Community Forums

Stan&Jacquie · 01-03-2016, 01:26 PM

I just upgraded my Magnum 2012 MSW inverter (it failed, 8yrs old) to their PSW unit (same output). Might I expect this inverter to consume more power from the house batts? If yes, would it be prudent to install a separate small (500 watt?) inverter to run my Samsung RF194 overnight? I boondock about 1/2 the time and also have a 480 watt solar system. If fully charged by 10pm, the batt bank (440 amp hrs) would read about 60% full around 7 am. If the PSW inverter is going to draw more juice, I would be concerned the batt bank would draw down even further by morning. Hence, my question about adding a smaller inverter for the frig. Your advice would be most appreciated! Is there a particular inverter you would recommend for this?

Sent from my iPad using iRV2 - RV Forum

FlyingDiver · 01-03-2016, 01:38 PM

If the load is the same, then the energy consumption by the inverter should be about the same. Can you see if Magnum publishes efficiency rating for the two different inverters?

How many batteries do you have now? I would think adding more batteries would be a better solution than another inverter.

Mr_D · 01-03-2016, 01:49 PM

Adding another inverter will increase the total draw, unless you plan on turning off the original one. Even then I would think more batteries would be a better solution.

Old Bounder · 01-03-2016, 03:22 PM

I think the two previous responders are correct. The new inverter will not draw significantly more current than the previous one, and should not present a problem.

Increasing your battery capacity could help in a couple of ways.

Additional battery capacity (additional batteries) would provide power for other activities and uses
Additional capacity would help your current batteries last longer, by decreasing the depth of discharge each cycle.

Just a suggestion.

Scarab0088 · 01-03-2016, 03:40 PM

Inverters pose a "tax" on the batteries while running...the bigger inverter, the bigger the "overhead".
This is part of the factors of the inverter called "efficiency".

With a second 500W inverter just for the Fridge, the overhead loss can be reduced to power the fridge. BUT, to see the goal increase in the battery life, you will need to turn-off the bigger inverter when not in use.

As far as the effiency of the described old MSW vs. the new PSW...I would venture a guess that the new one is more efficient. The manuals would describe these numbers.

Another benefit of having the second inverter is redundancy. If the one inverter fails, the Fridge can be kept running by switching to a plug on the other inverter with no loss of food stocks

More batteries will give you a deeper "well" to draw juice from. That is never a bad thing when boondocking, as long as charging demands are factored into the mix. But in our experience, energy use management provide the biggest gains to life off the grid.

Best luck.

twinboat · 01-03-2016, 03:46 PM

I would also think that the draw from the fridge compressor will be lower with a cleaner sinewave.

Stan&Jacquie · 01-03-2016, 10:26 PM

Quote:

Originally Posted by twinboat

I would also think that the draw from the fridge compressor will be lower with a cleaner sinewave.

Thank you everyone. Collectively, you all have made an excellent argument for adding to the battery bank. I will, however, compare the efficiency ratings of both Inverters.

Many, many thanks.

Sent from my iPad using iRV2 - RV Forum

Stan&Jacquie · 01-03-2016, 10:32 PM

Quote:

Originally Posted by FlyingDiver

If the load is the same, then the energy consumption by the inverter should be about the same. Can you see if Magnum publishes efficiency rating for the two different inverters?

How many batteries do you have now? I would think adding more batteries would be a better solution than another inverter.

FlyingDriver: I presently have 4 6v wetcell golf cart batteries for a total of 440 amp hrs and a 480 watt solar system. When boon docking, the inverter runs 24/7 to,power the residential frig.

Sent from my iPad using iRV2 - RV Forum

airbrushguy · 01-05-2016, 09:24 AM

The new inverter should be much more efficient. MSW typically require motors and appliances to draw more power to start and run due to the "dirty"wave and their compensation of it. They also generate more heat on MSW which translates into wasted energy. the PSW won't cause this and should be more efficient as a result of fewer losses.

2 Stroker · 01-05-2016, 08:40 PM

Quote:

Originally Posted by Stan&Jacquie

FlyingDriver: I presently have 4 6v wetcell golf cart batteries for a total of 440 amp hrs and a 480 watt solar system. When boon docking, the inverter runs 24/7 to,power the residential frig.

Sent from my iPad using iRV2 - RV Forum

I had a Magnum 2812 PSW inverter installed going on 3 years ago when I had my Samsung 197 installed and it has been running on the inverter from day 1, don't have to reset the microwave clock. I have 4 6v wet batteries and can run about 8 to 10 hrs then have to start the gen set for about 2 hrs best time to cook while the batteries are being charged.
No need to get another inverter, get an auto genset start when your batteries get to 12.2v the genset starts
Wireless Auto-Start EC-30W : RV Boat Parts
'Y' harness is required for installation (sold separately).
2 stroker

Stan&Jacquie · 01-05-2016, 11:08 PM

2-Stroker: Thanks for the tip. I actually just purchased Magmums Auto Gen Start kit for about $200 but have not installed it yet.

After you run your batts down for the 8-10 hrs, what voltage reading are you getting from the batts?

Sent from my iPad using iRV2 - RV Forum

Mr_D · 01-05-2016, 11:15 PM

Quote:

Originally Posted by 2 Stroker

I had a Magnum 2812 PSW inverter installed going on 3 years ago when I had my Samsung 197 installed and it has been running on the inverter from day 1, don't have to reset the microwave clock. I have 4 6v wet batteries and can run about 8 to 10 hrs then have to start the gen set for about 2 hrs best time to cook while the batteries are being charged.
No need to get another inverter, get an auto genset start when your batteries get to 12.2v the genset starts
Wireless Auto-Start EC-30W : RV Boat Parts
'Y' harness is required for installation (sold separately).
2 stroker

Thanks for the link. We have auto start built in but it doesn't work and I might just be easier and cheaper to bypass the whole thing and use the wireless unit. Kind of hate to do that but we do need to be able to start the gen set without stopping, running the gen slide out and starting it from the control panel then do the steps backwards each time we need to start it.

Good price BTW!!