Modified Wave Inverter

[Tikvah]

I have a 2000 Watt Modified Wave Inverter in my bus.  Someday, when I'm rich and famous, I'd like to upgrade to a better unit, but for now, it keeps my house-type refrigerator running when we're on the road and it provides the other necessities. 

However, there's some quirks while we're on the inverter that seem odd to me and I wonder if it is because of the Modified Wave, or if I have some other quirk in my electrical system. 

When on the inverter my convection oven needs to get unpluged.  The digital display goes all goofy and beeps. 
My charger plugs for my iPads get hotter than normal.
My coffee Pot won't function at all.

This isn't because of low voltage, these problems exist while driving as well as parked, so I know I have lots of charge going into the batteries.

I have two large golf cart batteries, and so far I've gone 14 hours running just the refrigerator and a few lights and still maintained... I don't know how long I could actually go.  I don't have a gauge. 

Thoughts?

Dave

[luvrbus]

What is the model and name of the inverter the old modified Trace's were almost a true sine I have a one in a  Trek rv it runs everything without any problems 

[Kitt]

Sounds like typical modified sine symptoms and not that anything is wrong with your inverter. I changed out my Xantrex Freedom modified sine inverter for a Magnum pure sine inverter to avoid what you've pointed out. The microwave, tv, and wall warts (charging transformers) are all happier now and run cooler. The fridge works great on it too.

I did the upgrade when we put in a residential fridge and I've been very happy with it. I got lucky and grabbed a "used" Magnum inverter on eBay from a brand-new but wrecked motorhome and paid less than half of the cost of a new one. So if you're patient you may find a similar deal.

[Tikvah]

It's a Heart HF12-2000U

Not a good picture, it's pretty tight inside the bay right now.

[luvrbus]

There are tons of those still in use in the all electric coaches stacked to make 4000 watts in Prevosts from the 80's they run everything, you are a little shy on the battery bank that could be the problem

[Seangie]

Dave -  I had a heart inverter that was modified sine and had the same issues.  I picked up a 2500w 12v true sine model for about 600$ new (search my posts...there is a link to it somewhere).  It doesn't have all the fancy stuff on it but it does its job. And its alot cheaper than most units out there.

For a cheap way to monitor your bats...grab one of these and wire a cigaretter lighter outlet somewhere easily accessible.
http://www.adventurerv.net/digital-voltage-meter-p-4020.html?utm_campaign=partsfeed_ppc&utm_medium=cpc&utm_source=Froogle&gclid=CKPz2MTxjLsCFYVZ7AodGykADg   the lighter can double as a USB outlet, light outlet or anything else that plugs into a cigarette lighter.  The voltage may not be exact on the meter but consistent enough that once you start using it you'll know when you have to recharge (definitely way before it gets to 7volts )

-Sean


www.herdofturtles.org
1984 Eagle Model 10S

[Dave5Cs]

Dave also needs to be as close to the bats as possible as long as there is separation between them.

[TomC]

I have an old Trace 2500 watt RV/Marine modified inverter with 130amp charger. It runs everything, but the microwave hums and takes longer to cook, the stove hood runs slower-all typical of a modified sine wave. But-it has been 100% reliable now for nearly 20 years.

I'll probably get a Magnum 2800 true sine for the truck. Or maybe an Outback-anyone have opinions on either? Good Luck, TomC

[Tikvah]

Is there a practical difference between the "True" and the "Pure"?

[Jon]

We had a pair of Heart 2500 inverters in our previous coach and they did everything, including powered a new Bosch refrigerator, ran the microwave, TVs, kept my computer charged etc.

Our current coach has a pair of Outback inverters hooked in series so we can run two AC units if we want (that will never happen) and from my layman's point of view the only difference I notice is the remote is significantly more sophisticated. I wouldn't know a sine wave, true sine wave or modified sine wave if I fell on them. I just know my stuff works.

[Oonrahnjay]

     Tom - I had "somebody who knows what he's doing" order my inverter.  I specifically said "load-sharing" meaning a unit that will "share" from the battery -- ie. if you're plugged into a small-capacity socket and you set it to pull only 10Amp but you need 12Amp, the inverter should pull 10Amp off the shore cord and 2Amp (or 240 watt) off the battery.  But until I was using the Outback that he sold me, I didn't know that the Outback was a "load switching" inverter.  If you have the max shore Amps set at 10 and momentarily you need 12A, it will switch off the shore cord and pull all 12Amp (2400 watts) from the batteries - then when your internal load is switched off, it will then pull the 10Amp off the shore cord to recharge the big battery drain that it just used. 
     I talked to the Outback customer service guy and he confirmed that that was the way they work and he generally but vaguely hinted that they were looking at models down the road that would actually load share. 
     But right now, I'd be careful to ask EXACTLY what I wanted.  (Just my experience, what I ran into.) 

BH  NC   USA

[niles500]

Is there a practical difference between the "True" and the "Pure"?

Not really any True or Pure sine wave inverters (sine wave only comes from the generator), a smaller square wave is all it means
                   l                          _
             ___l   or                  _l
             l                       
             l
           
                       

[bobofthenorth]

We've got identical Heart 2500's on the boat and the bus.  They run everything just fine with the exception of digital heating blankets/mattress warmers.  The one in the bus makes the bed warmer controls go wonky but unplugging the blanket and plugging it in again puts everything back to normal.  On the boat I switched to inverter once with the blanket plugged in and it completely destroyed the blanket controller.  Different blankets but expensive lesson - we now leave the blanket unplugged unless we're on shore power.  The only other item that we've noticed any effect on is my electric hair clippers (I'm too cheap to hire a real barber so mama cuts my hair)  The clippers appear to run on the inverter but they pull my hair rather than cutting it.  Other than that we've never seen any ill effects from the Hearts which are advertised as modified wave.  I tend to agree with the earlier post which said that the only way to get a genuine sine wave is with a rotating field - anything coming off an inverter is going to be square if you examine it close enough. 

[Lin]

We have a very old Trace modified sine wave inverter.  I had several complaints about how poorly it ran some things, but then found out that it was not the inverter's fault, but rather my anemic battery bank.

[edroelle]

Hi Dave,

I have 2 Xantrex modified sine wave inverters, RV3000s, and have similar problems.   Electronics do not like modified sine wave inverters.  My induction hot plate does not work.   Cell phone chargers get hotter.    Microwave makes odd sounds.   

I installed a new replacement, Whirlpool refrigerator, which was very similiar to the one I removed.   I burned-up 2 electronic defroster boards.   I replaced  the timer with an old style defroster control module and had no additional problems.

Electronics do not like modified sine wave inverters.

Ed Roelle
Flint, MI