt bank, with a 48 volt inverter.

Again, please remember that load support on the Magnum is NOT intended as voltage support. So, on low voltage 15 amp shore power, all the Magnum will do is blend power from the battery bank to allow the running of items which total more than 15 amps without blowing the shore power breaker. The Magnum can be "tricked" into voltage support by deliberately limiting the shore power amperage to an extremely low level, but I believe doing so may have caused my Magnum to become damaged which eventual caused it to catch on fire.

That said, I find the load support feature extremely useful, when I can use it.

ctilsie242 wrote:
This is definitely something I'm looking at doing in whatever rig I get, although Magnum Energy the way I'm leaning. I'm looking at the 3000 watt hybrid inverter, a monitor panel, a generator controller, and a battery temperature gauge. This way, if the power conks out on my rig with the A/C on, the batteries take over until they fall to 60% SoC, then the generator controller fires up the Onan. Power comes back on, the generator stays on until the batteries are at 90% SoC, genset drops offline, transfer switch flips to shore power, life goes on.

One big advantage of a hybrid inverter is that the locked rotor amps coming from the A/C are handled by the inverter and batteries. This doesn't add a strain onto the generator or anywhere upstream of the inverter, so power cords are not affected. The second big advantage is that power sags at a crowded campground are handled and are not passed onto the A/C's compressor which can burn out if it encounters too little voltage. The third is that you can have power coming in from shore power, a second vehicle alternator, generator, or solar... and still run the A/C on a combination of any or all (well, assuming the incoming power is adequate, of course.)

[time2roll]

Member pianotuna has posted that the Magnum hybrid does not really provide voltage support.
If utility power sags, RV voltage sags along with it.

This makes sense if the utility power is 105 and the inverter provided 120 all the power would go back into the grid.
In some cases you might be able to limit utility power amps such that voltage does not sag but this would be a manual function. Otherwise you are looking at double conversion with all AC power provided by the inverter.

I assume Victron and the rest will operate similar.

[ctilsie242]

This is definitely something I'm looking at doing in whatever rig I get, although Magnum Energy the way I'm leaning. I'm looking at the 3000 watt hybrid inverter, a monitor panel, a generator controller, and a battery temperature gauge. This way, if the power conks out on my rig with the A/C on, the batteries take over until they fall to 60% SoC, then the generator controller fires up the Onan. Power comes back on, the generator stays on until the batteries are at 90% SoC, genset drops offline, transfer switch flips to shore power, life goes on.

One big advantage of a hybrid inverter is that the locked rotor amps coming from the A/C are handled by the inverter and batteries. This doesn't add a strain onto the generator or anywhere upstream of the inverter, so power cords are not affected. The second big advantage is that power sags at a crowded campground are handled and are not passed onto the A/C's compressor which can burn out if it encounters too little voltage. The third is that you can have power coming in from shore power, a second vehicle alternator, generator, or solar... and still run the A/C on a combination of any or all (well, assuming the incoming power is adequate, of course.)

[mapguy]

There are a number of inverter chargers out there that provide load support from a second or even a third power source to start/run large loads like an AC unit.

The magnum inverter model spoken about up a couple of posts does not have load support like a MSH series Magnum does have load support...

Victron, Magnum, Xantrex, Mastervolt, Outback -plus others have load support. These type inverter charger installs are far more complicated than adding a small inline inverter to an RV.

I have been looking at a Victron unit myself.
Victron Multi-plus
These are really common in the marine market. Yeah, probably going to be a LFP battery bank and solar, too. Many design questions to resolve before spending the $$$.

[tad94564]

My Outback GFX1312 starts and runs my 11k truck camper A/C easily.

It's a hybrid, with a very high surge capability - 4600VA surge, 2900VA 5 second surge, 1800va surge for 30 minutes, 1300va for as long you have 12v juice.

I pair it with a 2200/2100 Powerhouse gen and two 160w solar panels/roguepower 35amp MPPT, and it will run the A/C all day long.

fun thing to do is set it for High Battery (HBX) mode - if your solar gets the battery charged, it will kick off shore power and run off the battery/solar. You can also "sell" power back to the electrical grid with this one - it's a true jack-of-all trades.

[jharrell]

My 15k BTU Coleman pulls about 1600w continuous according to my Magnum which varies by outdoor temperature. According to Coleman docs it can pull up to 1900w in 115 outdoor temps.

However its startup surge is up 61 amps! This is well beyond the Magnum's surge capability. Before the Easystart it would start the A/C most of the time but complain with a overload fault recorded, just like the Wynn's video, sometimes it would shutdown.

Another problem was the Magnum is very sensitive to voltage sags, if voltage drops below its VAC dropout for just 16ms (one cycle) it disconnects shore. Even when set to 60V for dropout sometimes the A/C start would trip to dropout causing the Magnum to try and start the A/C by itself even when connected to shore/generator.

The Micro-air lowered start up surge below 30 amps, it also waits a few seconds to start compressor so blower fan and compressor are staggered. Also if it sees a stall it shuts down compressor for 5 minutes. I have seen it do this when accidentally shutting down generator with A/C running, the Magnum tries to takeover but the compressor has already started to stall, the Easystart shuts down compressor and just the blower is running off inverter, although it does record an overload, without Easystart it would just shutdown the Magnum after fighting the compressor stall for a few seconds.

The Easystart is a great product and IMO should be factory installed by all RV A/C's to allow more flexible inverter and generators setups and make things easier on all equipment involved. I would imagine its much easier on the compressor to soft start as well.

[MrWizard]

that was a 2800w inverter ? correct ?
which means what 300+amps continuous DC use at 12v

40amps dc 500+ watts would not be much surge

it seems to me, that it would be 40 amps 120vac surge for motor starts

what is the rated AC surge wattage
40amps would be 4600va at 115vac

PS

according to this PDF file MS 2812

its 40amps AC surge for 100 milli-second

5 seconds for 3900 real watts
30 seconds for 3800 real watts
5 minutes for 3200 real watts
30 minutes for 3000 real watts
continuous for 2800VA

[pianotuna]

I still don't know what caused the Magnum to overheat to the point where it caught on fire.

I wonder what the surge of 40 amps means. Is that 40 amps @ 12 volts?

I do know it was not reversed DC polarity.

I do know it was not a short--because the catastrophic failure fuses did not blow.

That leaves a fault in the FET board. But what caused the fault after 2 years of running? I did have one instance of over heating of the fets. I did have one instance of shut down due to exceeding 125 amps of charging.

I can say that the inverter ran a lot hotter than 20 c (68 f), and that on the day it failed the case was at 37 C (98.6 f).

If I had it to do over I'd go for a 24 or 48 volt 4000 watt unit.

[MrWizard]

i think we are drifting off topic

the question was not "run a/c from inverter"

the question was about load support from inverter to 'START' a/c using smaller generator. large enough for run load but not large enough for reliable starting surge

and i think the magnum 40 amp 120vac surge support, should be enough for any RV roof top a/c than can run from the generator
after all the 40amps from the inverter is in addition to the generator power, as long as it is load support such as the magnum which syncs to the input power

situation with inverters where it switches to inverter for start and then back to generator
would be limited to the max the inverter can supply

battery bank size has little to do with 'start only' support
as long as it can supply the needed boost for a few seconds

as PT found out tricking the inverter into continuous support is Not good
better off doing double conversion and running directly from the inverter
with enough inverter to do the job safely, and charging the bank with however much wattage can be mustered

[pianotuna]

Searching_Ut

Invest in a Kill-a-watt meter. Wattage varies on air conditioners depending on the ambient temperature, and line voltage. Mine draws between 1200 and 1900 watts.

[time2roll]

Micro-Air wrote:
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