Inverter/Charger Transfer Switch

[rocco52]

I am upgrading to a 2000 watt Pure Sine Inverter/Charger and noticed that virtually all of them have a built in 30 amp Transfer Switch. My trailer is setup for 50 amps due to having two AC units. I would never attempt to power the AC units from the Inverter but wondered if the 50 amp input would damage it?

[uncle_bob]

Hi

The Victron MultiPlus 2,000 inverter / chargers have a 50A transfer switch.

If you have a 50A trailer and want to run everything off the inverter ( or at least switch it over) you will need a 100A transfer switch or an inverter set up for 230V. Both are not worth the trouble with a 2KW inverter.

Simple answer is to use the transfer switch to move over a sub-set of your loads. You can't run everything anyway.

Consider that you very much need to read the fine print on any inverter. They likely have a "short time surge" rating ( maybe 4KW). They likely have an energy limit ( maybe 2,000 volt amps). They might also have a long term power output ( maybe 1,600 W). Is that a 4KW or a 1.6KW inverter? Or maybe it's a "2,000" ...

Next up, a 2KW inverter running at 90% efficiency with 12V in will pull 185A. That's way more than a stock battery setup (batteries or cables) can reasonably deal with. Hopefully you have already upgraded that side of things.

Bob

[rocco52]

Thanks for the input Bob. I am upgrading to 4 six volt batteries and would be only using this while boondocking to run the TV for the grandkids and possibly the microwave for a few minutes. I have generators but don't want to start them up just for things like that. My other goal, to have a smart charging system, would be solved because most of these type of units have that. Eventually I will add Solar to the mix.

[uncle_bob]

Hi

I would look at lithium before you go to the 6V batteries ....

Even with a double stack of 6V, you only have about 400AH available at a low discharge rate. That gets you about 200AH usable. Drawing down lead acid's at C/2 sort of rates *significantly* decreases the amp hour ratings. Your "400AH" stack may only be a 250AH source at that sort of rate.

Next layer to the onion with lead acid's is - are they fully charged when you start using them? It may take > 12 hours to get them to full charge. A lot of people look at a voltage and get faked out. The battery is at 80% and they think it's full ....

Add this all up and you can flatten things pretty quickly (like in under a half hour ...).

Bob

[rocco52]

Good point about the batteries Bob. If you own a Victron how is the fan noise?

[uncle_bob]

Originally Posted by rocco52

Good point about the batteries Bob. If you own a Victron how is the fan noise?

Hi

Fan noise? What's that?

So far I have not noticed any. I also (for some of the reasons noted above) don't run the inverter much. In charge mode .... it's very quiet.

Bob

[rocco52]

Uncle Bob, Sometimes I overthink things so I apologize in advance. If the shore power goes out and the AC is running how could you keep the Victron from auto-switching to battery power and draining the batteries? Looking at the installation manual on line they have you run the incoming AC line through the Victron switch and then into the distribution panel.

[gypsydad]

I had the 2000W solar set up with "very big" 6V batteries stored under my night stand, on my 2008 25'AS. This was a "modification" by previous owner, and it was capable of running single 1500 AC for 3 hours... The person I purchased from told us about running till the batteries died...this was in Phoenix. The plugs were all re-wired to accept power from the inverter or shore power. In the new 2018 AS's, I note they now have the plugs also wired for inverter; the 2017 and earlier models have 2 plugs in a few locations (TV area) for using the inverter. Point is, in my 2017, the microwave is not plugged into an inverter plug; if I want to use the microwave, I have to use shore power or fire up my generator...we don't use often anyway, so not a big deal. I am not sure if your AC is wired to allow you running your AC from the inverter?

[uncle_bob]

Originally Posted by rocco52

Uncle Bob, Sometimes I overthink things so I apologize in advance. If the shore power goes out and the AC is running how could you keep the Victron from auto-switching to battery power and draining the batteries? Looking at the installation manual on line they have you run the incoming AC line through the Victron switch and then into the distribution panel.

Hi

The Victron (normally) will not supply enough current by it's self to start the AC. When the compressor cycles, it will trip out.

Bob