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BFL13

Victoria, BC

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Posted: 11/12/19 05:46pm Link  |  Quote  |  Print  |  Notify Moderator

time2roll wrote:

Shot-N-Az wrote:

I suck at math, and I’m no electrician, but real world experience is that I can microwave on my inverter but it takes a lot longer than normal.
Is that a sine wave inverter?
Very common for a MSW to cook slower as the peak wave voltage underdrives the megatron.


People might remember my tests on that for PWS vs MSW to heat a cup of water to a certain temp in the MW starting from the same cold temp. Yes it took longer with MSW to reach that temp.

However, in real life cooking a spud, Eg, you stick a fork in it to see if it is soft yet. How soft is soft? It turns out that you can stick the fork in at about the same time with MSW. It is soft "enough".

Same with frozen veggies. How soft is soft enough? Turns out you can over-do it with PSW and that the MSW for the same time is "enough".

So this is not a lab test using instruments.

If you are heating something and you need to let it cool down before you can eat it, you just wasted AHs. However some cooking does require you to heat it up just so, to "bring out" whatever, even if you then need it to cool before you can eat it and not burn your mouth.

I had no trouble with the 2000w MSW inverter to do everything with a newer MW. However, this 1991 MH has a 1991 Dometic "RV MW" that will not run at all on MSW. Turns out it runs perfectly on PSW. I had the opportunity to get a PSW 2000w so I did instead of swapping out the 1991 MW.

Several different brand, newer (say 2003 on?) MWs do run on MSW just fine except "slower" (when lab testing per above), when we tried them out in various RV set-ups in the slide- in camper and 5er we had.

It is only when you are operating on the margins that any of this matters. If you have lots of battery and proper size inverter (MSW or PSW) with proper wiring, you can run any newer MSW MW of the matching watts and not notice any real difference for most jobs.


1991 Oakland 28DB Class C
on Ford E350-460-7.5 Gas EFI
See Profile for House electronics set-up.

crosscheck

Coldstream, BC

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Posted: 11/12/19 06:24pm Link  |  Quote  |  Print  |  Notify Moderator

Trackrig wrote:

I have four Trojan T125 batteries and a 2000W inverter and often use our 1200W microwave to warm food for lunch or a cup of hot water, usually for no linger than four minutes at a time with no problems.

Bill


We have 4 GC-2, 450AH, 2000W PSW inverter, 490W solar, 1200W Micro. Average run time, no more than 3-4 minutes. Also, run a coffee machine if there is a lot of solar(but not at the same time as the micro.). Use a French press coffee maker if there is little solar. Toaster, hair dryer, magic bullet, curling iron etc. Mostly dry camp, no generator time.

This is not with the heater fan running. We watch our battery AH consumption carefully. Have had this fairly similar set up for the last 8 years in 2 different RV's. Never a problem.

Dave


2016 F350 Diesel 4X4 CC SRW SB,
2016 Creekside 23RKS, 490W solar, 2000W Xantrex Freedom 2012 inverter, 4 6V GC-2 (450AH)
2006 F350 CC 4X4 sold
2011 Outfitter 9.5' sold
Some Of Our Fun:http://daveincoldstream.blogspot.ca/

bid_time

Michigan

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Posted: 11/12/19 06:54pm Link  |  Quote  |  Print  |  Notify Moderator

The batteries are only half of the equation. What do you do so you can run the coffee maker and microwave the next day? And what about the times when the sun doesn't shine for 4 days? And what is the cost of that side of the equation?
Just buy the generator and be done.





doughere

Mooresville NC

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Posted: 11/12/19 07:10pm Link  |  Quote  |  Print  |  Notify Moderator

bid_time wrote:

The batteries are only half of the equation. What do you do so you can run the coffee maker and microwave the next day? And what about the times when the sun doesn't shine for 4 days? And what is the cost of that side of the equation?
Just buy the generator and be done.


I have a 2 K Honda; I HATE running generators.

otrfun

Desert SW

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Posted: 11/12/19 07:42pm Link  |  Quote  |  Print  |  Notify Moderator

Takes about 110a (12v) to power our microwave with 2 GC2 batteries using a Xantrex 2000w PSW inverter. We can power the microwave for almost 40 minutes before the batteries are down to 12.2v. Our inverter to battery cable run is almost 13 ft. so we used 4/0 cable. Even at 110 amps we only have a .15v (1.2%) drop.

FWIW, the Xantrex low-voltage alarm activates when the load voltage drops below approx. 11.3v. We've had it down to almost 11.0v (with a 110a load) without it shutting down. Output voltage was down to 109vac at that point. The Xantrex has a very low no-load draw--approx. 700ma.

Pretty pleased with the overall performance of everything. Would love to use 4 GC2's, but no room for 'em in our truck camper.

time2roll

Southern California

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Posted: 11/12/19 07:48pm Link  |  Quote  |  Print  |  Notify Moderator

bid_time wrote:

The batteries are only half of the equation. What do you do so you can run the coffee maker and microwave the next day? And what about the times when the sun doesn't shine for 4 days? And what is the cost of that side of the equation?
Just buy the generator and be done.
I have a 700 watt Ryobi propane generator for circumstances of several days of no sun or some other near fatal situation. Only puts 40 amps into the battery, not going to run the MW direct.
Inverter does run silent during quiet hours.


2001 F150 SuperCrew
2006 Keystone Springdale 249FWBHLS
675w Solar pictures back up

crosscheck

Coldstream, BC

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Posted: 11/12/19 09:17pm Link  |  Quote  |  Print  |  Notify Moderator

otrfun wrote:

Takes about 110a (12v) to power our microwave with 2 GC2 batteries using a Xantrex 2000w PSW inverter. We can power the microwave for almost 40 minutes before the batteries are down to 12.2v. Our inverter to battery cable run is almost 13 ft. so we used 4/0 cable. Even at 110 amps we only have a .15v (1.2%) drop.

FWIW, the Xantrex low-voltage alarm activates when the load voltage drops below approx. 11.3v. We've had it down to almost 11.0v (with a 110a load) without it shutting down. Output voltage was down to 109vac at that point. The Xantrex has a very low no-load draw--approx. 700ma.

Pretty pleased with the overall performance of everything. Would love to use 4 GC2's, but no room for 'em in our truck camper.


Got any room under the dinette seating? we had 4 AGM batts under the seating in our TC for 5 years. The 4 batts in a square did not take up that much room.

Dave

crosscheck

Coldstream, BC

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Posted: 11/12/19 09:43pm Link  |  Quote  |  Print  |  Notify Moderator

bid_time wrote:

The batteries are only half of the equation. What do you do so you can run the coffee maker and microwave the next day? And what about the times when the sun doesn't shine for 4 days? And what is the cost of that side of the equation?
Just buy the generator and be done.


We have a Honda i2000W inverter generator which we carry all the time. Might as well be a boat anchor. Never use it. Batteries are more than half the equation. They keep you going through the highs and lows of solar if you have enough AH. The inverter is the silent answer to the generator. Even in shade or cloudy conditions, we can harvest 4 A from the panels(high of 22A/hr). Our Micro in 4 minutes uses 12.5 AH which is around 3 hours of low sun. We have 450AH of available storage.

If you are the type that dry camps or boondocks like they are at home, then you will be running your genny constantly and running out of water within a few days.

If you camp like you are in a back country environment without the luxuries of home, then without giving up too many comforts, a few simple conservation choices for power and water will see you staying a lot longer in the bush without alot of genny noise complements of your hard working batteries, solar and your inverter.

Dave.

marcsbigfoot20b27

Phx

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Posted: 11/12/19 10:22pm Link  |  Quote  |  Print  |  Notify Moderator

ktmrfs wrote:

doughere wrote:

I have a unit with 1500 watt microwave and would like to be able to use it occasionally when dry camping (10 min or less at a time). I plan to use a 2000 watt pure sine wave inverter. Also plan using it on a 900 watt coffee maker (about 15 min a pot). Anyone have any experience with this setup?

Thanks,
Doug


run our microwave quite often on an inverter. you will need enough battery and big short cables from battery to inverter.

Now one thing to consider, which we did was to toss the original microwave in the donate pile and buy a panasonic true inverter microwave. It's operation is much different than traditional microwaves. when in partial power mode it doesn't cycle between 0% and 100%, it actually runs at the % set. So.... if you set it to 50% that's what it runs at continually. Ours is a 1500watt microwave and I run it easily on a 1000W inverter if power is set to 50% or less. At 50% power it does NOT take twice as long to heat something, more like 25% longer.

I also have a hotel type keurig that draws 900W and we run it off the 1000W inverter with no problems either.

for this type of draw I'd recomend either 4 GC2s or a bank of 12V. GC2's aren't great for large current draw and have high internal resistance compared to a 12V jar. So with only 2 GC2's your inverter may shut down when batteries are below 75%ish SOC. With 4 GC2's it should work down to 50%. I run 4GC2's, with only 2 it only worked with batteries charged above 75% or so. A few others have had similar experiences.


Same here....ditched the OEM microwave and got an inverter microwave. Cooks more evenly at 40-50% and uses less peak power with no cycling from 100% to 0 to 100 and irritating my psw inverter, even though with 3 AGM deep cycle 100 ah batteries and 360 watts of solar it never made a peep anyway. Would work with two 6 volts also at level 5 without the low voltage alarms.

Gjac

Milford, CT

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Posted: 11/13/19 08:03am Link  |  Quote  |  Print  |  Notify Moderator

doughere wrote:

I have a unit with 1500 watt microwave and would like to be able to use it occasionally when dry camping (10 min or less at a time). I plan to use a 2000 watt pure sine wave inverter. Also plan using it on a 900 watt coffee maker (about 15 min a pot). Anyone have any experience with this setup?

Thanks,
Doug
You don't say how many or what type of batteries you have, which will make a big difference in the answer to your question. I doubt you will get 10mins of MW use on one 12v battery. Also it depends on how it is wired and the gauge of the wire. I have a 1500 watt MSW inverter with 2 6 volt CG batteries. I can use the microwave when traveling down the road just fine. When stopped I can get several mins of use. 5 mins with the microwave will set off the alarm. After 15 years of dry camping I rarely use the inverter any more. Coffee is made on the stove, refer is run from propane no longer from inverter, small electronics like laptops are charged with a 150 watt plugin inverter. I hate to exercise the genset each month as general maintenance so I look for ways to actually use it with out just wasting gas, so microwave use on rare occasion or electric chain saw for campfires is about the only time it actually gets used, never to just recharge the batteries. I know others have more electrical requirements than myself like TV, radio, etc, so larger battery banks and 2000 watt inverters make sense , but for general dry camping, fishing, hiking enjoying nature without electronics I think a large inverter is not necessary. At least that is my experience.

* This post was edited 11/13/19 08:19am by Gjac *

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