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Old 07-17-2016, 08:11 PM   #15
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Thanks so much for sharing your experience and knowledge. I am going to conclude that the answer for me is a combination of the most recent posts by YC1 and BigBadDad.

I will try dropping the cutoff to 10 just to see if it is the surge issue, but it is possible to run the Micro off the battery bank alone.

If it will in fact work with the cutoff at 10 it wouldn't be a good practice to rely on day to day.

I wasn't sure what the expectations should be.

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Old 07-18-2016, 09:39 AM   #16
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Your profile reflects the 34' Ventana, you say Magnum and PSW. Is the MS2000, MS2812, or other?

A few general comments, and opinions:

-A properly sized battery bank and inverter, can handle microwave duties, coffee pots, hair driers, residential fridges, induction top burners, etc. (As info, we replaced our 04's Modified Sine Wave OEM inverter/charger with the MS2812. We also upsized our battery bank to X's 4 L16's Lifeline AGM's for 800AH's of bank power. We have 1200W of high efficiency solar feeding them. My rule of thumb with the DW is the Microwave can be run as long as she needs it during the daytime, with strong sunshine. Cloudy days, or shady campgrounds, I ask her to limit the time to 15 minutes and under. (I'd guess she uses it on average less then 5 minutes, 85% + of the time.) This is a convection microwave, and I do ask her to only run the convection oven part with the generator running.)

-Suggest you get your batteries completely charged up to 100% SOC. Then run do a test run on the microwave, and see if you get the same results. If yes, then you have the troubleshooting steps mentioned above.

-If your batteries have been abused, even AGM's, you could have one that has gone bad. So having the batteries load tested to confirm their health might also be a good idea. (The weakest battery in the chain, is what all other batteries will strive to join!)

-Do you have even 15A or 20A available to you where you're parked? That would help...

-You might also check in on the Newmar forum, to see if another Ventana owner is having a like problem.

-Magnum tech support is great, and will can help you walk thru your settings if you feel you need their help!

Best of luck, and please come back and update what you find out...

And as a low number poster, delayed welcome to the gang!!!

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Old 07-18-2016, 09:55 AM   #17
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Originally Posted by BigBadDad View Post
Generalizing probably won't give you the answer you want but "in general" running 800 to 1000 watt appliances is not a good practice for inverters and worse for the batteries they draw on. A quick call to the manufacturer tech folks will indicate that. You can do it but there is a fairly good chance you will not be satisfied in the end. I had a friend that had to do it to support a dialysis machine so he got 4 dedicated batteries just for that...it worked but he had to pay attention and it wasn't cheap.
With a proper setup it's really no problem to run 1000 watt devices. It typically takes less than 10-20 amp/hrs to make a pot of coffee. Not really an issue for most batteries. Many of the Luxury MH's have two 3000 watt Inverters to handle everything while driving.
It's the "proper" setup that gets many people....... and true, it's not cheap.
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Old 07-18-2016, 10:09 AM   #18
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One other thing to remember, the 50% rule or 12.1? volts is a static figure with no load. A heavy load can easily drop the voltage well below 12V, even if the batteries are fully charged. As soon as the load is removed, the static voltage will come back up.
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Old 07-18-2016, 02:56 PM   #19
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I thought I responded to the recent posts but I don't see it here so I will try again.

I think the answer for me is a combination of BigBadDad and YC1.

I will try the Low Battery Cutoff at 10 just to see if it it possible to run the micro off the battery bank if there is no other option, and take BigBadDad's advice and not do it as common practice.

I wasn't sure what my expectations should be.
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Old 07-18-2016, 05:53 PM   #20
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Originally Posted by Scottybdivin View Post
One other thing to remember, the 50% rule or 12.1? volts is a static figure with no load. A heavy load can easily drop the voltage well below 12V, even if the batteries are fully charged. As soon as the load is removed, the static voltage will come back up.
i have seen the current draw of 154a by microwave and the voltage on rc50 showed 11.5v while it was running. you can lower the low batt cut off to 11v in quick drop without damaging. once you remove the load, the voltage will bounce back to a normal level (mine was 13v or higher).
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Old 07-22-2016, 03:00 PM   #21
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Great info. Having family issues but just a quick reply to say thanks for the help.

MS2012 2000 wt pure sine

20 amps available which will run the micro but trying to test and learn battery power functions and capabilities.

Not sure if it helped but I happened to switch off the 50 amp breaker and the micro was working on batteries with no fault. I will do more testing and update.

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